TABLE OF CONTENTS

TABLE OF CONTENTS
TABLE OF CONTENTS
PAGE
FOREWORD
i
SECTION 1 – INTRODUCTION
1.1
1.2
1.3
1.4
PURPOSE
OWASA
DEFINITIONS
ABBREVIATIONS
I-1
I-1
I-1
I-5
SECTION 2 – STANDARD SPECIFICATIONS
00950 – MEASUREMENT AND PAYMENT
1.1 TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
00950-1
1.2 WATER
00950-6
1.3 SEWER
00950-15
02275-TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES REVISION SUMMARY SHEET
PART 1 - GENERAL
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
1.10
1.11
1.12
1.13
GENERAL
RELATED DOCUMENTS
SUMMARY
DEFININITIONS
SUBMITTALS
QUALITY ASSURANCE
QUALITY STANDARDS
TESTING SERVICES
PROJECT CONDITIONS
LOCATING SERVICES
COORDINATION
PUBLIC CONVENIENCE
EROSION AND SEDIMENTATION CONTROL AND NPDES
MONITORING, CONTROLS, AND LIMITATIONS FOR PERMITTED
DISCHARGES
02275-1
02275-1
02275-2
02275-2
02275-3
02275-4
02275-4
02275-6
02275-6
02275-6
02275-7
02275-7
02275-7
SOIL, BEDDING, AND BACKFILL
MISCELLANEOUS
02275-10
02275-12
PREPARATION
TRENCH EXCAVATION
BEDDING
BACKFILLING (MATERIALS AND METHODS)
COMPACTION/DENSITY
SERVICE CUTS, DIRECTION BORED OR PUNCHED SERVICE
PAVEMENT REPAIR AND REPLACEMENT
BLASTING
HIGHWAY CROSSING
RAILROAD CROSSING/TRACKS
UNDERGROUND RIVER OR CREEK CROSSING
SURFACE WATER CROSSINGS
CONCRETE COLLARS ON SEWER MAINS
02275-14
02275-20
02275-28
02275-29
02275-31
02275-34
02275-34
02275-35
02275-39
02275-39
02275-40
02275-41
02275-41
PART 2-PRODUCTS
2.1
2.2
PART 3-EXECUTION
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3.10
3.11
3.12
3.13
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April 2015
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3.14 CLEANUP AND RESTORATION OF SITE
3.15 SEEDING AND GROUNDCOVER
3.16 MISCELLANEOUS
02510 – WATER DISTRIBUTION
WATER DISTRIBUTION REVISION SUMMARY SHEET
02275-41
02275-42
02275-42
PART 1 - GENERAL
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
1.10
1.11
RELATED DOCUMENTS
SUMMARY
DEFINITIONS
SUBMITTALS
QUALITY ASSURANCE
QUALITY STANDARDS
PRODUCT DELIVERY, STORAGE AND HANDLING
PRODUCT SUBSTITUTIONS
PRODUCT CONDITIONS
LOCATING SERVICES
COORDINATION
02510-1
02510-1
02510-1
02510-2
02510-2
02510-3
02510-4
02510-5
02510-5
02510-7
02510-7
PIPE AND FITTINGS
VALVES AND FIRE HYDRANTS
MISCELLANEOUS APPURTENANCES
02510-7
02510-15
02510-21
3.1 PIPE AND FITTINGS
3.2 VALVES AND HYDRANTS
3.3 MISCELLANEOUS APPURTENANCES
3.4 TESTING AND DISINFECTION
3.5 FINAL ACCEPTANCE
02520 – RECLAIMED WATER DISTRIBUTION
02510-30
02510-40
02510-43
02510-47
02510-56
PART 2 – PRODUCTS
2.1
2.2
2.3
PART 3-EXECUTION
PART 1 - GENERAL
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
1.10
RELATED DOCUMENTS
SUMMARY
DEFINITIONS
SUBMITTALS
QUALITY ASSURANCE
QUALITY STANDARDS
PRODUCT DELIVERY, STORAGE AND HANDLING
PRODUCT SUBSTITUTIONS
PROJECT CONDITIONS
SEPARATIONS OF RECLAIMED WATER MAINS AND SANITARY
AND/OR COMBINED SEWERS
COORDINATION
CROSS CONNECTION CONTROL
02520-1
02520-1
02520-1
02520-2
02520-2
02520-2
02520-2
02520-2
02520-2
02520-2
2.1
2.2
2.3
PIPE, FITTINGS AND IDENTIFICATION
VALVES AND FIRE HYDRANTS
MISCELLANEOUS APPURENANCES
02520-2
02520-4
02520-5
3.1
3.2
3.3
3.4
3.5
PIPE AND FITTINGS
UTILITY PROTECTION
SURFACE GROUND WATER IN TRENCHES / PIPE
ABANDONING OF AN EXISTING WATER SERVICE/ LINES
STEEL ENCASEMENT PIPE – DRY BORING AND JACKING OR
OPEN CUT
HORIZONTAL DIRECTIONAL DRILLING OF HDPE WATER PIPE
PVC PIPE FOR RECLAIMED WATER MAIN
02520-6
02520-7
02520-7
02520-7
02580-7
1.11
1.12
PART 2 – PRODUCTS
PART 3 – EXECUTION
3.6
3.7
OWASA – Manual of Specifications, Standards and Design
April 2015
02520-2
02520-2
02520-7
02520-8
Table of Contents
Page 2
3.8
3.9
3.10
3.11
3.12
3.13
3.14
3.15
3.16
RECLAIMED GATE VALVES
VALVES 16 INCHES AND LARGER (GATE OR BUTTERFLY VALVES)
TAPPING SLEEVES AND VALVES
AIR / VACUUM RELEASE VALVES
MISCELLANEOUS APPURTENANCES
RESTRAINTS
VAULT CONSTRUCTION
MANHOLE INSTALLATIONS
CONNECTION TO EXISTING RECLAIMED MAINS
PART 4 – TESTING
4.1 TESTING
4.2 ORDER OF OPERATIONS
4.3 FINAL ACCEPTANCE
02530 – SANITARY SEWER
SANITARY SEWER REVISION SUMMARY SHEET
PART 1 - GENERAL
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
1.10
1.11
1.12
02530-1
02530-1
02530-1
02530-2
02530-2
02530-3
02530-3
02530-4
02530-5
02530-5
02530-7
02530-7
PIPE AND FITTINGS
MISCELLANEOUS APPURTENANCES AND MATERIAL
02530-8
02530-12
PIPE AND FITTINGS
TUNNELING METHOD
MANHOLE CONSTRUCTION
ABANDONING SEWER LINES & MANHOLES
BYPASS PUMPING
SERVICE CONNECTIONS
CONCRETE ENCASEMENTS
USE OF SLOPE ANCHORS ON STEEP LINES
TESTING
PUMP STATIONS AND FORCE MAINS
PIPE DESIGN LIFE
CLEANUP AND RESTORATION OF SITE
02530-19
02530-22
02530-24
02530-25
02530-26
02530-28
02530-29
02530-30
02530-30
02530-37
02530-42
02530-42
PART 3 - EXECUTION
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3.10
3.11
3.12
02520-10
02520-11
02520-11
RELATED DOCUMENTS
SUMMARY
DEFINITIONS
PERFORMANCE
SUBMITTALS
QUALITY ASSURANCE
QUALITY STANDARDS
PRODUCT DELIVERY, STORAGE AND HANDLING
PROJECT SUBMITTALS
PROJECT CONDITIONS
LOCATING SERVICES
COORDINATION
PART 2 – PRODUCTS
2.1
2.2
02520-8
02520-8
02520-8
02520-8
02520-8
02520-9
02520-9
02520-9
02520-9
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April 2015
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SECTION 3 – MODULES 1 & 2: WATER AND SEWER DESIGN
SANITARY SEWER REVISION SUMMARY SHEET
1.1 GENERAL
A. SPECIFICATIONS AND DESIGN MANUAL
B. PROJECT OVERVIEW REPORT REQUIREMENTS
C. PERMITS
D. PLAN REVIEW AND OBSERVATION FEES
1.2 WATER SYSTEM DESIGN STANDARDS
A. DISTRIBUTION SYSTEM
1.3 GRAVITY COLLECTION SYSTEM DESIGN STANDARDS
A. GENERAL
B. DEFINITIONS
C. COLLECTION SYSTEM DESIGN
D. DESIGN – MANHOLES
E. SEWERS IN RELATION TO STREAMS AND OTHER BODIES
F. PROTECTION OF POTABLE WATER SUPPLIES AND
STORM SEWERS
G. PUMP STATION
3-1
3-1
3-1
3-2
3-2
3-2
3-2
3-10
3-10
3-10
3-11
3-16
3-19
3-22
3-23
SECTION 4 – PROCEDURES FOR APPROVAL OF WATER AND/OR
SEWER EXTENSTION PROJECTS
PROCEDURES FOR APPROVAL OF WATER AND/OR SEWER EXTENSION PROJECTS
REVISION SUMMARY SHEET
1.1. INTRODUCTION
4-1
4-2
1.2 PLAN REQUIREMENTS
A. GENERAL
4-2
B. WATER LINE EXTENTION PLANS
4-4
C. SEWER LINE EXTENSION PLANS
4-4
4-5
1.3 DESIGN AND PLAN APPROVAL
A. DISCUSS PRELIMINARY DESIGN REQUIREMENTS WITH
4-5
OWASA
B. DISCUSS AVAILABILITY FEES WITH OWASA
4-5
C. SUBMIT PRELIMINARY PROJECT PLANS TO LOCAL
4-6
PLANNING UNIT AND OWASA
D. REVIEW OF PRELIMINARY (ZONING COMPLIANCE) PLANS
4-6
BY OWASA
E. PRELIMINARY DESIGN APPROVAL BY OWASA
4-6
F. SUBMIT CONSTRUCTION DRAWINGS TO OWASA
4-6
G. CONSTRUCTION DESIGN APPROVAL BY OWASA
4-7
H. SUBMIT PROJECT FACT SHEET
4-7
I. RECORDED OFF-SITE DEEDS OF EASEMENT
4-7
J. PROJECT CONSTRUCTION DRAWINGS APPROVAL
4-7
K. PROJECT DRAWINGS, APPLICATIONS, AND APPLICATION
4-8
FEES ARE SUBMITTED TO STATE REGULATORY
AGENCIES BY OWASA
L NCDOT RIGHT OF WAY ENCROACHMENT
4-8
M. DESIGN APPROVAL BY STATE REGULATORY AGENCIES
4-8
(DWQ, DEH)
N. FINAL DESIGN APPROVAL BY OWASA
4-8
4-8
1.4 CONSTRUCTION
A. PRECONSTRUCTION CONFERENCE
4-8
B. BEGIN CONSTRUCTION
4-9
C. CONSTRUCTION INSPECTION
4-9
D. PRESSURE, VACUUM, AND BACTERIOLOGICAL TEST
4-10
E. PRELIMINARY FINAL INSPECTION
4-10
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April 2015
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Page 4
1.5
1.6
1.7
1.8
F. PROVISION OF CONSTRUCTION METERS BY OWASA
G. FINAL INSPECTION BY OWASA
CLOSE-OUT DOCUMENTS
A. SUBMIT ENGINEER’S CERTIFICATION OF PUBLIC WATER
LINES TO OWASA
B. SUBMIT ENGINEER’S CERTIFICATION OF PUBLIC SEWER
LINES TO OWASA
C. SUBMIT RECORDED FINAL PLAT TO OWASA
D. SUBMIT 1”=100’ SCALE SITE PLAN TO OWASA
E. SUBMIT ORIGINAL RECORDED DEED OF EASEMENT TO
OWASA
F. SUBMIT LETTER OF DEDICATION TO OWASA
G. SUBMIT ASSET EVALUATION FORM TO OWASA
H. SUBMIT RECORD DRAWINGS TO OWASA FOR REVIEW
I. SUBMIT ELECTRONIC FILES TO OWASA
J. SUBMIT MANHOLE DATA SHEETS TO OWASA
K. SUBMIT OPERATION AND MAINTENANCE MANUALS TO
OWASA
L. SUBMIT LETTER OF CREDIT TO OWASA
TENTATIVE ACCEPTANCE AND BEGINNING OF ONE-YEAR
WARRANTY
PAYMENT OF FEES AND SETTING OF METERS
A. CALCULATION OF AVAILABILITY FEES BY OWASA
B. PAY AVAILABILITY FEES TO OWASA CUSTOMER SERVICE
DEPARTMENT FOR SERVICE INITIATION
C. SETTING OF WATER METERS
FINAL ACCEPTANCE
A. WARRANTY CHECKS AND REPAIRS
B. EXPIRATION OF WARRANTY
C. LETTERS OF FINAL ACCEPTANCE
OWASA – Manual of Specifications, Standards and Design
April 2015
4-10
4-10
4-10
4-10
4-11
4-11
4-11
4-11
4-11
4-12
4-12
4-12
4-12
4-13
4-13
4-13
4-13
4-13
4-14
4-14
4-14
4-14
4-14
4-15
Table of Contents
Page 5
TABLE OF DETAILS
Detail
Number
511.01
512.01
512.02
512.03
512.04
512.05
512.06
512.07
512.08
512.09
513.01
513.02
513.03
513.04
513.05
513.06
513.07
513.08
514.01
514.02
514.03
514.04
514.05
514.06
514.07
514.08
514.09
515.01
515.02
515.03
515.04
515.05
515.06
515.07
515.08
515.09
515.10
515.11
Water Details
WATER DISTRIBUTION REVISION SUMMARY SHEET
DETAIL OF ROCK EXCAVATION
STANDARD VERTICAL BEND DETAIL
BLOCKING DETAIL FOR HORIZONTAL BENDS AND TEE
BLOCKING DETAIL FOR PVC PIPE IN-LINE VALVE
4” TO 12” STANDARD TAPPING SLEEVE AND VALVE ASSEMBLY
LINE ABANDONMENT DETAIL
STANDARD ¾” AND 1” WATER TAPPING DETAIL
THRUST FOOTING DETAIL
THRUST COLLAR & BLOCKING WITH MEG-A-LUG THRUST RING
TIE ROD ANCHORS DATUM CHART
STANDARD SCREW VALVE BOX DETAIL
VALVE BOX STABILIZING PAD DETAILS
ZONE SEPARATOR DETAIL
1” AIR RELEASE VALVE & MANHOLE (PIPE 2” TO 12”)
2” AIR RELEASE VALVE & MANHOLE (PIPE 16” AND LARGER)
BUTTERFLY VALVE (16” AND LARGER) IN PRECAST MANHOLE
BLANK SHEET
GATE VALVE (16” AND LARGER) IN PRECAST MANHOLE
FIRE HYDRANT PAINTING SPECIFICATIONS
TYPICAL FIRE HYDRANT STREETS WITH BAR DITCH
TYPICAL FIRE HYDRANT STREETS WITH CURB & GUTTER
PERMANENT 2” BLOW-OFF ASSEMBLY FOR MAINS UP TO 8”
TEMPORARY 2” BLOW-OFF ASSEMBLY FOR MAINS UP TO 24”
PERMANENT BLOW-OFF ASSEMBLY FOR MAINS 12” AND LARGER
PURITY SAMPLING CONNECTION 2” BLOW OFF LINE
PURITY SAMPLING CONNECTION ON FIRE HYDRANT
PURITY SAMPLING CONNECTION AT BACKFLOW PREVENTER
¾” SINGLE & 1” DUAL SERVICE INSTALLATION
3/4” and 1” DUAL COMBINED DOMESTIC AND FIRE PROTECTION
SERVICE INSTALLATION
DETECTOR
METER INSTALLATION (FIRE SYSTEM)
STANDARD 2” METER VAULT
¾” TO 2” DCV, RPZ ASSEMBLY (INDOOR)
¾” TO 2” DCV, RPZ ASSEMBLY (ABOVE GROUND)
¾” OR 1” DCV ASSEMBLY (ALTERNATE UNDER GROUND BOX)
¾” OR 2” DCV ASSEMBLY (UNDER GROUND VAULT)
2 ½” TO 10” DCV, DDCV, RPZ ASSEMBLY (INDOOR)
2 ½” TO 10” DCV, DDCV, RPZ ASSEMBLY (ABOVE GROUND)
2 ½” TO 10” DCV, DDCV, RPZ ASSEMBLY (UNDERGROUND VAULT)
OWASA – Manual of Specifications, Standards and Design
April 2015
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515.12
515.13
515.14
515.15
516.01
517.01
BACKFLOW PREVENTION TANKER TRUCK (AIR GAP & REDUCED
PRESSURE)
3” TO 8” WATER METER WITH BYPASS (UNDERGROUND VAULT)
LOW PROFILE VAULT / OVERSIZED ACCESS (3” – 8”
UNDERGROUND
METER
VAULT)
1” OR 2” IRRIGATION
METER
ON A 3” TO 8” UNDERGROUND METER
VAULT
STANDARD
WATER MANHOLE FRAME AND COVER
TYPICAL DETAIL FOR BORE UNDER PAVED ROADS/HIGHWAYS
TABLE OF DETAILS
Detail
Number
531.01
531.02
532.01
532.02
532.03
532.04
532.05
532.06
532.07
532.08
532.09
533.01
533.02
534.01
534.02
535.01
536.01
536.02
536.03
536.04
536.05
536.06
536.07
536.08
537.01
538.01
539.01
539.02
539.03
539.04
539.05
SEWER DETAILS
SANITARY SEWER REVISION SUMMARY SHEET
SANITARY SEWER BEDDING DETAIL
EARTH FILL OVER SEWER PIPE DETAIL
STANDARD ECCENTRIC MANHOLE DETAIL
STANDARD SEWER INVERT PLANS FOR MANHOLE
STANDARD OUTSIDE DROP MANHOLE DETAIL
SANITARY SEWER MANHOLE PLUGGING DETAIL
STANDARD MANHOLE VENTING DETAIL
MANHOLE RING AND COVER GRADE ADJUSTMENT
STRUCTURE PROTECTION UNFINISHED ROAD GRADE
PRECAST CONCRETE DOGHOUSE MANHOLE
INFI-SHIELD EXTERNAL SEALING DETAIL
SANITARY SEWER MANHOLE FRAME AND COVER
SANITARY SEWER WATERTIGHT MANHOLE FRAME AND COVER
4” SEWER TAP AND STUB-OUT PAVED APPLICATION CLEAN OUT
TYPICAL SEWER EASEMENT DETAIL
CASING PIPE PEDESTRIAN BARRIER
CONCRETE COLLAR DETAIL
CONCRETE PIER DETAIL
CONCRETE PIER SADDLES DETAIL
DETAIL OF BRACING FOR CHANNEL CROSSINGS
SANITARY SEWER LINE AND MANHOLE ABANDONMENT DETAIL
STREAM CROSSINGS FOR PRIVATE SERVICE LINES
BLANK SHEET
SEWER
LINE CROSSING BENEATH STREAM BED
GREASE INTERCEPTOR DETAIL
COMBINATION AIR VALVE AIR RELEASE MANHOLE
TYPICAL SUBMERSIBLE PUMP STATION SITE LAYOUT
TYPICAL EMERGENCY PUMP CONNECTION
TYPICAL CHAIN-LINK FENCE DETAIL – 8 FT. HEIGHT
YARD HYDRANT (NON-FREEZE)
PUMP STATION SERVICE PANEL DETAIL
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April 2015
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Page 2
FOREWORD
About OWASA
OWASA is the public, nonprofit water and sewer utility serving the Carrboro-Chapel Hill
community. OWASA's 9-member Board of Directors is appointed by the Chapel Hill Town
Council, the Carrboro Board of Aldermen and the Orange County Board of Commissioners.
OWASA has served the community since February, 1977, when the University of North Carolina
at Chapel Hill and the Towns of Carrboro and Chapel Hill transferred their water and wastewater
facilities to OWASA.
Our services are funded entirely from our rates and fees, which reflect legal requirements to use
the "cost of service" approach in setting rates, fees, and charges. OWASA provides services
within a basic framework of State and Federal law, our 1977 Agreements of Sale and Purchase
with the University and the Towns, certain contractual obligations to holders of OWASA
Revenue Bonds, and agreements with the Towns and County regarding the extension and
provision of public water and sewer services.
OWASA is an equal opportunity employer and a member of the American Water Works
Association and the Water Environment Federation.
Manual Introduction
The latest approved version of OWASA’s Standard Specifications was prepared in September
1990. OWASA’s Standard Specifications explain the water and sewer extension and
construction process and establish minimum acceptable guidelines or standards for the design
and construction of water and sewer lines and appurtenances. Although the document still
serves as a good reference manual and guide to contractors, there have been changes in
materials, methods and procedures that need to be incorporated into a revised document.
Since 1990, new and revised standard details had also been developed by OWASA staff, and
need to be incorporated as revised Standard Specifications.
This new Standard Specifications Manual was prepared by Appian Consulting Engineers, PA,
Rocky Mount, NC for the Orange Water and Sewer Authority. The manual contains specific
technical information related to the proposed construction of infrastructure improvements within
the OWASA service area.
The materials, improvement specifications, standard details, and design methodology contained
herein are established as the minimum requirements for OWASA and have been determined to
be reasonable as applicable to OWASA. This document has been compiled from current
standards and practices used by OWASA, from improvement standards used in other areas of
the State of North Carolina, and applicable enabling legislation of the State of North Carolina.
Manual format
This manual was prepared to facilitate ease of use by both the design engineers and the
contractor. The various elements that comprise this book have been compiled from adopted
policies and procedures, both current and new standard details, specifications, and practices.
This manual contains the information needed by design engineers, developers, and contractors
OWASA – Manual of Specifications, Standards and Design
April 2015
Foreword
Page i
to facilitate design, development, and construction within the OWASA service area.
Additionally, the information contained herein is available on OWASA’s website.
Standard Specifications
The standard specification section includes the following sections:
 Trenching, Backfilling and Compaction of Utilities,
 Water Distribution, and
 Sanitary Sewer.
Technical Specifications and details excluded from this manual:
Erosion Control - permitting and plan review is administered by:
 NCDENR,
 Division of Land Quality, and
 Erosion and Sediment Control Planning and Design Manual, latest revision.
Street Repair and Paving – The Town of Chapel Hill, Town of Carrboro and/or the NCDOT will
provide review and permitting of their facilities.
The standard details provided herein are water and sewer construction details. All structures,
as well as a few non-structure type standards, are high-quality drawings, when practical, in both
isometric and exploded views.
Standard Details Sections included in manual:
 Sewer
 Water
Design Section
A design section has been provided which incorporates the following:
 regulatory requirements of the NCDENR,
 Division of Water Quality,
 NCAC Title 15A 2H .0200 Waste not Discharged to Surface Waters,
 NCDENR Division of Environmental Management,
 Public Water Supply Section,
 NCAC Title 15A Subchapter 18C,
 Rules for Governing Public Water Supply Systems,
 ASCE–Manuals of Reports on Engineering Practice-No. 60 “Gravity Sanitary Sewer
Design and Construction,”
 The “Recommended Standards for Sewage Works” by the Great Lakes-Upper
Mississippi River Board of State Sanitary Engineers, and
 The applicable requirements specific to OWASA.
To the best of their ability, the authors have insured that the information presented here is
correct and that the procedures are reliable. The execution of an engineering design, however,
involves the judgment of the design engineer, and only the engineer can ascertain whether a
technique or item of information can be applied to a given situation.
OWASA – Manual of Specifications, Standards and Design
April 2015
Foreword
Page ii
Policy and Ordinance
Rather than include the specific policies and ordinance in their entirety, a reference sheet has
been provide listing key policies and ordinances. These policies and ordinances can be
obtained directly from OWASA.
Jurisdiction
On or after August 15, 2003 this Manual of Specifications, Standards and Design shall be
applicable to all new improvements and alterations in existing improvements lying within the
regulatory jurisdiction of OWASA.
Variance or Modification
Any variances, alternate designs, construction methods and materials, not specifically
prescribed herein, shall be subject to the approval of the Executive Director or his (her)
designee.
Copyright
This is a copyrighted document. Reuse of the printed material or standard details contained in
this manual, either in whole or in part, by private concerns or individuals for the purpose of
monetary gain in the preparation of municipal public facilities manuals or similar documents,
without the written permission of Appian Consulting Engineers, PA, is strictly prohibited.
OWASA – Manual of Specifications, Standards and Design
April 2015
Foreword
Page iii
Project Team:
OWASA
Michael Jakubiak, EI, Utilities Engineer and Project Team Leader (2003)
Darren K. Berger, Engineering Associate and Project Team Leader (2007, 2011, 2012 Revision)
Mason Crum, P.E., Director of Engineering and Planning (2007, 2012 Revision)
Barbara Oslund, P.E., Engineering Manager, Capital Projects (2003)
Bob Russell, Customer Relations Manager (2003)
David Lewis, Jr., Purchasing Specialist (2003 and 2007 Revision)
Donald Robinson, LSI, Engineering Technician (2003)
Donnie Nolf, Construction Inspector (2003 and 2007 Revision)
Elijah Williams, EI, Utilities Engineer (2003)
John Greene, P.E., General Manager (2003 and 2007, 2012 Revision)
M. Imtiaz Ahmad, P.E., Director of Engineering and Planning (2003)
Mary Darr, P.E., Operations Engineer (2003 and 2007 Revision)
Patrick Davis, Utilities Engineer (2003)
Randy Horton, Assistant Distribution & Collection System Manager (2003 and 2007 Revision)
Sandy Beckham, Engineering Technician (2003 and 2007 Revision)
Ted Blake, Engineering Associate (2003 and 2007 Revision)
Thurman Green, Distribution & Collection System Manager (2003 and 2007 Revision)
Todd Spencer, P.E., Engineering Manager, System Development (2003 and 2007, 2011, 2012
Revision)
F. Stuart Carson, P.E., Engineering Manager, Capital Improvements Program (2007, 2012
Revision)
Joe Leo, Engineering Technician (2007, 2011, 2012 Revision)
Nick Parker, Engineering Associate (2007, 2012 Revision)
Adam Haggerty, Engineering Technician (2012 Revision)
Mike Smith, Purchasing Specialist (2012)
Appian Consulting Engineers, PA
Bobby L. Joyner, P.E., Project/Team Leader and Author
Pete Sokalski, EI, Assistant Project Manager
Mike Gallina, CAD Supervisor
Kevin Harrell, CAD Technician
OWASA – Manual of Specifications, Standards and Design
April 2015
Foreword
Page iv
(Last revised 6/1/13)
1.1
INTRODUCTION
PURPOSE
This manual was created to explain the water and sewer extension process and to
establish standards for design and construction of water and sewer lines and
appurtenances.
1.2
OWASA
The Orange Water and Sewer Authority is a regional public water and sewer utility
established in 1977 to serve the Chapel Hill-Carrboro community and nearby areas.
1.3
DEFINITIONS
Adjacent and Abutting
This policy for water and sewer projects ensures the orderly development of the system
by requiring that each property benefiting from the water or sewer lines must have at
least a part of that line abutting or adjacent to the property. This policy prevents
properties from simply installing long laterals across neighboring properties or
connecting to neighboring property’s laterals to reach public sewer or water lines.
Applicant
The person or company which is proposing new connections to or extension of the water
distribution and wastewater collection systems, also known as the developer.
Approved Equal
Approved equal is the annotation given to a product or material that has been approved
by OWASA as a substitute for the product or material specified in the specifications or
standard details. “Approved Equal” products and materials must be approved by the
OWASA Product and Design Review Committee.
Availability Fees
These are fees collected for each new connection to the water and sewer systems. The
availability charge is a charge to collect for the demand on the infrastructure of the
system as represented by meter size and use.
Collector
A collector is a sewer pipe typically 8 inches in diameter into which the wastewater from
two or more laterals (individual homeowner's pipe) is discharged and which
subsequently discharges into a main, interceptor, or other collector.
Conditional Use Permit
This is a permit from a zoning authority (e.g. the Towns of Chapel Hill and Carrboro)
which allows a plot of land to be used for a project provided specific conditions are met.
Contractor
The contractor is hired by the owner/developer to install the water and/or sewer lines in
accordance with approved plans.
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Cross Connection
Any physical connection between a potable water supply system and any other piping
system, sewer fixture, container, or device, whereby water or other liquids, mixtures, or
substances may flow into or enter the potable water supply system;
Any potable water supply outlet which is submerged or is designed or intended to be
submerged in non-potable water or in any source of contamination or;
An air gap, providing a space between the potable water pipe outlet and the flood level
rim of a receiving vessel of less than twice the diameter of the potable water pipe.
Developer
The person or company responsible for the design and construction of water and sewer
lines to serve their property.
Director of Engineering and Planning
The Director of Engineering and Planning for OWASA or his/her designee.
Division of Environmental Health (DEH)
Division of Environmental Health is one department of the North Carolina Division of
Environmental Health and Natural Resources. It is responsible for oversight of water
plant operations, water distribution, water supplies, water quality, and facility permitting
for compliance with state and federal regulations.
Division of Water Quality (DWQ)
Division of Water Quality is one department of the North Carolina Division of
Environmental Health and Natural Resources. It is responsible for oversight of
wastewater plant operations, collection systems, treatment plant effluent discharge, and
sludge disposal including permitting for compliance with state and federal regulations.
Easement
A piece of private property which the owner grants to a public utility or government to
use, maintain, access, and clear. The owner forfeits certain uses of the property.
Easements are acquired through the owner's signing of an easement agreement,
negotiation and monetary settlement or, if negotiations fail, condemnation under eminent
domain statutes.
Elastomers (Gaskets, o-rings, etc)
Approved elastomeric materials are: EPDM, fluorocarbon, silicone, or isobutyleneisoprene.
Executive Director
The Executive Director of OWASA.
Force Main
A force main is a pressure pipe joining the pump discharge at a wastewater pumping
station with a point of gravity flow.
Gravity Flow System
This is a system of conduits in which no wastewater pumping is required. Sewage flows
by gravity from service points to public sewer lines.
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Grinder Pump
A grinder pump is a mechanical device that shreds solids and raises the fluid to a higher
elevation through pressure sewers.
Interceptor
An interceptor is a sewer pipe which transports wastewater from collection sewers to a
treatment facility.
Lateral
A water lateral is the pipe which connects a building to the water meter located on the
customer's property. A sewer lateral is the pipe which connects a building to the
collector sewer located in the street. In the OWASA system, both the water and sewer
laterals are owned and maintained by the property owner.
Local Planning Unit
The local planning unit is the Planning Department and/or Planning Board of the Town of
Chapel Hill, Town of Carrboro, Orange County, Durham County; or the appropriate
planning office at the University of North Carolina at Chapel Hill or UNC Hospitals.
National Pollutant Discharge Elimination System (NPDES)
The federal government's system of controlling all discharge of pollutants from point
sources into U.S. waterways. NPDES permits discharges into navigable waters from all
point sources of pollution, including industries, municipal treatment plants, large
agricultural feed lots, and return irrigation flows.
Lift Station
A lift station is a specific kind of pump station. It is a small sewer pump used when
gravity can no longer carry wastewater through sewer. The lift station pumps
wastewater from a lower elevation to a higher elevation so that gravity can again be
used to carry the wastewater.
OWASA’s Engineer
The Project Engineer or his or her authorized representative.
Plat
A plat is a map or chart of a subdivision or piece of land that provides survey information
on lot size and location and often includes the tax identification code.
Professional Engineer
An engineer certified and licensed by the North Carolina Board of Examiners for
Engineers and Surveyors.
Project Engineer
The Project Engineer is the engineer hired by the owner/developer to prepare a set of
plans and specifications for the water and sewer utilities that serve the project. The
Project Engineer is also responsible for construction administration of the project.
The Project Engineer will prepare plans in accordance with OWASA Standard
Specifications, North Carolina Division of Environmental Health and Natural Resources,
and all other federal, state, and local regulations pertaining to the project.
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The Project Engineer will submit plans for review to OWASA, make revisions as
necessary to comply with OWASA guidelines, observe construction to ensure utilities are
constructed in accordance with OWASA standards, and provide certification to OWASA
and NCDENR that utilities were installed in accordance with approved plans.
Public Sewer System
Sewer lines, manholes, pump stations, force mains owned and maintained by OWASA.
Public Water System
Water mains and appurtenances owned and maintained by OWASA.
Pump Station
A pump station is a structure containing pumps, piping, valves, and other mechanical
and electrical equipment for pumping water, wastewater, or other liquids. A pump
station is used to pump wastewater from a sewer main of lower elevation to a sewer
main of higher elevation. A lift station; often used synonymously with the term pump
station, provides a vertical lift to sewage in order for it, in many instances, to again flow
by gravity.
Punch List
The punch list identifies deficiencies of the water and sewer construction found during
the pre-final inspection. A punch list is generated by the OWASA Inspector after a prefinal Inspection.
Right-of-Way
Right-of-way is land or property that has been dedicated to a public entity for use by the
public, the entity itself, or both and is maintained by that entity.
Sanitary Sewer
A sewer that carries liquid and waterborne wastes from residences, commercial
buildings, industrial plants, and institutions, together with minor quantities of ground,
storm, and surface waters that are not admitted intentionally. The spent or used water of
a community or industry which contains dissolved and suspended matter.
Service Area
This is an area that a utility serves or is authorized to serve.
Special Use Permit
This is a permit from a zoning authority (e.g. the Towns of Chapel Hill and Carrboro)
which allows a plot of land to be used for a purpose other than its normally permitted
use.
Supplemental Fire Protection
Fire protection services include fire lines that feed sprinkler systems and fire hydrants
that are not a part of the general hydrant service supplied by OWASA to the public but at
no charge.
Taps
The connection of a new main for extension or service line to public water or sewer lines
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that are in-service. OWASA must make all taps to in-service mains. A fee is charged to
cover the expense of time and equipment.
Third Party Project
This is a water or sewer project that is being constructed by a developer or party other
than OWASA. Third party projects are dedicated to OWASA upon completion and
become part of the public water and/or sewer system.
1.4
ABBREVIATIONS
AASHTO
ANSI
ASTM
AWWA
DEH
DENR
DWQ
NCDOT
NPDES
NSF
OWASA
UNC
USGS
American Association of State Highway Transportation Officials
American National Standards Institute
American Society for Testing Materials
American Water Works Association
North Carolina Division of Environmental Health
Department of Environment, Health, and Natural Resources
North Carolina Division of Water Quality
North Carolina Department of Transportation
National Pollutant Discharge Elimination System
National Sanitation Foundation
Orange Water and Sewer Authority
University of North Carolina
United States Geological Survey
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00950 – MEASUREMENT & PAYMENT
(Last revised 6-1-13)
SUGESTED SEARCH WORDS FOR THIS SECTION THIS SECTION APPLIES ONLY TO
OWASA CAPITAL IMPROVEMENT PROJECTS
Measurement & Payment - Trenching, Backfilling & Compaction of Utilities
Measurement & Payment - Sewer
Measurement & Payment - Water
1.1
TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
Measurements for purpose of payment shall be in accordance with the unit quantities
stated in the proposal as defined below. Whenever units of measure (i.e. linear feet,
each, and similar units of measurement) are mentioned in a proposal, it shall be
interpreted to mean the unit installed in accordance with the plans and specifications,
and ready for use. Prices for the following bid items shall include all labor, materials,
tools, equipment, and other incidentals necessary to complete the work as shown on the
plans and in accordance with these specifications.
A. Access or Haul Roads:
Measurement: Any grading or excavation required for equipment travel during the
course of construction as well as erosion control, removal, restoration, and seeding
and ground cover shall be included in other items bid.
Payment: Included in other items bid. Not a pay item.
B. Aggregate Backfill:
Measurement: Coarse granular fill will be measured by the ton in place in the
trench.
Payment: Price per ton for coarse granular fill shall include all materials, equipment,
and labor required to furnish and install clean coarse granular stone in the locations
designated by OWASA’s Engineer. For purposes of measurement, 1 cubic yard of
#57 stone = 1.5 tons.
C. Bedding, Crushed Stone for:
Measurement: Bedding stone is considered to be incidental to the cost of the pipe.
Payment: Not a pay item.
D. Clearing and Grubbing, Lightly Wooded Areas:
Measurement: Measurement for clearing and grubbing will be by the acre. Width
shall not exceed width as defined in the disturbing and construction limits criteria of
water and/or sewer construction.
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00950 – MEASUREMENT AND PAYMENT
Payment: Price per acre for clearing and grubbing in lightly wooded areas shall
include all material, equipment, and labor required to clear and grub lightly wooded
areas in accordance with these specifications. Lightly wooded areas shall be
defined as areas where the prevalent vegetation consists of trees less than 12
inches in diameter. The price shall also include the removal and disposal of items
that cannot be mulched or built into brush piles.
E. Clearing and Grubbing, Heavily Wooded Areas:
Measurement: Measurement for clearing and grubbing will be by the acre. Width
shall not exceed width as defined in the disturbing and construction limits criteria of
water and/or sewer construction.
Payment: Price per acre for clearing and grubbing in heavily wooded areas shall
include all material, equipment, and labor required to clear and grub heavily wooded
areas in accordance with these specifications. Heavily wooded areas shall be
defined as areas where the prevalent vegetation consists of trees 12 inches or
greater in diameter. The price shall also include the removal and disposal of items
that cannot be mulched or built into brush piles.
F. Concrete Encasement:
Measurement: Payment for furnishing concrete encasement will be at the unit price
bid per cubic yard for the class of concrete stated in the proposal, such price to be
paid in addition to that paid per foot of water or sewer main.
Payment: The unit priced stated in the proposal shall include the cost of additional
depth of excavation, forming, the furnishing and placing of concrete, cofferdams if
applicable, laying of pipe line to grade but excluding the cost of the pipe itself,
complete in place, including all labor, equipment and material necessary, and all
other work incidental to the complete installation of the concrete encasement in
accordance with the specification and details shown on the plans. Payment will be
made to neat lines of construction shown on the plans with no allowance being made
for extra ditch width.
G. Concrete Anchors and Piers:
Measurement: This item will be measured on and each basis for Concrete Anchors
and Piers. Concrete thrust blocking is considered incidental to the cost of water
lines and is not a pay item.
Payment: This item will be paid for at the contact unit price bid for Concrete Anchors
and Piers, complete in place, including all labor, equipment, and material necessary
for furnishing, excavating, forming, installing, backfilling, and all other work incidental
to the complete installation of the concrete anchors and piers in accordance with the
specification and details shown on the plans. Payment will be made to neat lines of
construction shown on the plans with no allowance being made for extra ditch width.
H. Concrete – Miscellaneous Unformed:
Measurement: Concrete, except that used in manholes, will be measured in cubic
yards of unformed concrete actually placed. Typical uses include concrete collars
(slope anchors), cradles, and all other miscellaneous concrete related to water or
sewer line installation.
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00950 – MEASUREMENT AND PAYMENT
Payment: This item will be paid for at the contract unit price per cubic yard for unformed concrete for collars, cradles, and all other miscellaneous concrete related to
water and sewer line construction, in place, including all material, equipment, and
labor to place the concrete in the locations shown on the construction drawings
and/or as directed by OWASA’s Engineer including the cost of removing and
disposing of the material replaced by the concrete. Payment will be made only for
the quantities and dimensions as shown on drawings or applicable details. Price
does not include pipe.
I.
Excavation and Backfill:
Measurement and Payment: All excavation and backfill shall be included in the cost
of the other items bid – not a pay item.
When the removal of existing structures or materials is classified separately as a
contract pay item, payment will be made in accordance with the contract price;
otherwise, such work will be considered as incidental work and will not be paid for
directly, but the cost shall be included in the unit price for other items of work. In
either case, such price or prices shall be full compensation for all labor, materials,
tools, equipment, and incidentals necessary to complete the work.
J. Exploratory Excavation:
Measurement:
the cubic yard.
Such excavation, where ordered by OWASA, will be measured by
Payment: The cost of such excavation, where ordered by OWASA, will be paid at
the contract unit price bid, per cubic yard.
K. Flowable Fill Concrete:
Measurement: Measurement shall be by the cubic yard of concrete placed,
regardless of the specified strength.
Payment: Paid for in place by the cubic yard.
L. Foundation Stone:
Measurement: Foundation stone used in stabilizing the bottom of trenches will be
field measured in the trench and converted to tons, complete in place. For purposes
of measurement, 1 cubic yard of #57 stone = 1.5 tons.
Payment: When the use of foundation stone is directed by OWASA’s Engineer,
foundation stone shall be paid for at the contract unit price for foundation stone by
the ton. Payment shall include all materials and labor incidental to the placing of the
stone and any additional extra depth of trench or excavation necessary to
accommodate the stone including disposal of unusable material necessary to allow
for placement of the foundation stone.
M. Pavement Removal and Replacement:
Measurement: Where pavement is encountered, as shown on the plans, pavement
removal and replacement will be measured by the linear foot along the centerline of
construction regardless of the existing pavement material or depth.
See
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00950 – MEASUREMENT AND PAYMENT
Specifications Section 02275– Trenching, Backfilling, and Compaction of Utilities,
paragraph 3.7, Pavement Repair and Replacement.
Payment: This item will be paid for at the contract unit price per linear foot for
pavement removal and replacement. The unit price bid shall include all labor, tools,
equipment, and material necessary to complete the work and shall include, but is not
necessarily limited to, saw cutting the pavement, removal of existing pavement
materials which are not suitable for backfilling the trench from the job, placement of
suitable backfill material, and the cost for compaction and compaction testing by a
certified and approved laboratory. In the case of pavement cut and removal, such
price or prices shall include the cost of the required permit for cutting pavement,
unless permit fees are included as a bid item in the Contract Documents. Extra
width will not be measured for payment and there will be no extra payment for any of
the above work, the cost of which shall be included in the unit price bid, for
pavement removal and replacement.
N. Portland Cement Concrete Sidewalk:
Measurement: Where existing concrete sidewalk is encountered, as shown on the
plans, removal and replacement will be measured by the square foot of sidewalk
ordered removed and replaced by OWASA, regardless of the depth of the existing
sidewalk.
Payment: This item will be paid for at the contract unit price per square foot for
removal and replacement of concrete sidewalk, depth to match the depth removed
with no extra compensation for depth. The unit price bid shall include all labor, tools,
equipment, and material necessary to complete the work and shall include, but is not
necessarily limited to, saw cutting the sidewalk, removal of all existing materials,
which are not suitable for backfill in the trench from the job, compaction of the
trench, and replacement of the sidewalk.
O. Remove and Replace Asphalt Drive and Remove and Replace Concrete Drive:
Measurement: Where either an existing asphalt or concrete drive is encountered,
as shown on the plans, pavement removal and replacement will be measured by the
linear foot along the centerline of construction regardless of the existing pavement
material or depth.
Payment: This item will be paid for at the contract unit price per linear foot for
removal and replacement of either asphalt or concrete drives. The unit price bid
shall include all labor, tools, equipment, and material necessary to complete the
work and shall include, but is not necessarily limited to, saw cutting the pavement,
removal of all paving materials which are not suitable for backfill in the trench from
the job, and compaction of the trench. Extra width will not be measured for payment
and there will be no extra payment for any of the above work, the cost of which shall
be included in the unit price bid, for removal and replacement of asphalt or concrete
drives.
P. Resurfacing Existing Pavement:
Measurement: Payment for resurfacing existing pavement will be made at the unit
price bid per square yard in accordance with field measurements made by OWASA.
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00950 – MEASUREMENT AND PAYMENT
Payment: The unit price bid shall include all labor, tools, equipment, and material
necessary to complete the work and shall include, but is not necessarily limited to,
saw cutting the pavement if necessary, adjusting valves and manholes, and meeting
density requirements. The Contractor shall furnish OWASA with all asphalt weight
tickets at the time the work is accomplished. The computed yield, arrived at by
dividing the weight used by the measured area, shall be a minimum of 200 pounds
per square yard. In those areas where the work is acceptable to the NCDOT and
OWASA, yet the computed yield is less than 200 pounds per square yard, payment
will be made in direct ratio to the square of the actual yield to the square of 200
pounds per square yard.
Q. Rock Excavation:
Measurement: Where rock excavation is to be measured for payment, quantities will
be as determined by OWASA. Rock excavation will be measured by the cubic yard.
For pay purposes, dimensions shall be computed as the difference in elevation
between the top and bottom of the rock (as determined by OWASA) multiplied by the
specified trench ditch width for the pipe size being laid. Where rock is encountered
in the bottom of the trench, the maximum depth for payment purposes shall be 6
inches below the bottom of the pipe. Rock excavation shall consist of the removal
and satisfactory disposal of all materials, which in the opinion of OWASA’s Engineer,
cannot be excavated except by drilling, blasting, “jack hammering or hoe ramming.”
All boulders containing a volume of more than one-half cubic yard will be classified
as rock.
Payment: Rock excavation will be paid for at the contract unit price per cubic yard
for rock excavation and shall include all labor, materials, tools, equipment, and
incidentals necessary to excavate and dispose of rock off site, backfilling the
excavated trench to the bottom of the pipe with select backfill material, and shall
include the cost of removing all excavated materials which are not suitable for
backfill. No payment will be made for rock which has been excavated subsequent to
ripping operation.
R. Sheeting and Bracing (Piling):
Measurement and Payment: Payment for sheeting and bracing, except when
ordered to be left in place, and all other work incidental to sheeting and bracing, shall
not be made separately unless specified or as shown on the plans or as directed by
OWASA, but shall be included in the bid price for other items.
When specified, payment for “Timber Sheeting Left in Place” shall be made at the
contract unit price bid per 1000 board feet.
When specified, payment for “Steel Sheet Piling” shall be made at the contract unit
price bid per square foot.
When specified, payment for “Steel Sheet Piling Left in Place” shall be made at the
contract unit price bid per square foot.
S. Sodding, Fertilizing, Seeding, and Fine Grading:
Measurement: Measurement of surfaces to be sodded or seeded shall be measured
to the nearest 1/10 acre for the class specified. Sodding, fertilizing, seeding, and
fine grading shall be provided as described in Section 02275, Trenching, Backfilling,
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00950 – MEASUREMENT AND PAYMENT
and Compaction of Utilities. Extra compensation will not be made for additional
seeding beyond all limits of construction as defined in applicable section.
Payment: Payment for sodding, fertilizing, seeding, and fine grading will be at the
contract unit price per acre for sodding, fertilizing, seeding, and fine grading as
described in Section 02275, Trenching, Backfilling, and Compaction of Utilities. No
compensation will be made for reseeding, if required. The cost of restoring areas
located beyond the designated area(s) shall be borne by the Contractor.
T. Trench Borrow - Select:
Measurement: Trench excavation determined to be unusable by OWASA’s
Engineer, or his representative, resulting from material which may be noncompactable, naturally wet (when removed from trench), and otherwise unusable
due to too high a moisture content for compaction (as opposed to unprotected soil
exposed carelessly to rain which becomes unusable in which case there is no claim
for payment for Trench borrow). Trench borrow shall be measured by the cubic yard
of material removed from the trench, limiting the trench width to a maximum of 2 feet
plus the pipe OD.
Payment: Trench borrow shall be paid by the cubic yard for material placed in the
trenches, compacted and in place. Trench borrow for water lines shall be included in
the contract unit price per linear foot bid for water line (see paragraph 1.2 EE of this
specification).
U. Other: Other items shall be paid for as stated in the Proposal.
1.2
WATER
Measurements for purpose of payment shall be in accordance with the unit quantities
stated in the proposal as defined below. Whenever units of measure (i.e. linear feet,
each, and similar units of measurement) are mentioned in a proposal, it shall be
interpreted to mean the unit installed in accordance with the plans and specifications,
and ready for use. Prices for the following bid items shall include all labor, materials,
tools, equipment, and other incidentals necessary to complete the work as shown on the
plans and in accordance with these specifications.
A.
Aggregate Backfill:
Measurement: Coarse granular fill will be measured by the ton in place in the
trench.
Payment: Price per ton for coarse granular fill shall include all materials,
equipment, and labor required to furnish and install No. 57 stone in the locations
designated by OWASA’s Engineer. For purposes of measurement, 1 cubic yard of
#57 stone = 1.5 tons.
B.
Bedding Stone for Pipe:
Measurement: When called for in the proposal or on the plans, aggregate material
used for bedding water lines will be measured by the ton of pipe bedding material
placed.
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00950 – MEASUREMENT AND PAYMENT
Payment: Pipe bedding stone will be paid for at the contract unit price per ton for
pipe bedding material, complete and in place.
C.
Concrete Encasement:
Measurement: Payment for furnishing concrete encasement will be at the unit price
bid per cubic yard for the class of concrete stated in the proposal, such price to be
paid in addition to that paid per foot of water main.
Payment: The unit priced stated in the proposal shall include the cost of additional
depth of excavation, forming, the furnishing and placing of concrete, cofferdams,
laying of pipe line to grade but excluding the cost of the pipe itself, complete in
place, including all labor, equipment and material necessary, and all other work
incidental to the complete installation of the concrete encasement in accordance
with the specification and details shown on the plans. Payment will be made to
neat lines of construction shown on the plans with no allowance being made for
extra ditch width.
D.
Concrete Piers:
Measurement: This item will be measured on and each basis for concrete piers.
Payment: This item will be paid for at the contract unit price bid for concrete piers
complete in place, including all labor, equipment and material necessary, for
furnishing, excavating, forming, installing, backfilling, and all other work incidental to
the complete installation of the concrete piers in accordance with the specification
and details shown on the plans. Payment will be made to neat lines of construction
shown on the plans with no allowance being made for extra ditch width.
E.
Connecting to Existing Mains:
Not a pay item. Fittings and specialty items used in making the connections will be
measured and paid for at the unit price bid by the Contractor for “Fittings” and at the
unit price bid for “Tapping Tees and Valve.”
F.
Copper Tubing (Pipe) for Water services (open cut):
Measurement: Measurement of copper pipe for water services shall be made by
the linear foot of pipe through all fittings from the center of the water main to the
center of the water meter box.
Payment: The accepted quantity of water service pipe shall be paid for at the
contract unit bid price per linear foot of the size indicated on the drawings, complete
and in place, at a minimum depth of 24 inches. The price shall include all
equipment, labor, and materials for installation, complete in place, to include testing
and disinfection.
G. Copper Tubing (Pipe) for Water services (by Jacking or Boring):
Measurement: Jacking water services will be measured by the linear foot of pipe
through all fittings from the center of the water main to the center of the water meter
box.
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00950 – MEASUREMENT AND PAYMENT
Payment: The accepted quantity of jacked service pipe shall be paid for at the
contract unit bid price per linear foot of the size indicated on the drawings, complete
and in place. This price shall include all equipment, labor, and materials for
installation, complete in place, including testing and disinfection.
H.
Ductile Iron Pipe:
Measurement: By the linear foot. All pipes shall be measured from the exact
beginning of the pipe to the end of the line without deduction for fittings (i.e. fittings
and valves) and shall be made through casings. Hydrants leads will be measured
as line.
Payment: The accepted quantities of water line pipe will be paid for at the contract
unit price per linear foot of the type and size pipe specified (fittings, valves, and
specialty items are paid separately), complete in place. This price shall include
labor, equipment, materials, trench excavation (excluding rock), shoring, or use of
trench box, installation, concrete thrust blocking, making connections to existing
mains, installing in existing casing, pumping, backfilling, compaction, testing of
failed trenches, disposal of excess material, pressure testing, chlorinating and
bacteriological testing, and all other work incidental to the complete installation of
the mains in accordance with these specifications. Fittings, valves, and specialty
items are paid separately.
I.
Ductile Iron Pipe, Bored and Jacked:
Measurement: Measurement of Ductile Iron Pipe, bored and jacked, shall be
measured by the linear feet of pipe installed. Bored and jacked Ductile Iron Pipe
shall include any excavation, any backfill, bore, jacking, the pipe, dewatering, clean
up, restoration, and any other work required for a complete in place installation.
Payment: Ductile Iron Pipe, bored and jacked will be paid for at the contract unit
price per linear foot for pipe bored, complete and in place. The price shall be full
compensation for pipe, labor, equipment, and all other work incidental to the
complete installation of the mains in accordance with these specifications. Fittings,
valves, and specialty items are paid separately.
J.
Encasement Pipe (bored):
Measurement: Steel casing pipe of the wall thickness and diameter specified will
be measured by the linear feet of steel casing pipe installed.
Encasement of water lines by the dry bore and jacking method shall include any
excavation, any backfill, the encasement pipe, bore, jacking, spiders, drain pipe,
french drain, the end seals, dewatering, clean up, restoration, and any other work
required for a complete in place installation.
Payment: Steel casing pipe will be paid for at the contract unit price per linear foot
per diameter per thickness for steel casing pipe bored, complete and in place.
However, the bore shall be paid one time on a linear foot basis and no extra
compensation will be paid for failures and the subsequent withdrawal and re-jacking
attempts. Lines off either on grade or alignment shall be rejected or corrected in a
manner approved by OWASA’s Engineer. The cost of the carrier pipe is not to be
included (see paragraph 1.3 F of this Section).
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00950 – MEASUREMENT AND PAYMENT
K.
Encasement Pipe (open cut):
Measurement: Steel casing pipe of the wall thickness and diameter specified will
be measured by the linear feet of steel casing pipe installed.
Encasement of water lines by the open cut method shall include any excavation,
any backfill, the encasement pipe, spiders, drain pipe, french drain, the ends seals,
dewatering, clean up, restoration, and any other work required for a complete in
place installation.
Payment: Steel casing pipe will be paid for at the contract unit price per linear foot
per diameter per thickness for steel casing pipe installed by the pipe open cut,
complete and in place. Lines off either on grade or alignment shall be rejected or
corrected in a manner approved by OWASA’s Engineer. The cost of the carrier
pipe is not to be included (see paragraph 1.3 F of this Section).
L.
Excavation and Backfill:
Measurement and payment: In accordance with Section 02275, Trenching,
Backfilling, and Compaction of Utilities, all excavation and backfill shall be included
in the cost of the other items bid – not a pay item.
M. Fittings and Accessories:
Measurement: Fittings and specialty items used in conjunction with ductile iron
pipe will be measured per each.
Payment: Payment for ductile iron fittings shall include all labor, equipment, and all
materials necessary for installing, making connections to existing mains, tie rods,
wedge action restrainer glands, backfilling, testing, sterilizing, and all other work
incidental to the complete installation of these fittings in accordance with the
specifications.
N.
Fire Hydrants:
Measurement: Fire hydrants will be measured by the number of hydrants installed
on an each basis.
Payment: Price shall include all labor, equipment, and all materials (including
extensions and fittings) necessary to install the hydrant including construction
staking, #57 stone, painting, testing, and disinfecting, complete and in place.
Valves and pipe will be paid for separately. The cost of surveying for staking
hydrant location is to be included in the cost of the hydrant unless an item is
provided in the proposal for utility construction staking whereupon the costs shall
then be included in that line item.
O. Fire Vaults and Large Meter Vaults:
Measurement: Vaults for backflow prevention devices, detector check, RPZ, or
large meters (meters larger than 2 inches) shall be paid lump sum. Cost for vault is
to include all labor, materials, equipment, backfill, compaction, etc. complete and in
place. The cost of the vault is to also include the precast reinforced concrete vault,
stone bedding, the backflow prevention device and/or meter, gate valves, post
indicator valves (if applicable), fittings, check valves, couplings, sleeves, fire
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00950 – MEASUREMENT AND PAYMENT
department connection (if applicable), hatch, floor drain, pipe stands, vents, ladder
(if applicable), painting of pipe and fittings (if applicable), defect repair, testing, etc.
necessary to render a complete unit as shown on the contract drawings.
Payment: Vault payment will be paid as lump sum.
P.
Installation of Fire Hydrants on Existing Water Mains:
Measurement: The work included under this item is the unit price for installing a
new hydrant on any existing water line within the OWASA utility district and any
incidental work normally associated with it. Items such as pipe, pavement cuts,
fittings, seeding, and grading, etc. will be paid under appropriate unit price items as
approved by OWASA’s Engineer. Installation of fire hydrants on existing water lines
will be measured by the number of hydrants installed on an each basis.
Payment: Price shall include all labor, equipment, and all materials (including
extensions and fittings) necessary to install the hydrant including construction
staking, #57 stone, painting, testing and disinfecting, complete and in place. Valves
and pipe will be paid for separately. No additional compensation will be made
regardless of whether the hydrant is a high or low pressure hydrant.
Q. Foundation Stone:
Measurement: Foundation stone used in stabilizing the bottom of trenches will be
field measured in the trench and converted to tons, complete in place. For
purposes of measurement, 1 cubic yard of #57 stone = 1.5 tons.
Payment: When the use of foundation stone is directed by OWASA’s Engineer,
foundation stone shall be paid for at the contract unit price for foundation stone by
the ton. Payment shall include all materials and labor incidental to the placing of
the stone and any additional extra depth of trench or excavation necessary to
accommodate the stone including disposal of unusable material necessary to allow
for placement of the foundation stone.
R.
Manholes – Valve and Air/Vacuum Release:
Measurement: Measurement for manholes will be by the vertical foot of manhole
constructed. Manholes shall be measured from the floor of the manhole to the top
of the concrete casting and recorded to the nearest ½ foot.
Payment: Manholes will be paid for at the contract unit price per linear foot for
manholes. The price shall include bedding stone, drains (if applicable), concrete
grade rings (if applicable), iron frames and covers, invert forming, and grade
adjustments to iron frame if necessary, complete in place.
S.
Miscellaneous Fittings:
Measurement: By the pound.
Payment: Payment for ductile iron fittings where specified on the plans shall be
made on the basis of AWWA C110/ANSI 21.10 published weights for mechanical
joint fittings without accessories. Accessories shall be paid for at the contract unit
price based on AWWA C110/ANSI 21.10 published weights.
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00950 – MEASUREMENT AND PAYMENT
T.
Pavement Removal and Replacement:
Measurement: Where pavement is encountered, as shown on the plans, pavement
removal and replacement will be measured by the linear foot along the centerline of
construction regardless of the existing pavement material or depth.
See
Specification Section 02275 – Trenching, Backfilling, and Compaction of Utilities,
paragraph 3.7, Pavement Repair and Replacement.
Payment: This item will be paid for at the contract unit price per linear foot for
pavement removal and replacement. The unit price bid shall include all labor, tools,
equipment, and material necessary to complete the work and shall include, but is
not necessarily limited to, saw cutting the pavement, removal of existing pavement
materials which are not suitable for backfilling the trench from the job, placement of
suitable backfill material, and the cost for compaction and compaction testing by a
certified and approved laboratory. In the case of pavement cut and removal, such
price or prices shall include the cost of the required permit for cutting pavement,
unless permit fees are included as a bid item in the Contract Documents. Extra
width will not be measured for payment and there will be no extra payment for any
of the above work, the cost of which shall be included in the unit price bid, for
pavement removal and replacement.
U.
Portland Cement Concrete Sidewalk:
Measurement: Where existing concrete sidewalk is encountered, as shown on the
plans, removal and replacement will be measured by the square foot of sidewalk
ordered removed and replaced by OWASA, regardless of the depth of the existing
sidewalk.
Payment: This item will be paid for at the contract unit price per square foot for
removal and replacement of concrete sidewalk, depth to match the depth removed
with no extra compensation for depth. The unit price bid shall include all labor,
tools, equipment, and material necessary to complete the work and shall include,
but is not necessarily limited to, saw cutting the sidewalk, removal of all existing
materials, which are not suitable for backfill in the trench from the job, compaction
of the trench, and replacement of the sidewalk.
V.
Remove and Replace Asphalt Drive and Remove and Replace Concrete Drive:
Measurement: Where either an existing asphalt or concrete drive is encountered,
as shown on the plans, pavement removal and replacement will be measured by
the linear foot along the centerline of construction regardless of the existing
pavement material or depth.
Payment: This item will be paid for at the contract unit price per linear foot for
removal and replacement of either asphalt or concrete drives. The unit price bid
shall include all labor, tools, equipment, and material necessary to complete the
work and shall include, but is not necessarily limited to, saw cutting the pavement,
removal of all paving materials which are not suitable for backfill in the trench from
the job, and compaction of the trench. Extra width will not be measured for
payment and there will be no extra payment for any of the above work, the cost of
which shall be included in the unit price bid, for removal and replacement of asphalt
or concrete drives.
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00950 – MEASUREMENT AND PAYMENT
W. Resurfacing Existing Pavement:
Measurement: Payment for resurfacing existing pavement will be made at the unit
price bid per square yard in accordance with field measurements made by OWASA.
Payment: The unit price bid shall include all labor, tools, equipment, and material
necessary to complete the work and shall include, but is not necessarily limited to,
saw cutting the pavement if necessary, adjusting valves and manholes, and
meeting density requirements. The Contractor shall furnish OWASA with all asphalt
weight tickets at the time the work is accomplished. The computed yield, arrived at
by dividing the weight used by the measured area, shall be a minimum of 200
pounds per square yard. In those areas where the work is acceptable to the
NCDOT and OWASA, yet the computed yield is less than 200 pounds per square
yard, payment will be made in direct ratio to the square of the actual yield to the
square of 200 pounds per square yard. New pavement shall be a minimum of 2
inches thick.
X.
PVC Pipe (when applicable):
Measurement: By the linear foot. All pipes shall be measured from the exact
beginning of the pipe to the end of the line without deduction for fittings (i.e. fittings
and valves). Hydrants leads will be measured as line.
Payment: The accepted quantities of PVC water line pipe will be paid for at the
contract unit price per linear foot of the type and size pipe specified (including
fittings and specialty items, but excluding valves), complete in place. This price
shall include all labor, equipment, materials, trench excavation (excluding rock),
shoring or use of trench box, installation, making connections to existing mains,
installing in existing casing, pumping, backfilling, compaction, testing of failed
trenches, disposal of excess material, pressure testing, chlorinating and
bacteriological testing, and all other work incidental to the complete installation of
the mains in accordance with these specifications. No special payment will be
made for fittings, specialty items, or pipe used in making connections to existing
mains where such connections are noted on the plans.
Y.
Removal and Disposal of Asbestos Cement Pipe:
Measurement: When the amount of pipe to be removed is less than 12 feet, the
Contractor shall be paid a lump sum per each event. When the amount removed
exceeds 12 feet, the Contractor shall be paid the lump sum plus the bid price per
linear foot for pipe removed in excess of 12 feet.
Payment: Asbestos Cement Pipe removal will be paid for at the contract unit price
per lump sum and/or by the foot as bid and shall include all labor, materials, and
equipment to excavate, remove, and properly dispose of pipe. Contractor shall
provide documentation to OWASA as to the legal disposition of the pipe in
accordance with the Solid Waste Disposal Act, as amended from time to time.
Z.
Rock Excavation:
Measurement: Where rock excavation is to be measured for payment, quantities
will be as determined by OWASA. Rock excavation will be measured by the cubic
yard. For pay purposes, dimensions shall be computed as the difference in
elevation between the top and bottom of the rock (as determined by OWASA)
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00950 – MEASUREMENT AND PAYMENT
multiplied by the specified trench ditch width for the pipe size being laid. Where
rock is encountered in the bottom of the trench, the maximum depth for payment
purposes shall be 6 inches below the bottom of the pipe. Rock excavation shall
consist of the removal and satisfactory disposal of all materials, which in the opinion
of OWASA’s Engineer, cannot be excavated except by drilling, blasting, “jack
hammering or hoe ramming.” All boulders containing a volume of more than onehalf cubic yard will be classified as rock.
Payment: Rock excavation will be paid for at the contract unit price per cubic yard
for rock excavation and shall include all labor, materials, tools, equipment, and
incidentals necessary to excavate and dispose of rock off site, backfilling the
excavated trench to the bottom of the pipe with select backfill material, and shall
include the cost of removing all excavated materials which are not suitable for
backfill. No payment will be made for rock which has been excavated subsequent
to ripping operations.
AA. Sodding, Fertilizing, Seeding, and Fine Grading:
Measurement: Measurement of surfaces to be sodded or seeded shall be
measured to the nearest 1/10 acre for the class specified. Sodding, fertilizing,
seeding, and fine grading shall be provided as described section in Section 02275,
Trenching, Backfilling, and Compaction of Utilities. Extra compensation will not be
made for additional seeding beyond all limits of construction as defined in
applicable section.
Payment: Payment for sodding, fertilizing, seeding, and fine grading will be at the
contract unit price per acre for sodding, fertilizing, seeding, and fine grading as
described in Section 02275, Trenching, Backfilling, and Compaction of Utilities. No
compensation will be made for reseeding, if required. The cost of restoring areas
located beyond the designated area(s) shall be borne by the Contractor.
BB. Tapping Tees and Valves:
Measurement: Tapping tees and valves will be measured on an each basis for the
number of each size and type of valve installed.
Payment: Tapping tees and valves will be paid for at the contract unit price per
valve for the type and size specified, complete in place. This price shall include all
labor, equipment and materials, concrete thrust blocking, concrete footing,
incidental to making the taps, includes installation and furnishing of the tees and
valves, backfilling, testing, sterilizing, and all other work incidental to the complete
installation of the tapping tee and valve, with necessary valve box, in accordance
with the specifications. Cost for accessory kit to be included in price of valve.
CC. Testing and Sterilizing:
Not a pay item. The associated work, materials, and labor involved in testing and
sterilizing water mains is incidental to the cost of the water main construction and
shall be included in other bid items.
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DD. Tie Rods, Restraint Flange, Retainer Glands and Retainer Clamps:
Measurement: Tie rods, wedge action restrainer glands, retainer glands, and
retainer clamps are considered incidental to the cost of construction.
Payment: Not a pay item.
EE. Trench Borrow - Select:
Measurement: Incidental to cost of line. Not a pay item.
Payment: Trench borrow shall be included in the unit price of the water line for
material placed in the water main trenches, compacted and in place.
FF. Tunneling:
Measurement: Tunneling will be measured by the linear feet of tunnel installed.
The tunneling method shall include any and all excavation, shoring and bracing, any
backfill, steel liner plates and bolts, ventilation system for workers, lagging, spiders,
grout plugs, sand-cement grouting of voids, steel drain pipe, french drain, concrete
paved invert, the ends seals, dewatering, clean up, restoration, and any other work
required for a complete in place installation.
Payment: Tunneling will be paid for at the contract unit prices per linear foot for
diameter installed by the tunneling cut, complete and in place. Lines off either on
grade or alignment shall be rejected or corrected in a manner approved by
OWASA’s Engineer. Unit price does not include the carrier pipe (see paragraph 1.3
F of this specification).
GG. Valves – Air Release:
Measurement: Air/Vacuum Release valves will be measured on a per each basis
for the number of units installed.
Payment: Air and vacuum valves will be paid for at the contract unit price per air
and vacuum valve for the size specified, and all materials incidental to the
installation of the air release valves, complete in place. This price shall include the
direct tap and/or saddle, brass plumbing valves, brass street ells and screen, vent
pipe, tapped tees/tees as applicable, pipe stands, (excluding the manhole, drain,
and frame and cover), and other incidentals as shown on Standard Details 513.04
and 513.05.
HH. Valve with Box:
Measurement: Gate valves, butterfly valves, and inserting valves will be measured
by the number of each size and type of valve installed.
Payment: Gate valves, butterfly valves, tapping valves, and inserting valves will be
paid for at the contract unit price, per valve for the type and size specified, complete
in place. This price shall include all labor, equipment, and materials necessary for
installing, valve footing (if applicable), furnishing, backfilling, testing, sterilizing, and
all other work incidental to the complete installation of the valves, with necessary
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00950 – MEASUREMENT AND PAYMENT
valve box, in accordance with the specifications.
included in price of valve.
II.
Cost for accessory kit to be
Vault (Large Meter/Fire):
Measurement: Measurement of the large meter vaults shall be made in terms of
one complete vault and piping assembly. This price shall include all equipment,
labor and materials, excavation, backfilling, chlorinating, bacteriological testing,
pressure testing, meter, vault, valves, access hatch, and other fittings, etc. as
shown on the contract drawings or in the standard details, complete in place.
Payment: Large meter vaults will be paid for at the contract price per unit of size
indicated, complete in place.
JJ. Water Meter Box and Assembly (5/8-inch x ¾-inch, 1-inch, and 2-inch):
Measurement: Measurement of the water meter box shall be made in terms of one
complete box and meter connection assembly. This price shall include all
equipment, labor, and materials for installation, complete in place.
Payment: Meter boxes, excluding meter, will be paid for at the contract price per
unit of size indicated, complete and in place and shall include excavation,
backfilling, testing, chlorinating, bacteriological testing, cost of the meter box, angle
stop, yoke, and double check valve. If replacing an existing meter box, cost shall
include removal and disposal of the old meter box and assembly. If meter box does
not require tying into existing service, pipe shall be plugged for future extension by
others.
KK. Wet Tap – Tapping Tee & Valve:
Measurement: Wet taps will be measured by the number of each size installed.
Payment: Wet tap price shall include furnishing all materials, equipment, and labor
to make a wet tap on an existing line, complete in place, to include valve, valve box,
tapping tee sleeve, tap, anchor blocks, excavations, backfill, and testing of sleeve.
Wet taps will be paid for at the contract unit price per tap for the size specified,
complete in place.
LL. Other: Other items shall be paid for as stated in the Proposal.
1.3
SEWER
Measurements for purpose of payment shall be in accordance with the unit quantities
stated in the proposal as defined below. Prices for the following bid items shall include
all labor, materials, tools, equipment, and other incidentals necessary to complete the
work as shown on the plans and in accordance with these specifications.
A. Aggregate Backfill:
Measurement: Coarse granular fill will be measured by the ton in place in the
trench.
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00950 – MEASUREMENT AND PAYMENT
Payment: Price per ton for coarse granular fill shall include all materials, equipment,
and labor required to furnish and install No. 57 stone in the locations designated by
OWASA’s Engineer. For purposes of measurement, 1 cubic yard of #57 stone = 1.5
tons.
B. Backfill, Select Granular (Trench Borrow):
Measurement: Trench excavation determined to be unusable by OWASA’s
Engineer resulting from material which may be non-compactable, naturally wet
(when removed from trench), and otherwise unusable due to too high a moisture
content for compaction (as opposed to unprotected soil exposed carelessly to rain
which becomes unusable in which case there is no claim for payment for trench
borrow). Measurement shall be made along the centerline of the pipe and the pay
quantity shall be determined based on the depth of fill placed times the maximum
trench width as shown on Standard Detail 531.01 (pipe outside diameter plus 2
feet). Select granular backfill in excess of the maximum quantity, as specified, shall
be furnished and placed by the Contractor.
Payment: Payment shall be made at the contract unit price bid per cubic yard for
selected granular backfill placed in sewer line trenches, compacted and complete in
place.
C. Bedding Stone, Granular:
Measurement: Stone for bedding, when required, is considered to be incidental to
the cost of the pipe.
Payment: Not a pay item.
D. Building Connections/Service Laterals:
1) Service Laterals – Pipe/Fittings:
Measurement: Measurement of building connection service pipe shall be along
the pipe from the outside surface of the main sewer to the extreme end of the
last pipe or fitting placed. Measurement shall be to the nearest 1 foot. See
Standard Detail 534.01.
Payment: Payment for Service Laterals shall be at the contract unit price bid,
per linear foot, for the sized indicated, complete-in-place. Bends, adapters, and
plugs shall be considered incidental to the construction and all costs thereof shall
be included in other pay items of the proposal. Any temporary pumps required to
by-pass sewer around work areas shall be provided at no additional cost.
2) Service Risers:
Measurement: Measurement for the service risers shall be from invert of the
service wye to the top of the riser fitting along the centerline of the pipe.
Measurement shall be to the nearest 1 foot.
Payment: Payment for Service Risers shall be at the contract unit price bid, per
linear foot, for the sized indicated, complete-in-place. Bends, adapters, plugs,
and clean-out box and lid shall be considered incidental to the construction and
all costs thereof shall be included. See Standard Detail 534.01.
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00950 – MEASUREMENT AND PAYMENT
3) Wye Branches
Measurement: Measurement for the wyes shall be on an each basis.
Payment: Payment for wyes shall be at the contract unit price bid, per each, for
the sized indicated, complete-in-place. Payment for cut-in connections to main
sewer, where no wye branch exists, shall be at the unit price bid for wye
branches, complete in place. Any temporary pumps required to by-pass sewer
around work areas shall be provided at no additional cost. See Standard Detail
534.01.
E. Bypass Pumping:
Measurement: Bypass pumping is considered to be incidental to the cost of the pipe
unless otherwise shown in the proposal.
Payment: Not a pay item.
F. Carrier Pipes (Installed in either Steel Encasements or Tunnel Liners):
Measurement: Measurement shall be along the centerline of the pipe.
Payment: Payment for carrier pipes will be made at the contract unit price bed per
linear foot and shall include all materials, tools, and equipment necessary to install
and, if necessary, grout the ductile iron pipe inside the casing. The unit price does
not include the casing pipe (see the individual pay items Encasement Pipe and
Tunneling). The unit price shall include the cost of excavation, bedding, backfilling,
cleanup, and testing.
G. Clearing and Grubbing, Lightly Wooded Areas:
Measurement: Measurement for clearing and grubbing will be by the acre in
accordance with Section 02275, Trenching, Backfilling, and Compaction of Utilities.
Width shall not exceed the width as defined in the disturbing and construction limits
criteria.
Payment: Price per acre for clearing and grubbing in lightly wooded areas shall
include all material, equipment, and labor required to clear and grub lightly wooded
areas in accordance with Section 02275, Trenching, Backfilling, and Compaction of
Utilities. Lightly wooded areas shall be defined as areas where the prevalent
vegetation consists of trees less than 12 inches in diameter. The price shall also
include the removal and disposal of items that cannot be mulched or built into brush
piles.
H. Clearing and Grubbing, Heavily Wooded Areas:
Measurement: Measurement for clearing and grubbing will be by the acre in
accordance with Section 02275, Trenching, Backfilling, and Compaction of Utilities.
Width shall not exceed the width as defined in the disturbing and construction limits
criteria.
Payment: Price per acre for clearing and grubbing in heavily wooded areas shall
include all material, equipment, and labor required to clear and grub heavily wooded
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00950 – MEASUREMENT AND PAYMENT
areas in accordance with Section 02275, Trenching, Backfilling, and Compaction of
Utilities. Heavily wooded areas shall be defined as areas where the prevalent
vegetation consists of trees 12 inches or greater in diameter. The price shall also
include the removal and disposal of items that cannot be mulched or built into brush
piles.
I.
Combination Air Valve and Air Release Manhole:
Measurement: Measurement for combination air valve and air release manholes
shall be on an each basis.
Payment: Payment for combination air valve and air release manholes shall be paid
for at the contract unit price bid for combination air valve and air release manholes.
The price shall include all labor, material, equipment, stone bedding, tap and saddle,
valve, and piping complete in place as shown on Standard Detail 538.01. Manhole
and cast iron frame and cover shall be paid for separately (see pay item Manholes –
Standard and Drop).
J. Concrete Encasement
Measurement: Payment for furnishing concrete encasement will be at the unit price
bid per cubic yard for the class of concrete stated in the proposal, such price to be
paid in addition to that paid per foot of sewer main.
Payment: The unit priced stated in the proposal shall include the cost of additional
depth of excavation, forming, the furnishing and placing of concrete, cofferdams, and
laying of pipe line to grade but excluding the pipe itself, complete in place, including
all labor, equipment and material necessary, and all other work incidental to the
complete installation of the concrete encasement in accordance with the
specification and details shown on the plans. Payment will be made to neat lines of
construction shown on the plans with no allowance being made for extra ditch width.
K. Concrete – Miscellaneous Unformed:
Measurement: Concrete, except that used in manholes, will be measured in cubic
yards of unformed concrete actually placed. Typical uses include concrete collars
(slope anchors), cradles, and all other miscellaneous concrete related to sewer line
installation.
Payment: This item will be paid for at the contract unit price per cubic yard for unformed concrete for collars, cradles, and all other miscellaneous concrete related to
sewer line installation, in place, including all material, equipment, and labor to place
the concrete in the locations shown on the construction drawings and/or as directed
by OWASA’s Engineer including the cost of removing and disposing of the material
replaced by the concrete. Payment will be made only for the quantities and
dimensions as shown on drawings or applicable details. Price does not include pipe.
L. Connections to Other Sewers or to Appurtenances:
Measurement: Measurement shall be by made on an each basis for connections
made to other sanitary sewers and appurtenances.
Payment: Connections to other sewers or appurtenances shall be made on a lump
sum basis and shall be full compensation for removing, repairing, and/or replacing
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00950 – MEASUREMENT AND PAYMENT
pipe and/or structures and shall be full compensation for the completed work in place
including all materials, labor, tools, and equipment.
M. Ductile Iron Sewer Line:
Measurement: See pay item Measurement of Sewer Pipe.
Payment: See pay item Measurement of Sewer Pipe.
N. Encasement Pipe (bored):
Measurement: Steel casing pipe of the wall thickness and diameter specified will be
measured by the linear feet of steel casing pipe installed.
Encasement of sewer mains by the dry bore and jacking method shall include any
excavation, any backfill, the encasement pipe, bore, jacking, spiders, drain pipe,
french drain, the end seals, dewatering, clean up, restoration, and any other work
required for a complete in place installation.
Payment: Steel casing pipe will be paid for at the contract unit price bid per linear
foot per diameter per thickness for steel casing pipe bored, complete and in place.
However, the bore shall be paid one time on a linear foot basis and no extra
compensation will be paid for failures and the subsequent withdrawal and re-jacking
attempts. Lines off either on grade or alignment shall be rejected or corrected in a
manner approved by OWASA’s Engineer. Unit price does not include the carrier
pipe (see pay item “Carrier Pipe”).
O. Encasement Pipe (open cut):
Measurement: Steel casing pipe of the wall thickness and diameter specified will be
measured by the linear feet of steel casing pipe installed.
Encasement of sewer mains by the open cut method shall include any excavation,
any backfill, the encasement pipe, spiders, drain pipe, french drain, the ends seals,
dewatering, clean up, restoration, and any other work required for a complete in
place installation.
Payment: Steel casing pipe will be paid for at the contract unit price bid per linear
foot per diameter per thickness for steel casing pipe installed by the pipe open cut,
complete and in place. Lines off either on grade or alignment shall be rejected or
corrected in a manner approved by OWASA’s Engineer. Unit price does not include
the carrier pipe (see pay item “Carrier Pipe”).
P. Excavation and Backfill:
Measurement and Payment: In accordance with Section 02275, Trenching,
Backfilling, and Compaction of Utilities, all excavation and backfill shall be included
in the cost of the other items bid – not a pay item.
When the removal of existing structures or materials is classified separately as a
contract pay item, payment will be made in accordance with the contract price;
otherwise, such work will be considered as incidental work and will not be paid for
directly, but the cost shall be included in the unit price for other items of work. In
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00950 – MEASUREMENT AND PAYMENT
either case, such price or prices shall be full compensation for all labor, materials,
tools, equipment, and incidentals necessary to complete the work.
Q. Exploratory Excavation:
Measurement:
the cubic yard.
Such excavation, where ordered by OWASA, will be measured by
Payment: The cost of such excavation, where ordered by OWASA, will be paid at
the contract unit price bid, per cubic yard.
R. Foundation Stone:
Measurement: Foundation stone used in stabilizing the bottom of trenches will be
field measured in the trench and converted to tons, complete in place. For purposes
of measurement, 1 cubic yard of #57 stone = 1.5 tons.
Payment: When the use of foundation stone is directed by OWASA’s Engineer,
foundation stone shall be paid for at the contract unit price for foundation stone by
the ton. Payment shall include all materials and labor incidental to the placing of the
stone and any additional extra depth of trench or excavation necessary to
accommodate the stone including disposal of unusable material necessary to allow
for placement of the foundation stone.
S. Cleanout Frame and Cover:
Measurement and Payment: Not a pay item. The cost, setting, and final
adjustment of the cleanout frame and cover is covered under the cost of the service
riser. See Standard Detail 534.01.
T. Manholes – Standard and Drop:
Measurement: Manholes shall be measured on an each basis for a basic 6 foot
deep manhole inclusive of frame and cover and base. For all depths in excess of 6
feet, manholes shall be measured by the vertical foot of depth of the manhole
constructed. For the purpose of determining the additional depth of manhole to be
paid for at the unit price bid per vertical foot, manholes shall be measured from the
invert of the pipe outlet to the top of the concrete casting and recorded to the nearest
1/10 of a foot.
Where more than one type or size (diameter) designation is shown on the drawings,
or called for in the special provisions, each shall be covered by a separate bid item
of the following form:
1)
2)
3)
Type (or Size) Manhole, per each.
Additional Depth of Manhole, per vertical foot.
Drop Manhole Connection, per vertical foot.
Payment: Manholes shall be paid for at the contract unit price bid for a 6 foot deep
manhole on an each basis plus a unit price per vertical foot for all depths in excess
of 6 feet deep, plus a unit price per vertical foot for each drop manhole connection,
where they occur. Price shall include furnishing and constructing manholes
complete-in-place including excavation, connection to existing sewers if necessary,
complete invert forming in accordance with the standards and drawings, rubber
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April 2015
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00950 – MEASUREMENT AND PAYMENT
boots, bedding stone, bolting castings to cone, gaskets, external joint sealing
system, parging interior joints, vent pipe if required, vacuum testing, backfill, and
compaction complete in every detail. See Standard Details 532.01, 532.02 and
532.03.
U. Manholes – Doghouse:
Measurement: Manholes shall be measured on an each basis for a basic 6 foot
deep manhole inclusive of frame and cover and a base constructed in accordance
with Standard Detail 532.08. For all depths in excess of 6 feet, manholes shall be
measured by the vertical foot of depth of the manhole constructed. For the purpose
of determining the additional depth of manhole to be paid for at the unit price bid per
vertical foot, manholes shall be measured from the invert of the pipe outlet to the top
of the concrete casting and recorded to the nearest 1/10 of a foot.
Where more than one type or size (diameter) designation is shown on the drawings,
or called for in the special provisions, each shall be covered by a separate bid item
of the following form:
1) Type (or Size) Manhole, per each.
2) Additional Depth of Manhole, per vertical foot.
3) Drop Manhole Connection, per vertical foot.
Payment: Doghouse manholes shall be paid for at the contract unit price bid for a 6
foot deep manhole on an each basis plus a unit price per vertical foot for all depths
in excess of 6 feet deep, plus a unit price per vertical foot for each drop manhole
connection, where they occur. Price shall include furnishing and constructing
manholes complete-in-place including excavation, base construction, complete invert
forming in accordance with the standards and drawings, rubber boots if applicable,
bedding stone, bolting castings to cone if applicable, gaskets, external joint sealing
system, parging interior joints, vent pipe if required, vacuum testing, backfill and
compaction complete in every detail. See Standard Detail 532.08.
V. Manhole Frames and Covers – Watertight:
Measurement: Frames and covers shall be measured on an each basis.
Payment: Frames and covers shall be paid for at the contract unit price bid per
each and shall include all labor, tools, materials, and equipment for furnishing and
installing this frame and cover in lieu of a standard frame and cover, complete-inplace.
W. Manhole - Precast Concrete Riser Ring:
Measurement: Manhole precast concrete riser rings, as shown on Standard
Details 532.01 and 532.06, shall include all labor, material, and equipment
necessary to adjust the height of manhole frame and cover by inserting a precast
concrete riser ring on top of a precast concrete manholes and sealing the joint with
mastic.
Payment: Manhole precast concrete riser rings shall be paid for at the contract unit
price on an each basis and shall include all labor, material, and equipment
necessary complete-in-place.
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00950 – MEASUREMENT AND PAYMENT
X. Measurement of Sewer Pipe:
Measurement: Sewer pipe shall be measured from center to center of manholes
and depth of cut from invert to original ground line at centerline. No deductions in
length will be made for branches and appurtenances along the line. The original
ground line must be determined by the Contractor immediately prior to any trench
excavation. It is the Contractor’s responsibility to provide this information to OWASA
within 24 hours of the beginning of the trench excavation activities.
Payment: Payment will be made at the contract unit prices bid per linear foot as
stated in the proposal for the type of pipe specified and shall include trench
excavation (excluding rock), shoring or use of trench box, installation, pumping,
backfilling, compaction, testing of failed trenches, disposal of excess material,
pressure testing, and cleanup complete in place.
Y. Pavement Removal and Replacement:
Measurement: Where pavement is encountered, as shown on the plans, pavement
removal and replacement will be measured by the square foot along the centerline of
construction regardless of the existing pavement material or depth.
See
Specification Section 02275 – Trenching, Backfilling, and Compaction of Utilities,
paragraph 3.7, Pavement Repair and Replacement.
Payment: This item will be paid for at the contract unit price per square foot for
pavement removal and replacement. The unit price bid shall include all labor, tools,
equipment, and material necessary to complete the work and shall include, but is not
necessarily limited to, saw cutting the pavement, removal of existing pavement
materials which are not suitable for backfilling the trench from the job, placement of
suitable backfill material, and the cost for compaction and compaction testing by a
certified and approved laboratory. In the case of pavement cut and removal, such
price or prices shall include the cost of the required permit for cutting pavement,
unless permit fees are included as a bid item in the Contract Documents. Extra
width will not be measured for payment and there will be no extra payment for any of
the above work, the cost of which shall be included in the unit price bid, for
pavement removal and replacement.
Z. Concrete Piers:
Measurement: Reinforced concrete piers shall be measured on an each basis
based on the class height and the structural details shown on the contract drawings.
See Standard Detail 536.02.
Payment: Reinforced concrete piers shall be paid for at the contract unit price bid
based on class height. The cost shall include excavation and disposal of excess
material, stone bedding, reinforcement, anchor bolts, stainless steel straps, forming,
concrete, testing, concrete finishing, drilling and epoxying of rock pins if required,
restoration of grade and all labor and equipment as required, complete in place.
AA. Portland Cement Concrete Sidewalk:
Measurement: Where existing concrete sidewalk is encountered, as shown on the
plans, removal and replacement will be measured by the square foot of sidewalk
ordered removed and replaced by OWASA, regardless of the depth of the existing
sidewalk.
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00950 – MEASUREMENT AND PAYMENT
Payment: This item will be paid for at the contract unit price per square foot for
removal and replacement of concrete sidewalk, depth to match the depth removed
with no extra compensation for depth. The unit price bid shall include all labor,
tools, equipment, and material necessary to complete the work and shall include,
but is not necessarily limited to, saw cutting the sidewalk, removal of all existing
materials, which are not suitable for backfill in the trench from the job, compaction
of the trench, and replacement of the sidewalk.
BB. Pump Stations:
Measurement: Sanitary sewer lift stations shall be measured based on an each
basis.
Payment: Sanitary sewer lift stations shall be paid for at the contract lump sum
price bid based on the contract drawings. Payment shall cover complete installation
including, but not necessarily limited to, auxiliary generator, fencing, access road,
water tank pad, wetwell and valve vault, pumps, yard hydrant, stoned fenced
enclosure, shower and eye wash station, water service and meter, electrical
service, disconnect and meter, area light, control panel, manufacturer’s start up,
witness and operational test, operational manuals, a hut or building for self priming
pumps if applicable, emergency backup pump valved connection, complete in
place.
CC. Remove and Replace Asphalt Drive and Remove and Replace Concrete Drive:
Measurement: Where either an existing asphalt or concrete drive is encountered,
as shown on the plans, pavement removal and replacement will be measured by
the linear foot along the centerline of construction regardless of the existing
pavement material or depth.
Payment: This item will be paid for at the contract unit price per linear foot for
removal and replacement of either asphalt or concrete drives. The unit price bid
shall include all labor, tools, equipment, and material necessary to complete the
work and shall include, but is not necessarily limited to, saw cutting the pavement,
removal of all paving materials which are not suitable for backfill in the trench from
the job, and compaction of the trench. Extra width will not be measured for
payment and there will be no extra payment for any of the above work, the cost of
which shall be included in the unit price bid, for removal and replacement of asphalt
or concrete drives.
DD. Resurfacing Existing Pavement:
Measurement: Payment for resurfacing existing pavement will be made at the unit
price bid per square yard in accordance with field measurements made by OWASA.
Payment: The unit price bid shall include all labor, tools, equipment, and material
necessary to complete the work and shall include, but is not necessarily limited to,
saw cutting the pavement if necessary, adjusting valves and manholes, and
meeting density requirements. The Contractor shall furnish OWASA with all asphalt
weight tickets at the time the work is accomplished. The computed yield, arrived at
by dividing the weight used by the measured area, shall be a minimum of 200
pounds per square yard. In those areas where the work is acceptable to the
NCDOT and OWASA, yet the computed yield is less than 200 pounds per square
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00950 – MEASUREMENT AND PAYMENT
yard, payment will be made in direct ratio to the square of the actual yield to the
square of 200 pounds per square yard. New pavement shall be a minimum of 2
inches thick.
EE. Rock Excavation – Trench:
Measurement: Where rock excavation is to be measured for payment, quantities
will be as determined by OWASA. Rock excavation will be measured by the cubic
yard. For pay purposes, dimensions shall be computed as the difference in
elevation between the top and bottom of the rock (as determined by OWASA)
multiplied by the specified trench ditch width for the pipe size being laid. Where
rock is encountered in the bottom of the trench, the maximum depth for payment
purposes shall be 6 inches below the bottom of the pipe. Rock excavation shall
consist of the removal and satisfactory disposal of all materials, which in the opinion
of OWASA’s Engineer, cannot be excavated except by drilling, blasting, “jack
hammering or hoe ramming.” All boulders containing a volume of more than onehalf cubic yard will be classified as rock.
Payment: Rock excavation will be paid for at the contract unit price per cubic yard
for rock excavation and shall include all labor, materials, tools, equipment and
incidentals necessary to excavate and dispose of rock off site, backfilling the
excavated trench to the bottom of the pipe with select backfill material, and shall
include the cost of removing all excavated materials which are not suitable for
backfill. No payment will be made for rock which has been excavated subsequent
to ripping operations.
FF. Sheeting and Bracing (Piling):
Measurement and Payment: Payment for sheeting and bracing, except when
ordered to be left in place, and all other work incidental to sheeting and bracing,
shall not be made separately unless specified or as shown on the plans or as
directed by OWASA, but shall be included in the bid price for other items.
When specified, payment for “Timber Sheeting Left in Place” shall be made at the
contract unit price bid per 1000 board feet.
When specified, payment for “Steel Sheet Piling” shall be made at the contract unit
price bid per square foot.
When specified, payment for “Steel Sheet Piling Left in Place” shall be made at the
contract unit price bid per square foot.
GG. Sodding, Fertilizing, Seeding and Fine Grading:
Measurement: Measurement of surfaces to be sodded or seeded shall be
measured to the nearest 1/10 acre for the class specified. Sodding, fertilizing,
seeding, and fine grading shall be provided as described is Section 02275,
Trenching, Backfilling, and Compaction of Utilities. Extra compensation will not be
made for additional seeding beyond all limits of construction as defined in
applicable section.
Payment: Payment for sodding, fertilizing, seeding, and fine grading will be at the
contract unit price per acre for sodding, fertilizing, seeding, and fine grading as
described in Section 02275, Trenching, Backfilling, and Compaction of Utilities. No
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00950 – MEASUREMENT AND PAYMENT
compensation will be made for reseeding, if required. The cost of restoring areas
located beyond the designated area(s) shall be borne by the Contractor.
HH. Testing:
Not a pay item. The associated work, materials, and labor involved in testing
sewer mains and manholes are considered to be incidental to the cost of the sewer
main construction and shall be included in other bid items.
II.
Trench Borrow - Select:
Measurement: Trench excavation determined to be unusable by OWASA’s
Engineer, or his representative, resulting from material which may be noncompactable, naturally wet (when removed from trench) and otherwise unusable
due to too high a moisture content for compaction (as opposed to unprotected soil
exposed carelessly to rain which becomes unusable in which case there is no claim
for payment for Trench borrow). Trench borrow shall be measured by the cubic
yard of material removed from the trench, limiting the trench width to a maximum of
2 feet plus the pipe OD.
Payment: Trench borrow shall be paid by the cubic yard for material placed in the
water main trenches, compacted and in place.
JJ. Tunneling:
Measurement: Tunneling will be measured by the linear feet of tunnel installed.
The tunneling method shall include any and all excavation, shoring and bracing, any
backfill, steel liner plates and bolts, ventilation system for workers, lagging, spiders,
grout plugs, sand-cement grouting of voids, steel drain pipe, french drain, concrete
paved invert, the ends seals, dewatering, clean up, restoration, and any other work
required for a complete in place installation.
Payment: Tunneling
diameter installed by
grade or alignment
OWASA’s Engineer.
“Carrier Pipe”).
will be paid for at the contract unit prices per linear foot for
the tunneling cut, complete and in place. Lines off either on
shall be rejected or corrected in a manner approved by
Unit price does not include the carrier pipe (see pay item
KK. Other: Other items shall be paid for as stated in the Proposal.
END OF SECTION 00950
Back to top
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April 2015
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02275 - TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
(Last revised 6-1-13)
SUGESTED SEARCH WORDS FOR THIS SECTION
Part 1- General
Part 2 – Products
Part 3 – Execution
Backfilling
Bedding Definitions
Bedding for Pipe
Blasting
Cleanup & Restoration
Clearing and Grubbing
Common Trench Backfill
Compaction – Min Require’ts
Def-Common Trench Backfill
Def-Select Earth Backfill
Detectable Warning Tape
Dewatering
Erosion Control, NPDES
Flowable Fill Concrete
Foundation Preparation
Highway Crossings
Minimum Pipe Cover
Pavement Repair
River & Creek Crossings
Rock Excavation
Seeding & Groundcover
Select Earth Backfill
Trench Backfilling
Unclassified Trench Excavation
PART 1 – GENERAL
1.1
GENERAL:
A. The Contractor shall furnish all labor, materials, tools, equipment, and perform all
work and services necessary for or incidental to the furnishing and installation,
complete, of all operations in connection with excavation, trenching, and backfilling
of underground utilities as shown on drawings and as specified, in accordance with
provisions of the Contract Documents, and completely coordinated with work of all
other trades.
Although such work is not specifically indicated, furnish and install all supplementary
or miscellaneous items, appurtenances and devices incidental to or necessary for a
sound, secure, complete and compatible installation.
Work included in the project consists of, but is not necessarily limited to, methods of
installation of the following:
1) Sanitary Sewer Pipe Installation & appurtenances.
2) Water Distribution Pipe Installation & appurtenances.
3) Relocation of piping systems.
1.2
RELATED DOCUMENTS
A. Drawings and general provisions of the Contract, including General and
Supplementary Conditions apply to this specification.
B. Section 02530 – SANITARY SEWER.
C. Section 02510– WATER DISTRIBUTION.
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
1.3
SUMMARY
A. This section includes:
1) Excavating and backfilling trenches for buried water and sewer, buried utility
structures, and appurtenances.
2) Preparing subgrade for buried water and sewer, buried utility structures, and
appurtenances.
1.4
DEFINITIONS
A. For the purposes of this specification, the following definitions refer to sanitary sewer
and water distribution systems that come under the authority of OWASA as specified
within this section and other sections of this manual.
B. Backfill: Soil materials used to fill an excavated trench:
1) Initial Backfill (Carefully Compacted Select Earth Backfill): Backfill placed
beside and over the top 12-inches of the pipe in a trench, including haunches to
support sides of pipe.
2) Final Backfill (Common Trench Backfill): Backfill placed over the initial backfill to
fill a trench.
C. Bedding Course: Layer of clean coarse stone placed over the excavated subgrade
in a trench before laying pipe.
D. Foundation Stone: Clean well-graded stone, authorized by OWASA’s Engineer,
used to strengthen and/or provide support to an otherwise weak subgrade.
Foundation stone is placed, and the subgrade improved before bedding stone is
placed.
E. Rock Excavation: Removal and satisfactory disposal of all unsuitable materials,
which, in the opinion of OWASA’s Engineer, cannot be excavated except by drilling,
blasting, wedging, jack hammering or hoe ramming.
It shall consist of
undecomposed stone, hard enough to ring under hammer. All boulders containing a
volume of more than ½ cubic yard and/or solid ledges, bedded deposits, unstratified
masses and conglomerations of material so firmly cemented as to possess the
characteristics of solid rock which cannot be removed without systematic drilling and
blasting, will be classified as rock.
F. Structures: Buildings, footings, foundations, retaining walls, slabs, tanks, curbs,
mechanical and electrical appurtenances, or other man-made stationary features
constructed above or below the ground surface.
G. Subgrade: Surface or elevation remaining after completing the trench excavation or,
the top surface of a backfill (stone or soil) immediately below the pipe conduit or pipe
bedding, as applicable.
H. Trench Borrow: Trench borrow shall consist of approved material imported from offsite for use as fill or backfill required to be placed in trenches either as initial carefully
controlled select earth backfill or final common trench backfill. Trench borrow shall
trench, unless authorized by OWASA’s Engineer. Unless otherwise designated on
the plans and in the contract documents, the Contractor shall make his own
arrangements for obtaining borrow and pay all costs involved.
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April 2015
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
I.
Unclassified Excavation: Removal and disposal of any and all material above
subgrade elevation, except solid rock and undercut excavation, located within the
limits of construction.
J. Undercut Excavation: Undercut excavation shall consist of the removal and
satisfactory disposal of all unsuitable material located below subgrade elevation.
Where excavation to the finished grade section results in a subgrade or slopes of
muck, peat, matted roots, etc., the Contractor shall remove such material below the
grade shown on the plans or as directed; and areas so excavated shall be backfilled
with approved select earth trench borrow or stone as ordered by OWASA’s
Engineer.
K. The following are industry abbreviation for various pipe materials:
1)
2)
3)
4)
5)
1.5
AC:
Asbestos Cement Pipe
DIP: Ductile Iron Pipe
HDPE: High Density Polyethylene Pipe
PVC: Polyvinyl Chloride Plastic Pipe
RCP: Reinforced Concrete Pipe.
SUBMITTALS
A. Submit product data and a sample of drainage fabric or separation fabric and fully
document each with specific location or stationing information, date, and other
pertinent information.
B. Material Test Reports: Provided from a qualified testing agency which either
indicate or interpret test results for compliance of the following requirements
indicated:
1) Classification according ASTM D2487 of each on-site or borrow soil proposed for
backfill, unless otherwise directed by OWASA’s Engineer.
2) Laboratory compaction curve according to ASTM D698 for each on-site or
borrow soil material proposed for backfill.
C. Blasting:
1) Insurance Certificate naming OWASA’s Engineer as “additional Insured.” See
paragraph 3.8.A – Blasting for other blasting insurance requirements.
2) Qualifications, proposed procedures, and schedule shall be submitted at least 2
weeks prior to commencing any blasting operations.
3) Permits from local Fire Department and Town officials.
4) Blasters shall, at all times, have their license and blasting permits on the job site,
and shall allow examination of same by any official that may have jurisdiction.
5) If required by OWASA’s Engineer, seismic survey agency report, for record
purposes.
D. Bury Depth Computations: Computations justifying pipe bury when bury depth
exceeds the allowable depth shown in this specification. Provide method, applicable
charts/graphs, printouts, assumptions, etc. used in justifying the adequacy of the
pipe to withstand the loads imposed by the excessive depth.
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
E. Product Data:
1) Each type of plastic warning tape
2) Stabilization/Separation fabric
3) Drainage Fabric
1.6
QUALITY ASSURANCE
A. Geotechnical Testing Agency Qualifications: An independent testing agency
qualified according to ASTM E329 Standard Specification for Agencies Engaged in
Construction Inspection and/or Testing to conduct soil materials and rock-definition
testing as documented according to ASTM D3740 Standard Practice for Minimum
Requirements for Agencies Engaged in the Testing and/or Inspection of Soil and
Rock as Used in Engineering Design and Construction.
B. Comply with all codes, laws, ordinances, and regulations of governmental authorities
having jurisdiction over this part of the work.
C. The contractor shall comply with North Carolina Department of Environment and
Natural Resources, “Erosion and Sedimentation Control Handbook,” latest revision.
D. Comply with applicable requirements of NFPA 495, “Explosive Materials Code.”
E. “Gravity Sanitary Sewer Design and Construction,” ASCE Manuals and Reports on
Engineering Practice – NO. 60, WPCF Manual of Practice NO. FD-5.
F. Comply with Uni-Bell PVC Pipe Association “Handbook of PVC Pipe: Design and
Construction,” 4th Ed. Dallas: UNI, August 2001 for the installation of PVC piping.
1.7
QUALITY STANDARDS
Materials and operations shall comply with the latest revision of the Codes and
Standards listed below:
American Society for Testing and Materials
ASTM C33
Standard Specification for Concrete Aggregates
ASTM D698
Test Method for Laboratory Compaction Characteristics of
Soil Using Standard Effort (12,400 ft-lbf/ft3) (Standard
Proctor).
ASTM D1556
Standard Method of Test for Density of Soil in Place by the
Sand-Cone Method
ASTM D1557
Test Method for Laboratory Compaction Characteristics of
Soil Using Modified Effort (56,000 ft-lbf/ft3) (Modified
Proctor).
ASTM D2167
Standard Method of Test for Density of Soil in Place by the
Rubber-Balloon Method
ASTM D2487
Standard Classification of Soils for Engineering Purposes
(Unified Soil Classification System).
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
ASTM D2922
Test Methods for Density of Soil and Soil-Aggregate in
Place by Nuclear Methods (Shallow Depth).
ASTM D2937
Standard Test Method for Density of Soil in Place by the
Drive-Cylinder Method
ASTM D4253
Standard Test Methods for Maximum Index Density and
Unit Weight of Soils Using a Vibratory Table.
ASTM D4254
Test Method for Minimum Index Density and Unit Weight of
Soils and Calculation of Relative Density.
ASTM D4318
Test Method for Liquid Limit, Plastic Limit, and Plasticity
Index of Soils.
American Association of State Highway & Transportation Officials
AASHTO T99
The Moisture-Density Relations of Soils using a
5.5-pound Rammer and a 12-inch drop.
AASHTO M 145
The Classification of Soils and Soil-Aggregate Mixtures
for Highway Construction Purposes.
AASHTO T180
The Moisture Density Relations of Soils using a
10-pound Rammer and an 18-inch drop.
AASHTO T191
Density of Soil In-Place by the Sand-Cone Method
AASHTO T204
Density of Soil In-Place by the Drive Cylinder Method
AASHTO T205
Density of Soil in Place by the Rubber-Ballon Mehtod
American Water Works Association
AWWA C600
Installation of Ductile Iron Water Mains and Their
Appurtenances.
Other
ANSI
American National Standards Institute
AREA
American Railway Engineers Association
DWQ
Division of Water Quality
MSDS
Material Safety Data Sheets
NCDENR
NC Department of Environment and Natural Resources
NCDOT
North Carolina Department of Transportation
NPDES
National Pollutant Discharge Elimination System
OSHA
Occupational Safety and Health Administration
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
NCDOT
1.8
North Carolina Department of Transportation
TESTING SERVICES
A. The Testing Laboratory shall be (selected by the Contractor) approved by OWASA’s
Engineer and will be responsible for conducting and interpreting tests. The Testing
Laboratory shall state in each report whether or not the test specimens conform to all
requirement of the Contract Documents and specifically note any deviation there
from.
B. Specific test and inspection requirements shall be as specified herein.
1.9
PROJECT CONDITIONS
A. Demolition: Demolish and completely remove from the site existing underground
utilities indicated on the plans to be removed.
B. Environmental - Wetlands: Before crossing or entering into any jurisdictional
wetlands, contractor shall verify whether or not a wetlands permit has been obtained
for the encroachment and whether special restrictions have been imposed. Care
shall be taken to prevent draining or otherwise destroying non-permitted wetlands.
Restore as stated on either the project drawings, the contract documents, and/or as
noted in the permit.
C. Environmental - Buffer Crossing Requirements:
Before crossing streams or
ditches or working within 50 feet of ponds, lakes, or rivers, the Contractor shall verify
whether either the line is exempt or a permit has been obtained to encroach into a
nutrient sensitive river basin buffer and if so, to what extent work is permitted to
occur. Unless otherwise permitted, shown on the contract drawings, or exempted, water
and sewer crossing stream, river, pond, or lake buffers are to be as near perpendicular as
possible (the crossing is considered to be perpendicular if it intersects the stream or surface
water between an angle of 75 and 105 degrees). Do not disturb more than 40 linear feet
(longitudinal) of riparian buffer. When permitted to encroach into zone 1 (the lower 30 feet
beside the stream or water), adhere to all of the following Best Management Practices in
during construction.
1) Woody vegetation is cleared by hand. No grading allowed.
2) Stumps to remain except in trench where trees are cut. Minimize disturbance to roots in
buffer zone.
3) Backfill trench with the excavated soil immediately following installation.
4) Do not use fertilizer except for the one-time application to reestablish vegetation.
5) Minimize removal of woody vegetation, the amount of disturbed area, and the time the
disturbed area remains disturbed.
6) Take measures to ensure diffuse flow of water through the buffer after construction.
7) In wetland areas, use mats to minimize soil disturbance.
D. Safety: The Contractor shall keep the surface over and along the trenches and other
excavation in a safe a satisfactory condition during the progress of the work.
1.10
LOCATING SERVICES
Contact OWASA Distribution and Collections Division to coordinate interruption of
service, operation of valves, line cut-ins, or placement of a tapping sleeve and valve. If
interruption is necessary, the interruption shall be arranged to occur at such a time to
cause the least disruption and minimize loss of service. At the direction of OWASA’s
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
Engineer, temporary service may be required to be provided. Provide a minimum of 10
working days notice of the proposed utility interruption or necessary operation of valves.
1.11
COORDINATION
A. Coordinate tie-in to municipal water mains with OWASA’s Engineer. OWASA will be
the sole operator of all valves and hydrants on the OWASA water distribution
system. Do not interrupt existing utilities or shut off valves of active lines unless
approved by OWASA’s Engineer. If interruption is necessary, the interruption shall
be arranged to occur at such a time to cause the least disruption and minimize loss
of service.
B. Coordinate tie-in to municipal sewer mains and manholes with OWASA’s Engineer.
C. At the direction of OWASA’s Engineer, temporary pumping/bypass of sewerage flow
may be required to be provided. See Section 02530 - Sanitary Sewer, Bypass
Pumping for by pass pumping requirements and procedure.
D. When traffic signals, loops, or their appurtenances are likely to be damaged or
interfere as a result of the construction, coordinate temporary operation with the
applicable agency having jurisdiction of the signals. Provide a minimum of 48 hours
notice prior to anticipated disturbance or interruption.
E. Contact “NC One Call” 1-800-632.4949 or The National “Call Before You Dig” 811
before digging. .
1.12
PUBLIC CONVENIENCE
The contractor shall at all times so conduct his work as to insure the least possible
inconvenience to the general public and the residents in the vicinity of the work. Fire
hydrants on or adjacent to the work shall be kept accessible to firefighting equipment at
all times. Temporary provisions shall be made by the Contractor to insure the proper
functioning of all gutters, sewer inlets, drainage ditches, and irrigation ditches, which
shall not be obstructed except as approved by OWASA’s Engineer.
1.13
EROSION AND SEDIMENTATION CONTROL AND NPDES
CONTROLS, AND LIMITATIONS FOR PERMITTED DISCHARGES
MONITORING,
The Project Engineer shall submit a sedimentation and erosion control plan to the
appropriate authority and obtain all necessary construction permits. The Contractor
shall follow all local and state requirements regarding sedimentation and erosion control.
Construction methods shall minimize sedimentation and erosion.
It is the Contractor’s responsibility to periodically monitor the Stormwater Discharge
Outfall points at the specified frequency and maintain reports as outlined in these
specifications.
A. Final Limitations and Controls for Stormwater Discharges
During the period beginning on the effective date of the permit and lasting until
expiration, the Owner (Permittee) is allowed and authorized to discharge stormwater
associated with construction activity. Such discharges shall be controlled, limited,
and monitored as specified below.
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1) The Contractor shall implement the Erosion & Sedimentation Control plan, which
has been approved by the approval authority. The approved plan is considered a
requirement or condition of the general NPDES permit. Deviation from the
approved plan, or approved amendment to the plan, shall constitute a violation of
the terms and conditions of this general permit except that deviation from the
approved plan will be allowed:
a. To correct an emergency situation where sediments are being discharged off
the site, or
b. When minor modifications have been made for the purpose of improving the
performance of the erosion and sedimentation control measures and
notification of the minor modification has been made to the Division of Land
Resources (or approved local program).
Such a deviation from the approved plan shall be noted on the approved plan
maintained at the job site. During active construction, a copy of the approved
plan shall be maintained on the site.
2) Equipment utilized during the construction activity on a site must be operated and
maintained in such a manner as to prevent the potential or actual pollution of the
surface or ground waters of the state. Fuels, lubricants, coolants, and hydraulic
fluids, or any other petroleum products, shall not be discharged onto the ground
or into surface waters. Spent fluids shall be disposed of in a manner so as not to
enter the waters, surface, or ground, of the state and in accordance with
applicable state and federal disposal regulations. Any spilled fluids shall be
cleaned up to the extent practicable and disposed of in a manner so as not to
allow their entry into the waters, surface or ground, of the state.
3) Herbicide, pesticide, and fertilizer usage during the construction activity shall be
consistent with the Federal Insecticide, Fungicide, and Rodenticide Act and shall
be in accordance with label restrictions.
4) All wastes composed of building materials shall be disposed of in accordance
with North Carolina General Statutes, Chapter 130A, Article 9 – Solid Waste
Management, and rules governing the disposal of solid waste (North Carolina
Administrative Code Section 15A NCAC 13B).
5) The Contractor, for the Permittee, shall control the management and disposal of
litter and sanitary waste from the site such that no adverse impacts to water
quality occur.
B. Minimum Monitoring and Reporting Requirements
Minimum monitoring and reporting requirements are as follows unless otherwise
approved in writing by the Director of the Division of Water Quality.
1) All erosion and sedimentation control facilities shall be inspected by or under the
direction of the permittee (the Owner). However, the responsibility for inspection
is herein delegated by the Owner to the Contractor as part of this project.
Inspections shall be made:
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a. At least once every seven calendar days (at least twice every seven days for
those facilities discharging to waters of the State listed on the latest EPA
approved 303(d) list1 for construction related indicators of impairment such as
turbidity or sedimentation),
b. And within 24 hours after any storm event of greater than 0.5 inches of rain
per 24-hour period.
A rain gauge shall be maintained on the site by the contractor and a record of
the rainfall amounts and dates shall be kept by the contractor.
2) Once land disturbance has begun on the site, stormwater runoff discharges shall
be inspected by observation for stormwater discharge characteristics as defined
below at the frequency in stated above to evaluate the effectiveness of the
pollution control facilities or practices. If any visible sedimentation is leaving the
disturbed limits of the site, corrective action shall be taken immediately to control
the discharge of sediments outside the disturbed limits.
Stormwater Discharge
Characteristics
Clarity
Floating Solids
Suspended Solids
Oil Sheen
Other obvious indicators
of stormwater pollution
Monitoring
Type1
By observation
By observation
By observation
By observation
By observation
Monitoring Location2
SDO
SDO
SDO
SDO
SDO
Footnotes:
1
Monitoring Type: The monitoring requires a qualitative observation of
each stormwater outfall. No analytical testing or sampling is required.
2
Sample (observation) location: SDO= Stormwater Discharge Outfall
3) The operator (Contractor) shall keep a record of inspections and forward copies
of these reports to OWASA’s Engineer. Visible sedimentation found outside of
the disturbed limits shall be recorded and a brief explanation kept with the
records as to the measures taken to control future releases. Any measures
taken to clean up the sediment that has left the disturbed limits shall also be
recorded. These records shall also be made available to DWQ or an authorized
agent upon request. If OWASA’s Engineer discovers sedimentation outside the
limits of disturbance, the Contractor will be notified in writing and requested to
remediate the situation.
4) All records of monitoring shall be turned over to OWASA along with the “red
lined” record water and/or sewer drawings.
1
The latest approved list may be obtained from the Division of Water Quality, or from the
following website location: http://h2o.enr.state.nc.us/su/construction303d.
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C. Schedule of Compliance
1) The Contractor shall comply with Final Limitations and Controls specified for
stormwater discharges once disturbance has begun on the site and until
completion of construction or development and the establishment of a permanent
ground cover.
2) During construction and until the completion of a construction or development
and the establishment of a permanent ground cover, the Contractor shall provide
the operation and maintenance necessary to operate the stormwater controls at
optimum efficiency.
PART 2 – PRODUCTS
2.1
SOIL, BEDDING AND BACKFILL
A. MATERIAL CLASSIFICATION
1) Bedding Material: #57 or #67 stone.
2) Excavation: All excavation material shall be classified as either Rock or
Unclassified Earth Excavation. Prices bid for the various sizes of pipe shall
include excavation and backfilling.
3) Flowable Fill Concrete Backfill
a. Non-excavatable flowable fill concrete shall have a minimum 28 day
compressive strength of 125 psi but no more than 200 psi (to be
excavatable by machine equipment). Materials shall comply with the
recommendations within chapter 3 of ACI 229, latest revision, which
include cement, aggregates, fly ash, water, admixtures, slag and other
non standard materials).
Excavatable is an application where it may be necessary to remove the
flowable fill at a later date. Non-excavatable is an application where it
is not necessary to remove or otherwise excavate the flowable fill at a
later date.
b. Flowable Fill Concrete for Pipe Abandonment Controlled Low Strength
Material. Concrete strength shall be liquid enough to flow, be selfleveling, excavatable, and have a minimum 56 day compressive
strength of 50 psi but not more than 150 psi.
4) Foundation Stone: Foundation/Trench Stabilization Material: #5, #357 or
#57 stone.
5) Select Earth Backfill: Select earth backfill shall be free of debris, roots,
frozen materials, organic matter, rock, or gravel larger than 1 inch in any
dimension, or other harmful matter and shall generally meet NCDOT
Standard Specifications for Roads and Structures, Section 1016 – Select
Material for properties and gradation.
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6) Common Trench Backfill:
a. Satisfactory Soils: ASTM D2487 soil classification group (Unified
Classification System) GW, GP, GM, SW, SW, SM, SC, ML, and CL or
a combination of these group symbols; free of rock or gravel larger than
3 inches in any dimension, debris, waste frozen materials, vegetation,
and other deleterious matter.
b. Unsatisfactory soils: ASTM D2487 soil classification group CH, MH,
OH, OL and PT; soils which contain rock or gravel larger than 3 inches
in any dimension, debris, waste frozen materials, vegetation, and other
deleterious matter. Unsatisfactory soils also include satisfactory soils
not maintained within 2-percent of optimum moisture content at time of
compaction, unless otherwise approved by either OWASA’s Engineer
or a Geotechnical Engineer.
7) Structures, Backfill around: Backfill shall be approved by OWASA’s
Engineer and shall be free from large or frozen lumps, wood, or rocks more
than 3 inches in their greatest dimension or other extraneous material.
Porous backfill shall be either #67, #57, or #357 clean stone.
8) Topsoil: Topsoil shall consist of friable clay loam, free from roots, stones,
and other undesirable material and shall be capable of supporting a good
growth of grass. Topsoil shall be free of material greater than 1-inch in any
dimension.
B. PIPE BEDDING DEFINITIONS
1) Pipe Bedding Definitions
a. Class D Bedding is that condition existing when the ditch is
excavated slightly above grade by excavation equipment and cut to
finish grade by hand. Bell holes are dug, to prevent point loading the
pipe bells, so that pipe bears uniformly upon the trench bottom.
Existing soil should be shovel sliced or otherwise compacted under
the hunching of the sewer pipe to provide some uniform support. Soil
is tamped to 90% of the maximum Standard Proctor dry density
around the pipe to a point one foot above the pipe. The remainder of
the soil to the ground surface is to be compacted to the density
specified in Table 02275.3. In poor soils, granular bedding material is
generally a more practical, cost effective installation. The bedding
factor for class D bedding is 1.1.
b. Class C Bedding is that condition where the sewer pipe is bedded in
compacted granular material. The granular bedding has a minimum
thickness of one-eighth the outside sewer pipe diameter, but not less
than 4 inches or more than 6 inches, and shall extend up the sides of
the sewer pipe one-sixth of the pipe outside diameter. The remainder
of the sidefills, to a minimum depth of 6 inches over the top of the
pipe, consists of lightly compacted backfill. The remainder of the soil
to ground surface is to be compacted to the density specified in Table
02275.3. The bedding factor for class C bedding is 1.5.
c. Class B Bedding is that condition where the sewer pipe is bedded in
carefully compacted granular material. The granular bedding has a
minimum thickness of one-eighth the outside sewer pipe diameter, but
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
not less than 4 inches or more than 6 inches, between the barrel and
the trench bottom, and covering the full width of the trench.
The haunch area of the sewer pipe must be fully supported; therefore,
the granular material should be shovel sliced or otherwise compacted
under the pipe haunch to the springline of the pipe. Both granular
haunching (to the springline) and initial backfill to a minimum depth of
12 inches over the top of the sewer pipe should be placed and
compacted. The initial backfill material, to a depth of 12 inches over
the top of the pipe, should be compacted to no less than 90% of the
maximum Standard Proctor dry density. The remainder of the soil to
the ground surface is to be compacted to the density specified in
Table 02275.3. The bedding factor for class B bedding is 1.9.
d. Class B-1 Bedding (PVC pipe applications) is the same as Class B
Bedding except that granular backfill is placed to the top of the pipe
rather than to the springline of the pipe. The remainder of the soil to
the ground surface is to be compacted to the density specified in
Table 02275.3.
e. Class A Bedding is that condition when the sewer pipe is bedded in
a cast-in-place cradle of either plain or reinforced concrete having a
thickness equal to one-fourth the inside pipe diameter, with a
minimum of 4 inches and a maximum of 15 inches under the pipe
barrel and extending up the sides for a height equal to one-fourth the
outside pipe diameter. The cradle width shall have a width at least
equal to the outside diameter of the sewer pipe barrel plus 8 inches.
The bedding factor for class A bedding is 2.2.
The haunching and initial backfill material above the concrete cradle
should be crushed stone or a well graded granular material and
carefully compacted to 12 inches above the crown of the sewer pipe.
The remainder of the soil to the ground surface is to be compacted to
the density specified in Table 02275.3.
2.2
MISCELLANEOUS
A. GEOTEXTILE FABRIC
Geotextile fabric shall be protected from mud, dirt, dust, sunlight, and debris
during transport and storage. Material shall be inert to commonly encountered
chemicals; resistant to mildew, rot, insects, and rodents; and biologically and
thermally stable. Geotextile fabric for subsurface installation shall not be
exposed to direct sunlight for more than 24 hours before or during installation.
Nonwoven geotextile, specifically manufactured as a drainage fabric; made from
polyolefins, polyesters, or polyamides; and with the following minimum properties
determined according to ASTM D4759 Standard Practice for Determining the
Specification Conformance of Geosynthetics and referenced test methods:
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1) Drainage Fabric:
Physical Property
Apparent opening size
Test Method
ASTM D4751
Permittivity
Tensile strength @ 20%
(max) elongation
ASTM D 4491
VT<52
Requirements
Equal to or greater
than No. 30 sieve
Minimum 0.51 sec.
Minimum 25 in-lbs/lin
2) Geotextile for use with Rip-Rap:
Physical Property
Apparent opening size
Test Method
ASTM D4751
Puncture Strength
Tensile strength @ 20%
(max) elongation
ASTM D751
VT<52
Requirements
Equal to or greater
than No. 50 sieve
Minimum 80 lb.
Minimum 30 in-lbs/lin
Seams shall be equal in strength to the basic material.
Additional fabric material or noncorrosive steel wire may be incorporated into
fabric to increase overall strength.
3) Separation Fabric:
Physical Property
Apparent opening size
Test Method
ASTM D4751
Puncture Strength
Grab Tensile strength
Water Flow Rate
ASTM D 4833
ASTM D 4632
ASTM D 4491
Requirements
Equal to or greater
than No. 30 sieve
90 lbf
Minimum 200 lbf
4 gpm per sq. ft.
4) Stabilization Fabric:
Provide fabric meeting Geotechnical Engineers recommendations for the
application intended.
B. DETECTABLE WARNING TAPE
Metallic Underground Warning Tape: Metallic detectable underground warning
tape shall consist of a solid aluminum foil core, 35 gauge minimum, encased on
each side with plastic (minimum overall thickness 5 mils) and be 3 inches wide
with black lettering imprinted on a color coded background that conforms to
APWA uniform color code specification with black ink letters. Minimum tensile
strength shall be 22 lbs/inch. Soil tolerance range to be pH 2.5 to pH 11.0. On
one side of the tape, the text shall include the wording “WATER LINE BELOW”,
“SEWER LINE BELOW” or “CAUTION - RECLAIMED WATER – DO NOT
DRINK” repeated along the length of the tape. Underground warning tape for
water or sewer mains shall be placed 18 to 24 inches below the finished grade
directly above the line. See section 02520 for Reclaimed warning tape
requirements. Standard color code for tape:
Blue:
Green:
Water Systems
Sewer Systems
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
Purple:
Reclaimed Water System
C. DEFORMED REINFORCING STEEL
Reinforcing Steel bars shall meet ASTM A615, grade 60, latest revision.
D. WELDED WIRE FABRIC
Welded wire fabric shall meet ASTM A185, latest revision.
PART 3 – EXECUTION
3.1
PREPARATION
A.
GENERAL REQUIREMENTS APPLYING TO ALL AREAS
1) Contractor shall plan construction to minimize disturbance to properties
adjacent to the water or sewer lines.
2) OWASA’s Engineer reserves the right to limit the width of land to be
disturbed and to designate on the drawings or in the field certain areas or
items within this width to be protected from damage.
3) Access and/or Haul Roads: Any grading or excavation required for
equipment travel during the course of construction as well as erosion control,
access or haul road removal, restoration, seeding and ground cover shall be
provided by the contractor.
4) The contractor shall be responsible for damage to areas or items designated
by OWASA’s Engineer to be protected. Repairs to, replacement of, or
reparations for areas or items damaged shall be made to the satisfaction of
OWASA’s Engineer before acceptance of the completed project.
5) The contractor shall protect all buildings or structures located along the utility
line. Hand trenching, shoring, or other methods may be required.
6) Any fences disturbed by the Contractor shall be repaired with new materials
to a condition equal to or better than their original condition or to the
satisfaction of OWASA’s Engineer.
7) Contractor shall limit width of disturbed area through garden areas to a width
absolutely necessary for construction of utility line.
8) Contractor shall obtain written permission from property owners for use of
any access other than ones located within public rights-of-way or easements.
Written permission shall contain conditions for use and restoration
agreements between property owner and contractor.
9) All areas disturbed shall be restored to a condition equal to or better than
their original condition and shall be graded to drain.
10) The contractor shall replace or repair all damaged or destroyed hedgerows
and property corners using the services of a licensed Professional Surveyor.
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B.
CONSTRUCTION LIMITS
1) Contractor shall not disturb any areas outside the limits contained in this
section without express written permission from OWASA’s Engineer.
2) Except as indicated on the plans, no “clear cutting” of timber shall be
permitted within the construction limits. Contractor shall make select cutting
of trees, taking smallest trees first, that are mandatory for the construction of
the utility line. The decision of OWASA’s Engineer shall be final on the
determination of which trees are to be cut.
3) The widths measured from the centerline of the water or sewer lines shall be
as shown on the contract drawings. The Contractor shall protect all areas
outside these construction limits unless written variations are granted by
OWASA’s Engineer.
4) Specific requirements applying to developed subdivision/lots
a. All trees located beyond 15 feet of the centerline of water or sewer line
shall be protected by the contractor. OWASA’s Engineer reserves the
right to designate other trees located closer to the centerline for
protection where possible.
b. All shrubs, hedges, or other ornamental plantings located along the line
shall be protected or removed and replanted by the contractor.
c. The contractor shall protect septic systems or springs located beyond 15
feet from the centerline of the line.
d. Contractor shall grub only brush, roots, and stumps of removed trees.
Damage to lawns shall be kept to an absolute minimum necessary for
construction.
e. Excavated or blasted rock shall be removed from the site unless
otherwise ordered by OWASA’s Engineer.
f.
Restoration and fine grading shall follow within 15 calendar days from the
time an area is disturbed or within 1000 feet from the immediate work
site, whichever occurs first. Seeding shall follow as ordered by OWASA’s
Engineer.
5) Specific requirements applying to undeveloped areas
a. In wooded areas, the clearing shall be 15 feet on each side of pipe,
unless indicated differently on the OWASA approved construction
drawings, in which case, the work shall be confined to the limits defined
on the plans. All permanent easements shall be fully cleared. All trees
12 inches in diameter or larger located beyond 15 feet of the centerline of
the water or sewer line shall be protected unless contractor obtains
written authorization from OWASA’s Engineer to remove them.
OWASA’s Engineer reserves the right to designate select trees located
closer to the centerline for protection where possible.
b. In areas where livestock is kept, the contractor shall notify property owner
prior to commencing work and keep owner advised of progress of work.
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Fences shall be kept secure at all times and livestock protected from
open ditches, machinery, blasting, and other hazards.
c. Restoration, fine grading, and permanent seeding shall follow within 15
working days or 30 calendar days, whichever is shorter, from the time an
area is disturbed or within 1000 feet from the immediate work site,
whichever occurs first. See paragraph 3.15 – Seeding and Groundcover.
C.
CLEARING AND GRUBBING
1) Description: This work shall consist of clearing, grubbing, removing, and
disposing of all vegetation and debris within the limits of construction, as
designated on the plans or as required by OWASA’s Engineer. The work
shall also include the preservation from injury or defacement of all vegetation
or objects designated to remain. Clearing shall consist of cutting, removal,
and satisfactory disposal of all trees, down timber, brush, rocks, projected
roots, stumps, rubbish, laps, and other material within easement.
2) A preconstruction meeting shall be held with appropriate urban forestry
personnel from the Town of Chapel Hill or Town of Carrboro prior to any
clearing. Tree protection fencing shall be installed and all tree ordinances
shall be followed.
3) The Contractor shall provide barricades, fences, coverings, or other types of
protection necessary to prevent damage to existing improvements, not
indicated to be removed, and improvements on adjoining property. All
improvements damaged by this work shall be restored to their original
condition to a condition acceptable to the owner or other parties or authorities
having jurisdiction. Trees and shrubs that are to remain within the
construction limits will be indicated on the drawings or conspicuously marked
on site. Unless otherwise noted, trees within the construction limits shall
become the property of the Contractor and shall be removed from the site.
4) Contractor shall protect existing tress and other vegetation indicated by
OWASA’s Engineer to remain in place against limb, bark or root damage
such as cutting, breaking, or skinning of roots, skinning and bruising of bark,
smothering of trees by stockpiling construction materials or excavated
materials within drip line, excess foot or vehicular traffic, or parking of
vehicles within drip line. When such damage does occur, all rough edges of
scarred areas shall be removed in accordance with accepted horticultural
practices.
5) Carefully and cleanly cut roots and branches of trees indicated to remain
where the roots and branches obstruct construction of the utility line. If
directed by OWASA’s Engineer, the Contractor shall provide protection for
roots and branches over 1 ½ inches diameter that are cut during construction
operations. Coat the cut faces with emulsified asphalt, or other coating
especially formulated for horticultural use on cut or damaged plant tissues.
Temporarily cover all exposed roots with wet burlap to prevent roots from
drying out. Provide earth cover as soon as possible.
6) Trees and vegetation designated to remain shall be repaired or replaced at
contractor’s expense in a manner acceptable to OWASA’s Engineer if they
are damaged by construction operations. Repair tree damage as directed by
a qualified tree surgeon.
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7) Debris from the site shall be removed in such a manner as to prevent
spillage. Keep pavement and area adjacent to site clean and free from mud,
dirt, dust, and debris at all times.
8) The method of stripping, clearing, and grubbing the site shall be at the
discretion of the Contractor. However, all stumps, roots and other debris
protruding through the ground surface or in excavated areas shall be
completely removed and disposed of off the site by the Contractor.
9) Stripping of Topsoil: Remove the existing topsoil to a depth of 6 inches or
to the depth encountered from all areas in which excavation will occur. The
topsoil shall either be stored in stockpiles separate from the excavated trench
material if the topsoil is to be re-spread or otherwise disposed of off-site.
Topsoil stockpiles shall be graded to freely drain surface water, and shall
have a silt fence placed around the base of the stockpile.
10) Disposal: All brush, tree tops, stumps, and debris shall be hauled away from
site or otherwise disposed of in a manner acceptable to OWASA’s Engineer.
The Contactor shall clean up debris resulting from clearing operations
continuously with the progress of the work and remove promptly all
salvageable material that becomes his property and is not to be reused in
construction. Sale of material on the site is prohibited.
Disposal of cleared material shall be in accordance with all local and state
laws. Trees cut down on the construction site will be hauled away from the
site for proper disposal unless instructed otherwise by OWASA. Stumps of
trees cut down outside of the excavation area will be removed. Perishable
material shall not be disposed of at the construction site. Brush, laps, roots,
and stumps from trees shall be disposed of in a NCDENR approved and
permitted land clearing and inert debris type landfill. The Contractor will be
responsible for obtaining all applicable permits and paying all fees for the
disposal of excess material.
D.
PROTECTION OF EXISTING UTILITIES AND STRUCTURES
1) Subsurface obstructions
a. Subsurface obstructions: Take necessary precautions to protect
existing utilities from damage due to any construction activity. The
contractor shall locate existing utilities, culverts, and structures (above or
below ground), before any excavation starts and coordinate work with
utility companies. The Contractor shall be responsible for notifying utility
companies when working within the vicinity of the existing utilities.
Omission from or inclusion of located utility items on plans do not
constitute non-existent or definite location. Even though for convenience,
the utility may be shown on the plans, the Contractor is responsible for
and shall call for utility location a minimum of 48 hours prior to
excavations. Contact underground damage protection services NC One
Call at 1.800.632.4949. Secure and examine local utility surveyor records
for available location data including building service lines.
b. Unless shown to be removed, protect active utility lines shown on the
drawings or otherwise made known to the Contractor prior to trenching.
In excavating, care must be taken not to remove or injure any subsurface
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
structure. All existing gas pipes, water pipes, steam pipes, telephone
lines, cable TV lines, electrical conduits, sewers, drains, fire hydrants, and
other structures which, in the opinion of the utility company, do not require
relocation shall be carefully supported, shored up, the flow maintained, if
applicable, and the line/main protected from damage by the Contractor. If
damaged, the contractor shall give immediate notice to the proper
authorities. The utility shall be restored, at the Contractor’s expense, by
the appropriate utility to original or better condition. Where pipes,
conduits, or sewers are removed from the trench leaving dead ends in the
ground, such ends shall be carefully plugged or bulkheaded by the
Contractor at the Contractor’s expense.
The Contractor shall be
responsible for any damage to persons or property caused by such
breaks.
c. The Contractor shall be responsible for anticipating and locating
underground utilities and obstructions. When construction appears to be
in close proximity to existing utilities, the trench(es) shall be opened a
sufficient distance ahead of the work or test pits made to verify the exact
locations and inverts of the utility to allow for changes in line and grade.
d. If active utility lines are encountered, and are not shown on the Drawings
or otherwise made known to the Contractor, promptly take necessary
steps to assure that service is not interrupted.
e. Should it become necessary to move the position of any underground
structure, the contractor may be required to do such work and shall be
paid on a force account basis or on an extra work basis.
f.
If existing utilities are found to interfere with the permanent facilities being
constructed under this Section, immediately notify OWASA’s Engineer
and secure his instructions.
g. Do not proceed with permanent relocation of utilities until written
instructions are received from OWASA’s Engineer.
2) Protection of Surface Features
a. Whenever the utility line is to be placed in or near a paved street, the
Contractor shall provide pads or take necessary precautions to protect
the pavement from damage by the construction equipment. Pavement
damaged by cleated or tracked equipment, or by any other means, shall
be repaired by the Contractor at his expense.
b. Where a utility line is in an existing paved area, the Contractor shall use
care to cut in sharp, neat lines ahead of the excavating/ditching
equipment and parallel to the pipe on each side as may be applicable. If
the existing road to be cut is located within either the Town of Carrboro or
Town of Chapel Hill’s corporate limits, the Contractor is responsible for
contacting the Town Engineer or representative about pavement
repair/replacement.
c. Avoid overloading or surcharge a sufficient distance back from edge of
excavation to prevent slides or caving. Maintain and trim excavated
materials in such manner to be as little inconvenience as possible to
public and adjoining property.
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
d. Provide full access to public and private premises, to fire hydrants, at
street crossings, sidewalks and other points as designated by OWASA’s
Engineer to prevent serious interruption of travel.
e. Protect and maintain benchmarks, monuments, or other established
points and reference points and if disturbed or destroyed, replace items to
full satisfaction of OWASA’s Engineer and the jurisdictional agency.
3) Procedures for repairing damaged utility services
a. If a located service is interrupted as a result of work under this Section,
immediately restore service by repairing the damaged utility at no
additional cost to OWASA.
b. House services: If a service pipe supplying water or gas to an adjoining
house is broken, the Contractor shall repair same at once and at his
expense. OWASA may, at the Contractor’s expense, repair any such
service without prior notice to the Contractor.
E.
PROTECTION OF PERSONS AND PROPERTY
1) Barricade open holes and depressions occurring as part of the work, and post
warning lights on property adjacent to or part of public access.
2) Protect structures, utilities, sidewalks, pavements, and other facilities from
damage caused by settlement, lateral movement, washout, and other
hazards created by operations under this or other related sections.
F.
TRAFFIC CONTROL
1) When working within the OWASA service area, conform to the Manual on
Uniform Traffic Control Devices, latest revision (MUTCD) as well as the
NCDOT Standard Specifications for Roads and Structures, latest revision.
2) Traffic Maintenance shall comply with the latest revision of the NCDOT
Standard Specifications for Roads and Structures, Division 9 – Signing and
Division 11 – Work Zone Traffic Control, as well as other applicable sections.
3) When traffic signals or their appurtenances are likely to be damaged or
interfere as a result of the construction, coordinate temporary operation with
the NCDOT or the applicable Town’s Traffic or Town Engineer. Provide 48
hours notice prior to anticipated disturbance or interruption.
4) Whenever it becomes necessary to leave a section of trench open after
completion of the day’s work, the Contractor shall provide barricades and
lights to protect the public. Operate warning lights during hours from dusk to
dawn each day and as otherwise required for inclement weather and visibility.
G.
DEWATERING
1) Water in trenches: When ground water in encountered, the contractor shall
remove the water that accumulates in the trenches or pits, which would affect
the construction of the lines or their appurtenances, by pumping, bailing, well-
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
pointing, or other approved dewatering method and shall perform all work
necessary to keep the trenches or pits entirely clear from water while bedding
is being placed, the pipe is being laid, masonry units are being placed, and
structures are either being set or constructed. All water removed from the
trench shall be conveyed in a proper manner to a suitable point of discharge
and shall comply with applicable erosion and sediment control laws.
2) No pipe shall be constructed in water and water shall not be allowed to drain
through the pipe. The open end of the pipe shall be kept closed with a tight
fitting plug to prevent washing of any foreign matter into the line.
3) No structure shall be constructed in water and water shall not be allowed to
flow over or rise upon any concrete masonry structure until the work has
been accepted.
4) The Contractor shall dispose of water from the trenches in such a manner to
cause no injury to public health, public or private property, work completed or
in progress, street surfaces, or which may cause any interference with the
use of the streets. Water, if odorless and stable, may be discharged into an
existing storm drain, channel, or street gutter in a manner approved by
OWASA’s Engineer. When required by OWASA’s Engineer, a means shall
be provided for desilting (filtering) the water before discharge. Under no
circumstances shall water be discharged to the sanitary sewer.
5) Prevent surface water from ponding on prepared subgrades and from
flooding project site and the surrounding area. Reroute surface water runoff
away from or around excavated areas.
6) Do not allow water to accumulate in excavations. Do not use excavated
trenches as temporary drainage ditches.
7) Install a dewatering system to keep subgrades dry and convey ground water
away from excavations. Maintain until dewatering is no longer required.
8) Protect subgrades from softening, undermining, washout, and damage by
rain or water accumulation. Include cost of de-watering in proposal for water
or sewer lines. No additional remuneration for this item is permitted.
9) Where underground streams or springs are encountered, provide temporary
drainage or bailing. Notify OWASA’s Engineer of such conditions.
3.2
TRENCH EXCAVATION
A.
GENERAL
1) Classification of Excavated Material: All excavated material shall be
classified as either earth or rock. Prices bid for the various sizes of pipe shall
include excavation and backfilling; such excavation shall be classified as
earth. Rock excavation shall be paid for as a separate item.
2) Remove all material of whatever nature, including but not limited to clay, silt,
and gravel. Material, of a compactable nature that can be re-used as trench
backfill shall be replaced and re-compacted to the requirements set forth in
these specifications.
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3) Unsuitable Material and Wasting: When directed by the Owner’s Engineer
or OWASA’s Engineer, unsuitable material in the trench shall be removed to
an appropriate depth and width. At the Contractor’s expense, dispose of all
unsuitable material, of whatever nature, to a site which legally can accept
such material as fill. Adhere to all applicable laws and ordnances regarding
permitting of waste site, erosion control, zoning, etc. as may be applicable.
4) Excavation shall be performed in accordance with OSHA Standard 29 CFR
Part 1926, OSHA Subpart P “Excavation and Trenching.”
5) Sewer Alignment and Grade: Offset stakes set at each manhole shall
indicate the line and grade of the sewer. Alignment and grade of the pipe by
the Contractor shall be established by laser beam. The Contractor shall
employ personnel experienced in the use of laser beams. The alignment and
grade of the sewer shall be constructed as indicated on the approved plans.
Prior to making changes in the field, OWASA’s Engineer shall approve any
change in grade or alignment which deviates from the approved plans.
6) Concrete collars shall be installed on lines with slopes 20% or greater. See
Standard Detail 536.01.
B.
PIPE COVER
1) General: Where lines transverse public property or are subject to other
governmental or utility company jurisdiction, provide depth, bedding, cover,
and other requirements as set forth by legally constituted authority having
jurisdiction, but in no case less than the depth shown in the Contract
Documents.
2) Minimum Cover: Unless shown otherwise on the construction documents,
provide minimum trench depth indicated below to maintain a minimum cover
over the top of the installed item. Minimum cover on pipe is measured
perpendicular from top of pipe or fittings to original ground or proposed
finished grade as applicable and shall be per Table 02275.1, below. Where
the minimum cover is not provided, either use Ductile Iron Pipe or encase the
pipe(s) in concrete as indicated. Provide concrete with a minimum 28-day
compressive strength of 3000 psi.
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Table 02275.1
Minimum Cover above top of Main Pipe Lines
Condition
Utility
Subject to
NOT subject to
With Concrete
Sanitary Sewer
Sewer Services
Water
Distribution
a
Water services
vehicular traffic
36b inches
vehicular traffic
24b inches
Encasement
As Designed
At depth shown
on plans but no
less than 36b
inches
42a inches
At depth shown
on plans but no
less than 12b
inches
42a inches
As Designed
30a inches
30a inches
(use DIP if < 36
inches of cover)
(use DIP if < 36
inches of cover)
18 inches
(encasement, if
required, shall
extend to at least
5 feet beyond
each side of a
ditch or culvert
crossing)
As Designed
Minimum/Maximum Cover for Water Pipe: OWASA’s Engineer must approve all
installations of water line with less than 30 inches of cover or greater than 72 inches
of cover.
b
Minimum/Maximum Cover for Sewer Pipe: OWASA’s Engineer must approve all
installations of sewer lines with 24 inches of cover or less or with greater than 18 feet
of cover. Ductile iron pipe is required where depth of pipe exceeds 12 feet or the line
is placed in fill.
3) Water lines which have no more than 18 inches of cover at ditch or culvert
crossings may be required by OWASA’s Engineer to be encased in concrete
for a length of at least 5 feet beyond each side of the ditch or culvert.
C.
TRENCHING
1) General: The trench for gravity pipe shall be excavated to conform to
Standard Detail 531.01, Standard Sewer Bedding Detail. Where it is
necessary to remove existing pavements, prepared road surfaces, sidewalks
and curbs, these structures/surfaces must be replaced by the Contractor.
When making a pavement cut, the Contractor shall use care to saw cut in
sharp, neat lines ahead of the excavating/ditching equipment and parallel to
the pipe on each side as may be applicable.
All trenching shall be open-cut from the surface. No tunneling or boring will
be allowed without the consent of OWASA’s Engineer. All trenches shall be
excavated to the lines and grades as shown on the plans. Where utility lines
are in an existing paved area, the edges of the pavement for the utility line
shall be cut in a straight line, parallel to the pipe.
Trenches shall be excavated in straight lines, in general, following the
contour of the ground, and shall be accurately graded in order to establish a
true elevation of the invert of the pipe. Trenches for water lines may be
curved within the limits of curvature of the pipe as allowed by AWWA C600.
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In no case shall the trench alignment exceed the allowable vertical or
horizontal pipe deflection of offset recommended by the pipe manufacturer.
a. Trench Width: The sides of trench shall be uniform and vertical. The
width of the trench at the top of the pipe shall be a width that will permit
the proper construction of joints and compaction of backfill around the
pipe and shall be equal to the largest outside diameter of the pipe plus 12
inches on each side of the pipe, measured at the top of the pipe. The
sides of the trenches shall be vertical unless otherwise approved by
OWASA’s Engineer. Vertical walls should project at least 2 feet above
the top of the pipeline laid to existing construction grade unless the
finished grade fill depth is less than 2 feet. Lowering trench wall height
may necessitate a change in either pipe or bury classification.
Notwithstanding, this section is subject to OSHA guidelines and
regulations regarding trench protection and shoring.
Every effort shall be made to maintain the width of the pipe plus 24
inches but trench width must also be wide enough to provide adequate
space for laying and connecting pipe and appurtenances. Sufficient
space shall be allowed at the joints for the free use of wrenches for
tightening of bolts.
The minimum trench width should generally be no less than 36 inches in
order to accommodate a “Rammax” tamp.
In excavating for the trench, it is essential that the trench bottom be
uniform in grade and remains static during backfilling and under all
subsequent trench conditions. To insure a uniform depth of stone, the
grade of the bottom of the trench shall be graded to within 0.04 foot (1/2inch) of the plan specified grade. The stone shall be graded to the same
tolerance.
Care shall be taken not to over excavate the trench. All trenches
excavated below grade (over excavated) shall be refilled to grade with
clean #57 stone. No extra compensation shall be allowed for this work
unless such excavations are ordered by OWASA’s Engineer.
b. Trench Depth:
i.
General: All trenches shall be excavated to accommodate the
bedding as shown in Standard Detail 531.01.
No extra
compensation will be made for stone bedding used to bring the trench
up to grade other than that required in Standard Detail 531.01.
ii. Water: Trench depth shall generally conform to that shown on the
plans and in conformity to the requirements of Table 02275.1,
Minimum Cover above top of Main Pipe Lines.
iii. Gravity sewer: Excavate to the depth and grades shown on the
plans. Trench depth shall generally conform to the requirements of
Table 02275.1, Minimum Cover above top of Main Pipe Lines.
c. Open trench exposure: Once trench is opened, proceed immediately
and with dispatch to place specified materials in trench, or to otherwise
utilize trench for intended purpose. Long stretches of open trench ahead
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
of pipe laying shall be avoided. Excavating, pipe laying, and backfilling
must move forward at approximately equal rates of progress. The
Contractor shall only open as much ditch as he can completely install
pipe, backfill, compact, and cleanup within that working day. The
Contractor shall string out the pipe that can be installed in one day, and
no more than 300 feet of trench shall be open in advance of the
completed work in any section. There shall be no trenches left open
without proper supervision during working hours or after work has been
completed for day. Any exception to this construction practice must be
approved, in writing, by OWASA’s Engineer. Schedule work and order
materials so that trenches are not left open for a longer period than is
reasonably necessary.
If the Contractor should fail to heed the
aforementioned requirement, OWASA’s Engineer may refuse payment
until these conditions are complied with.
d. Containment of Sediment (solids and mud): The Contractor shall at all
times so conduct his work to insure that all solids and mud are contained
within the trench. This containment shall be by the employment of a brick
or block weir at the junction of new construction and the existing OWASA
system in order to trap material for the Contractor’s removal and
OWASA’s inspection prior to acceptance. The installation and removal of
this dam shall be at the Contractor’s expense and shall be removed
before the line is televised.
D.
SHEETING AND BRACING, TRENCH BOXES
Trench walls may have vertical sides up to a maximum depth of 5 feet above
subgrades elevation. Above this depth the entire side must be laid back or either
shoring or a trench box, certified for the depths being used, must be used. The
contractor shall be required to furnish, put in place, and maintain such sheeting,
bracing, etc. as may be required to support the sides of the trenches. Brace and
sheet trenches must be in full compliance with OSHA requirements.
Brace trenches running near walls or columns, to prevent any settlement or other
disturbance of walls or columns.
Do not remove sheeting until backfilling has progressed to stage that no damage
to piping, utility service, or conduit will result due to removal. All shoring and
form material shall be removed before backfilling. When sheeting, bracing, or
trench boxes are required, in order to prevent damage to existing facilities or
structures, or as a matter of safety, or as directed by OWASA’s Engineer, the
costs are to be included in the unit prices as bid for sanitary sewers, storm
drains, water lines or structures as applicable and there shall be no additional
cost for these items.
Sloping trench walls: If trench walls are to be sloped or benched, contractor is
responsible for determining the proper and applicable slope based on soil type in
order to meet OSHA requirements. Laying back slopes also applies for areas
where the top of the trench box is lower than the top of the bank. Contractor
shall employ the services of a Geotechnical Engineer for direction and guidance
if unstable or difficult soils are encountered. In any event, the Contractor shall
hold OWASA harmless for injuries and/or damages resulting from failure to
properly adhere to trench protection regulations/requirements in force at the time
of a failure or mishap including, but not limited to, damage to utilities, equipment,
structures, paving, etc.
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
E.
ROCK:
1) Rock Excavation/Definition: Rock excavation shall consist of the removal
and satisfactory disposal of all materials, which in the opinion of OWASA’s
Engineer, cannot be excavated except by drilling, blasting, “jack hammering
or hoe ramming” (reasonable production for rock excavation by “jack
hammering or hoe ramming” will be defined as 5 or more cubic yards per
hour). Rock shall consist of undecomposed stone, hard enough to ring under
hammer. All boulders containing a volume of more than one-half cubic yard
will be classified as rock. When rock is encountered in the trench, OWASA’s
Engineer must be notified before any rock has been blasted or removed.
OWASA’s Engineer will measure the rock, after which, the rock shall be
excavated to a depth 6 inches below the grade of pipe and the bottom of
trench brought back to grade by using an approved fill material. See
paragraph 3.8, Blasting for other requirements regarding rock excavation.
2) Cushioning pipe in rock: Special precautions shall be exercised to prevent
any pipe from resting on rock or any other hard projection that might cause
breakage of pipe. At no time shall the pipe bell or the pipe barrel rest on
rock. A minimum of 6 inches of stone cushioning is required between the
barrel of the pipe and rock. A minimum of 12 inches of clearance is required
between the sides of the pipe and the rock. See Standard Detail 511.01.
Thicker cushioning may be required for deeper pipe on a case-by-case basis.
3) Disposal of Rock: Rock excavated from the trench shall be hauled off the
site at the Contractor’s expense. Borrow required to replace excavated rock
shall be provided by the Contractor and shall be included in the unit price bid
for rock excavation. No rocks or boulders shall be used as backfill in any part
of the trench. Where rock has scattered over adjoining property as a result of
blasting, the Contractor shall remove the rock and restore the area to its
original condition at no cost to OWASA.
F.
PREPARATION OF FOUNDATION FOR PIPE LAYING
1) Excavation of trenches for all pipe lines shall be done to line and grade as
established by the Engineer. The bedding surface shall provide a firm,
stable, and uniform support through the entire length of the pipe. Recesses
shall be excavated to accommodate bells and joints. When bedded firmly on
the subgrade, the pipe shall be on the exact grade of the completed water or
sewer line.
2) Unsuitable Trench Subgrade/Foundation Improvement: If the trench
subgrade is found to be soft, spongy, excessively wet, unstable or in any
other way unfit such that there is inadequate pipe support, when directed by
OWASA’s Engineer, the material shall be removed for the full width of the
trench, and the excavated area shall be strengthened for foundation
purposes by furnishing and placing either approved clean stone, a concrete
cradle, concrete mud mat, concrete encasement or a combination of these
materials. Whenever the bottom of the trench is such that it cannot be
reasonably stabilized, OWASA’s Engineer may require the sewer to be laid in
cradles or in cradles supported on piles. These foundations shall be placed
as directed by the OWASA’s Engineer.
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
Observe the following requirements when unstable trench bottom materials
are encountered:
a. Notify OWASA when unstable materials are encountered and define by
drawing station locations and limits when encountered.
b. Remove unstable trench bottom materials as directed and replace with
subgrade stabilization material specified.
3) Over-excavation: Unauthorized over-excavation consists of removal of
material beyond indicated subgrade elevations or side dimensions, without
specific approval of OWASA’s Engineer. Exercise care to avoid excavations
below established grade where firm earth conditions exist.
Where
unauthorized excavations have been carried beyond points required, restore
these areas to the elevations and dimensions shown on the drawings with
approved fill material and compact as specified (as noted in the preceding
paragraph). In no case shall the pipe be brought to grade by blocking under
the barrel of the pipe. A uniform support shall be provided for the entire
length of the pipe. Unauthorized excavation shall be replaced at Contractor’s
expense.
G.
TRENCH PREPARATION FOR PIPE
1) Preparation of trenches for Gravity pipelines
The bottom of the trench for gravity pipelines shall be excavated to a
minimum over depth as shown on Standard Detail 531.01 to provide for
improved pipe bedding material for the entire length of the gravity pipeline,
including sewer lateral connections, except in rock where bedding shall be a
minimum of 6 inches deep (see Standard Detail 511.01 and paragraph
3.2.E.2, above). The bedding shall be shaped so that the bottom half of the
pipe rests on the bed. Bell holes and depressions as required of the joint
shall be dug after the bedding has been graded and shaped, and shall be
only of such length, depth, and width as required for properly making the
particular type of joint. The trench for sanitary sewers and lateral connections
shall then be backfilled and compacted as indicated in Table 02275.3.
2) Preparation of trenches for Water Mains and Force Mains
The trenches for water lines and sewage force mains shall be graded to avoid
local high points. Trenches shall be graded either level or on a continuous
upslope to the high points designated on the drawings. Trenches shall be of
such depth as to provide a minimum cover over the top of the pipe as noted
in Table 02275.1. The trenches shall have 4 inches of loose soil in the
bottom before pipe is placed, so pipe is firmly and continuous in contact with
the soil. Pipe shall not bridge any areas. Rock larger than 3 inches shall be
removed from the trench bottom and any voids filled with soil or clean stone.
Bell holes shall be provided at each joint to permit proper joint assembly and
proper pipe support. Rock shall be removed 6 inches below pipe and the
void filled with clean stone.
3) Surface or Ground Water in Trenches/Pipe
When ground water is encountered, the Contractor shall pump, or otherwise
remove any water that accumulates in the trenches and shall perform all
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
work necessary to keep the trenches clear from water while pipe is being
laid. No pipe shall be laid in water and the pipe shall not be used as a means
of draining ground water from the trench. The open end of the pipe shall be
kept closed with a watertight plug to prevent washing of any foreign matter
into the line. At the conclusion of the workday, or at any other time when
pipe laying is not in progress, a watertight plug shall be placed in the bell of
the last joint of pipe laid. All water removed from the trench shall be
conveyed in a proper manner to a suitable point of discharge and shall
comply with the applicable erosion and sedimentation laws. See paragraph
3.1.G – Dewatering, of this specification.
H.
TRENCHING IN FILLS
In areas where trenching for pipes will be in fills, the fills shall be brought to an
elevation of at least 12 inches above the top of the pipe, and then the trench
excavated in the compacted fill, as herein specified for trench excavation.
I.
EXCAVATION FOR STRUCTURES
1) Excavate to provide a minimum of 12 inches of horizontal clearance between
outer surface of structure and trench wall.
2) Where rock is encountered so that a built-in-place manhole, precast structure
(such as a manhole or vault), or other structure will bear over rock, remove
the rock to a minimum of 8 inches below the foundation or footing of the
structure and place an 8 inch cushion of clean #57 stone over the rock.
J.
WATER MAIN BEND BLOCKING INSTALLATION
1) Excavate area to receive poured in place concrete blocking to exact
dimensions shown in Standard Detail 512.02. Blocking is to be placed in
undisturbed residual soils. If blocking is to be placed in areas where boulders
or stumps have been removed or in areas of loosely compacted fills, such as
in landscaped areas (outside of pavements or parking lots), contact
OWASA’s Engineer for directions.
2) Concrete shall be plain concrete with a minimum compressive strength of
3000 psi at 28 days.
3) Wrap bolts in plastic or provide other acceptable means of protection,
approved by OWASA’s Engineer before pouring concrete blocking.
4) Concrete thrust blocking and rodding is not required for installation of
restrained joint piping unless directed and at the discretion of the OWASA
Representative.
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
K.
DEPOSITION OF EXCAVATED MATERIAL
1) All excavated material shall be placed on one side of the trench away from
the roadway unless permission is given by OWASA’s representative to place
it on both sides. Excavated materials shall be so placed as not to endanger
the work and so that free access may be had at all times to all parts of the
trench and to all fire alarm boxes, fire hydrants and gate valves on water
pipes, which are located in the vicinity. Excavated material shall be placed so
as to inconvenience the public as little as possible. All fences and walls shall
be protected and, if damaged, shall be repaired or replaced in as good
condition as before it was disturbed. Protect shade trees from stockpiling of
material.
2) Exercise care when stockpiling excavated material on the bank in order to
prevent surcharging the bank of the trench and potentially rendering the
excavation unstable.
3) Wasting of Unsuitable Material: Material of an uncompactable nature,
material unsatisfactory for backfill, trash and excess material shall be
removed from project site and disposed at the Contractor’s expense. Where
removal of unsatisfactory material is due to negligence on the part of the
contractor (i.e. resulting from inadequate shoring or bracing, failure to
dewater, improper material storage exposing it to rain or flooding, or other
failure to meet specified requirements), work shall be performed at no
additional cost to OWASA. If additional material is required, the Contractor
shall supply same from an approved borrow pit at no additional cost to
OWASA. Rock excavated from the trench shall be hauled off the site at the
Contactor’s expense.
3.3
BEDDING
A.
BEDDING DEFINITIONS: see paragraph 2.1 B, Pipe Bedding Definitions.
B.
MINIMUM BEDDING REQUIREMENTS by type of pipe:
1) Sewer Pipe Bedding: Provide granular trench bedding material. In no case,
unless specifically exempted in writing by OWASA’s Engineer, shall the stone
bedding be less than the minimum bedding shown in Standard Detail
531.01.
2)
Bedding Water Pipe, Water Service Pipe, and Sewage Force Mains: Do
not bed water pipe, water service pipe, and sewage force mains in stone
except as indicated for rock areas.
3)
Bedding for Structures: The bottom of manhole bases and other precast
structures and appurtenances shall be excavated to minimum over depth of
12 inches below the bottom of the structure. The structures shall be placed
on a minimum of 12 inches of clean stone bedding that has been firmly
consolidated. Bedding material shall be shaped, graded, and compacted so
that the entire bottom of the structure rests level on the material for its entire
area.
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
C.
BEDDING MATERIAL PLACEMENT
1) Unless class D bedding is specified, the bottom of the pipe trench for sanitary
sewer shall be excavated to a minimum over depth of 6 inches below the bottom
of the pipe, to provide for the compacted bedding materials, expect as specified
in rock. Bedding material shall be placed, shaped, and compacted so that at
least the bottom half of the pipe rests uniformly upon the material for the entire
length of the pipe. Bell holes and depressions required for the jointing of pipe
shall be dug after the compacted bedding material has been graded and shaped
and shall be only of the length, depth, and width required to make the joint
properly. Care shall be taken to make sure bedding fills the voids beneath the
pipe haunches, by poking with a shovel or tamper.
3.4
BACKFILLING (MATERIALS AND METHODS)
A.
BACKFILLING
1) GENERAL:
a.
Materials: See paragraph 2.1.A - Material Classification for Select Earth
Backfill and Common Trench Backfill classification. In areas of extensive
rock excavation, where there is a shortage of suitable backfill, the
Contractor shall, at his own expense, haul suitable material in to be placed
over the pipe.
b.
Pipe and fittings shall be inspected before backfilling.
c.
Except as otherwise specified or directed for special conditions, backfill
trenches to the ground surface with Common Trench Backfill material
approved by OWASA’s Engineer. After the pipe has been brought to grade
on a proper foundation, earth fill shall be placed carefully about the pipe
and tamped properly to hold the pipe in position. Exercise extreme care in
backfilling operations to avoid displacing joints and appurtenances or
causing any horizontal or vertical misalignment, separation, or distortion.
Repair damages, distortions, or misalignments to full satisfaction of
OWASA’s Engineer. Pipe shall be removed if broken or damaged during
installation. Backfill shall closely follow the pipe installation. Unless
otherwise directed or permitted by OWASA’s Engineer, all pipe laid shall be
backfilled during the same day, and prior to the completion of the day’s
work, to provide a firm continuous support and covering for the pipe.
d.
Reopen trenches that have been improperly backfilled, to a depth as
required for proper compaction. Refill and compact as specified, or
otherwise correct to the approval of OWASA’s Engineer.
e.
Do not allow or cause any of the work performed or installed to be covered
up or enclosed by work prior to required inspections, tests, and approvals.
Should any of the work be so enclosed or covered up before it has been
approved, uncover all such work and, after approvals have been made,
refill and compact as specified, all at no additional cost to OWASA.
f.
Observe specific pipe manufacturer's recommendations regarding methods
of backfilling and compaction.
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
g.
Insure compaction of
specifications.
each lift
to requirements stated in these
h.
Metallic underground warning tape shall be installed directly over water or
sewer main pipe approximately 18 inches to 24 inches below finished
grade. See section 02520 for Reclaimed Water installation requirements.
2) METHODS:
Provide backfill and compaction methods of following types:
a.
Carefully Compacted SELECT EARTH BACKFILL: Furnish carefully
compacted select earth backfill where indicated on drawings and specified for
compacted backfill conditions up to 12 inches above top of pipe. See
paragraph 2.1 Soil, Bedding, and Backfill for definition of Select Earth Backfill.
Comply with the following:
Care shall be taken to prevent any disturbance to the pipe or damage to
newly made joints. The filling of the trench shall be carried on simultaneously
on both sides of the pipe in such a manner that injurious side pressures do
not occur such that the pipe could be displaced or dislodged. Do not backfill
on muddy or frozen soil.
Sheeting and shoring generally should be removed only when the trench
below it has become substantially filled, and every precaution shall be taken
to prevent any slides of material from the sides of the trench onto or against
the pipe.
i. Place backfill in lifts not exceeding 6 inches (loose thickness).
ii. Hand place, shovel slice, and hand tamp carefully compacted backfill
solidly around pipe. Only hand tamping shall be used to compact
earth around the pipe line. When the backfill has been brought to 12
inches above the top of the barrel, pneumatic tampers may be used to
compact the remainder of the soil.
b.
COMMON TRENCH (FINAL) BACKFILL. Perform remaining backfill in
accordance with drawings. See paragraph 2.1 Soil, Bedding, and Backfill for
definition of Common Trench Backfill. Comply with the following:
i.
Unless otherwise specified or approved by OWASA’s Engineer,
backfill the remainder of the trench, from 12 inches above the pipe to
grade, with clean earth fill free of stones larger than 3 inches in
diameter. Material shall be free from all perishable and objectionable
materials. Before placing any backfill, all rubbish, forms, blocks,
wires, or other unsuitable material shall be removed from excavation.
The backfilling shall be placed in layers not over 6 inches thick in the
street right of way and 12-inch layers outside of the street right of way.
See Table 02275.4. Final backfill shall be tamped with a mechanical
or pneumatic tamper. See Table 02275.3 below, for specific density
requirements.
ii.
All areas within the limits designated on the drawings, including
adjacent transition areas, shall be uniformly graded. The Contractor
shall finish surfaces within the specified tolerances with uniform levels
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
or slopes between points where elevations or existing grades are
shown.
a) Finish subgrade areas that are to receive topsoil. Bring such
areas to within 0.10 foot of required subgrade elevations.
b) Shape subgrade under sidewalks to line, grade, and crosssection. Subgrade is to be brought to within 0.10 foot of
required subgrade elevations.
c) Shape subgrade under pavement to line, grade, and crosssection.
Bring to within ½ inch of required subgrade
elevations.
iii. Surface Protection – Traffic: The Contractor shall protect newly graded
areas from traffic and erosion and repair and re-establish grade in settled,
eroded, or rutted areas. Where compacted areas are disturbed by
subsequent construction or adverse weather, the Contractor shall scarify
the surface, reshape, and re-compact to the required density. If the
Contractor shall fail to maintain any trench within 2 days after receipt of
written notice from OWASA’s Engineer, OWASA may refill said
depressions and the cost of such work may be retained from monies due
the Contractor. In case of emergency, OWASA’s Engineer may refill any
dangerous depressions without prior notice to the Contractor.
c. Structure Backfill: Backfill placed within 2 feet of manholes and other
special structures shall be of the same quality as that specified for backfill
around water or sewer lines. Take care to prevent wedging action of the
backfill against structure by carrying the material uniformly around the
structure so approximately the same elevation is maintained in each lift.
Material shall be solidly tamped with a mechanical or pneumatic tamper in
such a way as to avoid damaging the structures or producing unequal
pressures. The Contractor shall refill all excavations as rapidly as practical
after completion of the structural work therein, or after the excavations have
served their purpose.
3.5
COMPACTION/DENSITY
Soil shall be compacted using equipment suitable for the material and the work area
location. There are two types of testing discussed in section 3.5, Quality Control (QC)
and Quality Assurance (QA).
A. Testing
Testing of backfill shall be performed by an independent laboratory approved by
OWASA and the Contractor.
The CONTRACTOR shall be responsible for
excavation of both types (QC and/or QA) of testing at no additional cost to OWASA
Quality Control (QC) vs. Quality Assurance (QA):
QC testing is required testing that shall be performed by the Contractor to assure
compliance with the requirements of these specifications. The associated cost for
QC testing is the Contractor’s responsibility. The contractor is also responsible for
“re-testing” costs incurred by OWASA when OWASA’s test results (tests for QA)
results in a “failure.”
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
QA testing, and associated costs will be paid for by OWASA. OWASA will contract
with a separate testing firm for QA testing. QA testing may be conducted to ensure
CONTRACTOR compliance with these specifications.
B. Quality Assurance (QA):
In the course of backfilling trenches for utility installations, OWASA’s Engineer may
require “Field Density Determinations” or compaction tests. OWASA’s Engineer will
determine the location of the tests and OWASA shall engage a qualified testing firm
to perform the test. The CONTRACTOR shall perform the excavation during normal
working hours at no additional cost to OWASA. Field density determinations shall be
performed in accordance with AASHTO T191, T204, and T205 modified to include
material sizes used in the laboratory determination of density with nuclear field
density testing device or by other approved methods. A representative of OWASA
will observe tests and a copy of the test results and inspection report will be
submitted by the testing firm directly to the OWASA’s Engineer. When the average
of 3 test results, with no one test failing by more than 3 percentage points, indicate
that the density is less than the percent specified, the Contractor shall excavate and
re-compact the areas that have failed at no expense to OWASA. Payment for a
failed compaction test shall be made by the Contractor.
C. Quality Control (QC):
The CONTRACTOR is required to perform Quality Control testing. Field density or
compaction tests determinations shall be performed in accordance with AASHTO
T191, T204, and T205 modified to include material sizes used in the laboratory
determination of density with nuclear field density testing device or by other
approved methods. A representative of OWASA will observe tests and a copy of the
test results and inspection report will be submitted by the testing firm directly to the
OWASA’s Engineer. When the average of 3 test results, with no one test failing by
more than 3 percentage points, indicate that the density is less than the percent
specified, the Contractor shall excavate and re-compact the areas that have failed at
no expense to OWASA. However, where backfill compaction is suspect and
questionable, the material shall be removed as directed by OWASA’s Engineer and
the area tested. If a suspect area fails to meet the prescribed minimum moisture
density test requirements, the soil shall be removed, replaced, compacted, and retested, as directed by OWASA’s Engineer, until the backfill meets or exceeds the
minimum density requirements. The Contractor shall pay for all costs associated
with testing.
Table 02275.2
Testing Frequency
Location
Frequency
Trench areas in road 1 per road crossing, and/or
crossings
Trench areas
1 per 200 linear feet per two feet of fill thickness
Exception:
Where additional tests are required to determine the extent of unacceptable
compaction. In this case, the costs for these additional tests are the
responsibility of the contractor.
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D. Site access for testing: Insure OWASA, at all times, has immediate access to the
site for the testing of all soils related work. Insure excavations are in a safe condition
for testing personnel.
E. Compaction Requirements:
Unless noted otherwise on drawings or more
stringently by other sections of these specifications, place and insure backfill and fill
materials achieve an equal or "higher" degree of compaction than undisturbed
materials adjacent to the work; however, in no case shall degree of compaction fall
below the following percentages of the maximum density at optimum moisture
content. Tolerance is to be within +/- 2 percentage points of the optimum moisture
content.
Table 02275.3
Minimum Compaction Limits
Location
Beneath and
within 5 feet of
buildings
Areas under
roadway
pavement
surfaces, curb
and gutter, and
sidewalks
Roadway
shoulders
Under turf,
sodded, planted,
or seeded nontraffic areas
(Cohesive Soils)
Density
100% of the maximum dry density by ASTM D698
(Standard Proctor), AASHTO T99.
Top 12 inches
100% of the maximum dry density
by
ASTM
D698
(Standard
Proctor), AASHTO T99.
Up to within
95% of the maximum dry density
12 inches
by
ASTM
D698
(Standard
Proctor), AASHTO T99.
95% of the maximum dry density by ASTM D698
(Standard Proctor), AASHTO T99.
90% of the maximum dry density by ASTM D698
(Standard Proctor), AASHTO T99.
F. Compaction Lifts:
Table 02275.4
Compaction Lift Thickness
Lift Thickness (inches)
Location
6
Inside street rights-of-way
12
Outside street rights-of-way
G. In-place testing of soils shall be tested based on the following:
Table 02275.5
In-Place Density Tests
Soil Type/Classification
Reference Standard
Crushed Rock
ASTM D2049 by percentage of relative density
ASTM D1557 or D698 (standard Proctor)
GW, GP, SW and SP
ASTM D2049 by percentage of relative density
ASTM D1557 or D698 (standard Proctor)
GM, GC, SM, SC, ML, CL
ASTM D2167, D1556, D2922, or D2937 by
percentage of Standard Proctor Density according
to ASTM D698 or AASHTO T99
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3.6
SERVICE CUTS, DIRECTIONAL BORED OR PUNCHED SERVICES
A. Open trenches: Sewer lateral and water service connections that cross paved
streets shall be installed by saw cutting the pavement and opening the trench. The
open trench width shall be no wider than 12 inches.
Lateral connection trenches in non-paved areas shall be buried as specified for
gravity sewers and for water lines, as applicable. See Table 02275.1.
Do not bed water or sewer service pipe, except when rock is encountered.
B. Directional Boring or Punching: At the direction of OWASA’s Engineer, service
pipes may be required to be “punched” or “directional bored” beneath the pavement.
3.7
PAVEMENT REPAIR AND REPLACEMENT
A. General: This work shall consist of replacing sub base stone, and bituminous
material in the street in areas where it becomes necessary to remove the original
pavement for sewer and water main trenches. Pavement repair shall be the type to
match the existing street pavement, as shown on the drawings, or as determined by
OWASA’s Engineer. The pavement patch shall provide a uniform and smooth
driving surface free of humps or depressions.
B. Construction in Public Rights of Way: Water and sewer lines installed in or
across NCDOT roads shall be installed in accordance with, if applicable, the
requirements stipulated in the approved encroachment permit and the latest
requirements of both the NCDOT Standard Specifications for Roads and Structures
and the Roadway Standard Drawings. All water and sewer lines installed in or
across Town of Carrboro or Town of Chapel Hill roads shall be in accordance with
the respective Town’s standards.
When it is necessary to remove the existing pavements, prepared road surfaces,
sidewalks, or curbing, it shall be the responsibility of the Contractor to replace these
surfaces to original or better condition. The Contractor shall be responsible for
contacting NCDOT, the Town of Carrboro, or the Town of Chapel Hill regarding
pavement replacement, as applicable. Unless specified more stringently by the
owner of the right-of-way, the backfill shall be compacted in accordance with Table
02275.3.
Contractor shall replace pavement base with a minimum of 10 inches of ABC
compacted to 100% of the Modified Proctor (ASTM D1557) maximum dry density
prior to pavement overlay.
C. When water and/or sewer lines are installed in or across roadways that have been
macadamized or graveled, the Contractor shall save the gravel or stone and refill the
upper 12 inches of the trench with the material and supply sufficient new stone or
gravel to return the roadway to the original grade. It shall be the Contractor’s
responsibility to maintain the original grade by adding gravel or ABC until the ditch is
stable and the pipeline accepted by OWASA. Maintain area as outlined in paragraph
3.4.A.2.b.iii- Surface Protection - Traffic.
D. Cutting Pavement: See also paragraph 3.1.D-2 – Protection of Surface Features.
Perform cutting operations prior to commencing excavation operations to avoid
excessive removal of asphalt / damage to roadway.
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
E. Protection of Pavement: See paragraph 3.1.D-2 – Protection of Surface Features.
3.8
BLASTING
A.
GENERAL
1) Blasting procedures shall conform to all applicable local, state, and federal laws
and ordinances and shall be performed in accordance with OSHA Standard 29
CFR part 1910.109, Explosives and Blasting Agents, NCDOT Rules for
Transporting Explosives, and local Fire Department Regulations. Prior to any
blasting, a blasting permit shall be obtained. The approval of the OWASA’s
Engineer shall be obtained before any blasting takes place and OWASA’s
Engineer may fix the hours of blasting if he/she deems it to be necessary. The
use of explosives shall be in accordance with approved methods that safeguard
lives and property. Explosives shall only be handled, placed, and detonated by
persons licensed in this work. It is the responsibility of the Contractor to provide
proper notification to appropriate parties.
2) Rock Excavation: See paragraph 3.2.E., - Rock for the definition of rock.
3) The minimum insurance coverage for blasting shall be as annotated in Section
00800, Supplementary Conditions. The coverage shall include explosion and
collapse. If blasting occurs within 200 feet of any underground structure or utility,
underground coverage will be required. The owner and the property owners
shall be named as “additional insured.”
4) Storage: Store explosives in accordance with the Occupational Safety and
Health Act and with other Federal, State and Local ordinances and regulations.
The Contractor shall keep explosive materials that are on the job site in special
constructed boxes provided with locks. These boxes shall be plainly identified as
to their contents. Failure to comply with this specification shall be grounds for
suspension of blasting operations until full compliance is made. No blasting shall
be allowed unless a galvanometer is employed to check cap circuits.
5) OWASA may prohibit blasting when the method of detonation or the means of
protection provided is inadequate. Blasting conducted with or without direct
supervision of OWASA will not relieve the Contractor of the responsibilities
stipulated herein.
6) Blasters shall not explode or attempt to explode blasting powder or high
explosives unless it is performed with a suitable electric blasting machine.
Electric current from batteries, telephone, or power lines shall not be used for
detonation.
7) A minimum of 3 minutes prior to the detonation, the blaster shall inform
competent flagmen, equipped with red flags, stationed at reasonable distances
from the blast area at every avenue of approach, to warn all persons.
8) Immediately after the loading and tamping of the drill hole and before fixing the
blast, the material to be blasted shall be covered on all exposed sides with
blasting mats, or other approved protective material. After the protection has
been applied, the blast shall be fired without unnecessary delay.
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
B.
BLASTING PROCEDURE
1) The Contractor shall provide a blast warning signal system. The blast warning
signal system shall consist of one or more air horns located at the blast site. The
air horn(s) shall be audible a minimum of 1 mile from the blast site. The signals
shall be one long horn 5 minutes prior to the blast, one short horn 1 minute prior
to the blast, and one long horn after the blast to signal all clear. The Contractor
shall erect two clear and legible blast warning signal signs at locations
determined by OWASA’s Engineer. The signs shall list the blast warning signal
system, the Contractor Superintendent’s name and telephone number, and the
OWASA representative’s name and telephone number.
2) The Contractor shall establish test pits at up to two representative locations along
the alignment and up to three locations adjacent to the site proposed to be
blasted to determine if the rock is “rippable” with a track backhoe caterpillar 225
or equivalent and the feasibility of rock excavation by “hoe ramming.” If these
procedures do not offer reasonable production for rock excavation, then blasting
will be allowed unless otherwise indicated.
3) The Contractor shall notify in writing all property Owners within 300 feet of the
proposed blast at least 1 week prior to the proposed blast and verbally on the
day of the scheduled blast.
4) Blasting shall be limited to mid-morning hours on days of clear-to-partly cloudy
skies with increasing surface temperature and light wind. The Contractor shall
provide monitoring equipment to monitor all blasting. A copy of monitor record
shall be given to OWASA daily.
5) The use of unconfined explosives shall be prohibited.
6) Unless otherwise stipulated in Title 13 of the NC Administrative Code, chapter 7,
the maximum allowable peak particle velocity shall be 1.25 inches per second for
all structures located 0 to 300 feet from the blasting site. The maximum
allowable peak particle velocity shall be 1.00 inch per second for all structures
located 301 to 5,000 feet from the blasting site. The maximum allowable peak
particle velocity shall be 0.75 inch per second for all structures located 5,001 feet
and beyond from the blasting site.
7) To minimize vibration, minimum scaled distance (SD) of 50 shall be used to
determine maximum explosive weight per delay. A test blast shall be conducted
to verify the scaled distance. The maximum explosive weight per delay shall not
exceed the distance from the blast to the nearest structure divided by 50
squared. Maximum explosive weight per delay may be revised pending outcome
of test blast. The recommendations indicated for blasting criteria in no way
relieves the Contractor of his liability.
8) The peak overpressure of air blast shall not exceed 0.015 pound per square inch
or 138 decibels.
9) Pre-blast meetings may be scheduled with OWASA’s Engineer to document hole
depths and spacing, charge weight per delay, shot scheduling, and weather
conditions. The Contractor shall obtain accurate measured distances from
structures to center of blast area prior to determining the safe maximum chargeweight per delay and loading blast holes.
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10) Pre-blast and post blast surveys will be obtained by the Contractor using an
“Independent Blasting Firm”. The pre-blast and post blast surveys will include all
occupied and vacant buildings and other Structures within 250 feet of the blasting
area. Any pre-blast and post blast surveys performed by OWASA or the property
owner in no way relieve the Contractor of his liability. The firm selected by the
Contractor will be evaluated by the Engineer and Owner for approval. The
“Independent Blasting Firm” shall obtain written permission from the property
owners and submit a copy or copies to the engineer and owner prior to entering
upon private property.
C.
Blasting Monitoring Requirements
1) Monitoring of Blast-Related Vibrations
Pre-Construction Condition Assessment:
The geotechnical engineering firm shall perform a pre-construction condition
assessment to document the conditions of the nearby buildings and other
sensitive nearby structures prior to the beginning of construction. The
assessment shall be performed on all properties adjacent to the project site
and any other properties as directed by the engineer or owner. The
assessment shall include full color video and photographic documentation of all
exteriors including building foundations and installation of crack monitors on
façade cracks that might propagate due to blasting vibrations. All
documentation of existing building conditions and information concerning the
type and location of crack monitors shall be presented to the engineer and
owner in a report prior to construction.
2) Crack Monitoring During Blasting:
During blasting operations, the geotechnical firm shall perform periodic
readings of sufficient frequency of the crack monitors that were installed during
the pre-construction condition assessment to assess/monitor the effects of the
blasting operations. All readings shall be provided to the Engineer and Owner
within 48 hours of taking the reading. If the crack readings suggest that blasting
vibrations are contributing to crack width, then the geotechnical firm shall
immediately notify the Engineer and Owner and review the blasting operations.
The geotechnical firm and the contractor shall then submit a detailed plan for
repair, the contractor shall perform the repair at no cost to the Owner and
develop and submit for review a revised blasting plan to address the vibration
problems and minimize further damage and complaints.
3) Vibration Monitoring During Blasting:
Procedure – The geotechnical firm shall monitor vibrations at no less than two
locations at the closest structures to the project during all blasting activities.
The locations shall be selected by the geotechnical firm based on the location
of the blasting activities and their relative position to nearby structures. Prior to
blasting, a plan of the monitoring locations shall be submitted to the Engineer
and Owner for approval. The location of the vibration monitors shall be
adjusted during construction with approval by Engineer and Owner. The
vibration monitors shall be established at the site so that background vibrations
may be determined prior to beginning construction and blasting. The sensitivity
range of the seismograph shall be selected so that the recording is initiated
below the maximum allowable particle velocity and extends above the highest
excepted intensity. Specific activities of the vibration source shall be indexed in
time to allow correlation with the arrivals on the vibration.
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Project Vibration Criteria – The maximum allowable particle velocity is as
indicated in Section 3.8.B.6. If the data from the monitors indicate that
vibrations are exceeding the established criteria, then the geotechnical firm
shall immediately notify the Engineer and Owner and suspend the blasting
operations which are generating the vibrations, until the geotechnical firm and
Contractor have developed a revised blasting plan to resolve the problem. The
problem shall be resolved by the Contractor at no additional cost to the Owner.
Instrumentation – The vibration monitors shall consist of digital seismographs
that display the particle velocities and associated frequencies plotted against
the criteria for this project. Each seismograph shall contain geophones with
response capability in three mutually perpendicular axes or components; one
vertical and two horizontal (radial and transverse). The frequency response of
the geophones shall be linear from at least 4 Hz to more than 200 Hz. The
sensitivity shall range from less than 0.02 in/sec to more than 5.0 in/sec. The
Blastmate III by Instantel is one type of seismograph that is suitable for this
project.
Calibration and Instrument Use – The geotechnical firm shall field calibrate the
vibration monitors before the start of each recoding period. The transducer
shall be positioned with the longitudinal axis toward the vibration source.
Transducers must be adequately coupled with the ground. Operation of all
vibration monitors shall be in accordance with the instrument manufacturer’s
instructions and recommendations. Vibration records shall be collected in
waveform plot or strip chart plot. The peak vector sum of the particle velocity in
longitudinal, transverse, and vertical planes shall be shown along with the
respective dominant or principal frequencies. The highest recorded particle
velocity (i.e., the vector sum of the three orthogonal directions), when indexed
to a particle vibration event, shall be reported as the peak particle velocity. The
recorded peak particle velocity shall be compared to criteria appropriate for the
subject of concern.
Complaints – In the event of a complaint, the geotechnical firm shall
immediately contact the Engineer and Owner and review those blasting
activities that are introducing vibrations. The geotechnical firm shall prepare a
report documenting all relevant data such as the time and date presented in the
complaint, a description of the blasting activities during the subject time/date,
data from the monitoring instruments for the subject time/date, complaint
information and a description (including photographs, if possible) of the alleged
damage. The geotechnical firm and Contractor shall then submit for review a
detailed plan for repair, and revised blasting plan to address the complaints.
The Contractor will be required to perform the necessary repairs at no cost to
the owner.
Additional Requirements – In addition to the pre-construction condition
assessment report, the geotechnical firm shall also provide monthly reports, as
required, containing the results of the crack monitors and vibration monitors
during the blasting procedures. The reports shall document that the
geotechnical firm is providing the work described by this specification.
The geotechnical firm shall submit a final report after the completion of the
blasting operation that contains all previous reports in one document. The final
report shall contain an “executive” summary of the various reports.
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3.9
HIGHWAY CROSSING
A. Pipeline crossing shall be installed in a steel casing pipe installed by the “dry bore
and jacking” method. Length of steel pipe shall be welded to the preceding length
installed. The carrier pipe shall be protected by spiders/skids constructed as shown
on Standard Detail 517.01. The ductile iron carrier pipe shall be as specified for
sewer and water pipe and shall be slip joint ductile iron pipe. If, in the opinion of the
Contractor, boring and jacking of the highway crossing is not possible due to rock,
he shall test drill, in the presence of OWASA’s Engineer at the proposed crossing
locations, at least 3 evenly spaced points in the placement along the crossing
alignment. Upon verifying the presence of rock at a depth that would conflict with
the boring and jacking operation, the Contractor shall make application to the
applicable Town or the NCDOT, as applicable, to allow open cutting of the crossing.
The Contractor shall be responsible for providing all data and shall pay any fees
required for this application. If the trench is allowed to be open cut, casing pipe shall
be provided and the trench shall be backfilled entirely with #57 stone to the bottom
of the pavement base course and the pavement restored within one day of placing
the pipe. Non-woven fabric separation fabric is to be provided between the stone
and the pavement.
B. The steel casing pipe shall be of the thickness as specified in Standard Detail
517.01. Refer to specification Section 02530, Sanitary Sewer and Section 02510,
Water Distribution for casing pipe specifications.
C. Installation shall be in accordance with AREA.
D. The jacking operation shall be carried on in such a manner that settlement of the
ground or the highway above the pipeline will not occur. The use of water or other
fluids in connection with the boring and jacking operation shall not be allowed.
Excavation shall be made by auger or manual methods, at the Contractor’s option,
to suit the conditions encountered. The Contractor shall repair or replace, as
directed by OWASA’s Engineer, at his own expense, casing pipe damaged during
the jacking operation.
E. After installation of the casing pipe, the carrier pipe, if required, shall be installed.
The ends of the casing shall be plugged in accordance with Standard Detail
517.01. Place a ¾-inch diameter steel drain line at downstream end of casing and
drain either to daylight or a blind french drain consisting of 1/4 cubic yard of #57
stone.
F.
3.10
All operations of the Contractor shall be subordinate to the free and unobstructed
use of the highway right of way for passage of traffic without delay or danger to life,
equipment, or property. The Contractor shall provide all necessary bracing,
bulkheads, and shields to ensure complete safety to all traffic at all times.
RAILROAD CROSSING/TRACKS
Crossing of railroad tracks with water or sewer lines shall be by the method shown on
the contract drawings and approved by the applicable Railroad Company. It is the
responsibility of the Project Engineer and Contractor to contact the Railroad Company
and to comply with all Railroad Company requirements for specifications, drawings,
permits, etc. All water and sewer lines installed beneath railroad tracks shall be in
accordance with the Railroad Company’s policies, procedures, and permits
requirements. The railroad right of way and track structure shall be fully restored to its
original pre-existing condition and to the full satisfaction of the Railroad Company. The
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
work shall not interrupt the use of the railroad tracks or in any way endanger the traffic
on them.
3.11
UNDERGROUND RIVER OR CREEK CROSSINGS
In accordance with the contract drawings, underground river or creek crossings shall be
made either by horizontal directional drilling (HDD) with HDPE pipe or constructed in the
dry by providing a temporary cofferdam or bulkhead. River or creek crossings shall be in
accordance with OWASA’s “Policy on Sewer Lines Crossing Creeks and Easements.”
Unless horizontal directional drilling is specified in the contract documents, river or creek
crossings shall be made by providing a temporary cofferdam or bulkhead using ductile
iron pipe for the crossing.
River or creek crossings shall be as near to perpendicular as possible to the stream.
A. Cofferdam Method: The Contractor shall construct the river crossing in the “dry” by
providing a temporary cofferdam or bulkhead of non-erodible material. The
cofferdam shall not obstruct more than one-half of the water surface at any time and
shall not extend more than 3 feet above the normal water surface. The Contractor
shall not be allowed to operate construction equipment on the native steam bottom,
except during removal of the cofferdam. The Contractor shall be advised that the
level in the river can fluctuate rapidly.
1) Non-erodible material shall be defined as heavy coarse aggregate as specified
on the plans. An earth core for the cofferdam may be constructed over the
propose excavations; however, the non-erodible materials shall be in place prior
to the placement of the earth, so that the erodible earth does not come in contact
with the flowing water.
2) A bulkhead may be constructed in lieu of the cofferdam. The bulkhead shall be
made of wood, steel or some like material suitable to withstand the hydraulic
forces to permit construction in a dry trench.
3) Construct the crossings as indicated. The Contractor shall then remove the
cofferdam, bulkhead, or whatever equipment or material that was used to
construct the crossing. The bottom of the river in the construction area shall be
restored to its original cross section. All disturbed areas on the banks of the river
shall be seeded and mulched in accordance with paragraph 3.15 – Seeding and
Groundcover.
4) Comply with all terms and conditions of all permits issued by the US Army Corps
of Engineers and/or NCDENR for this work.
5) The pipe and joints of water or sewer main entering or crossing streams shall be
tested in place and shall exhibit zero infiltration. This testing shall be done prior
to encasing in concrete.
B. Horizontal Directional Drilling (HDD) Method: HDPE pipe shall be installed by
horizontal directional drilling using a surface mounted rig, first to drill a guided hole
along a bore path consisting of a shall arc and then to pull a string of pipe into the
hole. Pull back is facilitated by a back-reamer, which enlarges the hole to
approximately one and a half times the pipe diameter. Drilling fluids are injected into
the bore hole to stabilize the hole and lubricate the pipe and drilling string. Tracking
equipment is used to guide and direct the drilling. See Section 02510, Water
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
Distribution for installation, testing and other requirements for horizontal directional
drilling.
3.12
SURFACE WATER CROSSINGS
Surface water crossings, with pipe above the water, shall be adequately supported by
casing pipe or beams as shown on Standard Details 536.03, 536.04, 536.06. Surface
water crossings with pipe under streambed shall have the pipe encased in concrete in
accordance with Standard Detail 536.08.
3.13
CONCRETE COLLARS ON SEWER MAINS
Concrete collars shall be used on sewer lines with slopes 20% or greater. At least one
concrete collar shall be placed before the bell of each joint of pipe (see Standard Detail
536.01). Additional collars may be required by OWASA.
3.14
CLEANUP AND RESTORATION OF SITE
A. During the progress of the work, the Contractor shall keep the premises and the
vicinity of the work clear from unsightly and disorderly piles of debris. Suitable
locations shall be specified for the various construction materials and for debris. The
materials shall be kept in their storage locations, except as needed for the work and
debris shall be promptly and regularly collected and deposited in the specified
location.
B. Upon completion of section of pipeline and appurtenances, the Contractor shall fine
grade the ground adjacent thereto, removing all surplus excavated material, leaving
the area free from surface irregularities. He shall dispose of all surplus material, dirt,
and rubbish from the site; and shall keep the site free of mud and dust to the
satisfaction of OWASA’s Engineer. The contractor may be required to flush or
sprinkle the street to prevent dust nuisance.
C. When working on the shoulders of paved roads, the Contractor shall keep the
pavement clean of all loose earth, dust, mud, grave, etc., and shall restore road
surfaces, shoulders, and ditches as required by either the NCDOT or the right-of-way
owner.
D. Grading Easements: Easements shall be graded to have cross slopes of 4% or
less. The ground surfaces of easements shall be graded and cleared in such a way
to promote proper drainage and allow mowing by vehicular equipment without
damage to equipment from rocks and other debris.
E. After all work is completed, the Contractor shall remove all tools and other
equipment, leaving the site free, clean, and in good condition.
F. The Contractor shall keep the surface over and along the trenches and other
excavation in a safe and satisfactory condition during the progress of the work and
for a period of one year after the work has been completed. He shall be held
responsible for any accidents that may occur on the account of the defective
condition of such surface.
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
3.15
SEEDING & GROUNDCOVER
Seeding and groundcover includes seedbed preparation, liming, fertilizing, seeding, and
mulching of all disturbed areas. Areas inside or outside the limits of construction that are
disturbed by the Contractor’s operation and activity shall be seeded and mulched.
A. Unless called for otherwise on the Erosion and Sedimentation Control Plan, in areas
where natural sod or vegetation has been disturbed, the area shall be seeded with
the following:
Fertilizer: 10-10-10
Seed:
Kentucky 31 Fescue
Rate: 500 lbs. per Acre
Rate: 80 lbs. per Acre
If the line is installed through a landscaped lawn, the seeding shall be modified to
restore ground cover comparable to the existing lawn.
B. Seeding shall be carried out as soon as practical after the construction in any one
area, and shall be maintained against erosion through the completion of the project.
Seeding shall be accomplished as work progresses.
The Contractor shall be responsible for proper care of the seeded area during the
period that vegetation is being established. In the event of an erosive rain before an
adequate stand of vegetation has been established, damaged areas shall be
repaired, fertilized, seeded, and mulched at the Contractor’s expense.
Seeding on rights of way of NCDOT maintained roads shall be in accordance with
NCDOT specifications and the requirements of the approved encroachment permit.
C. Temporary Seeding: Denuded areas to be graded during the construction phases
that are not to be brought to final grade within 30 days shall receive temporary
seeding within 15 days of completing initial earthwork. Note that the time for
establishment of permanent ground cover is 15 working days or 30 calendar days
whichever is shorter. Temporary seeding shall also be used to stabilize finished
grade areas if the time of year is outside the specified permanent seeding periods.
D. Stockpile Area: The Contractor is responsible for securing a material lay down and
stockpile storage area for this contract. As such, the Contractor is responsible for
the necessary erosion control measures, including but not necessarily limited to, a
construction entrance, silt fence, protection of streams/buffers, clean up and
restoration of site to the satisfaction of both OWASA and the NCDENR, Department
of Water Quality, Land Quality Section. Stockpile and/or waste areas must be
maintained within the limits of the areas protected by the proposed measures and
otherwise temporarily seeded if to be left stockpiled over 30 days.
3.16
MISCELLANEOUS
A.
DUST CONTROL
The Contractor shall be required to sprinkle with water or to apply dust allaying
materials in the vicinity of dwellings, schools, churches, stores, or other places,
where in the opinion of OWASA’s Engineer, it is necessary to ensure that dust is
held to an absolute minimum. Dust control is considered incidental and shall be
carried out at the Contractor’s expense.
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
B.
IDENTIFICATION OF NEW WATER OR SEWER LINES
Underground Warning Tape
Placement of underground warning tape during backfill operations shall be required
on all newly installed mains and service laterals. Underground warning tape is to be
placed 18 to 24 inches below the finished grade directly above the line. For
reclaimed water mains see section 02520. The metallic locating tape shall be per
paragraph 2.2.2, Warning Tape of this specification. No separate payment will be
made for locating tape as it is considered to be incidental to the cost of construction
of the line being installed.
C.
FLOWABLE FILL CONCRETE BACKFILL
When directed by OWASA’s Engineer, the Contractor shall backfill trenches or
undercut areas with flowable fill concrete plant mix. To allow for future reexcavation of filled area, concrete strength shall be liquid enough to flow, be selfleveling, and have an ultimate minimum strength 225 psi (this product is a
combination of sand and Portland cement). Except for structural applications, traffic
can be placed on mixture within an hour or two after placement. Final surfacing of
pavements; however, should be delayed if possible at least 24 hours to allow for
shrinkage and hydration of concrete. Settlement of 2" to 3" is to be expected.
The option to use flowable fill is open to the Contractor to reduce delay and
inconvenience to traffic. However, payment for flowable fill backfill is considered
incidental to the cost of construction unless a pay item has been provided in the
proposal, a change order has been approved, or the Contractor is ordered by the
OWASA’s Engineer to place flowable fill concrete as an emergency measure.
D.
SALVAGE OF USEABLE MATERIALS
All materials such as paving blocks, brick, castings, and pipe etc., removed during
excavation that is useable on this project shall be used after approval of its use by
OWASA’s Engineer or the applicable owner of the street right-of-way. Such
material shall be stockpiled on site. Unnecessary abuse and damage to these
items shall be the Contractor’s responsibility and the cost of replacement may be
deducted from the retainage.
END OF SECTION 02275
OWASA-Manual.Specs.OWASAdv02275UtilTrench.doc
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02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES
Div 02275 –Trenching, Backfilling and Compaction of
Utilities
Revision Summary Sheet
Section
No.
Rev
No.
Rev.
Date
OWASA.Revisions-Util Trenching.doc
By
Reason for change
What Changed
Back to Top
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02275-44
02510 - WATER DISTRIBUTION
(Last revised 04-09-15)
SUGESTED SEARCH WORDS FOR THIS SECTION
Part 1 – General
Part 2 – Products
Part 3 – Execution
Air Release Valve-Spec
Backflow Preventers
Butterfly Valve-Spec
Check Valve-Spec
Ductile Iron Pipe - Spec
DIP-Installation
DIP Fittings
DIP Joints
Fire Hydrant Painting
Hydrant Bagging
Fire Hydrant-Spec
Fire Hydrants-Setting
Gate Valves-Spec
1 ½” & 2” Service-Spec
Meter Boxes, Small-Spec
Meters
Parallel Pipe-Clearances
Pipe Crossing Clearances
Pipe Separation Req’ts
Pressure Test & Leakage
PVC Pipe Spec
Steel Encas’t Pipe-Install
Steel Encasement Pipe-Spec
Sterilization
Small Service Connections-Spec
Tape, Detector
Tunneling Method
Tunnel Liner - Spec
Tapping Sleeve & Valve-Spec
Vault Access Frames-Spec
Valve Boxes-Spec
Valves-Settings
PART 1 – GENERAL
1.1
RELATED DOCUMENTS
A. Drawings and general provisions of the Contract, including the General
Requirements and Supplementary Conditions apply to this specification.
B. Section 02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES.
1.2
SUMMARY
This section includes all equipment, labor, material, and services required for complete
installation of water distribution piping and specialties for municipal water and fireservice mains and services.
1.3
DEFINITIONS
A. GENERAL:
For the purposes of this specification, the following definitions refer to water
distribution systems that come under the authority of OWASA as specified within this
and other sections of this manual.
1) Combined Domestic and Fire Protection Service: Service supplying a
residential dwelling that includes an integrated fire suppression system.
2) Fire Service: Exterior fire fighting/suppression water piping.
3) Water Main: Exterior water systems for both domestic water and fire
suppression needs.
4) Water Service: Exterior water piping used to provide water for domestic
purposes.
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02510 – WATER DISTRIBUTION
5) The following are industry abbreviation for various pipe materials:
a.
b.
c.
d.
1.4
AC:
CI:
DIP:
RCP:
Asbestos Cement Pipe
Cast Iron Pipe
Ductile Iron Pipe
Reinforced Concrete Pipe
SUBMITTALS
A. Submit product data for the following:
1)
2)
3)
4)
5)
6)
7)
Pipe and Fittings.
Valves and accessories.
Water meters and accessories.
Detector Check Valves.
Backflow preventers and assemblies.
Fire Hydrants.
Fire Department Connections.
B. Submit shop drawings for the following:
1) Precast concrete vaults including frames and covers, drains, access hatches,
wall sleeves, valve support stands, prefabricated above ground vaults, and
backflow prevention devices.
1.5
QUALITY ASSURANCE
A. Materials and operations shall comply with the latest revision of all applicable Codes
and Standards.
B. Piping materials shall be marked clearly and legibly.
1) Ductile Iron Pipe shall show identification marks on or near bell as follows:
a.
b.
c.
d.
e.
f.
Weight,
Class or nominal thickness,
The letters “DI” or “Ductile,”
Manufacturer’s identifying mark,
Year in which pipe was made,
Casting period.
2) Steel pipe shall be marked as follows. Each length of pipe and each special
section shall be legibly marked by paint stenciling, die stamping, or hot-roll
marking to show the following:
a. Manufacturer’s name or mark,
b. Size and weight of the pipe or special section,
c. The type of steel from which the pipe or special section was made.
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02510 – WATER DISTRIBUTION
3) PVC Pipe shall show proper marking of pipe as required in the applicable
product specification and shall remain legible during normal handling, storage,
and installation. The manufacture date of the pipe must be within 1 year of the
date of installation. Marking of PVC pipe commonly includes:
a.
b.
c.
d.
e.
f.
g.
Manufacturer’s Name,
Nominal Pipe Size and Size Base,
PVC Cell Classification or Material Code,
Dimension Ratio or Standard Dimension Ratio,
Product Type, Pressure Class or Pressure Rating,
Standard Specification Designation,
Production Record Code.
C. Comply with Factory Mutual’s “Approval Guide” and Underwriters Laboratories, Inc.
“Fire Protection Equipment Directory” for fire-service main products.
D. NFPA Compliance: Comply with NFPA 24 for materials, installations, tests, and
flushing and valve and hydrant supervision for fire mains.
E. Comply with NSF 61 for materials for water service piping and specialties for
domestic water.
F. Comply with all applicable AWWA and ANSI standards.
1.6
QUALITY STANDARDS
A. Materials and operations shall comply with the latest revision of the Codes and
Standards listed below. The use of ASTM standard specification references without
a year designation implies the most current applicable specification.
AASHTO
American Association of State Highway Transportation
Officials.
ANSI
American National Standards Institute
AREA
American Railway Engineers Association
ASSE
American Society of Sanitary Engineers
ASTM
American Society for Testing and Materials
AWWA
American Water Works Association
FM
Factory Mutual System
FS
Federal Specifications
MSDS
Material Safety Data Sheets
NCDENR
North Carolina Department of Environment and Natural
Resources
NCDOT
North Carolina Department of Transportation
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02510 – WATER DISTRIBUTION
1.7
NSF
National Sanitation Federation International
NFPA
National Fire Protection Association
OSHA
Occupational Safety and Health Administration
UL
Underwriters Laboratories, Inc.
PRODUCT DELIVERY, STORAGE AND HANDLING
Materials used for the construction of water mains and appurtenances in OWASA’s
water distribution system shall be new, free of defects, and meet the highest standards
set forth. An authorized OWASA representative must inspect, review, and approve all
materials to be used for water lines and appurtenances prior to installation. At the option
of OWASA, any material installed without inspection will have to be sufficiently removed
for inspection and review. Any additions, deletions, or changes from the OWASA
approved plan set must be submitted to OWASA’s Engineer for approval, prior to
making changes in the field.
A. PIPE CONDITION/PIPE EXAMINATION:
1) New pipe inspection: Inspect each truckload of materials thoroughly upon
arrival at the site. Examine material for damage and to ensure that the right pipe
has been delivered to the site. Pipe shall be protected during handling against
impact shocks and free fall. Care shall be taken when unloading pipe to avoid
damaging the pipe lining. Pipe that has been damaged either in transit or during
unloading shall be plainly marked and shall not be used in the construction of the
utility. Pipe shall be kept clean at all times, and no pipe shall be used in the work
that does not conform to the appropriate ASTM specifications.
2) Pre-Installation Inspection: Prior to being installed, each section of the pipe
shall be carefully examined for damage and conformity with these specifications.
All pipe in which spigots and bells cannot be made to fit properly, or pipe, which
has chipped bells or spigots, will be rejected. All pipes damaged or deemed not
to conform to these specifications, shall be plainly marked and shall not be used
in the construction of the utility. The faces of all spigot ends and all shoulders on
the bells must be true, without lumps or rough edges, and be brought in fair
contact. Examine bell and spigot for uniformity and smoothness of liner and
barrel.
B. Inspect fittings and structures thoroughly upon arrival for damage.
damaged or rejected materials from site.
Remove
C. Observe manufacturer's directions for handling, delivery, and storage of materials
and accessories.
D. Protect pipe coating during handling using methods recommended by the
manufacturer. Use of bare cables, chains, hooks, metal bars or narrow skids in
contact with coated pipe is not permitted.
E. Protect stored piping from entry of water or dirt into pipe. Store pipe on shoulders
and not in ditch lines. String out no more pipe than can be installed in a day. Also,
protect bells and flanges of special fittings from entry of moisture and dirt. If pipe is
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02510 – WATER DISTRIBUTION
provided with end protectors, do not remove protectors until ready for installation or
for inspection. Once inspected, replace protectors.
F. Support pipe to prevent sagging or bending.
G. Use slings to handle valves and fire hydrants if size requires handling by crane or
other type of lift. Do not use handwheels or stems to lift or for rigging points.
H. Store fire hydrants and valves in such a way as to prevent entry of water and dirt into
openings. Support on skids or pallets off the ground or pavement. If fire hydrants or
valves are provided with end protectors, do not remove protectors until ready for
installation or for inspection. Once inspected, replace protectors. Protect valves
against damage to threaded ends or flanges.
1.8
PRODUCT SUBSTITUTIONS
OWASA’s Engineer will approve materials not specified but deemed equal, on a caseby-case basis. OWASA’s Product and Design Review Committee (PDRC) meets on an
“as-needed” basis to evaluate new products for incorporation into these specifications. If
submitting new products, submit in writing 60 days prior to date meeting date.
Documentation and samples of materials must be submitted to OWASA. New materials
approved for the water distribution system will be incorporated into these specifications
after approval by the PDRC.
1.9
PROJECT CONDITIONS
A. SEPARATION OF WATER AND SANITARY AND/OR COMBINED SEWERS
1) Follow the NCDENR standards for separation of water mains and sanitary
sewers lines.
2) PARALLEL INSTALLATIONS:
a. Preferred/Normal Condition – water lines shall be constructed at least
10 feet horizontally from a sewer or sewer manhole whenever possible.
The distance shall be measured edge-to-edge.
b. Unusual Conditions – when local conditions prevent a horizontal
separation of at least 10 feet, the water line may be laid closer to a sewer
or sanitary sewer manhole provided that:
i.
The water main shall be placed in a separate trench, with elevation of
the bottom of the water line at least 18 inches above the top of the
sewer; or
ii. The water main shall be placed in the same trench as the sewer, and
located to one side, on a bench of undisturbed earth, and the
elevation of the bottom of the water main shall be at least 18 inches
above the top of the sewer; or
iii. Where this vertical separation cannot be obtained, the sewer shall be
constructed of AWWA approved Ductile Iron Pipe pressure-tested in
place to 150 psi without leakage prior to backfilling. The sewer
manhole shall be of watertight construction and tested in place.
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02510 – WATER DISTRIBUTION
3) WATER MAINS CROSSING ABOVE SEWERS:
a. Preferred/Normal Condition – water lines shall be constructed to cross
over sewers whenever possible and shall be laid to provide a vertical
separation of at least 18 inches between the bottom elevation of the
water line and the top of the sewer.
b. Unusual Conditions – when local conditions prevent an 18 inch vertical
separation as described in Water Mains Crossing Above Sewers,
Preferred/Normal Condition (paragraph above), the following
construction shall be used:
i. Both the sewer and water line itself shall be constructed of AWWA
approved Ductile Iron Pipe with joints that are equivalent to water
main standards for a distance of 10 feet on each side of the point of
crossing.
4) WATER MAINS CROSSING BELOW SEWERS:
a. Unusual Conditions – when local conditions prevent an 18 inch vertical
separation, as described in paragraph C, Water Mains Crossing Above
Sewers, Preferred/Normal Conditions, above, the following construction
shall apply:
i.
That the section of the water pipe is centered at the point of the
sewer crossing so that water pipe joints shall be equal distant and
as far as possible from the sewer such that, for a 90 degree
crossing, the water main joints are a minimum of 10 feet on each
side of the point of crossing.
ii.
Provide adequate structural support for the sewers to prevent
excessive deflection of the joints, which can result in settling on
and/or breaking the water line.
iii.
The sewer main shall be designed and constructed of ferrous pipe
and shall be pressure tested at 150 psi (reference minimum design
criteria for the permitting of gravity sewers) to assure water
tightness prior to backfilling, or either the water main or sewer main
be encased in a water tight carrier pipe which extends 10 LF
beyond both sides of the crossing. These options shall comply with
15A NCAC 2T regulations section .0305.
5) WATER MAINS AND OTHER UTILITIES:
a. Horizontal Separation – Preferred/Normal Condition – water lines
shall be constructed to provide at least 3 feet of horizontal separation
from other utilities whenever possible. The distance shall be measured
edge-to-edge. For Asbestos Cement lines, provide a minimum 5 feet of
clear horizontal separation.
b. Vertical Separation – Preferred/Normal Condition – whenever it is
necessary for another utility to cross a water main, a 12-inch vertical
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02510 – WATER DISTRIBUTION
separation shall be maintained between the lines. When local conditions
prevent a 12-inch vertical separation, the following construction shall
apply:
i. Provide adequate structural support for the utility to prevent excessive
deflection of the joints, which can result in settling on and/or breaking
the water line.
6) Sanitary Sewer Manholes: No water mains shall pass through or come
in contact with any part of a sewer manhole. A minimum of 10 feet of
horizontal separation shall be maintained between water mains and
sanitary or combined sewer manholes provided that the applicable
provisions of paragraph B, Parallel Installations, Unusual Conditions,
above, are also met.
7) New Utilities and Existing Water Mains: When installing a new utility
adjacent to or in close proximity to an existing water main, the new utility
line shall be installed to provide the minimum horizontal and vertical
clearances specified in paragraph B, Water Mains and other Utilities.
1.10
LOCATING SERVICES
Contact “NC One Call” 1-800-632-4949 or the National Three Digit “Call Before You
Dig” 811 before digging.
1.11
COORDINATION
A. Coordinate tie-in to all water mains with OWASA’s Engineer. OWASA will be the
sole operator of all valves and hydrants on the OWASA water distribution system.
B. Contact OWASA Construction Inspector, Distribution and Collections Division or
OWASA Project Manager to coordinate interruption of service, operation of valves,
line cut-ins, or placement of a tapping sleeve and valve. If interruption is necessary,
the interruption shall be arranged to occur at such a time to cause the least
disruption and minimize loss of service. At the direction of OWASA’s Engineer,
temporary service may be required to be provided. Provide a minimum of 10
working day notice of the proposed utility interruption for necessary operation of
valves.
PART 2 – PRODUCTS
2.1
PIPE AND FITTINGS
NOTICE: The use of STANDARD GASKETS WITH PUSH-ON PIPE IS NO LONGER
PERMITTED for sizes less than 16 inches.
The following references provide the minimum standards as they apply to the specific
item listed. In all cases, the latest revision shall apply.
A. DUCTILE IRON PIPE
Ductile iron pipe shall be manufactured in accordance with all applicable
requirements of AWWA C151/ ANSI A21.51 for 4-inch and larger diameter pipe,
pressure class rated, Class 350, minimum (see Section 3 – Water & Sewer Design)
and shall be in 18 or 20-foot lengths. The thickness of Ductile Iron Pipe shall be
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02510 – WATER DISTRIBUTION
determined by considering trench load and internal pressure (the pressure zone and
variances in which the pipe will be used) separately in accordance with AWWA
C150/ANSI A21.50.
The ductile iron pipe shall be cement mortar lined with a seal coat in accordance
with AWWA C104/ANSI 21.4. Outside coat shall be a minimum of 1-mil bituminous
paint according to AWWA C151/ANSI A21.51 Section 51-8.1.
Each joint of ductile iron pipe shall be hydrostatically tested before the outside
coating and inside lining are applied at the point of manufacturer to 500 psi. Testing
may be performed prior to machining bell and spigot. Failure of ductile iron pipe
shall be defined as any rupture or leakage of the pipe wall.
All materials used in production of the pipe are to be tested in accordance with
AWWA C151 for their adequacy within the design of the pipe, and certified test
results are to be provided to OWASA upon request. All certified tests, hydrostatic
and material are to be performed by an independent testing laboratory at the
expense of the pipe manufacturer.
Push-on and mechanical joint pipe shall be as manufactured by the American Cast
Iron Pipe Company, Atlantic States Cast Iron Pipe Company, United States Pipe and
Foundry Company, or Griffin Pipe Products Company.
DUCTILE IRON JOINTS:
1)
Pipe joints shall be restrained by either mechanical joint or manufactured
restrained joint system, as outlined in number 3) below. The use of restraining
gaskets shall be permitted. This applies to all pipe sizes 4 inch through 12 inch.
Pipe 16 inch and larger shall be as approved by the OWASA Engineer.
Acceptable types of pipe joints are as follows:
a. Push-on Joint, Ductile Iron Pipe THE USE OF STANDARD PUSH-ON
GASKETS IS NOT PERMITTED! The pipe shall conform to AWWA
C151/ANSI A21.51 (such as "Fastite," "Tyton," or "Bell-Tite."). The
dimensions of the bell, socket, and plain end shall be in accordance with
the manufacturer's standard design dimensions and tolerances. The
gasket shall be of such size and shape to provide an adequate
compressive force against the plain end and socket after assembly to
affect a positive seal. Gaskets shall be manufactured of an acceptable
elastomeric material, and comply with AWWA C111/ANSI A21.11. and
shall be as manufactured by American Pipe (Fast-Grip), Griffen Pipe
(Talon RJ), US Pipe (Field Lok 350), Atlantic States (Sure Stop 350)
b. Mechanical Joint, Ductile Iron Pipe AND TEE BOLTS
i.
The mechanical joint shall consist of:
a) A bell cast integrally with the pipe or fitting and provided with an
exterior flange having cored or drilled bolt holes and interior
annular recesses for the sealing gasket and the spigot of the pipe
or fitting;
b) A pipe or fitting spigot;
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02510 – WATER DISTRIBUTION
c) Rubber EPDM material and comply with
A21.11 sealing gasket;
AWWA C110/ANSI
d) Separate ductile iron follower gland having cored or drilled bolt
holes; as outlined in number 3) below.
e) Stainless steel Tee Head bolts and hexagon nuts. All threads are
Coarse-Thread Series Class 2A, External and Class 2B, Internal,
per ANSI B1.1. Nuts to be furnished in accordance with ASTM
F594. Use of a stainless steel anti-seize compound is required or
specially coated nuts to prevent galling.
ii.
The joint shall be designed to permit normal expansion, contraction,
and deflection of the pipe or fitting while maintaining a leak proof joint
connection. The mechanical joint shall conform to the requirements
of Federal Specification WW-P-421, AWWA C111/ANSI A21.11, and
ASTM A536, Standard Specification of Ductile Iron Castings.
iii.
Tee bolts and nuts: All tee bolts shall be 304 or 316 stainless steel
with either a coated heavy hex nut, or the use of stainless steel antiseize compound, to prevent galling. Bolts shall conform to AWWA
C111/ANSI A21.11. This requirement supersedes all other bolt
references in the standard. Only bolts and nuts that are 304, or 316,
stainless steel shall be permitted for use in the OWASA jurisdiction.
iv.
Mechanical Joint Bolt Torque: See Section 3.1.A, paragraph 2, item
a, Installing Mechanical Joint Pipe, below.
c. Mechanical Joint Restraint: Acceptable types of joint restraints shall
be:
i.
Restrained Joints shall consist of the use of a mechanical joint
restraint system, using Megalug series 1100 mechanical joint restraint
by EBAA Iron Sales, Inc., Ford wedge action restrainer gland UFR
Series 1400, Sigma One-Lok, Tyler Union TUFGrip, or approved
equal. Bolt heads are to be “auto-torque” twist off. Auto-torque twist
off bolts are exempt from the stainless steel requirement. See
Standard Detail 512.08, sheet 2 of 2 for figure of Megalug.
ii.
Restrained Joint Pipe shall be TR Flex or Lok Tyte as manufactured
by United States Pipe and Foundry Company, Flex-Ring or Lok-Ring
as manufactured by American Cast Iron Pipe Company, Snap-lok as
manufactured by Griffin Pipe Products Company.
iii.
Concrete thrust blocking and rodding is required for connection to all
existing water mains or as shown on plans.
d. Flanged Joints shall be firmly bolted with machine bolts; however, where
valves or special fittings are attached to a flange pipe, stud or tap bolts
may be used, providing the number used and diameter for each joint is
the same for each respective size of pipe, specialty, or valve, as
recommended by the latest AWWA Standard for flanged drilling. Bolts
are specified in ANSI B18.2.1 and nuts are specified in ANSI B18.2.2.
Bolts and nuts are to be cold worked 304 stainless steel meeting ASTM
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02510 – WATER DISTRIBUTION
F593 Standard Specification for Stainless Steel Bolts, Hex Cap Screws
and Studs for sizes up to 1.5 inches. Stainless steel bolts and nuts shall
have a minimum yield strength of 50,000 psi. For high strength
applications, use 304L stainless steel bolts. Bolts shall be of sufficient
length to pass through two flanges and the nut threads shall be
accurately cut, close fitting, and the prevailing standard. Bolt heads shall
be cut square and nuts hexagon in shape, both the heads and nuts being
chamfered. Gaskets to be of 1/8-inch thick plain rubber (Styrene
Butadiene [SBR]) per AWWA C110/ANSI A21.11 or equal as approved
by OWASA’s Engineer.
2) DUCTILE IRON FITTINGS:
Fittings shall be ductile iron, grade 70-50-05, and shall conform to AWWA
C110/ANSI A21.10 or AWWA C153/ANSI 21.53 for compact fittings, pipe sizes 4
inches through 48 inches with the exception of manufacturer’s proprietary design
dimensions and thicknesses for iron, in accordance with AWWA C110/ANSI
A21.10. All ductile iron fittings shall have a minimum working pressure rating of
350 psi and shall be cement mortar lined and bituminous coated (minimum 1millimeter), in accordance with AWWA C104/ANSI A 21.4. The fittings shall be
tested and the manufacturer shall provide certified test results when requested
by OWASA. This testing shall include hydrostatic proof testing of fittings.
Glands, gaskets, and bolts shall conform to AWWA C111/ANSI A 21.11. The
use of push on fittings is not permitted. Acceptable manufacturers are:
American Cast Iron Pipe Company, Griffin Pipe Company, Union/Tyler Pipe
Company, or U. S. Pipe & Foundry Company. Acceptable types of fittings are:
a. Full Body Mechanical Joint Fittings: Full body ductile iron mechanical
joint fittings shall be class 250 minimum and shall conform to AWWA
C110/ANSI A21.10. Glands, Gaskets and Bolts shall conform to AWWA
C111/ANSI A21.11.
b. Mechanical Joint Fittings – Compact: Compact fittings shall be minimum
class 350 and shall comply with AWWA C 153/ANSI A21.53, pipe sizes 4
inches through 48 inches. Glands, Gaskets and Bolts shall conform to
AWWA C111/ANSI A21.11.
c. Mechanical Joint Restraints: Joint restraints shall consist of the use of a
Megalug joint restraint system using Megalug series 1100 mechanical joint
restraint by EBAA Iron Sales, Inc., Ford wedge action restrainer gland UFR
Series 1400, Sigma One-Lok, Tyler Union TUFGrip, or approved equal. Bolt
heads are to be “auto-torque” twist off. Auto-torque twist off bolts are exempt
from the stainless steel requirement. See Standard Detail 512.08, sheet 2
of 2 for figure.
B.
COPPER TUBE
Copper pipe shall meet ASTM B88 Standard Specification for Seamless Copper
Water Tube.
¾” and 1” copper pipe shall be Type “K” soft drawn copper pipe with flare type
brass fittings. See Standard Detail 515.01 and 515.02, sheets 1 and 2.
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02510 – WATER DISTRIBUTION
2” copper pipe shall be Type “K” hard drawn copper, brazed with Silvalloy, Excel,
SilFos, or approved equal comprised of 15% silver. Brazing temperature shall be
between 1,300 and 1,500 degrees Fahrenheit.
C.
PVC PIPE
PVC water pipe meeting ASTM D2241 Standard Specification for Poly (Vinyl
Chloride) (PVC) Pressure-Rated Pipe (SDR Series), SDR 21, class 200
minimum for pipe 2-inches in diameter and smaller. Pipe design shall also meet
AWWA M23, latest revision. PVC pipe larger than 2-inches in diameter is not
permitted. Pipe older one (1) year is not permitted for use. Joints in 2-inch pipe
shall be bell-end with gasket. PVC pipe less than 2-inch in diameter is not
permitted for use in the OWASA service area.
D.
STEEL CASING PIPE
1) Steel Casing Pipe: Pipe shall be high strength steel, spiral welded or
smooth-wall seamless manufactured in accordance with ASTM A139
Standard Specification for Electric-Fusion (Arc)-Welded Steel Pipe (NPS 4
and Over) and ASTM A283 Standard Specification for Low and Intermediate
Tensile Strength Carbon Steel Plates and consisting of grade “B” steel with a
minimum yield strength of 35,000 psi. All encasement pipes shall meet the
applicable NCDOT, Municipal, or AREA specifications but shall be no less
than 6 inches larger than the outside diameter of the carrier pipe bell. The
steel pipe shall be capable of withstanding the design load. No interior lining
and exterior coating shall be required except that all exposed metal is to be
coated with epoxy or asphaltic material. Casing pipe shall include pipe
carriers (Spiders) to support carrier pipe. The steel encasement pipe shall be
of leak proof construction and shall include end caps.
2) Spiders/Skids for Encasement Pipes: Spiders shall be placed at the bell of
each carrier pipe within a steel encasement. Steel Spiders/Skids shall be as
manufactured by ITT Grinnell, Charlotte, NC; Spider Manufacturing, Durham,
NC; Advanced Products & Systems (APS) model SSI with EPDM skids,
Lafayette, LA, or approved equal. See Standard Detail 517.01. For bolted
connections, bolts shall be 304 ASTM F593 stainless steel.
3) Steel Casing End Seals: Casing end seals shall be 1/8” thick synthetic
rubber seamless pull-on end seals with T-304 stainless steel banding with
100% non-magnetic worm gear mechanism. End seals shall permit pipe
movement while maintaining a seal.
Acceptable manufacturers are:
Advance Products & Systems, Inc., Lafayette, LA, or equal.
E.
TUNNEL LINERS AND APPURTENANCES
1) Grout mix for filling voids in between carrier pipe and tunnel shall consist of
the following materials properly mixed in proportions by weight.
a. 1.0 Part Cement.
b. 3.0 Parts Fine Sand, 100 Percent Shall Pass No. 16 Sieve.
c. 0.5 to 0.6 Part Water.
2) Tunnel lining construction shall comply with the “Specification for Steel
Tunnel Liner Plates” in the American Railway Engineering Association
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Manual for Railway Engineering. The design and shape of the liner plates
shall be such that erection and assembly of the liner plate structure can be
completely and readily effected from inside the tunnel. Plates shall be
accurately curved to suit the tunnel cross section, and all dimensions shall be
of the size and accuracy that plates of similar curvature shall be
interchangeable. All plates shall be connected by bolts on both longitudinal
and circumferential joints.
3) The steel lining shall consist of plates 16, 18, or 24 inches wide. Each
circumferential ring shall be composed of the number and length plates
necessary to complete the required shape shown on the drawings. The
nominal tunnel diameter shall be of sufficient size to install the carrier pipe.
4) Plates shall be one-piece steel meeting the requirements of ASTM A1011,
Standard Specification for Steel, Sheet and Strip, Hot-Rolled, Carbon,
Structural, High-Strength Low-Alloy, High-Strength Low-Alloy with Improved
Formability, and Ultra-High Strength, or ASTM A1008, Standard Specification
for Steel, Sheet, Cold-Rolled, Carbon, Structural, High-Strength Low-Alloy,
High-Strength Low-Alloy with Improved Formability, Solution Hardened, and
Bake Hardenable. Plates shall have an ultimate tensile strength of at least
42,000 psi and yield strength of 28,000 psi. Gage thickness shall be a
minimum of 8 gauge. The liner plate and bolts shall be galvanized in
accordance with ASTM A153. Standard Specification for Zinc Coating (HotDip) on Iron and Steel Hardware. In addition, the liner plates shall be asphalt
coated to meet AREA 1-14-13. For two flange plates, the minimum thickness
shall be 0.135 inches. Plates shall be manufactured by Armco Steel
Corporation, Commercial Shearing, Incorporated, Republic Steel
Corporation, or equal.
5) Grout holes 1½ inches or 2 inches (or larger) in diameter shall be provided in
each ring to permit grouting as the erection of the tunnel liner plates
progresses. Grout hole screw plugs shall be provided in plates.
6) Steel bolts shall meet requirements of ASTM A449 for plate thickness equal
to or greater than 0.209 inch and ASTM A307 for plate thickness less than
0.209 inch. The nut shall meet requirements of ASTM A307, Grade A.
7) Steel bolts shall meet requirements of ASTM A449, Specification for Hex Cap
Screws, Bolts, and Studs, Steel, Heat Treated, 120/105/90 ksi Minimum
Tensile Strength, General Use for plate thickness equal to or greater than
0.209 inch and ASTM A307, Standard Specification for Carbon Steel Bolts
and Studs, 60 000 PSI Tensile Strength for plate thickness less than 0.209
inch. The nut shall meet requirements of ASTM A307, Grade A.
F.
CARRIER PIPE FOR CASINGS AND TUNNELS
Carrier pipe shall be ductile iron pipe of the class indicated on the drawings.
G.
POLYETHYLENE PIPE
1) USED ONLY A THE DIRECTION OF THE OWASA REPRESENTATIVE. All
polyethylene pipe, tubing, and fittings shall conform to all applicable
provisions and requirements of the latest revision of AWWA C901, AWWA
C906, or CSA B137.1 and, by inclusion, all appropriate standard references
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therein. Polyethylene compounds utilized in the manufacture of products
furnished under this specification shall have a grade of PE24 with a minimum
cell classification of PE 234343(C, D, or E) for PE2406 materials, or a grade
of PE34 with a minimum cell classification of PE 345444(C, D, or E) for
PE3408 materials, as defined in ASTM D3350, Standard Specification for
Polyethylene Plastics Pipe and Fittings Materials. In conformance with
AWWA C901, AWWA C906, or CSA B137.1, they shall have a PPI
recommended Hydrostatic Design Basis (HDB) of 1250 psi (PE2406) or 1600
psi (PE3408) at a temperature of 73.4°F (23°C).
All materials that come in contact with water, including lubricants, shall be
evaluated, tested, and certified for conformance with ANSI/NSF Standard 61.
Clean re-work material of the same type grade, and cell classification
generated from the manufacturer’s own pipe and fitting production may be
used by the same manufacturer as long as the pipe, tubing, and fittings
produced meet the requirements of AWWA C901, AWWA C906, or CSA
B137.1.
2) REFERENCE STANDARDS:
AWWA C901: Polyethylene (PE) Pressure Pipe and Tubing, 1/2-inch through 3inch for Water Service.
AWWA C906: Polyethylene (PE) Pressure Pipe and Tubing, 4-inch through 63inch for Water Service.
ASTM D2657: Standard Practice for Heat Joining Polyolefin Pipe and Fittings.
ASTM D2683: Standard Specification for Socket-Type Polyethylene Fittings for
Outside Diameter-Controlled Polyethylene Pipe and Tubing.
ASTM D2837: Standard Test Method for Obtaining Hydrostatic Design Basis for
Thermoplastic Pipe Materials or Pressure Design Basis for Thermoplastic Pipe
Products
ASTM D3261: Standard Specification for Butt Heat Fusion Polyethylene (PE)
Plastic Fittings for Polyethylene (PE) Plastic Pipe and Tubing.
ASTM D3350: Standard Specification for Polyethylene Plastic Pipe and Fittings
Materials.
ASTM F1055: Standard Specification for Electrofusion Type Polyethylene
Fittings for Outside Diameter Controlled Polyethylene Pipe and Tubing.
PPI TR-3: Policies and Procedures for Developing Recommended Hydrostatic
Design Stresses for Thermoplastic Pipe Materials.
PPI TR-4: Recommended Hydrostatic Strengths and Design Stresses for
Thermoplastic Pipe and Fitting Compounds.
ANSI/NSF: Standard Number 61 for Drinking Water Systems Components –
Health Effects.
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02510 – WATER DISTRIBUTION
NSF Standard #14: Plastic Piping Components and Related Materials.
CSA B137.1: Polyethylene Pipe, Tubing, and Fittings for Cold Water Pressure
Services.
3) QUALIFICATION OF MANUFACTURERS:
The manufacturer shall have manufacturing and quality control facilities capable
of producing and assuring the quality of the pipe and fittings required by these
specifications. Given reasonable notice, the manufacturer’s production facilities
shall be open for inspection by OWASA or their representative. Qualified
manufacturers shall be approved by the Project Engineer.
Approved
manufacturers include Plexco Performance Pipe Division-Chevron Chemical
Company.
4) MANUFACTURER’S QUALITY CONTROL:
The manufacturer of the Polyethylene pipe and fittings shall have an established
quality control program responsible for inspecting incoming and outgoing
materials. Incoming polyethylene materials shall be inspected for density, melt
flow rate, and contamination. The cell classification properties of the material
shall be certified by the supplier. Incoming materials shall be approved by
Quality Control before processing into finished goods. Outgoing products shall
be tested as required in AWWA C901 or AWWA C906, as applicable.
5) PIPE AND TUBING:
Pipe and tubing furnished under this specification shall be manufactured using
compounds complying with the requirements of paragraph A above.
Dimensional performance characteristics shall conform to the requirements of
AWWA C901, C906, or CSA B137.1. The pipe’s DR (Dimension Ratio) and
Working Pressure (WPR) shall be as specified or shown on the drawings.
6) FITTINGS:
Polyethylene fittings furnished under this specification shall be manufactured
using compounds complying with the requirements of paragraph A above and all
appropriate requirements of AWWA C901, C906, or CSA B137.1. Socket type
fittings shall comply with ASTM D2683. Butt fusion fittings shall comply with
ASTM D3261. Electrofusion fittings shall comply with ASTM F1055. Mechanical
fittings produced from material not listed in paragraph A, above, shall be
approved only after submission of appropriate test data and service histories
indicating their acceptability for the intended service.
In all cases, the
specifications and requirements of the fittings supplied shall comply with the
appropriate section of AWWA C901, C906, or CSA B137.1.
7) PRESSURE CLASS:
The Pressure Class of the Polyethylene pipe and fittings shall be specified on the
basis of the Working Pressure Rating of the water system as defined in AWWA
C906. Recurring positive pressure surges of up to one half of the pipe’s nominal
pressure class and occasional pressure surges of up to 100% of the pipe’s
nominal pressure class may be ignored due to the fatigue endurance of the
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02510 – WATER DISTRIBUTION
polyethylene materials. Non-polyethylene fittings shall be specified and used in
accordance with the surge tolerance of the particular appurtenance in use.
8) MARKING:
Pipe and tubing shall be marked in accordance with either of AWWA C901,
AWWA C906, or CSA B137.1, whichever applies. Marking shall be legible and
shall remain legible under normal handling and installation practices. Indent
marking may be utilized provided; 1) the marking does not reduce the wall
thickness to less than the minimum value for the pipe or tubing, 2) it has been
demonstrated that these marks have no effect on the long term strength of the
pipe or tubing and, 3) the marks do not provide leakage channels when
elastomeric gasket compression fittings are used to make the joints.
Fittings shall be marked on the body or hub. Marking shall be in accordance with
either ASTM D2683, ASTM D3261, AWWA C906, or ASTM F1055, depending
on fitting type and the standard that applies. Mechanical fittings shall be marked
with size, body material designation code, pressure rating, and manufacturer’s
name or trademark.
9) WORKMANSHIP:
Pipe, tubing, and fittings shall be homogeneous throughout and free of visible
cracks, holes, foreign inclusions, blisters, dents, or other injurious defects. The
pipe, tubing, and fittings shall be as uniform as commercially practicable in color,
opacity, density, and other physical prosperities.
2.2
VALVES AND FIRE HYDRANTS
A.
GATE VALVES
1) Gate Valves, Resilient Wedge (2 inches through 12 inches): All gate
valves shall be iron body of the resilient wedge type complying with AWWA
C509 and shall be UL listed and FM approved for a working pressure of 200
psi. All internal parts shall be accessible without removing the body from the
line. The wedge shall be of cast iron completely encapsulated with resilient
material. The resilient sealing material shall be permanently bonded to the
cast iron wedge with a rubber-tearing bond to meet ASTM D429 Standard
Test Methods for Rubber Property-Adhesion to Rigid Substrates and AWWA
C550.
Non-Rising Stems (NRS) shall be cast bronze with internal collars in
compliance with AWWA. OS&Y stems shall be bronze. The NRS stuffing
box shall have two "O"-Ring seals above the thrust collar. These rings shall
be field replaceable without removing the valve from service.
Each valve shall be hydrostatically tested at 400 psi to the requirements of
both AWWA and UL/FM.
All gate valves 4 through 12 inches shall be of the mechanical joint type. 2inch gate valves shall be iron pipe threads.
All bolts and nuts shall be stainless steel.
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02510 – WATER DISTRIBUTION
Valves shall open counter-clockwise (left) and shall be equipped with a 2inch square AWWA operating nut.
The valve body and bonnet shall be coated interior and exterior with fusion
bonded thermosetting plastic or epoxy. ALL RUBBER GASKETS AND ORINGS SHALL BE MANUFACTURED WITH AN APPROVED
ELASTOMER.
Acceptable gate valves, sizes 4-inch through 12 inches, shall be:
Manufacturer
American Flow Control
Clow (M&H)
Mueller
Model
Series 2500SS
F-6100
A-2360-20
All resilient seat gate valves furnished for a project shall be from the same
manufacturer.
2) Gate Valves, Resilient Wedge (16 inches and larger): NOTICE: THESE
MUST BE APPROVED BY THE OWASA REPRESENTATIVE FOR USE!
Valves shall be iron body of the resilient wedge type complying with AWWA
C509 and shall be UL listed and FM approved for a working pressure of 250
psi. Valves shall meet or exceed the requirements of AWWA C515. Valve
body, bonnet, wedge, and operating nut shall be constructed of ductile iron.
The exterior of the ductile iron wedge shall be fully encapsulated with rubber.
The resilient sealing material shall be permanently bonded to the ductile iron
wedge with a rubber-tearing bond to meet ASTM D429 Standard Test
Methods for Rubber Property-Adhesion to Rigid Substrates and AWWA
C550. Buried and Non-buried valves shall have all internal and external
surfaces of the valve body and bonnet shall have a fusion-bonded epoxy
coating complying with AWWA C550, applied electrostatically prior to
assembly.
Non-Rising Stems (NRS) shall be cast bronze with internal collars in
compliance with AWWA. Stem and stem nut shall be high-strength bronze.
Stem shall be sealed by three O-rings. The NRS stuffing box shall have the
top two O-ring seals shall be replaceable with valve fully open and while
subject to full rated working pressure. O-rings set in a cartridge shall not be
allowed. Valve shall have thrust washers located with 1 above and 1 below
the thrust collar to ensure trouble-free operation of the valve.
Each valve shall be hydrostatically tested at 500 psi to the requirements of
both AWWA and UL/FM.
All gate valves (16” and larger) shall be of the flanged joint type.
Valves 16” and larger of the MJ type will require written approval from the
OWASA engineer.
All bolts and nuts shall be stainless steel.
Valves shall open counter-clockwise (left), be equipped with operational
assist with a 2-inch square AWWA operating nut. This can be in the form of
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02510 – WATER DISTRIBUTION
a Spur or Bevel gear. Bevel gear will require additional engineering for detail.
Or can come in the form of a bypass assembly. Bypass assembly will require
additional engineering for detail. ALL RUBBER GASKETS AND O-RINGS
SHALL BE MANUFACTURED WITH AN APPROVED ELASTOMER.
Gate valves 16” and larger shall be installed in a manhole. See detail 513.08.
Acceptable gate valves, sizes 16 inches and larger, shall be:
Manufacturer
American
Flow Control
Model
Series
2500
w/options
A-2361
w/options
Mueller
All resilient seat gate valves furnished for a project shall be from the same
manufacturer.
3) Inserting Valves: Inserting valves shall meet requirements of gate valves
specified above for valve mechanism and AWWA C110/ANSI A21.10 for the
sleeve for pressure ratings shown on the drawings.
4) Gate valves smaller than 3 inches shall be resilient seat, solid wedge,
inside screw, non-rising stem, bolted bonnet, stainless steel bolts, and
threaded ends. All valves shall be furnished with a 2-inch operator nut and
open left. ALL RUBBER GASKETS AND O-RINGS SHALL BE
MANUFACTURED WITH AN APPROVED ELASTOMER. Acceptable gate
valves are:
Manufacturer
American Flow Control
Clow (M&H)
Mueller
B.
Model
2502SS Series
F-6103
H-2360-8
COMBINATION AIR VACUUM VALVE
Automatic Air and Vacuum Valves shall be infinitely variable automatic air
and vacuum valves designed to allow escape of air, close watertight when
liquid enters the valve and allow air to enter in the event of a vacuum. The
valve shall be a NPT threaded Stainless Steel body. The valve outlet is to be
protected from debris entering the outlet of the valve. Valves shall be all brass.
Valves shall be designed for a maximum cold water pressure of 200 psig.
Combination air and vacuum release valves shall be located as shown on the
drawings or as otherwise directed by OWASA’s Engineer. The valve shall be
housed in a precast concrete eccentric manhole and shall be installed in
accordance with Standard Detail 538.01. Acceptable Models are, X-Series (1 or
2 inch outlet) by Crispin-Multiplex Manufacturing Co. and 986 Stainless Steel by
H-Tec Inc.
Size
Manufacturer
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April 2015
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02510 – WATER DISTRIBUTION
2-inch
Crispin
Type X Series
2-inch
H-Tec
986 Stainless
Steel
Manhole units shall consist of standard modular precast riser sections, modular
riser sections, and a doghouse base. Where conditions do not favorably
accommodate the use of an eccentric cone, eccentric precast reinforced
concrete flat tops are to be used. See Standard Details 513.04 and 513.05.
C.
BUTTERFLY VALVES
Butterfly valve applications 16 inches and larger, shall meet AWWA C504,
AWWA Standard for rubber-seated butterfly valves. See Standard Detail
513.06. OWASA’s Engineer must approve the installation of 16-inch and larger
butterfly valves. Valves shall be short body and rated at no less than 250 psi.
Valves shall be flanged joint in accordance with AWWA C111. Accessories
(bolts, glands, and gaskets) shall be supplied by the valve manufacturer.
All bolts shall be stainless steel.
Valve operators shall meet the requirements of AWWA C504 and shall be of the
traveling-nut type, sealed, gasketed, and lubricated for direct-bury underground
service. Valve operators shall be sized for the pressure indicated on the
drawings. Operator shall be capable of withstanding an input torque of 450 ft-lbs
at full open or closed position, without damage to the valve or valve operators.
Valves shall be factory tested in accordance with Section 5 of AWWA C504
specification. Upon request the manufacturer shall furnish certified copies of test
reports.
Valves shall open counter-clockwise (left) and shall be equipped with a 2-inch
square AWWA operating nut and have a 4 to 1 gear ratio.
Valves shall be coated interior with fusion bonded thermosetting plastic, rubber,
or epoxy. The exterior of buried valves shall be epoxy coated per AWWA C550
standard. ALL RUBBER GASKETS AND O-RINGS SHALL BE
MANUFACTURED WITH AN APPROVED ELASTOMER.
Acceptable butterfly valve manufacturers are:
Manufacturer
Clow (M&H)
Mueller / Pratt
DeZurik
Model
4500-02(250 psi) FLG by FLG
Linseal XP 250B FLG by FLG
/ Triton HP250 FLG by FLG
BAW/EPDM (250 psi) FLG by
FLG
All Butterfly valves furnished for a project shall be from the same manufacturer.
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Butterfly valves shall be placed in a precast concrete manhole. See Standard
Detail 513.06.
D.
CHECK VALVES
All swing check valves used for pressure zone separation shall be iron body, with
a disc of extra heavy cast iron, ASTM A126 Standard Specification for Gray Iron
Castings for Valves, Flanges, and Pipe Fittings construction, bronze mounted
with either mechanical joint or flanged ends as noted on the drawings. Standard
mechanical joint ends shall be furnished with bolts, glands, and rubber gaskets.
ALL RUBBER GASKETS AND O-RINGS SHALL BE MANUFACTURED WITH
AN APPROVED ELASTOMER. Flanged ends shall be provided with bolts and
gaskets. The shaft shall be of 304 stainless steel and the seat ring shall be of
bronze with an easily replaceable resilient disc seat. The valve shall be tight
seating.
Check valves shall be non-slamming (such as shock absorber) type. All valves
shall have a minimum non-shock cold-water pressure rating of 250 psi.
Flanged check valves shall meet the dimensional requirement of ANSI B16.1 and
meet or exceed the requirements of ANSI/AWWA C-508.
When more positive control is needed a lever-and-spring may be specified.
When check valves are used in vault applications, a ball drip valve is to be
provided.
All check valves shall be furnished with an arrow cast into the body indicating the
direction of flow during system operation.
Acceptable manufacturers are:
Manufacturer
G. A. Industries
American Flow Control
E.
Model
Model 250-U
Series 2100
CROSS-CONNECTION CONTROL
Refer to OWASA Cross-Connection Control Ordinance and Manual adopted
January 21, 1999, latest revision as applicable.
F.
TAPPING SLEEVES AND VALVES
The tapping sleeve and valve shall be suitable for wet installation without
interrupting water service.
1) Iron Body Tapping Sleeve: The sleeve body shall be of split type, full body
ductile iron construction with mechanical joint ends and epoxy coating (10 mil
minimum). The sleeve shall be suitable to fit the type and class of pipe being
tapped. The mechanical joint type shall have longitudinal compound rubber
gaskets that fit against the rubber end gaskets effecting a totally enclosed
rubber, watertight seal. Side and end bolts shall be stainless steel. Tapping
sleeve shall meet the requirements of AWWA C110/ANSI 21.10. For
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02510 – WATER DISTRIBUTION
asbestos cement pipe, the Contractor shall measure the diameter of the pipe
prior to selecting a tapping sleeve to ensure the sleeve will fit the pipe (this
information shall be provided to OWASA on the as-built drawings). See
Standard Detail 512.04.
Acceptable resilient seat tapping sleeves are listed below:
Manufacturer
American Flow Control
Mueller
Tyler/Union
Model
2800-C for CI to PVC
2800-A for AC
H-615 for CI to PVC
H-619 for AC
For CIP/DIP to DIP
2) Tapping Valves: Resilient seat tapping valves shall be epoxy coated
(minimum 10 mil thickness) and otherwise meet the requirements of Section
2.2.1, Gate Valves, except that the seat openings shall be larger than
nominal size with a raised alignment ring on the flange. Valve ends shall be
mechanical joint by flange. Valves shall open counter-clockwise (left) and
shall have a 2-inch operator nut. See Standard Detail 512.04.
All bolts and nuts are to be stainless steel.
Tapping valves shall be an "O" ring type mechanical joint end conforming to
AWWA non-rising stem construction. Inlet flange end shall be Class 125
(ANSI B16.1). ALL RUBBER GASKETS AND O-RINGS SHALL BE
MANUFACTURED WITH AN APPROVED ELASTOMER.
Acceptable
resilient seat tapping valves are listed below:
Manufacturer
American Flow Control
Clow
Mueller
G.
2500 TM
F-6114
T-2360
Model
FIRE HYDRANTS
1) See Standard Details 514.02 and 514.03. ALL RUBBER GASKETS AND
O-RINGS SHALL BE MANUFACTURED WITH AN APPROVED
ELASTOMER. ALL BRASS PRODUCTS SHALL BE LEAD FREE AND
COMFORM TO NSF61-ANNEX G IN CONJUNCTION WITH NSF372
REQUIREMENTS. Fire hydrants shall comply with ANSI/AWWA C502, latest
revision, UL 246 and FM1510. Hydrants shall be hub end, triple nozzle,
improved AWWA type. Interior coating to be in accordance with AWWA
C550. Minimum working pressure shall be 250 PSI working pressure in ALL
pressure zones. Hydrants shall consist of the following:
a.
b.
c.
d.
Two 2½-inch fire nozzles and one 4½-inch steamer nozzle, National
Standard hose threads.
All nozzles shall be provided with caps and chains.
The hydrant valve opening shall be 5¼ inches.
Bronze to bronze threads shall be provided between the hydrant seat or
seat ring and the seating attaching assembly.
OWASA – Manual of Specifications, Standards and Design
April 2015
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02510 – WATER DISTRIBUTION
e.
f.
g.
h.
i.
j.
k.
l.
m.
n.
o.
All hydrants must include cast or ductile epoxy lined shoe (minimum 4
mils), rubber drain seals and positive protective valve stop device.
Hydrants shall open left and shall have a National Standard pentagontype operating nut (1 ½” point to flat). The operating nut shall be of
one-piece bronze construction. A thrust washer shall be supplied
between the operating nut and stem lock nut. The valve stem shall
have a safety flange and a safety coupling.
Hydrants shall have a 6-inch hub-end or mechanical joint elbow.
The hydrant barrel shall be of sufficient length to provide a minimum
bury of 4 feet.
Hydrants shall be of the compression type closing with line pressure
and shall be of the traffic model breakaway type.
Hydrant cap and stuffing box shall be of unitized, one-piece design
creating a watertight cavity without the use of gaskets.
The
combination of O-Rings to a crimped brass ferrule around the stem
shall seal the cavity from contact with water. Hydrant caps shall have a
means for providing periodic lubrication of the operating threads.
The main valve shall be of synthetic rubber reinforced with steel. The
seat shall be of a bronze ring threaded to a bronze insert in the hydrant
shoe, with O-Rings to seal the drain way and barrel from leakage of
water in the shoe.
The hydrant drain hole shall momentarily force flush with each
operation.
All hydrant extension kits, flange kits, stems, couplings or other repair
parts must be of the original hydrant manufacturer. Only one 24-inch
extension kit is allowed.
Hydrants are to be painted in accordance with Standard Detail 514.01.
Barrels are to be painted red with the caps and bonnet painted
reflective silver.
If line is to be pressurized within 7 days of setting hydrant, then 4000psi high early strength concrete shall be used.
Approved fire hydrants including model and manufacturer are listed below:
Manufacturer
Clow (M&H)
Mueller
American Flow Control
Model
F-2545 Medallion
A-423 Super Centurion 250
B62B Traffic Model (Long Barrel)
All hydrants furnished for a project shall be from the same manufacturer.
See Section 3.2.E, Fire Hydrants for installation requirements.
H.
BLOW OFFS
Blow-Off Assembly for Future Extension: Blow-off assemblies for future
extensions shall consist of two standard valve boxes, one for a NRS gate valve
and one for a 2-inch brass pipe riser (see Standard Detail 514.05), thrust collar,
a push-in plug tapped for 2-inches, a 2-inch brass pipe riser with a 2-inch
threaded male threaded plug.
Permanent Blow-Off Assembly: Permanent blow-off assemblies shall consist
of a standard valve box (see Standard Detail 514.06) with a concrete stabilizing
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02510-21
02510 – WATER DISTRIBUTION
pad, a NRS gate valve, a mechanical joint reducer as applicable, thrust collar, a
riser with elbow and blocking, and if applicable, a flange 90 degree elbow placed
above grade. See Standard Details 514.04 and 514.06.
I.
CORPORATION STOPS
ALL BRASS PRODUCTS SHALL BE LEAD FREE AND COMFORM TO
NSF61-ANNEX G IN CONJUNCTION WITH NSF372 REQUIREMENTS. ALL
RUBBER GASKETS AND O-RINGS SHALL BE MANUFACTURED WITH AN
APPROVED ELASTOMER. Corporation stops for ¾-inch and 1-inch taps only
shall be all bronze CC tapered threaded inlet by flare copper outlet, as
manufactured by Ford or Mueller. Acceptable corporation stops shall be the
Ford FB600-(3 OR 34)-NL Series or the Mueller B25000N Series. 2-inch
corporation OR BALL stops are not permitted. See Standard Detail 512.06.
2.3
MISCELLANEOUS APPURTENANCES
A.
DETECTABLE WARNING TAPE
Metallic Underground Warning Tape: Metallic detectable underground warning
tape shall consist of a solid aluminum foil core, 35 gauge minimum, encased on
each side with plastic (minimum overall thickness 5 mils) and be 3 inches wide
with black lettering imprinted on a color coded background that conforms to
APWA uniform color code specification (BLUE) and silver with black ink letters.
Minimum tensile strength shall be 22 lbs/inch. Soil tolerance range to be pH 2.5
to pH 11.0. On one side of the tape, the text shall include the wording “WATER
LINE BELOW” repeated along the length of the tape. Underground warning tape
is to be placed 18 to 24 inches below the finished grade directly above the line.
Tracer Wire: Tracer wire shall be as manufactured by Copperhead Industries,
LLC. The wire shall be 12 AWG superflex expanded or approved equal. The wire
color shall be appropriate for the utility being installed. Blue for potable water,
green for sewer, purple for reclaimed water, etc…
B.
DUCTILE IRON TRANSITION COUPLINGS
Transition couplings shall be ANSI/NSF Standard 61 Certified, fusion bonded
powder epoxy coating and constructed of ASTM A536 Standard Specification for
Ductile Iron Castings, grade 65-45-12 ductile iron flanges and middle ring.
Coupling to be rated at a minimum of 200 psi working pressure per AWWA
C219, and -20ºF to 212º F. Gaskets shall be specially compounded new rubber
polymer suitable for use on water and sewage. Bolts are to be stainless steel
18-8 Type 304. Transition couplings are to accommodate IPS PVC, C-900 PVC,
Ductile Iron Pipe, Cast Iron, and Asbestos Cement Classes 100/150/200.
Acceptable couplings are Smith-Blair Type 441 and 461, JCM 240 for line sizes
3-inch through 12-inch and the Dresser Style 253 Modular Cast Coupling (2-inch
through 16-inch), Ford Style FC2W Ultra-Flex Ductile Iron Wide Range Coupling
(4-inch through 12-inch). ALL RUBBER GASKETS AND O-RINGS SHALL BE
MANUFACTURED WITH AN APPROVED ELASTOMER.
C.
MISCELLANEOUS CONCRETE WORK
Concrete classes (NCDOT) to Design Compressive Strength at 28 days (f’c):
OWASA – Manual of Specifications, Standards and Design
April 2015
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02510 – WATER DISTRIBUTION
.
Concrete shall be constructed of a minimum of 3000 psi concrete at 28 days.
Ready mixed concrete shall comply with ASTM C94, Standard Specification for
Ready-Mixed Concrete. This applies to concrete blocking, valve box stabilizing
pads, thrust collars, concrete encasement, and Fire Hydrant setting and thrust
pads. All exposed concrete shall be air entrained.
D.
BEDDING
Bedding material, when specified, shall be clean coarse aggregate No. 57, and
shall meet the requirements of section 1016-3, Classifications of the NCDOT
Standard Specifications for Roads and Structures, latest revision for class VI
stone.
E.
PRECAST CONCRETE MANHOLE STRUCTURES
Structures of precast reinforced concrete manholes shall be designed and
manufactured in accordance with ASTM C478, Standard Specification for
Precast Reinforced Concrete Manhole Sections, latest revision (“O” ring joints),
or AASHTO M-199 (gasketed joints). The standard joint shall be sealed with
plastic cement putty meeting Federal Specification SS-C-153. An “O” ring or
“mastic” joint seal may be used. The “O” ring joint shall conform to the
requirements of ASTM C443 Standard Specification for Joints for Circular
Concrete Sewer and Culvert Pipe, Using Rubber Gaskets. Type Concrete used
in the construction of the manholes shall have a minimum 28-day compressive
strength of 4000-psi air entrained (with 4 to 6 percent air) conforming to ASTM
C33 Standard Specification for Concrete Aggregates and ASTM C94 Standard
Specification for Ready-Mixed Concrete. Manholes shall have monolithic base
and eccentric cone flat top as applicable. See Standard Details 513.04, 513.05,
and 513.06.
Structures are not permitted to have steps.
Acceptable
manufacturers are: Oldcastle Precast/N. C. Products Concrete Corporation,
Stay-Right Tank, Concrete Pipe and Precast, LLC (Hanson), Precast Solutions,
Mack Industries or Tindall Precast Concrete Products, Inc.
Manhole Size Determination:
F.
1)
Unless shown otherwise, the minimum diameter of manholes shall be 5
feet.
2)
Manholes with 16-inch diameter or larger pipe shall be a minimum of 6-foot
diameter.
PRECAST UNDERGROUND CONCRETE UTILITY STRUCTURES
Structures of precast reinforced concrete shall be designed and manufactured in
accordance with ASTM C858, Standard Specification for Underground Precast
Concrete Utility Structures, latest revision with preformed butyl rubber joint
sealant meeting ASTM C990, Standard Specification for Joints for Concrete
Pipe, Manholes, and Precast Box Sections Using Preformed flexible Joint
Sealants, latest revision. Type Concrete used in the construction of the Utility
Structures shall have a minimum 28-day compressive strength of 4000-psi air
entrained (with 4 to 6 percent air) conforming to ASTM C33 Standard
Specification for Concrete Aggregates and ASTM C94 Standard Specification for
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02510-23
02510 – WATER DISTRIBUTION
Ready-Mixed Concrete. Unless shown otherwise on the drawings, structures are
not to have steps. Steel reinforcing shall conform to the requirements of ASTM
C857, Standard Practice for Minimum Structural Design Loading for
Underground Precast Concrete Utility Structures, latest revision. Structures shall
be designed for an H20-44 loading in traffic areas. Acceptable manufacturers
are: Oldcastle Precast/N. C. Products Concrete Corporation, Stay-Right Tank,
Concrete Pipe and Precast, LLC (Hanson), Precast Solutions, Mack Industries,
Tindall Precast Concrete Products, Inc. or M.C. Precast Concrete.
G.
MANHOLE FRAME AND COVERS
Manhole frames and covers shall be meet ASTM A48 Standard Specification for
Gray Iron Castings, Class 30, traffic frame and cover as manufactured by Capitol
Foundry, US foundry or East Jordan Iron Works. Cover shall read OWASA,
“WATER” in the center and “DANGER ENTRY PERMIT REQUIRED” around the
circumference. See Standard Detail 516.01. Provide four 1-inch diameter holes
in the top at each compass point.
Weights shall not vary more than 5% +/- of the weight shown on Standard Detail
516 .01.
Acceptable Manufacturers and models are:
Manufacturer
Capitol Foundry
US Foundry
East Jordan Iron Works
H.
Model
MH-2001
USF-669
V-1384
PIPE SADDLE SUPPORT - ADJUSTABLE
Adjustable Pipe Saddle Support - For Dry Conditions 2½-inch through 36inch pipe: Material to be cast iron saddle formed to ductile iron pipe, with lock
nut, and special cast iron reducer. Vertical adjustment range to be from 0 up to
4½ inches.
Adjustable pipe saddle supports shall comply with Federal
Specification WW-H-171E (Type 39). Pipe saddle supports shall equal or
exceed the Standon Model S92, as manufactured by Material Resources, Inc.,
Hillsboro, OR., or Grinnell Figure 259.
Adjustable Pipe Saddle Support For Wet or harsh corrosive conditions 2inch through 24-inch pipe: Material to be steel saddle formed to ductile iron
pipe, lock nut, and special steel reducer. Vertical adjustment range to be from 0
up to 4½ inches. Material to be 100% 304 stainless steel with saddles formed of
ductile iron pipe. Saddle strap to meet ASTM A36 Standard Specification for
Carbon Structural Steel.
Collar and base cups ASTM A53 Standard
Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and
Seamless D.O.M. tubing. Thread Stud to meet ASTM A36, rolled thread, grade
ASTM A307 Standard Specification for Carbon Steel Bolts and Studs, 60,000PSI Tensile Strength. Base Plate to meet ASTM A36 sheet steel, 0.25-inch.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02510-24
02510 – WATER DISTRIBUTION
Pipe saddle support shall equal or exceed the Standon Model S92, as
manufactured by Material Resources, Inc., Hillsboro, OR., or approved equal.
I.
SERVICES
1) DOMESTIC / IRIGATION SERVICES:
General:
State Requirements (House Bill 2499) includes new legislation designed to
improve drought preparedness and response.
More specifically, “Local
government water systems and large community water systems shall require
separate meters for new in-ground irrigation systems that are connected to their
systems”. This requirement shall become effective on July 1, 2009.
Specific Requirements:
Effective July 1, 2009, connections for irrigation service or meter may not occur
behind (on the customer-side) of the domestic water meter.
All irrigation services must connect to the public water system and all meters
must be purchased from and installed by OWASA. All work to install irrigation
services which connect to the existing, in-service water lines will be performed by
OWASA personnel.
Standard irrigation service for a 5/8” meter shall be accomplished using a ¾”
service line tapped to the public main. There will be no ‘splitting’ of service from
an existing ¾” domestic line to connect a new irrigation service and meter.
Only 1-inch and larger services may be tapped into or ‘split’ for construction of a
service line and irrigation meter. One inch services that are already being
utilized as a dual service setup for domestic service (i.e. already have two 5/8”
meters connected) cannot be further ‘split’ for installing an additional irrigation
meter.
2) SMALL SERVICES: 3/4-INCH AND 1-INCH WATER SERVICES:
Type K Copper, soft drawn; comply with ASTM B88, Standard Specification for
Seamless Copper Water Tube, FS WW-T-799 (2-inch and smaller pipe).
Services shall be ¾-inch to 1-inch and shall be one continuous run from main to
meter with no joints or couplings in between. On these water services, the
fittings shall be brass AWWA C-800, flared copper type fittings. See Standard
Detail 515.01 and 515.02.
Service saddles shall be used on all service connections. Direct service taps are
not permitted. See Standard Detail 512.06.
Service Saddles: ALL BRASS PRODUCTS SHALL BE LEAD FREE AND
COMFORM TO NSF61-ANNEX G IN CONJUNCTION WITH
NSF372
REQUIREMENTS. ALL RUBBER GASKETS AND O-RINGS SHALL BE
MANUFACTURED WITH AN APPROVED ELASTOMER. Saddles shall be all
bronze saddle with either a single or double bronze strap and a grade 60
neoprene "O" ring gasket attached to the body. The saddle casting, straps, and
nuts shall be water works bronze 85-5-5-5. The saddle shall have CC flared
OWASA – Manual of Specifications, Standards and Design
April 2015
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02510 – WATER DISTRIBUTION
corporation stop threads. See Standard Detail 515.01 and 515.02. Acceptable
service saddles are:
Manufacturer
Ford
Mueller
Model
101B Series
BR1B
Water Service 5/8 x 3/4-inch and 1-inch meter setter/yoke: ALL BRASS
PRODUCTS SHALL BE LEAD FREE AND COMFORM TO NSF61-ANNEX G
IN CONJUNCTION WITH
NSF372 REQUIREMENTS. ALL RUBBER
GASKETS AND O-RINGS SHALL BE MANUFACTURED WITH AN
APPROVED ELASTOMER. 5/8-inch x ¾-inch and 1-inch meter setters/yokes
shall conform to AWWA C800 and be factory tested for water-tightness before
shipping. Setters shall be comprised of all brass and copper padlock wing stop
inlet ball valve (lockable cut-off), angle double check outlet valve, with inlet and
outlet copper connections, and a 12-inch rise. See Standard Detail 515.01.
Acceptable meter setters/yokes are:
Size
5/8-inch x ¾-inch
1-inch
Both 5/8-inch x ¾inch and 1-inch
Manufacturer
Ford
Ford
Mueller
Model
VBHH72-12W-11-33-NL
VBHH74-12W-11-44-NL
B-2404N-2A & two H14222N couplings
Combined Domestic and Fire Protection SERVICE 3/4 x 3/4-inch and 1-inch
meter setter/yoke: 3/4-inch x 3/4-inch and 1-inch meter setters/yokes shall
conform to AWWA C800 and be factory tested for water-tightness before
shipping. Setters shall be comprised of all brass and copper padlock wing stop
inlet ball valve (lockable cut-off), angle double check outlet valve, with inlet and
outlet copper connections, and a 12-inch rise. See Standard Detail 515.02.
Acceptable meter setters/yokes are:
Size
Manufacturer
Model
5/8-inch x ¾-inch
Ford VBHH73-11-33-NL
1-inch
Ford VBHH74-12W-11-44-NL
Both 5/8-inch x ¾B-2404N-2A & two HMueller
inch and 1-inch
14222N couplings1
Notes:
1
Specify size of yoke when ordering Mueller setter
Meter boxes: Meter boxes shall be 12-inch deep lightweight boxes with heavyduty lid/cover. The box shall be ultraviolet light and chemical resistant as well as
unaffected by freezing and moisture. Boxes shall equal or exceed model WAO41118-12C as manufactured by CDR Systems Corporation, Ormond Beach, FL.,
Model MSBCF1118-12 by Mid-States Plastics, Inc. Sterling, KY. or approved
equal. See Standard Detail 515.01 and 515.02.
3) 2-INCH WATER SERVICES:
Type K Copper, hard drawn; comply with ASTM B88, Standard Specification for
Seamless Copper Water Tube, FS WW-T-799. Water service pipe for 2-inch
connections shall be type "K" hard drawn copper with silver soldered joints with
brass fittings and shall be one continuous run from main to meter with no joints
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02510-26
02510 – WATER DISTRIBUTION
or couplings in between. On these water services, the fittings shall be threaded
type brass fittings. 1 ½” copper tubing is not permitted.
The service line for a 2-inch meter shall consist of a 2-inch tap, 2-inch type K
hard drawn copper service line, a 2-inch Clow F6103, AFC series 2500SS, or
Mueller H-2360-8 threaded Iron Body Gate Valve and a 2-inch x 4-inch long
threaded (iron pipe thread) brass nipple. See Standard Detail 515.04.
Service saddles: ALL BRASS PRODUCTS SHALL BE LEAD FREE AND
COMFORM TO NSF61-ANNEX G IN CONJUNCTION WITH
NSF372
REQUIREMENTS. ALL RUBBER GASKETS AND O-RINGS SHALL BE
MANUFACTURED WITH AN APPROVED ELASTOMER. Service saddles shall
be 2-inch all bronze saddle with double bronze straps and with a grade 60
neoprene "O" ring gasket attached to the body. The saddle casting, straps, and
nuts shall be water works bronze 85-5-5-5. The saddle shall have 2-inch iron
pipe threads. Acceptable service saddles are:
Manufacturer
Ford
Mueller
Model
202B Series
BR2B
2-inch meter setter/yoke: ALL BRASS PRODUCTS SHALL BE LEAD FREE
AND COMFORM TO NSF61-ANNEX G IN CONJUNCTION WITH NSF372
REQUIREMENTS. ALL RUBBER GASKETS AND O-RINGS SHALL BE
MANUFACTURED WITH AN APPROVED ELASTOMER. Meter Setters shall
be constructed from 85-5-5-5 Brass (AWWA C800) and copper tubing, and
factory tested for water-tightness before shipping. 2-inch meter setter/yoke shall
be comprised of all brass and copper padlock wing inlet ball valve (lockable cutoff), angled double check outlet ball valve, 1 ¼-inch by-pass line with a 1 ¼-inch
stop ball valve, in-line double check valve, and brace pipe eyelets for 1-inch pipe.
Outlet connections are to be threaded.
See Standard Detail 515.04.
Acceptable meter setters/yokes are:
Size
Manufacturer
2-inch
Ford
2-inch.
Mueller
Model
VBHH77-18BHC-11-77 (standard 18-inch rise)
Ford Drawing No. B-95270-02
Mueller Drawing No. B2423-2 (must specify 2inch meter with 15-inch rise)
Meter Setter Idlers: ALL BRASS PRODUCTS SHALL BE LEAD FREE AND
COMFORM TO NSF61-ANNEX G IN CONJUNCTION WITH
NSF372
REQUIREMENTS. Meter idlers shall be provided for the 2-inch setter. The idler
is used to maintain proper spacing until a system is ready for a meter to be set.
The meter idler for a 2-inch setter is manufactured by Ford and is designated as
No. 7 Idler.
Small Meter Vaults: Small meter vaults shall be constructed of precast concrete
See section 02510-2.3.E. The size and shape shall be as shown on Standard
Detail 515.04. The cover shall have a minimum opening dimension of 30 inches
x 36 inches. The access hatch shall be constructed with an aluminum tread
plate cover, extruded aluminum frame with concealed hinges, hatch drain, and
stainless steel hardware. The hatch shall have a slam lock and shall have an HOWASA – Manual of Specifications, Standards and Design
April 2015
Page 02510-27
02510 – WATER DISTRIBUTION
20 load rating. Vaults located within vehicular travel lanes shall meet the
minimum AASHTO guideline H-20 traffic loads for full H20 loads. See
specification Section 2.3.L, Vault Access Hatch, below. Acceptable hatches are:
Manufacturer
Bilco
Halliday Products
US Foundry &
Manufacturing Corporation
Model
J-3AL-H20
H1R3036
THS 30x36 W/OP
4) LARGE METER SERVICES (3-INCH AND LARGER):
Piping: For services greater than 2 inches, the water service pipe shall be 4, 6,
8, 10, or 12 inches in diameter and shall be constructed of ductile iron pipe. 3inch meters shall be served by a 4-inch tap and 4-inch service line. Ductile iron
fittings shall be used on these services. 3-inch diameter pipe is not allowed in
the OWASA distribution system. All taps will be made by using the appropriate
size tapping sleeve and valve. On a dry line, the connection may be made with a
tee and valve.
Large Meter Vaults: Meter vaults for 3-inch and larger meters shall be
constructed of precast concrete with a floor drain with a connection that is
compatible with 4-inch diameter ductile iron pipe. Meter vault floors shall be
sloped toward the drain. Sump pumps are not permitted. Meter vaults shall
have aluminum, cast-in-place double leaf, and spring-loaded doors with slam
locks. Doors shall be rated H-20 in All areas. Vaults located within vehicular
travel lanes shall meet the minimum AASHTO guideline H-20 traffic loads for full
H20 loads. The vault doors shall be located over the water meter. See
specification Section 2.3.L, Vault Access Hatch, below.
Acceptable
manufacturers for large meter vault access doors are Halliday Products, Inc.,
The Bilco Company, or an approved equal. Door sizes vary according to water
main size. See Standard Details 515.13, 515.14, and 515.15.
Manufacturer
Bilco
Halliday Products
US Foundry &
Manufacturing Corporation
H-20 Model No.
JD-2AL H20
H2W4848
Type THD 48x48 W/OP
See also Standard Detail 515.11.
Precast meter vault manufacturers are listed in Section 02510-2.3.E. See
Section 02275 – Trenching, Backfilling and Compaction of Utilities, Section
3.3.B, paragraph 3 for bedding requirements for Structures. Minimum meter vault
dimensions shall be as follows below.
Meter Size
3- and 4-inch
6- and 8-inch
OWASA – Manual of Specifications, Standards and Design
April 2015
Minimum Vault Size
10’-0” L x 8’-0” W x 6’-6” H
12’-0” L x 10’-0” W x 6’-6” H
Page 02510-28
02510 – WATER DISTRIBUTION
Combinations Vaults: Combination vaults shall be designed and constructed to
provide the following minimum clearances between the pipe, fittings or vault
walls:
Conflict
Vault side wall to meter
Vault side wall to side of pipe or
valve
Vault end wall to nearest bolted
connection
Pipe to pipe, fitting or valve
Top of OS&Y valve stem (fully
opened) to vault ceiling
Minimum Clearance
(inches)
24
6
6
6
6
5) LOW PROFILE VAULTS: SOME AREAS MAY REQUIRE THE USE OF A
SHOLLOW VAULT. DETAIL 515.14 PROVIDES THE MINIMUM DEPTH
PERMITTED.
6) METERS:
All water meters are to be purchased from OWASA. Meters that are 2-inches
and smaller shall be delivered and set by OWASA. For meters 3-inches and
larger, Contractor shall pick up and install under supervision of OWASA.
Appropriate lead-time for supplying meters shall be given to OWASA by the
Contractor or Owner requesting the water meter. No meters will be installed until
“Tentative Acceptance” of the lines has been granted and the appropriate fees
paid.
Meters larger than 2-inches are to be provided with remote read out meter
reading capabilities (see Standard Detail 515.13 for detail of remote readout in
relation to vault).
J.
TIE-RODS
Tie rods shall be 304 or 316 stainless steel, and of size and number as shown on
Standard Detail 512.09. No duck lugs shall be allowed. All eyebolts shall be
304 or 316 stainless steel. All nuts and rod couplings shall be stainless steel,
and be coated to prevent galling, or the use of stainless steel anti-seize
compound used..
K.
VALVE BOXES
Adjustable valve boxes shall be US made gray cast iron of the dimensions
shown in Standard Detail 513.01 (2-Piece Adjustable Screw Valve Box and
Cover Detail) of these specifications. Lids shall be heavy-duty traffic weight with
the word “WATER” cast into the lid. Provide cast-iron telescoping top section of
length required for depth of burial of valve and bottom section with base of size
to fit over valve. Acceptable valve boxes are: Charlotte Pipe and Foundry
Company Figure UTL 273 or Tyler Pipe Company 6850 Series or approved
equal.
L.
VAULT ACCESS HATCH
OWASA – Manual of Specifications, Standards and Design
April 2015
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02510 – WATER DISTRIBUTION
1) All Areas shall be Low Density Traffic H-20 Loading (incidental) – of 16,000
lb. wheel load on an 10-inch x 20-inch wheel area:
2) Streets, Parking decks, Etc… Vaults access Hatches located within
vehicular travel lanes shall meet the minimum AASHTO guideline H-20 traffic
loads for continuous vehicular traffic. .
3) The aluminum access frames and covers are provided with a 1/4-inch thick
structural grade aluminum channel frame with the flanges acting as a
continuous concrete anchor. The inside of the frame has a continuous door
support angle that must have a full bed of Class "A" concrete under both the
frame and support angle. Door leaves shall be a minimum of 1/4-inch thick
aluminum diamond plate with structural grade aluminum. Door reinforcing
shall withstand an H-20 live load designation. The doors also have lifting aids
of aluminum tubular construction with compression springs to assist in
opening and closing of the doors. The doors are provided with heavy-duty
stainless steel hinges with tamper-proof fasteners. All hardware is to be
stainless steel. The doors open to 90 degrees and lock automatically in that
position with a
steel positive locking arm and a stainless steel release
handle. Doors are provided with a stainless steel lifting handle, stainless steel
snap-lock with removable key handle. Two key handles shall be provided with
each door. The door leaves extend to the outside perimeter of the frame for
added support.
4) Guarantee and Manufacturer: The aluminum access frames and covers
shall carry a 10-year guarantee against defects in materials and workmanship.
The frame and cover shall equal or exceed the units manufactured by Halliday
Products, Inc. or The Bilco Company.
PART 3 – EXECUTION
INSTALLATION – PIPE AND FITTINGS
3.1
PIPE AND FITTINGS
Refer to Section 02275 – TRENCHING, BACKFILLING AND COMPACTION OF
UTILITIES.
A. DUCTILE IRON PIPE
1) DIP INSTALLATION:
a. Trenching & Bedding: Refer to Section 02275 – Trenching, Backfilling,
and Compaction of Utilities.
b. Installation of DIP Water Mains: Comply with AWWA C600, Installation
of Ductile Iron Water Mains and Their Appurtenances.
c. Pipe Laying - Separation: The contractor shall comply with the
NCDENR standards for separation of water mains from sanitary sewers
or storm drainage lines. See Part 1 – GENERAL, Section 1.9, Project
Conditions of this specification.
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02510 – WATER DISTRIBUTION
d. Materials, Storage, and Handling: See Section 1.7, Product Delivery,
Storage and Handling.
2) CONSTRUCTION:
a. Construction: Water mains and fittings shall be installed with approved
tools in accordance with the requirements of ANSI/AWWA Standard
Specification C600, Installation of Ductile Iron Water Mains and Their
Appurtenances, which is herein made part of the specification by
reference.
Construct piping to accurate lines and grades avoiding localized high
points and support as required on drawings or described in specifications.
When temporary supports are used, insure that sufficient rigidity is
provided to prevent shifting or distortion of pipe.
Pipe shall be laid with bell ends upgrade and facing the direction of
laying.
Due care shall be taken in the storing and handling of pipes, fittings and
valves to avoid contamination with the ground and prevent foreign matter
from entering pipe and fittings. String out no more pipe than can be
installed in a day. Gaskets shall be lubricated as per manufacturer’s
recommendations.
Pipe, fittings, and valves shall be carefully handled and lowered into the
trench. Under no circumstances shall any pipe or fitting be dumped or
rolled into the trench, or be allowed to drop against the pipe or fitting
already in the trench. Great care shall be taken to prevent the pipe lining
and coating from being damaged, and the Contractor shall not install any
damaged pipe. The Contractor shall be responsible for removal and
disposal of damaged pipe.
Prior to being lowered in to the trench, all pipes shall be carefully
inspected to see that each pipe is clean. If necessary, pipes shall be
fitted together to ensure sufficient opening for the gasket or joint
compound and smooth inside flow line.
Special care shall be taken to insure that the pipe is well bedded on a
solid foundation, and any defects due to settlement shall be made good
by the Contractor at his own expense. Bell holes shall be dug sufficiently
large to insure the making of proper joints. Special precautions shall be
exercised to prevent any pipe barrel or bell from resting on rock. A
minimum of 6 inches is required between rock and the bottom of pipe
(see Standard Detail 511.01 and Section 3.2.E, paragraph 2, Cushioning
Pipe in Rock, of Section 02275 – Trenching, Backfilling, and Compaction
of Utilities). If the bed formed in the bottom of the trench is too low, the
pipe shall be removed, clean stone placed in the bottom, and a new bed
prepared for the pipe. In no case shall the pipe be brought to grade by
blocking under the barrel of the pipe. A uniform support shall be provided
for the entire length of the pipe.
Whenever a pipe requires cutting, to fit in the line or to bring it to the
required location, the work shall be done in a satisfactory manner with an
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02510 – WATER DISTRIBUTION
approved cutting tool or tools which will leave a smooth end at right
angles to the axis of the pipe, and not otherwise damage the pipe or liner.
When the cut end is to be assembled in a Fastite bell, an adequately
smooth (without sharp edges) bevel should be ground or filed on the cut
edge to prevent damage to or dislodgement of the gasket during
assembly. Generous bevels are advantageous in the assembly of field
prepared ends. The approved methods of cutting pipe are: rotary type,
abrasive wheel, and snapcutter on DIP. No welding, flame cutting, or
flame tapping will be allowed.
Mains shall be installed to the depth as directed by OWASA’s Engineer,
but in no case with a cover of less than 42 inches below finished grade.
In the event site conditions prevent adherence to minimum cover
requirements, approval of an alternate design by OWASA’s Engineer is
required. See Table 02275.1 of Section 02275 – Trenching, Backfilling,
and Compaction of Utilities.
The Contractor shall be required at the end of the day’s work to keep the
end of the line, under construction, plugged to prevent foreign matter from
entering pipe and fittings. A watertight plug shall be placed in the bell of
the last joint of pipe laid. The pipe shall not be used as a means of
draining ground water from the area.
Maximum horizontal deflections for ductile iron pipe shall meet AWWA
C600, latest revision.
i.
Allowable Joint Deflection
Size
(inches)
Nominal Laying Length
(feet)
4
6
8
12
16
20
24
30
36
42
48
18
18
18
18
18
18
18
18
18
18
20
Maximum Allowable Deflection
Offset per Length
Deflection Angle
(inches)
(degrees/radius,ft)
19
19
19
19
11
11
11
11
11
11
12
5°/205
5°/205
5°/205
5°/205
3°/340
3°/340
3°/340
3°/340
3°/340
3°/340
3°/380
Installing Mechanical Joint Pipe:
a) Gaskets shall not be exposed to oil, grease, ozone, extensive
heat, sunlight, or other elements that would degrade the gasket.
Store gasket in a cool dark place until installation in accordance
with manufacturer’s recommendations.
b) Clean socket and plain end thoroughly, removing mud, oil, gravel,
or any other foreign matter. Gaskets shall be lubricated. Paint
the bell and the spigot with soap solution (half cup granulated
soap dissolved in 1 gallon of water). Slip ductile iron gland on
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02510 – WATER DISTRIBUTION
spigot end with the lip extension of the gland toward the end of the
pipe. Paint rubber gasket with or dip into the soap solution and
place on the spigot end with thick edge toward the gland.
c) Push the spigot end forward to seat in the bell. Then, press the
gasket into the bell so that it is located evenly around the joint.
Move the gland into position, insert bolts, and screw nuts up finger
tight. Then tighten all nuts to torque listed below (excerpted from
Table 2 of AWWA C600-99):
Bolt Size (Inches)
5/8
3/4
1
1 1/4
Torque (Ft. – Lbs)
45-60
75-90
100-120
120-150
Tighten nuts on alternate side of the gland until pressure on the
gland is equally distributed.
d) Permissible deflection in mechanical joint pipe shall not be greater
than listed in Table 4 of AWWA C600-99.
Size
(inches)
4
6
8
12
16
20
24
ii.
Allowable Joint Deflection
Nominal Laying
Length
(feet)
18
18
18
18
18
18
18
Maximum Allowable Deflection
Offset per Length
Deflection Angle
(inches)
(degrees/radius,ft)
31
27
20
20
13.5
11
9
8°-18’/125
7°-07’/145
5°-21’/195
5°-21’/195
3°-35’/285
3°-00’/340
2°-23’/450
Installing Push on pipe: Standard PUSH-ON GASKETS ARE NOT
PERMITTED FOR USE IN OWASA SERVICE AREA!
a) Gaskets shall not be exposed to oil, grease, ozone, extensive
heat, sunlight, or other elements that would degrade the gasket.
Store gasket in a cool dark place until installation in accordance
with manufacturer’s recommendations.
b) Clean the socket and 8 inches of the outside of the plain end
thoroughly, removing mud, gravel, or any other matter that might
cause the front of the gasket to protrude into the path of the
entering spigot. Flex rubber gasket and apply lubricant supplied
with the pipe to the plain end and to the inside surface of the
gasket before assembly. Start the spigot end of the pipe in to the
socket with care. The circumferential stripe on the plain end
provides a visual indication for checking the proper insertion of the
joint. Insert gasket fully in the gasket recess of the socket, large
end of the gasket entering first. For assurance of proper gasket
positioning, a thin automotive, blade-type feeler gauge can be
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02510 – WATER DISTRIBUTION
used for quick and easy probing to confirm a properly installed
gasket position around the joint. Then complete the joint by
forcing the plain end to the bottom of the socket with a forked tool
or jack-type device.
b. Cutting Pavement/Driveways:
Where the water line is in an existing paved area, the edges of the
pavement for the water line shall be cut in a straight line, parallel to the
pipe on each side. Perform cutting operations prior to installation of water
line to avoid excessive removal of asphalt. Care shall also be taken
during installation of pipe to avoid damage to adjoining paved surfaces.
Refer to the applicable Municipal or NCDOT standard pavement repair
details pavement width and patching requirements. Driveway crossings
shall be completed within 48 hours after the initial cutting of the
pavement.
c. Protection of Pavement:
Whenever the water line is to be placed in or near a paved street, the
Contractor shall provide pads or take necessary precautions to protect
the pavement from damage by construction equipment. Pavement
damage by cleats or tracked equipment, or by any other means, shall be
repaired by the Contractor.
3) CONNECTIONS TO EXISTING MAINS:
The Contractor shall furnish all materials for connection to existing water mains.
THIS INCLUDES ALL RODDING, BLOCKING AND BRACING NECESSARY TO
PLACE WATER MAIN INTO SERVICE AS SOON AS TIE-IN IS COMPLETE.
OWASA shall be the sole operator of all EXISTING valves and fire hydrants.
In making connections to the existing distribution system, valves shall be set as
shown on the plans.
Before shutting off any main, residents are to be notified by an OWASA
representative in writing 48 hours in advance of cut off. The Contractor shall
provide assistance to OWASA in notification distribution.
If connection to an existing main requires a wet tap, such tap shall be performed
by OWASA. Fees must be paid 48 hours in advance of tapping the main.
Contactor is responsible for traffic control, excavating, dewatering, and safe
access in the trench at the time of tap. The contractor is to provide taping sleeve
and valve. Contractor must have approved traffic control plan.
Work shall be scheduled at least one week in advance through OWASA’s
inspector. A crewman from the OWASA Distribution and Collections Division
shall be present during the operation. After installation of the tapping sleeve and
valve and prior to performing the tap, the assembly shall be air tested at 100 psi.
Such pressure shall be maintained with no loss for a minimum time of 5 minutes.
4) REMOVAL OF ASBESTOS CEMENT PIPE:
The Contractor is hereby advised that some of the pipe within the OWASA
distribution system may contain asbestos. Removal, handling, and disposal of
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02510 – WATER DISTRIBUTION
asbestos cement pipe shall be performed in accordance with applicable EPA and
OSHA regulations and applicable Federal, State and local regulations.
Documentation and paperwork as well as a chain of custody are to be provided
to OWASA.
5) UTILITY PROTECTION:
Take necessary precautions to protect existing utilities from damage due to any
construction activity. The Contractor shall locate existing utilities, culverts, and
structures (above or below ground), before any excavation starts and coordinate
work with utility companies. Protect, maintain in service, and prevent damage to
utilities not designated to be removed. Omission from or inclusion of located
utility items on plans does not constitute non-existent or definite location. Secure
and examine local utility surveyor records for available location data including
building service lines. Contact underground damage protection services by
contacting “National Cal Before You Dig” at 811 or NC One Call Center at 1800-632-4949l 48 hours before you dig.
The Contractor shall protect, maintain in service, and prevent damage to utilities
not designated to be removed. When utilities are encountered and are not
shown on drawings or when locations differ from those shown on drawings, notify
Project Engineer for instruction before proceeding. In the event that a gas line,
water line, power cable or conduit, or telephone cable or conduit is broken or
damaged, the Contractor shall give immediate notice to the proper authorities
and shall be responsible for any damage to persons or property caused by such
breaks. If a service pipe supplying water or gas to an adjoining house is broken,
the Contractor shall repair same at once. OWASA may, at the Contractor’s
expense, repair any such service without prior notice to Contractor.
Should it become necessary to move the position of any underground structure,
the Contractor may be required to do such work.
The Contractor shall be responsible for protecting all existing utilities that could
be damaged by excavation near the proposed line. Trench boxes may be
necessary to prevent sloughing, etc., as well as to protect workmen, the motoring
public, and the pavement. Failure to use a box, which subsequently results in
damage to an existing line or other public improvements, shall be cause for
liability against the Contractor for the repair costs.
6) SURFACE OR GROUND WATER IN TRENCHES/PIPE:
When ground water is encountered, the Contractor shall pump, or otherwise
remove any water that accumulates in the trenches and shall perform all work
necessary to keep the trenches clear from water while pipe is being laid. No pipe
shall be constructed in water and water shall not be allowed to drain through the
pipe. At the end of the day, the open end of the pipe shall be kept closed by
placing a watertight fitting plug into the bell end to prevent washing of any foreign
matter into the line. All water removed from the trench shall be conveyed in a
proper manner to a suitable point of discharge and shall comply with the
applicable erosion and sedimentation laws. See also Section 3.1.G, Dewatering
of Section 02275 – Trenching, Backfilling, and Compaction of Utilities.
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7) ABANDONING OF AN EXISTING WATER MAINS/SERVICES/LINES:
Services: When abandoning services 2-inch in diameter, the valve shall be
closed and the pipe cut and removed from the valve, a threaded plug shall be
installed into the valve body. On lines smaller than 2” in diameter, the corporation
stop shall be turned to the off position, a flair cap placed on the corporation stop
and the line shall be cut as close to the main as possible and a one-foot segment
of the line removed.
Mains: When an existing water main is replaced with a new water main,
abandonment of the existing line is required once it is no longer in service. The
line shall be abandoned as shown in Standard Detail 512.05 or as directed in
the plans and Specifications. Additionally, the following water pipes shall be
abandoned by removal or by filling with grout / flowable fill concrete (50 psi
minimum/ 150 psi maximum) in accordance with the following criteria:
a. Pipes larger than 24-inches diameter
b. Pipes located within roadway section and meeting one of the following
conditions:
i. pipes that are 12-inches diameter up to and including pipes that are
24-inches diameter and are buried less than 20 feet below finished
grade
ii. pipes that are 6-inches diameter up to 12-inches diameter that are not
cast iron, ductile iron, PVC, or HDPE and are buried less than 12 feet
below finished grade
c. Pipes located below groundwater table that could become a conduit for
water movement:
Optionally, pipe may be excavated and removed subject to Engineer’s approval
and approval of controlling agency of Right-of-Way. Additionally, if a valve is not
located at the source, plugging of the branch at the source will be required.
Location of abandonment shall be approved by an OWASA representative.
B.
STEEL ENCASEMENT PIPE – DRY BORING & JACKING OR OPEN CUT
General: Where required, steel encasement pipe shall meet the length as shown on
the plans and the thickness and diameter as shown on Standard Detail 517.01.
Boring across roads and railways shall be performed by dry boring and jacking a steel
encasement pipe under the pavement or rail. The encasement shall be located in an
area that is relatively free from material such as rock and stone that may hamper the
boring operation.
Construction shall be executed in such a manner as to prevent settlement of the
ground surface above the pipeline. The installation of the pipeline shall follow the
heading or tunneling excavation as closely as possible.
All operations of the Contractor shall be subordinate to the free and unobstructed use
of the right of way of the passage of traffic without delay or danger to life, equipment,
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02510 – WATER DISTRIBUTION
or property. Installation shall be in accordance with of the NCDOT Standard
Specifications for Roads and Bridges, latest revision or AREA, as applicable.
The pipe shall be beveled and prepared for field welding at the circumferential joints.
Joining of steel casing pipe shall meet the requirements of AWWA C206, AWWA
Standard for Field Welding of Steel Water Pipe. Casing shall be installed either by dry
boring and jacking or open cut, as indicated on the drawings.
Encasement ends shall be enclosed as shown on Standard Detail 517.01. All
exposed metal is to be coated with epoxy, asphaltic material OR BE STAINLESS
STEEL.
All carrier piping shall be ductile iron pipe supported by spiders.
Manufactured Spiders: The spiders necessary to support the carrier pipe inside of
the steel encasement pipe shall conform to both the shape and dimensions of
Standard Detail 517.01 and shall be in accordance with Section 2.1.D, paragraph 2,
Spiders/Skids for Encasement Pipes. Unless otherwise shown on the drawings, one
spider shall be placed at each bell as well as at each end of the encasement pipe (see
Standard Detail 517.01 for location of spiders).
C.
TUNNELING METHOD
1) GENERAL:
a. The Contractor shall submit shop drawings to OWASA’s Engineer for
approval prior to construction. All liner plates and ribs used in the tunnel
shall be of one type. All material removed shall be disposed of off the site
by the Contractor.
b. All operations of the Contractor shall be subordinate to the free and
unobstructed use of the rights of way for passage of traffic without delay
or danger to life, equipment, or property. The Contractor shall provide all
necessary bracing, bulkheads, and shields to ensure complete safety to
all traffic at all times. The Contractor shall provide all traffic control
devices as necessary and as shown on the approved traffic control plan
at no additional cost.
2) TUNNELING (BORING METHOD):
a. Commence boring operation from a pit, with the bottom excavated to
grade, and sheeted or shored if necessary. Boring through soil shall
have a steel pipe jacked in place as a casing pipe. Boring through rock
shall be oversized to allow installation of carrier pipe but no casing pipe
shall be required unless liner plate is necessary for safety reasons.
b. Smoothly pave the bottom of the tunnel with concrete. Pull the carrier
pipe in place a joint at a time. Securely block each section in place.
3) TUNNELING (HAND MINING):
a. Commence tunneling operation from a pit, with the bottom excavated to
plan grade, and sheeted or shored if necessary.
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02510 – WATER DISTRIBUTION
b. Trim the periphery of the tunnel smoothly to fit the outside of the steel
liner plate as nearly as practical.
All blasting shall conform to
requirements for blasting in Section 02275 – Trenching, Backfilling and
Compaction of Utilities.
c. Install the steel liner plates immediately after the excavated material has
been removed, and remove the material not more than 24 inches ahead
of the installed liner plates.
d. Grout all voids between the soil and tunnel liner plates. The maximum
grouting pressure shall be 30 psi. Start grouting at the bottom of the
tunnel liner plates and proceed upward progressively and simultaneously
on both sides of the tunnel. Install liner plates no more than 6 feet ahead
of grout section. Prohibit traffic over ungrouted sections of tunnel unless
this section is in solid rock. Thoroughly dry-mix grout ingredients before
adding water. After adding water, mix the batch for 3 minutes. Batches
shall be of size to allow continuous placement of freshly mixed grout.
Grout not used within 30 minutes after mixing shall be discarded. Placing
shall be quick and continuous. Placement shall be under pressure with a
grout pump. The period between installation of the tunnel liner plate and
the placing of grout shall not exceed 7 hours, without the approval of
OWASA’s Engineer. Upon completion of grouting, fill grout plugs with
provided grout hole plugs.
e. Smoothly pave the bottom of the tunnel with concrete: After installation of
the tunnel liner plates, the Contractor shall pour concrete pavement on
the bottom quadrant (invert) of the tunnel, the surface of the pavement
being parallel to the liner plate, with screed rails embedded in it, on line
and grade for the installation of pipe in the tunnel.
f.
The periphery of the tunnel shall be trimmed smooth to fit the outside of
the steel liner plate as nearly as is practical, so that the void outside the
plates is a minimum.
g. After installation of the casing pipe or the tunnel liner, pull the carrier pipe
in place a joint at a time. Securely block each section in place. Each
joint of the carrier pipe shall be supported at two points by steel saddles
or by pressure treated wood skids, strapped to the carrier pipe with steel
straps. The carrier pipe shall be blocked, in place to the prevent flotation.
h. Close tunnel liner ends to protect against entrance or foreign matter. The
open ends of the casing pipe or tunnel shall be closed off by an 8-inch
grout or masonry block wall prior to backfilling. A steel drain line to a 1
cubic yard French drain shall be provided.
i.
If installation is under railway tracks, all permits shall be obtained and
Railway Company shall be notified prior to such installation. The same
shall apply to contacting applicable Municipality or NCDOT if installation
is under roadway.
4) See also PART 2 – PRODUCTS, Section 2.1.E, Tunnel Liners and
Appurtenances.
D.
HORIZONTAL DIRECTIONAL DRILLING OF HDPE WATER PIPE
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02510 – WATER DISTRIBUTION
1) HDPE pipe shall be installed by Horizontal Directional Drilling (HDD) using a
surface mounted rig, first to drill a guided hole along a bore path consisting of
a shallow arc and then to pull a string of pipe into the hole. Pull back is
facilitated by a back-reamer, which enlarges the hole to approximately one
and a half times the pipe diameter. Drilling fluids are injected into the bore
hole to stabilize the hole and lubricate the pipe and drill-string. Tracking
equipment is used to guide and direct the drilling.
a. Mechanical Restraint
When Polyethylene pipe is pressurized, it expands slightly and shortens
slightly. Shortening may be enough to disjoin unrestrained mechanical
joints that are in line with PE pipe. Disjoining can be prevented by
installing external joint restraints at mechanical connections, by installing
line anchors, or by a combination of both. Contractor shall install
mechanical connections with joint restrain at connection to mechanical
joint pipe.
Note: Poisson Effect pipe shortening must be taken into account
whenever the pipe is pressurized, both during the pressure testing, and
when it is placed in service. Because pressures are usually higher during
pressure testing (up to 150% of the system pressure rating), pipe
expansion and Poisson Effect pipe shortening may be slightly greater
during pressure testing. Before pressure testing, all mechanical joint
restraints must be completely installed and secured per manufacturer’s
instructions. Concrete in-line anchors and thrust blocking (if used) must
be fully cured (minimum of 21 days for 3,000 psi or 7 days for 4,500 psi
concrete) and properly backfilled before testing. Restraint is not required
at PE to PE butt fusion joints. Restraint is not required at bolted flanged
joints.
Mechanical coupling: Stainless steel internal stiffeners shall be used on
all couplings to increase the seal. All couplings shall have restraint
devices per the manufacturer’s recommendation and installed per the
Manufacturer’s direction.
2) INSTALLATION AND TESTING:
The Manufacturer shall supply an Installation Manual to OWASA’s Engineer,
which outlines guidelines for handling, joining, installing, embedding, and testing
of the Polyethylene Pipeline. These guidelines shall be used as reference
material by OWASA’s Engineer in his determination of the required procedures.
Joints between plain ends of Polyethylene pipe shall be made by butt fusion
when possible. The pipe manufacturer’s fusion procedures shall be followed at
all times as well as the recommendations of the fusion machine manufacturer.
The wall thicknesses of the adjoining pipes and fittings shall have the same DR
at the point of fusion.
When saddle connections are fusion welded, the Manufacturer’s recommended
saddle fusion procedures shall be used.
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02510 – WATER DISTRIBUTION
If mechanical fittings (which are designed for, or tested and found acceptable for
use with Polyethylene pipe) are utilized for transitions between pipe materials,
repairs, joining pipe sections, saddle connections, or at other locations; the
recommendation of the Mechanical Fitting manufacturer must be followed.
These procedures may differ from other pipe materials.
On each day butt fusions are to be made, the first fusion of the day shall be a
trial fusion. The trial fusion shall be allowed to cool completely, and then fusion
test straps shall be cut out. The test strap shall be 12 inches long or 30 times the
wall thickness in length (minimum) and 1 inch or 1.5 times the wall thickness in
width (minimum). Bend the test strap until the ends of the strap touch. If the
fusion fails at the joint, a new trail fusion shall be made, cooled completely, and
tested. Butt fusion of pipe to be installed shall not commence until a trail fusion
has passed the bent strap test.
Socket and Straddle fusions shall be tested by a bent strap test as described by
the Pipe manufacturer. The pipe manufacturer shall provide visual guidelines for
inspecting the butt, saddle, and socket fusion joints.
Pressure testing shall be conducted in accordance with manufacturer’s
recommended procedure. Pressure testing shall use water as the test media.
Pneumatic testing is prohibited.
3) SHOP DRAWINGS:
Contractor shall submit shop drawings and details on the proposed HDPE pipe,
fittings, bore methods, etc., for review and approval of OWASA’s Engineer before
ordering material or beginning installation of the HDPE. Contractor shall also
submit to OWASA’s Engineer proposed subcontractor’s name as well as
references on who he/she plans to use on this project.
All
subcontractors/installers must be approved by OWASA’s Engineer.
E.
PVC PIPE
PVC pipe shall only be used with written approval from OWASA’s Engineer.
3.2
VALVES AND FIRE HYDRANTS
A.
Valve Applications
1) Valves – vault/above ground applications:
a.
Plumbing Gate Valves:
valve manholes)
b.
Gate Valves 2-inch & smaller:
Bronze ¼ turn ball type
c.
Gate valves 4-inch & larger:
OS & Y
d.
Relief Valves:
Air/Vacuum Release Valves
e.
Water-Regulating Valves:
Flow-regulating valves
Pressure-regulating valves
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02510 – WATER DISTRIBUTION
f.
Detection of unauthorized water: Detector Check Valves
g.
Backflow prevention:
Reduced Pressure Zone Backflow
Preventers – USC approved
Double Check Valve Assemblies –
UL/FM and USC approved
2) Valves – below ground applications: Non-rising stem.
B.
GATE VALVES
1) Setting of valves and valve boxes: Valves shall be installed with stems in
a vertical plane through the pipe axis and perpendicular to the pipe axis. The
Contractor shall clean the valves before installation and check for satisfactory
operation. All valves adjacent to tees or bends shall be tied to the fitting with
A restraint flange joint restraint system OR APPROVED RESTRAINT
METHOD. Valve nut extensions shall not be installed unless approved by
OWASA’s Engineer.
Nipples for 4-inch through 12-inch valves shall be cut so that the valves are
installed 30 inches from the fitting (centerline to centerline). 2-inch valves
shall be installed with a 4-inch long brass nipple.
2) All underground valves without gearing or operators shall be equipped with a
2-piece valve box with lid (see Standard Detail 513.01). Valve boxes shall
be set on concrete brick placed beneath the bottom outstanding flange of the
valve box. Place a minimum of 1 inch of earth cushion beneath the concrete
brick and the valve and the valve box set in alignment with the valve stem
centered on the valve nut, set in a manner to prevent transmitting shock or
stress to the valve. Place #57 stone around pipe and under valve box. Valve
box cover must be set flush with the finished ground surface or pavement.
The Contractor shall be responsible for keeping valve boxes clean and free
of any foreign matter until acceptance of the project.
3) Valve boxes shall be set to grade and a concrete stabilizing pad placed
around the valve box. Valve boxes in easements are to be provided with a
valve box marker post. See Standard Detail 513.02.
4) When valve box tops project more than 1 inch above the unfinished road
surface, a temporary layer of asphaltic concrete feathering shall be required
to provide a smooth transition from 1 inch below the edge of the rim and
cover to the unfinished road surface. The exposed sides of the valve box
shall be painted bright orange. See Standard Detail 532.07.
5) Valves at intersections shall be restrained with restraint flange system.
C.
VALVES 16 INCHES AND LARGER (GATE OR BUTTERFLY VALVES)
Valves with gearing or operators shall be installed in a manhole. The manhole
shall be constructed/set in such a way as to prevent transmitting any load or
shock to the valve. It is also to be set in such a way that the packing, operator,
and other parts of valve are readily accessible for minor repairs. The valve is to
be provided with a flanged coupling adapter to permit valve removal for
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maintenance. Manholes shall be constructed in accordance with the Standard
Details 513.06 and 513.08. Manhole opening shall be positioned over the
operating nut. Either a gate valve or a butterfly valve may be used.
D.
TAPPING SLEEVES AND VALVES
Tapping sleeves and valves shall be installed in accordance with the
manufacturer's recommendations at locations shown on the plans. With prior
approval, when taps are made on asbestos cement pipe, the Contractor shall
excavate at the location of the tap and measure the diameter of the pipe prior to
selecting a tapping sleeve to ensure the sleeve will fit the pipe (this information
shall be provided to OWASA on the as-built drawings). See Standard Detail
512.04. Taps shall be performed by OWASA. Fees must be paid 48 hours in
advance of tapping the main. Contactor is responsible for traffic control,
excavating, dewatering, and safe access in the trench at the time of tap. The
contractor is to provide taping sleeve and valve. Contractor must have approved
traffic control plan.
Work shall be scheduled at least one week in advance through OWASA’s
inspector. A crewman from the OWASA Distribution and Collections Division
shall be present during the operation. After installation of the tapping sleeve and
valve and prior to performing the tap, the assembly shall be air tested at 100 psi.
Such pressure shall be maintained with no loss for a minimum time of 5 minutes.
E.
AIR RELEASE VALVES
Air release valves are to be used to bleed air during filling of a water line and to
automatically vent air that collects in the water lines. Pressure air release valves
shall be located as shown on the drawings. The valve shall be housed in a
precast concrete eccentric manhole and shall be installed in accordance with
Standard Details 513.04 and 513.05. All pipe and fittings are to be brass
including the plumbing gate valve. Air release valve locations shall be as shown
on the plans and or as otherwise directed by OWASA’s Engineer.
F.
FIRE HYDRANTS
1)
Construction: Fire hydrants shall be installed where shown upon the plans
UNLESS the Fire Marshall of the governing municipal REPRESENTATIVE
HAVING jurisdiction CHANGES THE LOCATION. Hydrants shall be set
upon a concrete setting slab in such manner as to preclude the possibility of
settlement of hydrants. Place loose #57 stone around the hydrant elbow.
See Standard Detail 514.03.
Hydrants are to be located at a distance from the curb or edge of pavement
to provide ready access and minimize the possibility of damage from vehicle
and set to the height prescribed by Standard Detail 514.03 with the pumper
nozzle facing or pointing to the street or fire access lane. Care shall be taken
to keep concrete away from bolts and weep holes. Hydrants must be set
with the stem vertical/plumb and the flange above grade. The Contractor is
responsible for determining barrel length and ordering to meet conditions.
Where adjustments in height are needed, provide extension kits at no
additional cost. However, only one 24-inch riser extension is allowed per
hydrant. Where hydrants are set behind guardrails, the pumper nozzle shall
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be set with its centerline a minimum of 12 inches and a maximum of 18
inches above the top of the guardrail.
An OWASA representative must inspect fire hydrants prior to backfilling.
2) Operation and Painting: Hydrants, upon installation and prior to acceptance
of the project, shall be painted and greased, the caps are to be greased with
a food grade anti-seize lubricant after installation, and individually operated in
front of an OWASA representative to verify the hydrant is greased and in
working condition. Paint is to be Sherwin Williams Industrial Enamel or
equal. The hydrant barrel is to be painted red with the caps and bonnet
painted reflective silver. See Standard Detail 514.01. Do not remove
chains.
3)
Hydrant Bagging:
a. New Hydrants: Place a heavy-duty orange plastic bag over newly
installed fire hydrant until hydrant is placed in service and accepted by
OWASA.
b. Out of service Hydrants: During times when a fire hydrant is taken out
of service, such as when it has been replaced with a new hydrant, or
when it is abandoned, place a heavy-duty orange bag on hydrant.
4) Valving of Main: A resilient seat gate valve shall be installed 30 inches
from the fitting OF THE MAIN and properly restrained.
Provide a
concrete stabilizing pad in accordance with Standard Detail 513.02.
5) Fire hydrants are to be pressure tested with the main.
G.
BACKFLOW PREVENTERS
See OWASA Cross-Connection Control Ordinance and Manual, adopted
January 21, 1999, latest revision as applicable.
3.3
MISCELLANEOUS APPURTENANCES
A.
SERVICES
1) General: Taps into existing (in-service) water mains shall be made by
OWASA personnel only. All fees must be paid and work scheduled with
OWASA Operations Department before OWASA will make the tap. All
materials must be on-site, trenches open, and shoring and traffic control
devices in-place before OWASA will perform the tap. Contractor may be
required to provide approved traffic control plan if required by inspector.
Allowable Tapping methods:
a. ¾ or 1-inch taps are to be made using an all bronze single or double
strap tapping saddle. See Standard Detail 512.06.
b. 1 ½-inch and 3-inch taps are not permitted.
c. 2-inch taps shall be made using a 2-inch all bronze double strap tapping
saddle.
d. Taps 4-inches and larger are to be made using an iron body tapping
sleeve. Steel sleeves are not permitted.
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Service Connections on “In-Service” water mains.
Size Connection
Responsibility
¾-inch and 1-inch services
OWASA makes tap and runs service
2-inch and larger services
Contractor digs hole at main, runs line, and
furnishes all material. OWASA makes tap.
Tap Location: Taps 2-inches and smaller shall be made no closer than 18
inches apart (see Standard Detail 512.06). Taps shall be made in line with
the meter box. Copper service lines shall be installed in a straight line from
the tap to the box. Services shall be perpendicular to the main.
Three-Quarter (¾) and 1-inch taps: All ¾-inch and 1-inch taps into water
mains shall be made using an all bronze tapping saddle. Corporation stops
shall have AWWA Standard CC tapered threads. Taps shall be made at a
45° angle above the horizontal on the upper half of the pipe. A bend or
"gooseneck" in the service line shall be provided to insure flexibility. A
double strap saddle shall be used on both PVC and AC pipe. Multiple taps in
the same section of the pipe shall be staggered (see Standard Detail
512.06). Two ¾-inch services in the same location shall be served by a
single 1-inch tap (see Standard Detail 515.01 and 515.02). On these water
services, the fittings shall be flared type brass fittings. (ALL BRASS
PRODUCTS SHALL BE LEAD FREE AND COMFORM TO NSF61-ANNEX
G IN CONJUNCTION WITH NSF372 REQUIREMENTS. ALL RUBBER
GASKETS AND O-RINGS SHALL BE MANUFACTURED WITH AN
APPROVED ELASTOMER.) Corporation stops shall be placed in clean #57.
Stone is to be carried under and around the pipe to protect the corporation
stop. Service saddles are also to be embedded in 1 cubic foot of #57 stone.
2-inch taps: All 2-inch taps shall be made using a 2-inch all bronze double
strap saddle, a 2-inch diameter x 4-inch long brass threaded nipple, and a 2inch threaded Iron body gate valve. Water service pipe for 2 inch
connections shall be type K hard drawn copper pipe with silver brazed joints.
For short distances between the main and the meter, threaded brass pipe
may be used. See Standard Detail 515.04 and Section 2.3.J., paragraph 2.
Large taps: Taps 4-inch and larger shall be made using iron body tapping
sleeves and tapping valves. Only one 4-inch or larger tap shall be made per
joint of pipe on AC and/or pit cast (gray iron) pipe. The outside diameter of
the pipe must be measured at the location of the tap to determine the
appropriately sized tapping saddle.
An OWASA representative must inspect all service connections prior to
backfilling.
Tapping Sleeve Support – AC Pipe: A concrete pad shall be poured under
tapping sleeves placed on AC pipe to support the weight of the tapping
sleeve and valve. Wrap sleeve with plastic to protect bolts and nuts. Care
shall be taken to ensure that bolts and nuts are free of concrete and debris to
allow accessibility for future repairs. An OWASA representative must inspect
all blocking prior to backfilling.
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2) Small Meter Boxes and setters – Installation: Meter boxes for ¾-inch x
5/8-inch and 1-inch meters shall be installed within the utility strip behind the
curb, or within the right of way at the back of the sidewalk. Meter boxes shall
be set on four 4-inch x 8-inch concrete bricks, one on each corner. All meter
boxes shall be set so that there is a minimum of 8-inch clearance between
the top of the box and the cut-off nut on the meter setter. The meter setter
shall be straight, level and centered in the box. Meter boxes shall be set to
avoid inflow of surface water into the box. See Standard Detail 515.01 and
515.02.
3) Three-quarter (¾)-inch and 1-inch copper service lines: Copper service
lines shall have a minimum of 30 inches of cover from the water line to the
top of the back of curb or centerline of the drainage ditch. Service lines shall
run perpendicular from the water main to the property served. Water service
pipe shall be one continuous run, from main to meter setter, of type K soft
copper with no joints or couplings in between.
4) 2-inch Meters: Meter boxes for 2-inch meters shall be placed on a 6-inch
bed of clean #57 stone. Meter boxes shall be set so that there is a minimum
12 inches of clearance between the top of the box and the cut-off nut on the
meter setter. The meter setter shall be straight, level, and centered in the
box. Meter boxes shall be set to avoid inflow of surface water. Drains for 2
inch meter vaults shall be installed if grade allows.
Meter setters 2-inch meters shall be provided with a section of copper pipe
extending horizontally 24 inches out the back of the meter box. The outlet
connection on 2-inch meter setters shall be plugged with a pipe plug until
pressure testing has been completed on the section of main to which it is
connected. Setters are to be perpendicular to meter and vertical. For 2-inch
setter, use a 17-inch long idler bar with two 1/8 rubber gaskets.. The idler is
used to maintain proper spacing until a system is ready for a meter to be set.
The setter should have an opening of 17 ¼ inch.
5) Meter Vaults: Meter vaults for 3-inch and larger meters shall be placed level
on a 6-inch bed of #57 stone that has been thoroughly and firmly
consolidated. The vault floor shall have a floor drain with the floor sloped
toward the floor drain. A minimum 4-inch diameter drain on negative grade
to daylight shall be provided. Sump pumps are not permitted. Meters and
fittings shall be supported by mortared concrete masonry units. Vault doors
shall be centered over the meter and otherwise located as shown. See
meter vault Standard Details 515.13, 515.14, and 515.15 and DCV and
DDCV vault on Standard Detail 515.11.
6) Grounding to Water Services: Grounding shall not be allowed to be
connected to meter boxes or vaults.
As a minimum, place meter
boxes/vaults no closer than 10 feet from a building. If unavoidable, place a
grounding jumper around meter box/vault.
7) Abandoning Water Services: Water services shall be abandoned by closing
the corporation stop at the main and cutting out a section of the water
service, 1 foot from the corporation stop.
8) Testing: All taps and services shall be pressure tested with the main.
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B.
RESTRAINTS/CONCRETE THRUST BLOCKING
1) Thrust Blocking: Thrust Blocking SHALL be installed at the direction of the
OWASA Representative or as shown on the plans. Thrust blocks shall be
constructed from 3000 psi concrete (at 28 days) and poured against an
undisturbed earth trench wall. Concrete thrust blocking shall be constructed
in accordance with Standard Detail 512.02. Sacrete is not permitted.
Concrete anchors may be unformed but minimum dimensions must be
maintained. All fittings and pipe shall be wrapped in plastic prior to
installation of concrete to insure that bolts and nuts are free of concrete and
debris to allow accessibility for future repairs. When soft, mucky, unsuitable,
or unstable soils are encountered, thrust shall be resisted by running tie rods
to solid foundations by removing the soft materials and replacing it with
ballast of sufficient size and weight to resist thrust.
Vertical upward thrust at fittings or vertically deflected joints shall be resisted
with thrust collars of adequate size and weight to resist thrust. See Standard
Detail 512.01.
Pipe manufacturer’s installation manuals shall be followed for the anchoring
of valves and fittings in difficult locations unless superseded by the
requirements of these specifications.
Concrete thrust blocking is not recommended where the blocking may bear
on other utilities or where the area behind the block may be excavated in the
future.
An OWASA representative must inspect all blocking and anchoring prior to
backfilling.
2) Rodding: 4-inch and larger valves and assemblies of fittings shall be
secured to a blocked fitting by threaded rods with eyebolts. Refer to
Standard Detail 512.09 for the minimum size and number of rods needed for
various test pressures. No more than one coupling shall be allowed between
rods. Rodding length between fittings shall not exceed 20 feet. When the
length between fittings exceeds 20 feet, place a thrust collar on the line and
rod to the thrust collar.
All eyebolts and threaded steel rods shall be 304 or 316 stainless steel.
3) Thrust Collars: Thrust collars shall be constructed as shown in Standard
Detail 512.08 for pipes up through and including 36 inches in diameter. The
thrust collar shall consist of a wedge action restrainer gland (see Section
2.1.A, paragraph 2, item c., Mechanical Joint Restraints, of this specification
for manufacturer and model number of approved restrainer gland) placed
around a joint of ductile iron pipe encased in a reinforced 3000 psi concrete
block. Where the blocking provides thrust resistance for fittings, threaded
rods shall be connected to the restraint flange fitting secured to a full joint of
ductile iron pipe. On dead end lines, the thrust collars must be placed on a
full joint of ductile iron pipe just after the terminal end line valve.
C.
MANHOLE INSTALLATIONS
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Manhole bases shall be placed on a level 12-inch bed of #57 stone that has been
thoroughly and firmly consolidated. Voids around the pipe, joints, grade rings,
and other openings in the manhole shall be thoroughly and neatly grouted inside
and outside with a non-shrink gout to prevent infiltration. A maximum of 2 grade
rings or one grade ring and one course of concrete bricks will be allowed to bring
the rim and cover to finished grade (see Standard Detail 532.06). If additional
height is required, a riser must be installed.
Manhole rings and covers shall be installed a minimum of 12 inches above grade
in easements and cemented to the cone section. In paved areas, an 8-inch thick
by 18-inch wide annular concrete pad is to be placed around the manhole iron
casting (see Standard Detail 532.06) beginning 2 inches from the top of the
manhole ring. In other areas, the ring is to be placed beginning ½ inch below the
top of the ring. For air release manholes, flat tops shall be used.
3.4
TESTING, DISINFECTION AND SAMPLING
A. GENERAL
Pipelines shall be hydrostatically pressure tested, in sections between valves, as
soon as the installation is completed. Disinfection shall occur after hydrostatic
test has passed, then sampling may begin. Testing, Disinfection and sampling
shall be as follows:
1) Pipelines and appurtenances have been laid and the trench backfilled. Pipe
subjected to contaminating materials (any type) shall be removed from the
project site immediately. OWASA shall bear no portion of any cost sustained
by the Contractor in meeting the specification.
2) Hydrants shall be properly located, operable and plumb, and at correct
elevation.
3) Valves shall be properly located, operable, and at correct elevation. Valve
boxes or manholes shall be centered over operating nuts and the top of the
box or manhole shall be at proper elevation.
4) All services shall be installed complete with setters (Contractor shall provide
a meter, approved by OWASA, for pressure testing). There shall be no
bypass around the meter used for pressure testing.
5) All reaction anchors (if any) have had sufficient set of 7 days or high early
strength concrete may be used to reduce the curing time to 3 days. For high
early concrete mix, use 4,500 psi or greater concrete. Temporary bracing
may be allowed at the discretion of the OWASA Representative.
6) Lines shall be properly vented where entrapped air is a consideration.
7) All visible leaks, broken or cracked pipe, valves, hydrants, etc. shall be
repaired.
8) Air release valves shall be installed complete and in place after pressure test.
9) All construction activities on the project, that requires trenching or excavation
within the limits of the water location shall be completed. Pavement base
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course and curb and gutter shall be in place before sampling, if applicable.
Pressure testing is to be performed before pavement is put down.
10) Line shall be disinfected and samples collected.
11) Approval from OWASA’s Representative on section of line to be sampled.
B. ORDER OF OPERATIONS
1) Fill Line: Fill the system slowly with water, at a velocity of approximately 1
foot per second, while necessary measures are taken to eliminate all air at
the highest points of the system where air may collect in pockets. After
filling, shut off system in order to prevent contaminated water from flowing
back in the line supplying the water.
2) Flushing: Allow filled system to set undisturbed for a minimum of 24 hours,
then begin flushing operations. Flushing shall be a velocity of not less than
2.5 feet per second to remove sediment and other foreign matter until the
water runs clear. For lines larger than 12 inches, follow AWWA guidelines.
The Contractor shall be responsible for making adequate provisions for
drainage of large volume of flushing water, including proper dechlorination/disposal of chlorinated water. All water shall be chemically dechlorinated. Any damages that may occur from this operation shall be the
sole responsibility of the Contractor.
3) Pressure Test: A pressure test shall be scheduled with an OWASA
representative in advance of chlorination of the main. Testing shall be in
accordance with Section 3.4.C, Pressure Tests & Leakage.
4) Chlorination of line: Chlorination of the line shall be performed by one of the
methods described in section 3.4.D.1. An OWASA representative will perform
a high range chlorine concentration test. Chlorine concentration of 100 mg/l
minimum must be provided. Allow chlorinated water to set in the test section
for 48 hours. The chlorine concentration shall not drop below 20 ppm within
a minimum period of 48 hours. See Section 3.4.D, Disinfection and
Bacteriological Testing.
5) Sampling – Day 1: Check chlorine and turbidity. Once the control valve has
been opened a continuous flow of water shall be maintained until all samples
have been collected. After allowing the system to flush so that at least two
volumes of water pass through the main, the first bacteria sample shall be
collected at regular intervals not exceeding 1,200 feet, and tested for
bacteriological quality. The contractor shall be responsible for making
adequate provisions for drainage of large volume of flushing water, including
proper de-chlorination/disposal of heavily chlorinated water. See Section
3.4.D, Disinfection and Bacteriological Testing.
a. Services shall be included in the main line disinfection process. The
Contractor shall have the same responsibility for laterals as for the
mains in regard to bearing full cost of any corrective measures
needed to comply with either the bacteriological test or other such
requirements.
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6) Sampling – Day 2: The water main shall not be flushed for more than 5
minutes before the first sample is collected. OWASA’s Representative will
check both chlorine concentration and turbidity. If within the acceptable
limits, a second bacteriological test will be performed collecting from the
same discharge points as on day one. If the second bacteria sample has
passed, the system may be left in service if NCDENR PWS section final
approval has been granted.
7) Final: After Final Approval by NCDENR PWS section is granted, confirm all
valves are fully open and flow all fire hydrants.
C. PRESSURE TESTS & LEAKAGE
The Contractor shall hydrostatically test completed sections of water line,
including service lines, fire hydrants, and fittings with water. OWASA reserves
the right to test all lines connected to the OWASA system. This testing, however,
does not relieve the Contractor of his responsibility to repair or replace all
workmanship and defective pipe. All work necessary to secure a tight line shall
be done at the Contractor’s expense. Testing shall be performed in the presence
of OWASA’s Representative.
All additions or replacements to water system, including water services, fire lines
and backflow prevention devices, shall be tested. Such work must take place
under the supervision of OWASA’s Representative.
The newly laid piping or any valved section of piping shall, unless otherwise
specified, be subjected for two hours to a leakage test with a beginning test
pressure of 150% of design working pressure, but no less than 200 psi. The test
pressure shall be slowly brought to the designated pressure by use of a hand
pump or power pump. Only OWASA personnel shall operate water valves on
OWASA’s existing water system. Extreme care shall be used to prevent
backflow into the potable water supply. The lines should be allowed to stand
under pressure for a period of 24 hours prior to the test. Air should be vented
from all high points just prior to the test. Only clean water, free of dirt and other
debris, from a clean container shall be used for testing. The Contractor shall
notify OWASA’s Inspector a minimum of 48 hours in advance of any expected
test. The Contractor shall pretest all mains for a period of 2 hours before
notifying OWASA for a final pressure test. No final pressure test will begin after
2:00 PM. The maximum allowable leakage shall be no greater than allowances
shown in Section 5.2, Table 5A - Hydrostatic Testing of AWWA C 600-05,
AWWA Standard for Installation of Ductile Iron Water Mains and Their
Appurtenances. No leakage shall be allowed for services.
OWASA’s Representative will verify 1 pressure test – the final observation of the
test section. A fee will be charged if the OWASA Representative is required to
make more than 1 trip to verify a pressure test on the same section of main being
tested.
1) ACCEPTANCE TESTS:
a. Pressure Test: Subject the pipe system to a hydrostatic pressure test.
Raise the pressure by pump to 200 psi, 150% of system design working
pressure, or test pressure as shown on the drawings, whichever is
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greater. Measure pressure at the high point on the system compensating
for gauge elevation. A pressure loss greater than 5 psi over a 2 hour
period results in an automatic failure of test. Pressure loss less than 5 psi
(between 200 and 195 psi) is acceptable if the allowable leakage
permitted (shown in table 5A AWWA 600-05 SECTION 5.2) is not
exceeded. All water used to determine the amount of leakage shall be
measured thru a water meter (measuring in tenths of a gallon) approved
by the OWASA Representative. Tests that exceed the allowable leakage
are deemed failed and the Contractor shall determine cause, repair, and
repeat the test until successful. Contactor shall be responsible for all
labor, materials, and equipment to perform the testing.
b. Leakage Test: Leakage shall be defined as the quantity of water that
must be supplied into the pipe to attain the initial test pressure, after all air
in the pipeline has been expelled and the pipe has been tested for
duration of 2 hours. Leakage shall not exceed the quantity determined by
Table 5A (shown in AWWA C600-05).
If leakage exceeds allowances, the Contractor shall be responsible for
locating and repairing leaks, and retesting of line until successful.
No leakage will be allowed for 2 inch mains regardless of material.
D. DISINFECTION
Pipe Disinfection: Comply with ANSI/AWWA C-651, Disinfecting Water Mains.
The Contractor shall disinfect water mains and accessories in accordance with
the procedures listed in AWWA C-651 and meet the requirements of OWASA,
whichever is more stringent.
1) FORMS OF CHLORINE FOR DISINFECTING:
a. Calcium hypochlorite – two forms are available – granular and tablets (both
with 65% available chlorine). It will normally require 6.5 lbs. of Calcium
Hypochlorite to produce a concentration of 50mg/L of available chlorine in
10,000 gallons of water.(Warning Note: This chemical must not be used on
solvent-welded or on screwed-joint steel pipe because of the danger of fire
or explosion from the reaction of the joint compounds with the calcium
hypochlorite!)
b. Sodium hypochlorite – is supplied in strengths of 5.25% to 16% available
chlorine. The required amount of sodium hypochlorite to produce a 50mg/L
concentration of available chlorine in 10,000 gallons of water can be
calculated from the following formula:
Gallons of Sodium Hypochlorite needed = 50  % of available chlorine
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2) METHODS OF CHLORINE APPLICATION:
The Contractor will inject a chlorine solution as specified in AWWA Standard
C651, latest revision, into the water main. Chlorination shall be in
accordance with the following guidelines for calcium hypochlorite granules:
Pounds of calcium Hypochlorite granules
per 1000 feet of pipe to provide 100 ppm
6-inch diameter pipe 1.9 lbs.
8-inch diameter pipe 3.33 lbs.
12-inch diameter pipe 7.5 lbs.
16-inch diameter pipe 13.4 lbs.
24-inch diameter pipe 30.1 lbs.
a. The chlorine solution shall be injected in the section of the main
nearest an existing main. The chlorine solution shall result in a
chlorination concentration of 100 ppm or greater. Chlorine injected on
Friday yielding a 48 contact time of 20ppm must be achieved or
samples cannot be collected, on a case by case basis 50 ppm
chlorine concentration with a 24 hour contact time yielding 20 ppm
may be accepted. Manually operated pumps shall not be used to
inject the solution into the main.
b. Application for Continuous Feed and Slug Method
Taps will be made at the control valve at the upstream end of the line
and at all extremities of the line including valves. These taps shall be
located in such a manner as to allow chlorine solution to be fed into all
parts of the line.
The chlorine solution shall be circulated in the main opening of the
control valve while systematically manipulating hydrants and taps at
the line extremities. The chlorine solution must be pumped in at a
constant rate for each discharge rate in order that a uniform
concentration will be produced in the lines.
c. Continuous feed method- potable water shall be introduced into the
pipe main at a constant flow rate. Chlorine shall be added at a
constant rate to this flow so that the chlorine concentration in the
water in the pipe is 100mg/L. The chlorinated water shall remain in
the main at 48 hours, after which, the chlorine concentration in the
water shall be at least 20mg/L. All valves and appurtenances shall be
operated while the chlorinated water remains in the main.
d. Slug method – Shall be as described in AWWA C-651 SECTION
4.4.4 and the following requirement. The water shall receive a
chlorine dosage, which will result in a chlorine concentration of
100mg/L in a “slug” of the water.
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3) BACTERIOLOGIC TESTS-GENERAL:
Before the water main is placed in service, all samples shall be collected
at regular intervals not exceeding 1,200 feet and tested for bacteriologic
quality and shall show the absence of both background growth (gram
positives) and coliform organisms.
a. Bacteriological testing shall comply with Section 5 of AWWA C651.
All samples shall be tested for bacteriological (chemical and physical)
quality in accordance the Standard Methods for the Examination of
Water and Wastewater, and shall show the absence of coliform
organisms and the presence of chlorine residual.
b. Purity Testing includes a series of tests that must be taken on two
consecutive days. Samples cannot be collected if any type of
precipitation is falling unless, an acceptable protective covering
(approved by the OWASA Representative) is constructed suitable to
prevent contamination.
c. All sampling pipe shall be either brass or PVC and as shown in detail
#514.07, 514.08 and 514.09.
d. The Contractor is responsible for furnishing all material, construction
of sampling points and performing all labor associated with collecting
samples. Temporary pipes used for sampling shall be composed of
sections of vertical pipe terminating into a 90-degree horizontal bend
and nipple at least 18 inches above ground level. Copper tubing used
for sampling shall terminate horizontally with the ground, at least 18
inches above ground level. Samples will not be taken from a hose.
e. OWASA’s representative will prepare a Sampling Log, including a
sketch of the sampling points, as specified by OWASA’s chemist. An
OWASA Representative will collect the samples and deliver them to
the OWASA Laboratory. Day 1 samples can be taken on Monday and
Tuesday during regular business hours. Day 1 samples cannot be
collected on Wednesday. Day 2 samples collected on Wednesday
must be received in the laboratory by 3:00 p.m. The normal
turnaround time for OWASA’s laboratory to acquire results is 3
working days.
f.
Sampling Costs: Samples will be taken at each discharge point for
Day 1 and Day 2 sampling free of charge. If purity testing fails on
either Day 1 or Day 2, OWASA’s Inspector will resample each
discharge point at no cost. However, a charge will be assessed after
the second set of samples has failed. Cost will be based on time,
travel, equipment and material used/expended to collect and obtain
results.
Samples for bacteriological analysis shall be collected in sterile
bottles treated with sodium thiosulfate. Day 1 results will not be
available until 24 hours after sample has been run by lab. If
laboratory results indicate the presence of coliform bacteria, the
samples are unsatisfactory. If laboratory results indicate background
OWASA – Manual of Specifications, Standards and Design
April 2015
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02510 – WATER DISTRIBUTION
growth masking the detection of coliform bacteria, the sample will be
considered unsatisfactory. If the line fails either day 1 or day 2
sampling, the main shall be re-chlorinated by the Contractor and new
tests performed prior to moving to the next section of main. OWASA
will furnish water and operate the control valves for these operations.
The Contractor shall be responsible for loading, removal, hauling,
and, discharging of water.
Samples for bacteriological analysis shall be collected for each
section of pipe between main line valves after flushing is completed.
Primary sampling points are blow-offs, 2-inch setters and all fire lines.
Sampling will be allowed at hydrants only if no other acceptable
sampling point is available. All work required shall be at the
Contractor’s expense.
4) NEW WATER
PROCEDURE:
MAIN
DISINFECTION
AND
PURITY
TESTING
–
STEP 1: Disinfection
The Contractor is responsible for furnishing all taps and materials required to
satisfactorily disinfect the water system. All sample points shall be setup as
shown in detail# 514.07, 514.08 or 514.09 as applicable. The following steps
will be completed by OWASA and the Contractor cooperatively.
a. OWASA’s representative will witness the flushing of the section of
main to be disinfected until turbidity readings indicate 1.0 or less NTU.
Minimum blow-off sizes:
2” – 8” lines 2” blow-offs
12” lines 4” blow-offs
16” & larger lines 6” blow-offs
The Contractor is responsible for adequate disposal of the large
volumes of water generated from flushing and de-chlorinating.
b. The Contractor will inject a chlorine solution as specified in Section
3.4 of this 02510, into the water main.
i.
Do not use manually operated pumps to inject the solution into the
main.
ii. The chlorine solution shall result in a chlorine concentration of 100
ppm or greater.
iii. The chlorine solution should be injected in the section of main
nearest an existing water main.
c. OWASA’s representative will witness water being drawn from the
following areas until 100 ppm chlorine concentration has been
measured at all points of discharge at which time each point will be
closed:
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April 2015
Page 02510-53
02510 – WATER DISTRIBUTION




End of the main,
Hydrants,
Lateral lines, and
Other connections as necessary.
i.
OWASA’s representative will witness the closing of all control
valves feeding water into the main.
ii. The chlorine concentration shall not drop below 20 ppm within a
minimum period of 48 hours.
iii. After the 48-hour period expires, OWASA’s representative with the
assistance of the Contractor will check the chlorine concentration
to confirm that it has not dropped below 20 ppm. Day 1 samples
will not be collected if the concentration is below 20 ppm after
contact time has ended.
STEP 2: Preparing for Purity Testing
The Contractor is responsible for furnishing all material and constructing sample
points.( See Standard Detail # 514.07, # 514.08, # 514.09) For Blow off 4” and
larger consult OWASA Representative.
a. OWASA’s representative is responsible for preparing a Sampling Log
that includes a sketch of sampling points, which is specified by
OWASA’s Chemist.
b. The Contractor must ensure that each sample point terminates
horizontally 18” or greater above ground level, but no more than 36”.
c. SAMPLES WILL NOT BE TAKEN FROM A HOSE.
Now the water main is ready for purity testing which includes a series of tests
that must be taken on two consecutive days. The normal turnaround time for
OWASA’s Laboratory to acquire results is about three working days. Day 1
samples can only be taken during normal business hours on Monday, and
Tuesday. Day 2 samples may be collected on Wednesday, but must be received
in the OWASA Laboratory by 3:00 p.m. Samples collected but not received in the
Laboratory by 3:00 p.m. on Wednesday will be considered failing and rechlorination must be completed.
STEP 3: Purity Testing
OWASA is responsible for collecting and approving samples. ONCE THE
CONTROL VALVE HAS BEEN OPENED AND WATER FLOW HAS BEGUN
THRU THE NEW WATER MAIN THE FLOW SHALL NOT BE STOPPED, THE
BLOWOFF/DISCHARGE POINT SHALL NOT BE CLOSED UNITL ALL
SAMPLES HAVE COLLECTED. THE BLOWOFF/DISCHARGE POINT SHALL
NOT BE CLOSED, EITHER UNTIL THE CONTROL VALVE(S) HAVE BEEN
CLOSED OR SIMUTANIOUSLY.
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April 2015
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02510 – WATER DISTRIBUTION
SAMPLING – DAY 1
a. OWASA’s Representative with assistance from the contractor will
check both chlorine concentration and turbidity.
b.
If the chlorine concentration and turbidity are within limits, OWASA’s
inspector will collect samples from the new main and from an
approved/control water main in the distribution system.
Obtaining a control sample allows the laboratory to compare the
water quality in the distribution system with that in the new water
main.
c.
On the day of collection, OWASA’s Representative will deliver the
collected sample to OWASA’s Laboratory either on Monday or
Tuesday before 5:00 p.m.
d. OWASA’s Laboratory personnel will conduct a Colilert
bacteriological test. This test requires 24 hours of incubation
before the result is obtained. The Laboratory begins these tests
around 3:30 p.m. on Monday, Tuesday and Wednesday. Samples
delivered on Monday and Tuesday after 3:00 p.m. will be refrigerated
and Colilert test run the following day.
e.
The Colilert results must be negative for coliform and E. Coli
bacteria.
i.
If the samples from the water main are positive (fail), the main
must be disinfected again which means Step 1 must be repeated
in its entirety.
ii. In the rare event that the samples from the control main are
positive (fail), the new main must be disinfected again which
means Step 1 must be repeated in its entirety.
Laboratory personnel will also conduct a Heterotrophic Plate Count
(HPC) bacteriological test. This test required 48 hours incubation
before the result is obtained.
The HPC result must be less than or equal to 500 CFU (colony
forming units/ml.
If the results from the control main are greater than 500 CFU, the
control main must be flushed and re-sampled at a later date. This is
not a responsibility of the contractor to perform.
SAMPLING – DAY 2
a.
The water main shall not be flushed again.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02510-55
02510 – WATER DISTRIBUTION
b.
OWASA’s Inspector will check both chlorine concentration and
turbidity.
If the chlorine concentration and turbidity are within the limits, OWASA’s
Representative will collect samples from the new main and from an
approved/control water main in the distribution system. Samples will be
collected from the same discharge points as in Day 1.
c.
d.
Laboratory personnel will conduct a Colilert bacteriological test.
This test required 24 hours of incubation before the result is
obtained. (If results are positive, step 1 must be repeated).
In the rare event that the samples from the control main are positive
(fail). The new main must be disinfected again which means Step 1
must be repeated in its entirety.
5) Dechlorination: Water containing even very small concentrations of
chlorine or chloramines is harmful to aquatic life in the receiving streams.
The state standard for water entering surface waters should be below 17
ppb for total residual chlorine (NC DENR- Division of Water Quality “Red
Book” Surface Water and Wetland Standards NC Administrative Code
15A NCAC 02B.0100 and .022). Therefore, no discharge of chlorinated
water into a storm sewer or a stream will be permitted unless the
discharge is first treated by a neutralizing chemical applied to the water to
be wasted to neutralize thoroughly the residual chlorine. A dechlorinating device is required. The use of tankers or pools to hold
chlorinated water will not be permitted. Disposal of chlorinated water
shall be by as outlined in the flowing: 1. For water with chlorine residuals
between .1 and 4.0 ppm a tablet form (sodium sulfite 81.3%) of dechlorination shall be used thru an acceptable de-fuser approved by the
OWASA Representative. 2. ONLY APPLIES TO DIRECT STREAM
DISCHARGE. For water with chlorine residuals between .1 and 4.0 ppm
only Vita-D-Chlor tablets (ascorbic acid) shall be used if the discharged
water goes directly into the stream. The appropriate de-fuser with tablet
screen is required 3. For water with chlorine residuals above 4 ppm a
liquid form (Calcium thiosulfate 20-30%) of de-chlorination shall be used.
This chemical shall be run thru an acceptable de-fuser which allows the
chemical to be gravity feed (at the appropriate rate) or siphoned (at the
appropriate rate) directly into the water flow. And meet the applicable
sections of AWWA C651, latest revision. See Standard Detail 514.07,
Purity Sampling Connection Detail for 2” Blow Off Line, Standard Detail
514.08, Purity Sampling Connection Detail on Fire Hydrant , and
Standard Detail 514.09, Purity Sampling Connection Detail at Backflow
Preventer.
3.5
FINAL ACCEPTANCE
Upon completion of water main installations and prior to acceptance, the Contractor
shall provide adequate and competent personnel to conduct, in conjunction with the
OWASA – Manual of Specifications, Standards and Design
April 2015
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02510 – WATER DISTRIBUTION
OWASA Representative, an inspection of each valve and hydrant on the newly
completed main. The purpose of this inspection shall be to insure the operability and
location of each valve and to further insure that all valves are left in the open position.
Fire hydrants shall be greased and painted.
Flow tests are to be performed on each hydrant to verify both that flows are in line with
the design flows and that all line and leg valves are open.
OWASA – Manual of Specifications, Standards and Design
April 2015
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02510 – WATER DISTRIBUTION
Location:
Test Made by:
Test Requested
by:
Make of Hydrant:
Nozzle Size:
Static Pressure:
Residual
Pressure:
Pitot Reading:
Flow (GPM):
Orange Water and Sewer Authority
Water Pressure Test Report
Time:
Date:
psi
psi
Hydrant #1
Hydrant #2
Hydrant #3
Sketch:
END OF SECTION 02510
Back to top
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02510-58
02510 – WATER DISTRIBUTION
Section
No.
2.1.A 1) b
and 2.3 J
and 3.3 B
2)
Rev
No.
Div 02510 – Water Distribution
Revision Summary Sheet
Rev.
Date
By
Reason for
change
1
9-22-14
DKB
Conform with
stainless steel
requirement
2.3 L
1
9-22-14
DKB
Clarity of intent
2.3 I 3)
1
9-22-14
DKB
Clarity of intent
3.3 A 4)
1
9-22-14
DKB
Clarity of intent
OWASA – Manual of Specifications, Standards and Design
April 2015
What Changed
Requirement for threaded
rod, couplings, and nuts shall
be stainless
Specific language for H-20
rating
Specific language for H-20
rating
Added actual length of
opening on setter
Page 02510-59
02510 – WATER DISTRIBUTION
Section
No.
Rev
No.
Div 02510 – Water Distribution
Revision Summary Sheet
Rev.
Date
By
Reason for
change
OWASA – Manual of Specifications, Standards and Design
April 2015
What Changed
Page 02510-60
02510 – WATER DISTRIBUTION
Section
No.
Rev
No.
Div 02510 – Water Distribution
Revision Summary Sheet
Rev.
Date
By
Reason for
change
What Changed
OWASA.Revisions-Water.doc
Back to top
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02510-61
02510 – WATER DISTRIBUTION
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02510-62
02520 – RECLAIMED WATER DISTRIBUTION
(Last revised 06-01-13)
SUGESTED SEARCH WORDS FOR THIS SECTION
Part 1 – General
Part 2 – Products
Part 3 – Execution
Part 4 - Testing
Air Release ValveSpec
Backflow Preventers
Butterfly Valve-Spec
Check Valve-Spec
Ductile Iron Pipe - Spec
DIP-Installation
DIP Fittings
DIP Joints
Steel Encas’t Pipe-Install
Steel Encasement Pipe-Spec
Gate Valves-Spec
1 ½” & 2” Service-Spec
Meter Boxes, Small-Spec
Meters
Parallel Pipe-Clearances
Pipe Crossing Clearances
Pipe Separation Req’ts
Pressure Test & Leakage
PVC Pipe Spec
Small Service ConnectionsSpec
Tape, Detector
Tunneling Method
Tunnel Liner - Spec
Tapping Sleeve & Valve-Spec
Vault Access Frames-Spec
Valve Boxes-Spec
Valves-Settings
PART 1 – GENERAL
1.1
RELATED DOCUMENTS
Refer to section 2510.
1.2
SUMMARY
Refer to section 2510.
1.3
DEFINITIONS
A. GENERAL:
For the purposes of this specification, the following definitions refer to
reclaimed water transmission and distribution systems that come under the
authority of OWASA as specified within this and other sections of this
manual.
1. Reclaimed Water Main: Exterior reclaimed water systems for approved
uses.
2. Reclaimed Water Service: Exterior reclaimed water service piping used
to provide water for domestic purposes.
B. The following are industry abbreviation for various pipe materials:
1.
2.
3.
4.
5.
AC
CIP:
DIP:
RCP:
Cu:
Asbestos Cement Pipe
Cast Iron Pipe
Ductile Iron Pipe
Reinforced Concrete Pipe
Copper
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02520-1
02520 – RECLAIMED WATER DISTRIBUTION
1.4
SUBMITTALS
Refer to section 2510.
1.5
QUALITY ASSURANCE
Refer to section 2510.
1.6
QUALITY STANDARDS
Refer to section 2510.
1.7
PRODUCT DELIVERY, STORAGE AND HANDLING
Refer to section 2510.
1.8
PRODUCT SUBSTITUTIONS
Refer to section 2510.
1.9
PROJECT CONDITIONS
Refer to section 2510.
1.10
SEPARATION OF RECLAIMED WATER AND SANITARY AND/OR
COMBINED SEWERS
Follow the NCDENR standards for separation of reclaimed water mains and
sanitary sewers lines and potable water mains.
1.11
COORDINATION
Refer to section 2510.
1.12
CROSS-CONNECTION CONTROL
Refer to section 2510
PART 2 – PRODUCTS
2.1
PIPE, FITTINGS AND IDENTIFICATION
Refer to section 2510.
A. DUCTILE IRON PIPE
Refer to section 2510.
B.
DUCTILE IRON PIPE JOINTS
OWASA – Manual of Specifications, Standards and Design
April 2015
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02520 – RECLAIMED WATER DISTRIBUTION
All pipe joints shall be restrained joint as manufactured by its respective pipe
manufacturer in sizes 4 inches through 48 inches. Acceptable types of pipe joints
are as follows:
1) Mechanical Joint Restraint: Acceptable types of joint restraints
shall be:
Restrained Joint Pipe shall be TR Flex as manufactured by United States
Pipe and Foundry Company, or Flex-Ring as manufactured by American
Cast Iron Pipe Company, Snap-lok as manufactured by Griffin Pipe
Products Company.
2) Flanged Joints
Refer to section 2510.
C. DUCTILE IRON FITTINGS:
Refer to section 2510.
All retainer glands shall be as manufactured by; Ebba Iron (Mega- Lug), Ford
(Uni-Flange), Sigma (One-Lok) or approved equal.
D. POLYETHYLENE WRAP
All pipe and fittings shall be wrapped with a polyethylene wrap, unless
otherwise indicated on the Drawings. The polyethylene wrap shall be purple
(Pantone 522C) as required for reclaimed water. Polyethylene wrap shall
conform to ANSI 21.5 and installation shall be in accordance with AWWA
C105. Polyethylene wrap shall be provided in tube rolls, accordion bundles or
sheets, and shall be manufactured of virgin polyethylene material conforming
to ANSI/ASTM D1248. The specified nominal thickness for low-density
polyethylene film is 0.008 in. (8 mils). The specified nominal thickness for
high-density cross-laminated polyethylene film is 0.004 in. (4 mils). The minus
thickness tolerance shall not exceed 10% of the nominal thickness on both
material types. Joints in the polyethylene wrap shall be taped. Installation of
polyethylene wrap shall conform to ANSI/AWWA C105/A21.5 and DIPRA's
"Polyethylene Wrap" brochure.
E. DETECTABLE WARNING TAPE
Metallic Underground Warning Tape: Metallic detectable underground
warning tape shall consist of a solid aluminum foil core, 35 gauge minimum,
encased on each side with plastic (minimum overall thickness 5 mils) and be
3 inches wide with black lettering imprinted on a color coded background that
conforms to APWA uniform color code specification PURPLE and silver with
black ink letters. Minimum tensile strength shall be 22 lbs/inch. Soil
tolerance range should be pH 2.5 to pH 11.0. On one side of the tape, the
text shall include the wording “CAUTION - RECLAIMED WATER – DO NOT
DRINK” repeated along the length of the tape. Underground warning tape is
to be below grade and affixed directly to the pipe.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02520-3
02520 – RECLAIMED WATER DISTRIBUTION
F.
COPPER TUBE
Refer to section 2510
G. PVC PIPE
Refer to section 2510 except as noted below:
All PVC reclaimed piping shall be either colored Pantone 522C (Purple) or
bagged in poly wrap as specified in the ductile iron pipe section of this
standard.
H. STEEL CASING PIPE
1) Steel Casing Pipe: Refer to section 2510
2) Spiders/Skids for Encasement Pipes: Refer to section 2510
3) Steel Casing End Seals: Refer to section 2510
I.
CARRIER PIPE FOR CASINGS
Refer to section 2510
J. TUNNEL LINERS
Refer to section 2510.
2.2
VALVES and VALVE BOXES
A. GATE VALVES
Refer to section 2510
B. VALVE BOXES
Refer to section 2510 and the following requirements.
Valve box covers shall be square in shape (NOT round) and shall be
designed for AASHTO H-20 truck loadings. All valve box covers shall be of
non-interchangeable shape with potable water covers, and cast on the top
surface with a recognizable inscription indicating “Reclaimed Water”. All
valve box covers shall be painted purple, Pantone 522. All top sections of
reclaimed the reclaimed system shall be square
C. AIR RELEASE VALVE
Refer to section 2510
D. BUTTERFLY VALVES
Refer to section 2510
OWASA – Manual of Specifications, Standards and Design
April 2015
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02520 – RECLAIMED WATER DISTRIBUTION
E. CHECK VALVES
Refer to section 2510
F. TAPPING SLEEVES AND VALVES
Refer to section 2510
G. BLOW OFFS
Refer to section 2510
H. CORPORATION STOPS
Refer to section 2510
I.
MANHOLE FRAME AND COVERS
Manhole frames and covers shall be meet ASTM A48 Standard Specification
for Gray Iron Castings, Class 30, traffic frame and cover as manufactured by
Capitol Foundry, US Foundry or East Jordan Iron Works. Cover shall read
“CAUTION - RECLAIMED WATER – DO NOT DRINK” in the center and
“DANGER ENTRY PERMIT REQUIRED” around the circumference. See
Standard Detail 516.01. Provide four 1-inch diameter holes in the top at
each compass point.
Weights shall not vary more than 5% +/- of the weight shown on Standard
Detail 516.01.
Acceptable Manufacturers and models are:
Manufacturer
Capitol Foundry
US Foundry
East Jordan Iron Works
Model
MH-2001
USF-669
V-1384
2.3 MISCELLANEOUS APPURTENANCES
A. CAST STRAIGHT AND TRANSITION COUPLINGS
Refer to section 2510
B. DUCTILE IRON TRANSITION COUPLINGS
REFER TO SECTION 2510
C. MISCELLANEOUS CONCRETE
Refer to section 2510
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02520-5
02520 – RECLAIMED WATER DISTRIBUTION
D. BEDDING
Refer to section 2510
E. PRECAST CONCRETE MANHOLE STRUCTURES
Refer to section 2510
F. Manhole Size Determination:
Refer to section 2510
G. PIPE SADDLE SUPPORT - ADJUSTABLE
Refer to section 2510
H. SERVCES, VAULTS AND BOXES
Refer to section 2510 and the following requirements.
All exposed (visible piping) shall be pantone 522C in color. This can be
achieved by poly wrap taped to piping or paint.
1) RECLAIMED WATER METER BOXES AND PRECAST CONCRETE
VAULTS
All covers shall be color coded purple, Pantone 522C, with words
“Reclaimed Water – Do Not Drink” cast into the lid.
I.
VAULT ACCESS HATCH
Refer to section 2510 and the following requirements.
All covers shall be color coded purple, Pantone 522C, with words
“Reclaimed Water – Do Not Drink” cast into the lid.
PART 3 – EXECUTION (INSTALLATION)
3.1
PIPE AND FITTINGS
Refer to Section 02275 – TRENCHING, BACKFILLING AND COMPACTION
OF UTILITIES.
A. DUCTILE IRON PIPE
1) DIP INSTALLATION:
Refer to section 2510.
B. CONSTRUCTION:
Refer to section 2510 and the following requirements.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02520-6
02520 – RECLAIMED WATER DISTRIBUTION
Polyethylene wrap application: The pipe shall be slid into the poly
bag and cut in a manner to allow for a minimum of 1 foot over lap on
each section, this requirement applies to both horizontal and vertical
applications. Prior to being lowered into the trench, all pipes shall be
carefully inspected to see that each pipe is clean inside and on the
outside. Joints in the polyethylene wrap shall be taped to ensure
complete coverage of the piping with sufficient slack to allow for
stretching of poly bag/wrap. In addition, joints in the polyethylene
wrap shall also be taped every two (2’) foot along the length of the
pipe. Installation of polyethylene wrap shall conform to ANSI/AWWA
C105/A21.5 and DIPRA's "Polyethylene Wrap" brochure.
a. Cutting Pavement/Driveways:
Refer to section 2510.
b. Protection of Pavement:
Refer to section 2510.
3.2
UTILITY PROTECTION:
Refer to section 2510.
3.3
SURFACE OR GROUND WATER IN TRENCHES/PIPE:
Refer to section 2510.
3.4
ABANDONING OF AN EXISTING WATER SERVICES/LINES:
Refer to section 2510.
3.5
STEEL ENCASEMENT PIPE – DRY BORING & JACKING OR OPEN CUT
Refer to section 2510.
A: TUNNELING METHOD
Refer to section 2510.
B: TUNNELING (BORING METHOD):
Refer to section 2510.
C: TUNNELING (HAND-MINING):
Refer to section 2510.
3.6
HORIZONTAL DIRECTIONAL DRILLING OF HDPE WATER PIPE
Refer to section 2510 and the following requirements.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02520-7
02520 – RECLAIMED WATER DISTRIBUTION
All HDPE pipe shall be purple in color and properly indentified as being
reclaimed water line or wrapped in polyethylene as previously described and
properly indentified.
A. INSTALLATION AND TESTING:
Refer to section 2510.
3.7
PVC PIPE FOR RECLAIMED WATER MAIN
Refer to section 2510 and the following requirements.
All PVC pipe shall be purple in color and properly indentified as being reclaimed
water line or wrapped in polyethylene as previously described and properly
indentified.
3.8
RECLAIMED GATE VALVES
Refer to section 2510.
3.9
VALVES 16 INCHES AND LARGER (GATE OR BUTTERFLY VALVES)
Refer to section 2510.
3.10
TAPPING SLEEVES AND VALVES
Refer to section 2510.
3.11
AIR / VACUUM RELEASE VALVES
Refer to section 2510.
3.12
MISCELLANEOUS APPURTENANCES
A. SERVICES
Refer to section 2510 and the following requirements.
1) General: Taps into in-service reclaimed water mains shall be
made by OWASA personnel only. All fees must be paid and work
scheduled with OWASA Operations Department before OWASA
will make the tap. All materials must be on-site, trenches open,
and shoring and traffic control devices in-place before OWASA
will perform the tap. Contractor may be required to provide
approved traffic control plan if required by inspector.
2) Allowable Tapping methods:
Refer to section 2510.
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April 2015
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02520 – RECLAIMED WATER DISTRIBUTION
3) Tap Location sizes and support:
Refer to section 2510.
a. Small Meter Boxes and setters
Refer to section 2510.
b. ¾-inch and 1-inch copper service lines:
Refer to section 2510.
c. 1 1/2-inch and 2-inch Meters:
Refer to section 2510.
d. Meter Vaults:
Refer to section 2510.
e. Grounding to Water Services:
Refer to section 2510.
3.13 RESTRAINTS
Refer to section 2510 and the following requirements.
A. Thrust Collars:
Refer to section 2510.
3.14 VAULT CONSTRUCTION
Refer to section 2510.
3.15 MANHOLE INSTALLATIONS
Refer to section 2510.
3.16 CONNECTIONS TO EXISTING RECLAIMED MAINS:
The Contractor shall furnish all materials for connection to existing reclaimed
water mains. OWASA shall be the sole operator of all valves and fire hydrants.
In making connections to the existing reclaimed water distribution system, valves
shall be set as shown on the plans.
Before shutting off any reclaimed water main, customers are to be notified by an
OWASA representative in writing at least 24 hours in advance of cut off. The
Contractor shall provide assistance to OWASA in notification distribution.
OWASA – Manual of Specifications, Standards and Design
April 2015
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02520 – RECLAIMED WATER DISTRIBUTION
OWASA shall be notified at least 10 days in advance of request for operation of
valves and making either a wet tap or cut-in.
If the connection to the existing reclaimed mains requires a wet tap, such tap
shall be done by a firm experienced and equipped to do this type of work. All
materials and labor shall be provided by the Contractor to include, but not
necessary limited to the sleeve, valve, tapping machine, accessories, installation,
and testing of such materials to complete the work. OWASA shall have the right
to approve the firm or crew performing the work.
Work shall be scheduled at least 10 working days in advance through OWASA’s
inspector. A crewman from the OWASA Distribution and Collections Division
shall be present during the operation. After installation of the tapping sleeve and
valve and prior to performing the tap, the assembly shall be hydrostatically tested
at a pressure equal to the test pressure of the new line installed. Such pressure
shall be maintained with no loss for a minimum time of 15 minutes.
PART 4 TESTING
4.1
Pipelines shall be tested, in sections between valves, as soon as the installation
is completed. Using this method, errors in workmanship can be identified
immediately and leaks can be fixed quickly and with minimum expense.
Prerequisite conditions for Testing and Disinfection shall be as follows:
A. Pipelines and appurtenances have been laid and the trench backfilled.
B. Valves shall be properly located, operable, and at correct elevation. Valve
boxes or manholes shall be centered over operating nuts and the top of the
box or manhole shall be at proper elevation.
C. All services shall be installed complete with setters (Contractor shall provide
a meter, approved by OWASA, for pressure testing). There shall be no
bypass around the meter used for pressure testing.
D. All reaction anchors (if necessary) have had sufficient set of 7 days or high
early strength concrete may be used to reduce the curing time to 3 days. For
high early concrete mix, use 4,500 psi or greater concrete. Temporary
bracing shall not be allowed.
E. Lines shall be properly vented where entrapped air is a consideration.
F. All visible leaks, broken or cracked pipe, valves, etc. shall be repaired.
G. Air release valves shall be installed complete and in place after pressure test.
H. All construction activities on the project, that requires trenching or excavation
within the limits of the water location shall be completed. Pavement base
course and curb and gutter shall be in place before sampling. Pressure
testing is to be performed before pavement is put down.
I.
Approval from OWASA’s Inspector on section of line to be tested.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02520-10
02520 – RECLAIMED WATER DISTRIBUTION
J. The Contractor shall provide all materials, equipment, taps, and accessories
required for filling, testing, and flushing.
4.2
ORDER OF OPERATIONS
A. Fill Line:
Refer to section 2510.
B. Pressure Test:
Refer to section 2510.
C. Flushing:
System shall be filled and left undisturbed for a minimum of 24 hours prior to
beginning flushing operations. Flushing shall be a velocity of not less than
2.5 feet per second to remove sediment and other foreign matter until the
water runs clear. The flushing will be considered complete when the turbidity
of a water sample taken after flushing does not exceed 3.0 NTU. The
turbidity analysis will be completed by the OWASA Inspector. The Contractor
shall be responsible for making adequate provisions for drainage of large
volume of flushing water. Any damages that may occur from this operation
shall be the sole responsibility of the Contractor.
D. Final:
After final flushing, flow all blow-offs to confirm the valves are open.
4.3
FINAL ACCEPTANCE
Refer to section 2510.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02520-11
02520 – RECLAIMED WATER DISTRIBUTION
AWWA C600 TABLE 6A
ALLOWABLE PRESSURE TEST LEAKAGE
(Allowable Leakage per 1000 ft. of Pipeline * in gph)
(This table is excerpted from AWWA C-600, Section 5.2 Table 6A)
NOMINAL PIPE DIAMETER-IN.
AVG. TEST PRESSURE
PSI
2
3
4
6
8
10
12
14
16
18
20
24
30
36
42
48
54
450
0.32
0.48
0.64
1
1.3
1.6
1.9
2.2
2.6
2.9
3.2
3.8
4.8
5.73
6.69
7.64
8.6
400
0.3
0.45
0.6
0.9
1.2
1.5
1.8
2.1
2.4
2.7
3
3.6
4.5
5.41
6.31
7.21
8.11
350
0.28
0.42
0.56
0.8
1.1
1.4
1.7
2
2.3
2.5
2.8
3.4
4.2
5.06
5.9
6.74
7.58
300
0.26
0.39
0.52
0.8
1
1.3
1.6
1.8
2.1
2.3
2.6
3.1
3.9
4.68
5.46
6.24
7.02
275
0.25
0.37
0.5
0.8
1
1.2
1.5
1.7
2
2.2
2.5
3
3.7
4.48
5.23
5.98
6.72
250
0.24
0.36
0.47
0.7
1
1.2
1.4
1.7
1.9
2.1
2.4
2.9
3.6
4.27
4.99
5.7
6.41
225
0.23
0.34
0.45
0.7
0.9
1.1
1.4
1.6
1.8
2
2.3
2.7
3.4
4.05
4.73
5.41
6.03
200
0.21
0.32
0.43
0.6
0.9
1.1
1.3
1.5
1.7
1.9
2.1
2.6
3.2
3.82
4.46
5.09
5.73
175
0.2
0.3
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.4
3
3.58
4.17
4.77
5.36
150
0.19
0.28
0.37
0.6
0.7
0.9
1.1
1.3
1.5
1.7
1.8
2.2
2.8
3.31
3.86
4.41
4.97
125
0.17
0.25
0.34
0.5
0.7
0.8
1
1.2
1.3
1.5
1.7
2
2.5
3.02
3.53
4.03
4.53
100
0.15
0.23
0.3
0.5
0.6
0.8
0.9
1.1
1.2
1.4
1.5
1.8
2.3
2.7
3.15
3.6
4.05
*
For pipe with 18 ft. nominal lengths. To obtain the recommended allowable leakage for pipe with 20 ft. nominal lengths, multiply the leakage calculated from the table by
0.9. If the pipeline under test contains sections of various diameter, the allowable leakage will be the sum of the computed leakage for each size.
OWASA – Manual of Specifications, Standards and Design
April 2015
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02520 – RECLAIMED WATER DISTRIBUTION
Location:
Test Made by:
Test Requested by:
Make of Hydrant:
Nozzle Size:
Static Pressure:
Residual Pressure:
Pitot Reading:
Flow (GPM):
Orange Water and Sewer Authority
Water Pressure Test Report
Time:
Date:
psi
psi
Hydrant #1
Hydrant #2
Hydrant #3
Sketch:
END OF SECTION 02520
Back to top
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02520-13
02520 – RECLAIMED WATER DISTRIBUTION
Section
No.
Div 02520 – Reclaimed Water Distribution
Revision Summary Sheet
Rev
No.
Rev.
Date
OWASA.Revisions-Water.doc
By
Reason for change
What Changed
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OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02520-14
02530 – SANITARY SEWER
(Last revised 06-01-13)
SUGESTED SEARCH WORDS FOR THIS SECTION
Part 1 – General
Part 2 – Products
Part 3 – Execution
Bypass Pumping
Concrete Encasements
Ductile Iron Pipe - spec
DIP Fittings
Iron Castings
KOR-N-SEAL
Line Air Pressure Test - Table
Low Press Air Test Gravity Lines
Manhole Corrosion Protection
Manhole Plugs
Manholes Precast - Spec
Manhole Vent Pipes
Manhole Vacuum Test
Pipe Laying
Pipe Separation Req’ts
Pump Station & Force Mains
PVC Pipe
Service Connections
Steel Encasement Pipe
Testing
Tunneling
Tunnel Liners
UG Damage Protection
PART 1 – GENERAL
1.1
RELATED DOCUMENTS
A. Drawings and general provisions of the Contract, including General and
Supplementary Conditions apply to this specification.
B. Section 02275 – TRENCHING, BACKFILLING AND COMPACTION OF UTILITIES.
1.2
SUMMARY
This section includes sanitary sewer piping and specialties for municipal sewer and
services outside of building structures.
1.3
DEFINITIONS
A. GENERAL:
For the purposes of this specification, the following definitions refer to sanitary sewer
collection and pressure systems that come under the authority of OWASA as
specified within this section and other sections of this manual.
1) Cleanouts: A riser pipe off of a service line that provides access to the line for
the purpose of line cleaning.
2) Easement: An instrument that depicts/describes and conveys rights and
privileges to OWASA for the placement, access to and maintenance of a utility
line across and/or on the property of a second party. Ownership of the land
remains with the second party.
3) Sanitary Sewer: Exterior gravity or pressure public sanitary sewer systems.
4) Force Main: Pressure sanitary sewer systems.
5) Lift/Pump Station: A combination wetwell/pump station and appurtenances.
OWASA – Manual of Specifications, Standards and Design
April 2015
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02530 – SANITARY SEWER
6) Sewer Service: Exterior domestic sewer piping which connects to the public
sewer system.
B. ABBREVIATIONS: The following are industry abbreviation for various pipe
materials:
1)
2)
3)
4)
1.4
AC:
CI:
DIP:
RCP:
Asbestos Cement Pipe
Cast Iron Pipe
Ductile Iron Pipe
Reinforced Concrete Pipe
PERFORMANCE
A. Gravity Flow, Non-pressure Piping Pressure Ratings: At least equal to the system
test pressure.
B. Force Main Pressure Ratings: Shall be equal to the system operating pressure
PLUS 50 PSI, but no less than 200 psi.
1.5
SUBMITTALS
A. Submit product data for the following. For third party projects, the Developer/Project
Engineer shall perform all product review and make a submittal at the end of the
project to OWASA.
1)
2)
3)
4)
5)
6)
7)
8)
Piping Specialties.
Air & vacuum release valves and accessories.
Autodialers.
Sewage Pumps and appurtenances, operating manuals.
Auxiliary Generators.
Alarm Devices.
Precast Concrete Manhole Castings.
Piping Paint.
B. Submit shop drawings for the following:
1) Precast Concrete Vaults and wetwells, including frames and covers, ladders,
drains, access hatches, wall sleeves, valve support stands, pumps, and motors.
C. Coordination Drawings: Show manholes and other structures in vicinity, pipe sizes
and elevations, elevations of lift station elements such as influent lines, floats, etc.
D. Computations:
1) Buoyancy calculations for wetwells, manholes, interceptor/outfalls, and mains
with shallow cover.
2) Provide structural calculations for any elevated main and pier system where span
of the main exceeds the joint length. Provide calculations for all aerial mains,
and their supporting structures that are subject to hydrodynamic forces.
E. Bypass Pumping: Bypass pumping operations must be approved by OWASA
before starting. Provide a detailed written plan of how the bypass pumping operation
OWASA – Manual of Specifications, Standards and Design
April 2015
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02530 – SANITARY SEWER
shall be performed two weeks prior to the operation.
specification.
See Section 3.5 of this
F. Project Closeout: Submit 3 copies of manufacturer’s maintenance and operation
manuals on all sewage pumps and/or package lift stations and appurtenant devices.
1.6
QUALITY ASSURANCE
A. Materials and operations shall comply with the latest revision of the Codes and
Standards listed in Section 1.7, below.
B. Piping materials shall be marked clearly and legibly.
1) Ductile Iron Pipe shall show on or near bell:
a.
b.
c.
d.
e.
f.
Weight,
Class or nominal thickness,
The letters “DI” or “Ductile,”
Manufacturer’s identifying mark,
Year in which pipe was made, and
Casting period.
2) Steel pipe shall be marked as follows. Each length of pipe and each special
section shall be legibly marked by paint stenciling, die stamping or hot-roll
marking to show the following:
a. Manufacturer’s name or mark,
b. Size and weight of the pipe or special section,
c. The type of steel from which the pipe or special section was made.
C. “Gravity Sanitary Sewer Design and Construction,” ASCE Manuals and Reports on
Engineering Practice – NO. 60, WPCF Manual of Practice NO. FD-5.
D. AWWA C600: Installation of Ductile Iron Water Mains and Appurtenances.
E. NC Department of Environment and Natural Resources, Division of Water Quality,
NCAC Title 15A 2T REGULATIONS, latest revision.
1.7
QUALITY STANDARDS
A. Materials and operations shall comply with the latest revision of the Codes and
Standards listed below:
AASHTO
American Association of State Highway Transportation Officials.
ACI
American Concrete Institute
ACPA
American Concrete Pipe Association
ANSI
American National Standards Institute
AREA
American Railway Engineers Association
ASCE
American Society of Civil Engineers
OWASA – Manual of Specifications, Standards and Design
April 2015
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02530 – SANITARY SEWER
1.8
ASSE
American Society of Sanitary Engineers
ASTM
American Society for Testing and Materials
AWWA
American Water Works Association
CISPI
Cast Iron Soil Pipe Institute
CRSI
Concrete Reinforcing Steel Institute
FS
Federal Specifications
MSDS
Material Safety Data Sheets
NCDENR
North Carolina Department of Environment and Natural
Resources
NCDOT
North Carolina Department of Transportation
NCMA
National Concrete Masonry Association
NCPI
National Clay Pipe Institute
NSF
National Sanitation Federation International
OSHA
Occupational Safety and Health Administration
UL
Underwriters Laboratories, Inc.
WEF
Water Environment Federation
PRODUCT DELIVERY, STORAGE AND HANDLING
Materials used for the construction of gravity sewer, pressure mains and appurtenances
in OWASA’s sewer collection system shall be new, free of defects, and meet the highest
standards set forth. An authorized OWASA representative must inspect, review, and
approve all materials to be used for sewer main and appurtenances prior to installation.
At the option of OWASA, any material installed without inspection will have to be
sufficiently removed for inspection and review.
A. PIPE CONDITION/PIPE EXAMINATION:
1) New Pipe Inspection: Inspect materials thoroughly, including the interior, upon
arrival. Examine materials for damage and to ensure that the right pipe has been
delivered to the site. Remove damaged or rejected materials from site. Pipe
shall be protected during handling against impact shocks and free fall. Pipe shall
be kept clean at all times, and no pipe shall be used in the work that does not
conform to the appropriate ASTM Specifications.
2) Pre-Installation Inspection: Prior to being installed, each section of the pipe
shall be carefully examined for damage and conformity with these specifications.
All pipe damaged or deemed not to conform to these specifications shall be
rejected and removed from site. All pipe in which the spigots and bells cannot be
OWASA – Manual of Specifications, Standards and Design
April 2015
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02530 – SANITARY SEWER
made to fit properly, or pipe, which has chipped bells or spigots, will be rejected.
The faces of all spigots ends and of all shoulders on the bells must be true.
Examine bell and spigot for uniformity and smoothness of liner and barrel.
B. Protect pipe coating during handling using methods recommended by the
manufacturer. Use of bare cables, chains, hooks, metal bars, or narrow skids in
contact with coated pipe is not permitted.
C. Prevent damage to pipe during transit. Repair abrasions, scars, and blemishes to
the satisfaction of OWASA. If repair of satisfactory quality cannot be achieved,
replace damaged material immediately.
D. Observe manufacturer's directions for delivery and storage of materials and
accessories.
E. Protect stored piping from entry of water or dirt into pipe. Protect bells and flanges
of special fittings from entry of moisture and dirt.
F. Support pipe to prevent sagging or bending. Do not store plastic pipe, structures,
and fittings in direct sunlight.
G. Handle precast concrete manholes and other structures according to manufacturer’s
written rigging instructions.
H. Construct piping to accurate lines and grades and support as shown in drawings or
prescribed in specifications. When temporary supports are used, insure that
sufficient rigidity is provided to prevent shifting or distortion of pipe.
1.9
PRODUCT SUBSTITUTIONS
OWASA’s Engineer will approve materials not specified but deemed equal, on a caseby-case basis. OWASA’s Product and Design Review Committee (PDRC) meets on an
“as-needed” basis to evaluate new products for incorporation into these specifications. If
submitting new products, submit in writing 60 days prior to meeting date.
Documentation and samples of materials must be submitted to OWASA. New materials
approved for the sewer collection system will be incorporated into these specifications
after approval by the PDRC.
1.10
PROJECT CONDITIONS
A. SEPARATION OF WATER AND SANITARY AND/OR COMBINED SEWERS
1) Follow the NCDENR standards for separation of water mains and sanitary
sewers lines.
2) PARALLEL INSTALLATIONS:
a. Preferred/Normal Conditions – sewer mains or sewer manholes shall
be constructed at least 10 feet horizontally from water lines whenever
possible. The distance shall be measured edge-to-edge.
b. Unusual Conditions – when local conditions prevent a horizontal
separation of at least 10 feet, the sewer main or sanitary sewer manhole
may be laid closer to a water line provided that:
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April 2015
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02530 – SANITARY SEWER
4) The sewer line shall be placed in a separate trench, with elevation of
the top of the sewer line at least 18 inches below the bottom of the
water line; or
5) The sewer line shall be placed in the same trench as the water, and
located to one side, on a bench of undisturbed earth, and the elevation
of the top of the sewer line at least 18 inches below the bottom of the
water main; or
6) Where this vertical separation cannot be obtained, the sewer shall be
constructed of AWWA approved Ductile Iron Pipe pressure-tested in
place to 150 psi without leakage prior to backfilling. The sewer
manhole shall be of watertight construction and tested in place.
3. SEWER MAINS CROSSING BELOW WATER MAINS:
a. Preferred/Normal Condition – sewer lines shall be constructed to cross
below water lines whenever possible and shall be laid to provide a
vertical separation of at least 18 inches between the bottom elevation of
the water line and the top of the sewer.
b. Unusual Conditions – when local conditions prevent an 18 inch vertical
separation as described in Sewer Mains Crossing Below Water Mains,
Preferred/Normal Conditions (paragraph above), the following
construction shall be used:
a) Both the sewer crossing above water line and the water line itself shall
be constructed of AWWA approved Ductile Iron Pipe with joints that are
equivalent to water main standards for a distance of 10 feet on each
side of the point of crossing.
4. SEWER MAINS CROSSING ABOVE WATER MAINS:
a. Unusual Conditions – when local conditions prevent an 18 inch vertical
separation, as described in paragraph C, Sewer Mains Crossing Below
Water Mains, Preferred/Normal Condition, above, the following
construction shall apply:
i. That a section of DIP sewer pipe, with water main type pipe joints, is
centered at the point of the water crossing so that the joints are equal
distant and as far as possible from the water main such that, for a 90
degree crossing, the water main type joints are a minimum of 10 feet on
each side of the point of crossing.
ii. Provide adequate structural support for the sewers to prevent excessive
deflection of the joints, which can result in settling on and/or breaking
the water line.
iii. THE SEWER MAIN SHALL BE CONSTRUCTED OF FERROUS
MATERIAL AND TESTED TO 150 PSI.
5. SEWER MAINS AND OTHER UTILITIES:
OWASA – Manual of Specifications, Standards and Design
April 2015
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02530 – SANITARY SEWER
a. Horizontal Separation – Preferred/Normal Condition – sewer lines
shall be constructed to provide at least 3 feet of horizontal separation
from other utilities whenever possible. The distance shall be measured
edge-to-edge.
b. Vertical Separation – Preferred/Normal Condition – whenever it is
necessary for another utility to cross a sewer main, a 12-inch vertical
separation shall be maintained between the lines. When local conditions
prevent a 12-inch vertical separation, the following construction shall
apply:
i.
Provide adequate structural support for the utility to prevent excessive
deflection of the joints, which can result in settling on and/or breaking
the sewer line.
ii. A 24” VERTICAL SEPERATION SHALL BE PROVIDED BETWEEN
STORM SEWER AND SANITARY SEWER LINES OR FERROUS
PIPE SPECIFIED.
6. Sanitary Sewer Manholes: No water main shall be allowed to pass through or
come in contact with any part of a sewer manhole. A minimum of 10 feet of
horizontal separation shall be maintained between water mains and sanitary
sewer manholes provided that the applicable provisions of paragraph B, Parallel
Installations, Unusual Conditions, above, are also met.
7. Storm Drainage System: No gravity sewer or sewer lateral shall pass through a
storm drain pipe or manhole system.
8. New Utilities and Existing Sewer Mains: When installing a new utility adjacent
to or in close proximity to an existing sewer main, the new utility line shall be
installed to provide the minimum horizontal and vertical clearances specified in
paragraph E, Sewer Mains and other Utilities.
9. Protection of Wells – No gravity sewer, force main, or manhole structure shall
pass or be placed within 25 ft of a private well or 50 feet of a public water supply
well, source or structure. This offset distance assumes that ferrous sewer pipe
with joints equivalent to water main standards are used.
1.11
COORDINATION
A. Contact OWASA Construction Inspector to coordinate interruption of services. If
interruption is necessary, the interruption shall be arranged to occur at such a time to
cause the least disruption and minimize loss of service. At the direction of OWASA’s
Engineer, temporary service may be required to be provided. Provide a minimum of
10 working days notice of the proposed utility interruption.
1.12
LOCATE SERVICES
A. Contact “NC One Call” 1-800-632-4949 or “National Call Before You Dig” at 811
before digging.
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April 2015
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02530 – SANITARY SEWER
PART 2 – PRODUCTS
2.1
PIPE & FITTINGS
The following references provide the minimum standards as they apply to the specific
item listed. In all cases, the latest revision shall apply.
A.
DUCTILE IRON PIPE
Ductile iron pipe shall be manufactured in accordance with all applicable
requirements of AWWA C151/ANSI A21.51 and ASTM A746, Standard
Specification for Ductile Iron Gravity Sewer Pipe for 4-inch and larger diameter
pipe, pressure class rated, class 200 minimum. The thickness of Ductile Iron
Pipe shall be determined by considering trench load in accordance with
ANSI/AWWA C150/A21.50 (Public Sewers shall be no less than 8-inch
diameter).
All pipe and fittings 6 inches and larger shall be lined with SewperCoat as
manufactured by Lafarge Calcium Aluminates or approved equal. SewperCoat
is a calcium aluminate mortar made of fused calcium aluminate cement and
fused calcium aluminate aggregates. The thickness of the lining shall be the
thickness identified on AWWA C104, Sec. 4.7, paragraph 4.7.1, latest revision
but no less than 0.125 inch for 6-inch through 12-inch and 0.1875 inch for 14inch through 24-inch pipe. The lining thickness may taper to less than the
specified at the ends of the pipe. Cracks, other than closed hairline cracks
and/or fine crazing shall not be acceptable. Loose areas of cement lining are
not allowable. A seal coat shall be applied to the lining as identified on AWWA
C104, Sec. 4.11.
Epoxy Liners: Protecto 401 and Novocoat SP-2000W
are acceptable
alternatives to SewperCoat calcium aluminate mortar lining when pipe is to be
used for sewer only.
Outside coat shall be a minimum of 1 mil bituminous paint according to
ANSI/AWWA C151/A21.21 Section 51-8.1.
Each joint of ductile iron pipe shall be hydrostatically tested before the outside
coating and inside lining are applied at the point of manufacturer to 500 psi.
Testing may be performed prior to machining bell and spigot. Failure of ductile
iron pipe shall be defined as any rupture or leakage of the pipe wall.
All materials used in production of the pipe are to be tested in accordance with
AWWA C151 for their adequacy within the design of the pipe, and certified test
results are to be provided to OWASA upon request. All certified tests,
hydrostatic and material are to be performed by an independent testing
laboratory at the expense of the pipe manufacturer.
Push-on and mechanical joint pipe shall be as manufactured by the American
Cast Iron Pipe Company, Atlantic States Cast Iron Pipe Company, United
States Pipe and Foundry Company, or Griffin Pipe Products Company.
1) DUCTILE IRON JOINTS:
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April 2015
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02530 – SANITARY SEWER
Pipe joints may be either push-on or mechanical joint pipe sizes 4 inches
through 48 inches in diameter. Rubber Gasket Joints and Mechanical
Joints shall comply with AWWA C111/ANSI A21.11, ASTM A536 Standard
Specification for Ductile Iron Castings. Acceptable pipe joints are as
follows:
a.
Gravity Main Push-on Joint, Ductile Iron Pipe shall conform
to AWWA C151/ANSI A21.51 (such as "Fastite," "Tyton," or
"Bell-Tite."). The dimensions of the bell, socket, and plain end
shall be in accordance with the manufacturer's standard design
dimensions and tolerances. The gasket shall be of such size
and shape to provide an adequate compressive force against
the plain end and socket after assembly to affect a positive seal.
Gaskets shall be manufactured with an approved elastomeric
material, and comply with AWWAC111/ANSI A21.11.
b.
FORCE MAIN Push-on Joint Ductile Iron Pipe: Gaskets shall
be manufactured with an approved elastomeric material, and
comply with AWWA C111/ANSI A21.11. and shall be as
manufactured by American Pipe (Fast-Grip), Griffen Pipe
(Talon RJ), US Pipe (Field Lok 350), Atlantic States (Sure
Stop 350). The pipe shall conform to AWWA C151/ANSI
A21.51 (such as "Fastite," "Tyton," or "Bell-Tite.").
The
dimensions of the bell, socket, and plain end shall be in
accordance with the manufacturer's standard design dimensions
and tolerances. The gasket shall be of such size and shape to
provide an adequate compressive force against the plain end
and socket after assembly to affect a positive seal.
c.
Mechanical Joint, Ductile Iron Pipe shall be used only at the
specific locations indicated on the drawings or as approved by
OWASA’s Engineer.
i.
ii.
The mechanical joint shall consist of:
a)
A bell cast integrally with the pipe or fitting and
provided with an exterior flange having cored or
drilled bolt holes and interior annular recesses for
the sealing gasket and the spigot of the pipe or
fitting;
b)
A pipe or fitting spigot;
c)
A sealing gasket;
d)
Separate ductile iron follower gland having cored
or drilled bolt holes; and
e)
Ductile iron tee head bolts and hexagon nuts.
The joint shall be designed to permit normal expansion,
contraction, and deflection of the pipe or fitting while
maintaining a leak proof joint connection.
The
OWASA – Manual of Specifications, Standards and Design
April 2015
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02530 – SANITARY SEWER
mechanical joint shall conform to the requirements of
Federal Specification WW-P-421, AWWA C111/ANSI
A21.11, and ASTM A536 Standard Specification of
Ductile Iron Castings.
iii.
2)
Mechanical Joint Bolt Torque: See Section 3.1.B,
paragraph 2, Mechanical Joint Bolt Torque, below.
DUCTILE IRON FITTINGS:
Fittings shall be ductile iron at least class 54 thickness and shall
conform to AWWA C110/ANSI A21.10 or AWWA C153/ANSI 21.53 for
compact fittings. All ductile iron fittings shall have a minimum working
pressure rating of 250 psi and minimum iron strength of 25,000 psi. All
fittings shall be high alumina cement mortar lined in accordance with
ANSI/AWWA C-104/A21.4, fitting 6” and larger shall be lined with
Sewper coat or Protecto 401 lined and the outside shall be bituminous
coated. The fittings shall be tested and the manufacturer shall provide
certified test results when requested by OWASA. This testing shall
include hydrostatic proof testing of fittings. Acceptable types of fittings
shall be Mechanical Joint.
a.
B.
Mechanical Joint Fittings - Restraint shall be Megalug series
1100 mechanical joint restraint by EBAA Iron Sales, Inc., Ford
wedge action restrainer gland UFR Series 1400, Sigma “OneLok”, or approved equal. Ductile Iron fittings shall conform to
AWWA C110/ANSI A21.10 or AWWA C153/ANSI A21.53
(compact). Glands, Gaskets and Bolts shall conform to AWWA
C111/ANSI A21.11.
PVC PIPE
1)
GENERAL: Prior approval from OWASA’s Engineer must be granted
before use of PVC pipe. PVC pipe shall not be permitted under paved
surfaces.
2)
PVC PIPE FOR SEWER FORCE MAINS (4-inch through 12-inch):
PVC pressure pipe, 4-inch through 12-inch, with bell end with gasket
and spigot end shall comply with AWWA C900, Pressure Class 150, DR
18. C-900 pipe shall be used with ductile iron fittings (restrained joint).
3)
PVC PIPE FOR SEWER FORCE MAINS (2-inch):
2-inch PVC pressure pipe, bell end with gasket and spigot end shall
comply with ASTM D2241, Standard Specification for Poly(Vinyl
Chloride) (PVC) Pressure-Rated Pipe (SDR Series), SDR 21, Class
200.
C.
STEEL PIPE (Use of steel pipe - approved on a case-by-case basis)
1)
STEEL PIPE FOR SEWER MAINS, AERIAL CREEK CROSSINGS,
ENCASEMENT, BORING APPLICATIONS, AND VENT PIPES:
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Steel pipe for gravity sewer mains and aerial crossings shall meet the
requirements of AWWA C200, AWWA Standard for mill type steel water
pipe. Nominal pipe diameter and wall thickness shall be as indicated on
the drawings. Pipe shall be high strength steel, spiral welded or
smooth-wall seamless manufactured in accordance with ASTM A139,
Standard Specification for Electric-Fusion (Arc)-Welded Steel Pipe
(NPS 4 and Over) and ASTM A283/A283M, Standard Specification for
Low and Intermediate Tensile Strength Carbon Steel Plates, Grade “B”
steel with a minimum yield strength of 35,000 psi. The interior lining
shall be a coal-tar enamel coating as specified under AWWA C203.
D.
a.
Steel Pipe for Gravity Sewer Mains: Pipe shall be seamless
and either furnace-welded or electrically welded pipe, Grade A.
The exterior coating shall be coal-tar enamel in accordance with
AWWA C203.
b.
Steel Pipe for Aerial Creek Crossings (without encasement and
carrier pipe): The outside of the pipe shall have one coat of zinc
chromate primer conforming to Federal Specification TT-86-a
and afterwards painted with coal-tar enamel.
c.
Steel Encasement Pipe for Boring Applications:
Encasement pipe shall meet applicable NCDOT and AREA
specifications. Casing pipe shall include pipe carriers (spiders)
to support carrier pipe.
d.
The spiders necessary to support the carrier pipe inside of the
steel encasement pipe shall conform to Standard Detail 517.01.
Refer to Standard Detail 517.01 for spider spacing.
e.
Steel Vent Pipes for Manholes: The vent pipe shall be made
from 4-inch Schedule 40. The pipe shall be coated inside and
out in accordance with AWWA C203 and a finish coat of paint
(Hunter Green) applied to the exposed portion of the vent once
installed on the manhole casting. See Standard Detail 532.05.
TUNNEL LINERS
1)
Carrier pipe shall be mechanical joint or restrained joint ductile iron pipe
pressure class 350 psi.
2)
Grout mix for filling voids in between carrier pipe and tunnel shall
consist of the following materials properly mixed in proportions by
weight.
3)
a.
1.0 Part Cement.
b.
3.0 Parts Fine Sand, 100 Percent Shall Pass No. 16 Sieve.
c.
0.5 to 0.6 Part Water.
Tunnel lining construction shall comply with the “Specification for Steel
Tunnel Liner Plates” in the AREA Manual for Railway Engineering. The
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design and shape of the liner plates shall be such that erection and
assembly of the liner plate structure can be completely and readily
effected from inside the tunnel. Plates shall be accurately curved to suit
the tunnel cross section, and all dimensions shall be of the size and
accuracy such that plates of similar curvature shall be interchangeable.
All plates shall be connected by bolts on both longitudinal and
circumferential joints.
E.
4)
The steel lining shall consist of plates 16, 18, or 24 inches wide. Each
circumferential ring shall be composed of the number and length plates
necessary to complete the required shape shown on the drawings. The
nominal tunnel diameter shall be of sufficient size to install the carrier
pipe.
5)
Plates shall be one-piece steel meeting the requirements of ASTM
A1011, Standard Specification for Steel, Sheet and Strip, Hot-Rolled,
Carbon, Structural, High-Strength Low-Alloy, High-Strength Low-Alloy
with Improved Formability, and Ultra-High Strength, or ASTM A1008,
Standard Specification for Steel, Sheet, Cold-Rolled, Carbon,
Structural, High-Strength Low-Alloy, High-Strength Low-Alloy with
Improved Formability, Solution Hardened, and Bake Hardenable.
Plates shall have an ultimate tensile strength of at least 42,000 psi and
yield strength of 28,000 psi. Gage thickness shall be a minimum of 8
gage. The liner plate and bolts shall be galvanized in accordance with
ASTM A153. Standard Specification for Zinc Coating (Hot-Dip) on Iron
and Steel Hardware. In addition, the liner plates shall be asphalt
coated to meet AREA 1-14-13. For two flange plates, the minimum
thickness shall be 0.135 inches. Plates shall be manufactured by
Armco Steel Corporation, Commercial Shearing, Incorporated, Republic
Steel Corporation, or equal.
6)
Grout holes 1½ inches or 2 inches (or larger) in diameter shall be
provided in each ring to permit grouting as the erection of the tunnel
liner plates progresses. Grout hole screw plugs shall be provided in
plates.
7)
Steel bolts shall meet requirements of ASTM A449, Specification for
Hex Cap Screws, Bolts, and Studs, Steel, Heat Treated, 120/105/90 ksi
Minimum Tensile Strength, General Use for plate thickness equal to or
greater than 0.209 inch and ASTM A307, Standard Specification for
Carbon Steel Bolts and Studs, 60 000 PSI Tensile Strength for plate
thickness less than 0.209 inch. The nut shall meet requirements of
ASTM A 307, Grade A.
CARRIER PIPE FOR CASINGS AND TUNNELS
Carrier pipe shall be mechanical joint ductile iron pipe of the class indicated on
the drawings.
2.2 MISCELLANEOUS APPURTENANCES AND MATERIAL
A.
AIR AND VACUUM RELEASE VALVES
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Combination Air Valves shall conform to the following:
Automatic Air and Vacuum Valves shall be infinitely variable automatic air
and vacuum valves designed to allow escape of air, close watertight when
liquid enters the valve and allow air to enter in the event of a vacuum. The
valve shall be a NPT threaded Stainless Steel body. The valve outlet is to be
protected from debris entering the outlet of the valve. Valves shall be all brass.
Valves shall be designed for a maximum cold water pressure of 200 psig.
Combination air and vacuum release valves shall be located as shown on the
drawings or as otherwise directed by OWASA’s Engineer. The valve shall be
housed in a precast concrete eccentric manhole and shall be installed in
accordance with Standard Detail 538.01. Acceptable Models are, X-Series (2
inch outlet) by Crispin-Multiplex Manufacturing Co. and 986 Stainless Steel by
H-Tec Inc.
B.
BEDDING
1)
Bedding material, shall be clean coarse aggregate No. 67 or smaller,
and shall meet the requirements of Section 1005 of the NCDOT
Standard Specifications for Roads and Structures.
Minimum Bedding Allowed: The minimum bedding depth shall
be 6 inches under the pipe with an additional 1 inch depth of
cushioning material added for each additional 2 feet of depth in
excess of 16 feet up to a maximum of 12 inches of cushioning
material. Pipe shall be bedded to the spring line of the pipe.
See Standard Detail 531.01.
a.
C.
SOLID BRICK (for modifications to manholes)
Sold brick shall be hard clay, grade SM, ASTM C32, Standard Specification for
Sewer and Manhole Brick (Made From Clay or Shale) and AASHTO M91.
D.
CONCRETE
Concrete classes (NCDOT) to Design Compressive Strength at 28 days (f’c):
Class
28-day Compressive Strength
(f’c)
AA
4500 psi
A
3000 psi
B
2500 psi
Ready mixed concrete shall comply with ASTM C94, Standard Specification for
Ready-Mixed Concrete. All exposed concrete shall be air entrained. Concrete
strength shall be as specified on the standard details and drawings. Unless
otherwise specified, all concrete shall be minimum class A.
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E.
CONCRETE BLOCK (for manholes)
Concrete block shall conform to the requirements of ASTM C139, Standard
Specification for Concrete Masonry Units for Construction of Catch Basins and
Manholes.
F.
Detectable warning tape: Metallic detectable underground warning tape
shall consist of a solid aluminum foil core, 35 gauge minimum, encased on
each side with plastic (minimum overall thickness 5 mils) and be 3 inches
wide with black lettering imprinted on a color coded background that
conforms to APWA uniform color code specification with black ink letters.
Minimum tensile strength shall be 22 lbs/inch. Soil tolerance range to be pH
2.5 to pH 11.0. On one side of the tape, the text shall include the wording,
“SEWER LINE BELOW” repeated along the length of the tape. Underground
warning tape for water or sewer mains shall be placed 18 to 24 inches below
the finished grade directly above the line. See section 02520 for Reclaimed
warning tape requirements. Standard color code for tape:
Tracer Wire: Tracer wire shall be as manufactured by Copperhead Industries,
LLC. The wire shall be 12 AWG superflex expanded or approved equal. The
wire color shall be appropriate for the utility being installed. Blue for potable
water, Green for sewer, Purple for reclaimed water, etc…
G.
MORTAR FOR CONCRETE BLOCK & CLAY BRICK
1)
Mortar shall be type S, ASTM C 270, Standard Specification for Mortar
for Unit Masonry and ASTM C-144, Standard Specification for
Aggregate for Masonry Mortar. Mortar shall be prepared from cement
in perfect condition and shall be prepared in boxes for that purpose. No
mortar that has stood beyond forty-five minutes shall be used.
Proportion by volume for the different types of application shall be as
follows:
Brick masonry =
Pointing =
1 part cement to 2 parts sand
1 part cement to 1 part sand
H. IRON CASTINGS: MANHOLE FRAMES AND COVERS
1)
General: Manhole frames and covers shall be manufactured from
Class 35B gray iron, meeting the requirements of ASTM A48, Standard
Specification for Gray Iron Castings as noted in section 3.1 of AASHTO
M306. Standard manhole frames and covers shall be built to the
dimensions and configurations shown on Standard Details 533.01 and
533.02. Minimum inside diameter of the opening shall be 23 ½ inches.
Manholes castings are to be uncoated. The bearing surface of the
frames and covers shall be machined and the cover shall seat firmly
into the frame without rocking. Covers are to be embossed along the
perimeter with the name “OWASA” and with the words “Sanitary Sewer”
and “Entry Permit Required.” See Standard Details 533.01 and
533.02.
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Watertight Frames and Covers: Watertight bolt-down frames and
covers shall have 4 stainless steel bolts at 90 degrees and one
polyvinyl gasket between cover and frame seat. Frame is to have four
1-inch diameter holes in flange at 90 degrees. Watertight frames and
covers are to be utilized whenever a manhole top is set lower than 2foot above the 100-year base flood elevation.
2)
Manufacturer
Approved castings are:
East Jordan
Iron Works
US Foundry
Standard
V-1384
USF-669
Model
Watertight
Bolt-down
Model
669-KL-BWT
V-2384
(Bolt-Down)
Cover Weight
135
125
Frame Weight
180
190
Note: Weights shall not deviate by - 5% from that shown in the above table.
Capitol
Foundry
MH -2001
MH-2001-WT
120
190
An East Jordan Iron Works V-1883 or US Foundry 1261-KL is to be used with flat top manholes
unless the top of the manhole is less than 2-foot above the 100-year base flood elevation. In that
case a bolt-down watertight frame and cover is to be used.
3)
I.
Frame weights shall not vary more than 5%+/- from that shown on the
standard details.
IRON CASTINGS: SEWER CLEANOUT BOX
General: Sewer cleanout frames and covers shall be manufactured from
Class 30 gray iron, meeting the requirements of ASTM A48, Standard
Specification for Gray Iron Castings. Standard sewer cleanout frame and
covers shall be built to the dimensions and configurations shown on Standard
Detail 534.01. Approved casting is Capitol Foundry model VB-9 By-Pass
Valve Box and the US Foundry 7610 FC.
J. MANHOLE EXTERIOR JOINT SEALANT
Manhole castings shall be sealed to the structure with an “O” ring or “ram neck”
joint seal and AN external sealing system such as Infi-Shield® Uniband as
manufactured by Sealing Systems, Inc. The seal shall be continuous bands,
made of high quality EPDM (Ethylene Propylene Diene Monomer) rubber with
a minimum thickness of 60 mils. Each unit shall have a 2-inch wide mastic
strip on the top and bottom of the band. The mastic shall be non-hardening
butyl rubber sealant, with a minimum thickness of 3/16-inch, and shall seal to
the cone/top of the manhole and over the lip of the casting.
The seams on each manhole joint section shall be sealed with a minimum of
one layer of “ram neck” or O ring made of nonhardening butyl rubber and an
external sealing wrap. Acceptable manufacturers of “ram neck” or o ring are
Conseal Concrete Sealants, Inc. item CS-202. The wrap shall be a minimum of
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6” wide. Acceptable products are Gator Wrap as manufactured by sealing
systems, Inc.
See Standard Details 532.09 and 532.01.
K. MANHOLE FLEXIBLE INTERIOR COATING SEALANT
THIS PRODUCT IS TO BE USED ON ALL REHABILITATED MANHOLES
LOCATED WITHIN THE PAVED ROADWAYS. Internal sealant system (see
Standard Detail 532.06) shall prevent leakage of water into the manhole
though the frame joint area and the area above the manhole cone including all
extensions to the chimney area. The seal shall remain flexible allowing for
repeated vertical or horizontal movements of the frame due to frost lift, ground
movement, or the thermal movement of pavement. The product shall have a
minimum elongation of 800% and a Durometer hardness of 75. The manhole
sealant shall conform to the physical requirements of ASTM D412 Standard
Test Methods for Vulcanized Rubber and Thermoplastic Rubbers and
Thermoplastic Elastomers-Tension. Sealant shall equal or exceed “Flex-Seal”
as manufactured by Sealing Systems, Inc., Loretto, MN.
L. MANHOLE PLUGS
Manhole plugs shall be of the mechanical type and shall not rely upon air
pressure to secure the plug to the inside of the pipe. The plug shall be of cast
iron construction with a Neoprene rubber “O” ring. The plug shall be secured
to the inside of the pipe by means of a large wing nut that, when tightened,
compresses the Neoprene rubber “O” ring against the inside of the pipe. The
plug shall include a minimum ½ inch diameter NPT by-pass. Backpressure on
the plug shall not exceed the manufacturers recommended pressure ratings.
Approved manhole plugs shall be Cherne Iron-Grip by-pass style mechanical
plug or approved equal. See Standard Detail 532.04.
M. PORTLAND CEMENT
Type I, CSA normal, ASTM C150 Standard Specification for Portland Cement.
N. PRECAST REINFORCED CONCRETE STRUCTURES
Manholes of precast reinforced concrete shall be designed and manufactured
in accordance with ASTM C478, Standard Specification for Precast Reinforced
Concrete Manhole Sections, or latest revision. Manhole diameters shall be 4ft. minimum. The wall shall be a minimum of 5 inches thick and have a 6-inch
minimum base. Either an “O” ring or “ram neck” joint seal shall be used. The
“O” ring joint shall conform to the requirements of ASTM C443, Standard
Specification for Joints for Circular Concrete Sewer and Culvert Pipe, Using
Rubber Gaskets or latest revision. The gasketed joint shall conform to ASTM
C990, Standard Specification for Joints for Concrete Pipe, Manholes, and
Precast Box Sections Using Preformed Flexible Joint Sealants (or AASHTO M199) or latest revision. Rubber boot and stainless steel clamps, meeting the
requirements of ASTM C923, Standard Specification for Resilient Connectors
Between Reinforced Concrete Manhole Structures, Pipes and Laterals, shall
be supplied with the manhole bases to tie the pipe to the base section of the
manhole. Concrete used in the construction of the manholes shall have a
minimum 28-day strength of 4000-psi air entrained (with 4 to 6 percent air)
conforming to ASTM C33, Standard Specification for Concrete Aggregates and
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ASTM C94/C94M, Standard Specification for Ready-Mixed Concrete. Manhole
units shall consist of standard modular precast riser sections, modular riser
sections, and a monolithic base (except doghouse bases are to be used when
placing manholes over existing mains). Where conditions do not favorably
accommodate the use of an eccentric cone, eccentric precast reinforced
concrete flat tops are to be used. In areas of high H2S concentration, provide
protection of manhole by providing linings or coatings on the interior of the
manhole such as Polyethylene, PVC, Reinforced Thermosetting Resin (RTR),
“Strong-Seal,” or coal-tar epoxy. : Mack Industries, Precast Solutions,
Concrete Pipe and Precast, LLC (Hanson), Oldcastle Precast/N.C. Products,
Stay-Right Tank, Tindall Precast Concrete Products, Inc., M.C.Precast
Concrete.
Manhole steps are not permitted.
Refer to the Standard Detail 532.01 for boot to pipe connection detail.
Extended Bases: Manholes over 12 feet in depth, as measured from
top of casting to effluent invert, shall have extended bases with
appropriate reinforcing.
Drop Manholes: Unless otherwise allowed by OWASA’s Engineer,
manholes will be precast reinforced concrete. New drop manholes
shall be a minimum of 4 feet in diameter and shall be constructed in
accordance with Standard Detail 532.03.
Joint Seal: The standard joint shall be sealed/parged inside and out
with plastic cement putty meeting Federal Specification SS-C-153. All
buried joints shall also have an Infi-Shield® Seal Wrap external sealing
system, as manufactured by Sealing Systems, Inc., are to be placed on
the perimeter of the manhole joint. Infi-Shield® Uniband shall be
placed at the top of manholes where the iron casting mates with the
precast concrete cone section and/or grade rings. See Infi-Shield®
specification elsewhere in this specification. See also Standard
Details 532.01, 532.06, and 532.09
1)
Flexible Pipe-to-Manhole Connector: A flexible Pipe-to-Manhole
connector shall be employed in the connection of the sanitary sewer to
precast manholes.
The connector shall be KOR-N-SEAL, as
manufactured by NPC, Inc., Milford, New Hampshire, PSX, or equal.
The connector shall be the sole element relied on to assure a flexible
watertight seal of the pipe to the manhole. No adhesives or lubricants
shall be employed in the installation of the connector into the manhole.
The rubber for the connector shall comply with ASTM C923 Standard
Specification for Resilient Connectors Between Reinforced Concrete
Manhole Structures, Pipes and Laterals, and consist of EPDM and
elastomers designed to be resistant to ozone, weather elements,
chemicals, including acids, alkalis, animal and vegetable fats, oils and
petroleum products from spills.
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All stainless steel elements of the connector shall be totally nonmagnetic Series 304 Stainless, excluding the worm screw for tightening
the steel bands around the pipe, which shall be Series 305 Stainless.
The worm screw for tightening the steel band shall be torqued by a
breakaway torque wrench available from the precast manhole supplier,
and set for 60-70 inch/lbs.
The connector shall be of a size specifically designed for the pipe
material and size being utilized on the project.
O. SERVICES
Ductile iron pipe for sewer services shall be minimum class 350 slip joint pipe
with mechanical joint fittings. The service shall include the clean-out stack
provided with a cast iron ferrule with brass clean-out plug. See Standard
Detail 534.01.
Service Saddles: Sewer pipe saddles shall be Romac Industries, Inc. CB-4.80
(6-inch through 12-inch) or CB4.80LS (14-inch through 24-inch).
See
Standard Detail 534.01.
Service saddles may be used only on existing sewer mains. Tee/wyes shall be
used for new construction.
P. WETWELL/VALVE VAULT ACCESS HATCHES
1)
All Areas (Low Density Traffic (incidental) H-20 Loading – 16,000 lb.
wheel load on an 8 1/2-inch x 20 1/2-inch wheel area): The aluminum
access frames and covers are provided with a 1/4-inch thick structural
grade aluminum channel frame with the flanges acting as a continuous
concrete anchor. The inside of the frame has a continuous door
support angle that must have a full bed of Class "A" concrete under
both the frame and support angle. Door leaves shall be a minimum of
1/4-inch thick aluminum diamond plate with structural grade aluminum.
Door reinforcing shall withstand an H-20 live load designation. The
doors also have lifting aids of aluminum tubular construction with
compression springs to assist in opening and closing of the doors. The
doors are provided with heavy-duty stainless steel hinges with tamperproof fasteners. All hardware is to be stainless steel. The doors open
to 90 degrees and lock automatically in that position with a stainless
steel positive locking arm and a stainless steel release handle. Doors
are provided with a stainless steel lifting handle, stainless steel snaplock with removable key handle. Two key handles shall be provided
with each door. The door leaves extend to the outside perimeter of the
frame for added support. Provide padlock hasp for doors on wetwells
and valve vaults.
2)
Guarantee and Manufacturer: The aluminum access frames and
covers shall carry a 10-year guarantee against defects in materials and
workmanship. The frame and cover shall equal or exceed the units
manufactured by Halliday Products, Inc. or The Bilco Company.
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Q. YARD HYDRANTS
Yard hydrants shall equal or exceed the Clayton Mark model 5451 Lever type
Frostproof Yard Hydrant or the Woodford W-34 for 3/4-inch and the Woodford Y-1
for 1-inch. See Standard Detail 539.04.
PART 3 – EXECUTION
INSTALLATION – PIPE AND FITTINGS
3.1
PIPE AND FITTINGS
A.
CONS TRUCTION – ALL PIPE
TRAFFIC CONTROL: All operations of the Contractor shall be subordinate
to the free and unobstructed use of the right of way of the passage of
Pedestrians and traffic without delay or danger to life, equipment, or property.
1)
Trench width shall be in accordance with OSHA regulations and as
shown in detail 531.01.
2)
Protection of Existing Sewers: Sewer lines under construction shall be
plugged with a mechanical plug at the first manhole upstream from the point
of connection. Plug shall be placed in the outlet connection and secured with
a steel cable. Plug shall remain in place until acceptance of lines by
OWASA. Water, stone, dirt, or any other debris shall not be allowed to enter
the OWASA sanitary sewer system during flushing operations or at any other
time. Construction taking place in the vicinity of any existing OWASA sewer
lines or manholes shall not cause any inflow of surface water or debris to
enter the OWASA sanitary sewer system. Existing OWASA manholes
located in construction sites are to remain accessible at all times. The Owner
and/or Contractor shall be responsible for any damages incurred to the
OWASA sanitary sewer system and any fines imposed by the State of North
Carolina Division of Water Quality due to sewer spills or overflows.
3)
Pipe Laying Direction: Place piping beginning at low point and progress
uphill. Place on grade, with unbroken continuity in invert, horizontally and
vertically, and on alignment as indicated on plans. Place bell ends of piping
facing upstream. Install gaskets, seals, sleeve, and couplings according to
manufacturer’s written instructions for using lubricants, cements, and other
installation requirements.
4)
Directional changes in gravity lines: Use manholes for changes in
direction of gravity lines.
5)
Stringing out Pipe: Only the amount of pipe that will be used in one day
may be strung out. When pipe is strung out, it shall be set on high ground
and in a position to prevent silt deposits, storm water, or other matter from
entering the pipe prior to its placement in the trench.
6)
Pipe Laying: The foundation for gravity sewer pipe shall be a firm flat
bottom trench with a minimum of 6-inches of stone compacted with bell
holes. The pipe and fittings shall be laid in the trench so that its interior
surface shall conform to the grade and alignment as shown on the plans.
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Pipe laying shall be done in such a way as to disturb as little as possible the
pipe that has already been laid. The alignment and grade of the sewer main
may be field adjusted whenever, in the opinion of OWASA’s Engineer, it is
necessary, so long as the adjustments are within that allowed by NCDENR
based on regulations in affect at the time of the change and so long as the
changes are consistent with OWASA’s policy in affect at the time of the
change. Changes in either grade or alignment may only occur at manholes.
Before laying, the bell and spigot will be wiped free from any dirt or other
foreign matter. All surfaces of the portion of the pipe to be joined, and the
factory-made jointing material, shall be clean and dry. Lubricants, primer,
adhesives, etc., shall be used as recommended by the pipe or joint
manufacturer's specifications. The jointing material or factory-fabricated
joints shall then be placed, fitted, and adjusted in such workmanlike manner
as to obtain the degrees of water tightness required.
Trenches shall be kept as dry as possible during bedding, laying and jointing
and for as long a period as required until the trench is backfilled. As soon as
possible after the joint is made, sufficient bedding material shall be placed
along each side of the pipe to offset conditions that might tend to move the
pipe off line or grade. The greatest care shall be used to secure water
tightness and to prevent damage to or disturbing of the joints during the
backfilling process, or at any other time.
All special fittings, such as wyes and other connections, shall be installed at
the points indicated on the plans, in accordance with the standard detail
drawings. Use appropriate adaptors to tie connection pipe to wyes or
saddles. Plug end of connection with appropriate plug. See Standard Detail
534.01.
After the trench foundation has been properly graded to receive the pipe, the
pipe shall be carefully lowered into the trench with approved methods. Under
no circumstances shall the pipe or accessories be dropped or dumped into
the trench. All damaged pipe shall be replaced.
Any defects due to settlement shall be corrected by the Contractor.
7)
Temporary Suspension of Work: When the trench is left for the night or if
pipe laying is suspended, the upper end of the pipe shall be plugged to keep
out dirt, water, animals and other foreign matter or substances. This plug
shall be kept in the end of the pipe line at all times when laying is not in
actual progress.
8)
Cutting or Fitting Pipe: Whenever a pipe requires cutting, to fit in the line or
to bring it to the required location, the work shall be done in a satisfactory
manner with an approved cutting tool or tools which will leave a smooth end
at right angles to the axis of the pipe and not otherwise damage the pipe or
liner. When the cut end is to be assembled in a Fastite bell, an adequately
smooth (without sharp edges) bevel should be ground or filed on the cut
edge to prevent damage to or dislodgement of the gasket during assembly.
The method of cutting pipe shall be in accordance with manufacturer’s
recommendations. No welding, flame cutting or flame tapping will be
allowed. Such cuts shall be made by the Contractor.
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9)
Surface Water Crossings: Surface water crossings with pipe under
streambed shall have the pipe encased in either a concrete or steel casing.
Concrete or steel casing shall extend from top of stream bank to top of
stream bank. See Standard Detail 536.08.
10)
Ravine/Channel Crossings: Surface water crossings with pipe above the
water shall be adequately supported by pipe support piers or steel girders as
shown on Standard Details 536.03, 536.04, and 536.06. NEOPRENE
RUBBER shall be placed between pipe and all points of contact with
concrete and stainless steel straps. Disturbed banks are to be stabilized with
rip rap placed over a non-woven fabric.
11)
Crossing Conflicts: All drains, gutters, culverts, and sewers for surface
drainage are to be kept open. If unavoidable, Interruptions shall be
coordinated with the jurisdiction having authority. They shall approve the
plans to interrupt service.
B.
DUCTILE IRON PIPE
1)
CONSTRUCTION:
Gravity DIP shall conform to the same foundation and backfill requirements
as those prescribed for water mains. Minimum laying length shall be 18 feet
except for Tee/Wye connections or tie-in at a structure. However, bury
limitations shall govern as follows:
Table 02530.1
Bury Limitations on DIP
Pipe
Maximum Bury to Invert of Pipe
8-inch DIP thru 24 inch
18 feet (need OWASA approval if > 18 feet)
Class 350
2)
MECHANICAL JOINT BOLT TORQUE:
Where mechanical joint fittings are required, unless otherwise advised by the
manufacturer, the minimum bolt torque shall comply with Table 2 of AWWA
C600 for mechanical joints, as follows:
Bolt Size
(Inches)
5/8
3/4
1
1 1/4
C.
Torque
(Ft-Lbs)
45-60
75-90
100-120
120-150
3)
See also Section 02275 – Trenching, Backfilling, and Compaction of Utilities.
4)
Minimum cover shall not be less than 3 feet. IF 36” CANNOT BE OBTAINED
AT FINAL GRADE THAN 15A NCAC 2T .0305 (g) (4) SHALL APPLY.
STEEL PIPE
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1)
AERIAL PIPE:
Where required, steel aerial pipe shall meet the length, thickness, and
diameter shown on the plans.
Pipe is to be joined by welding. The pipe shall be beveled and prepared for
field welding at the circumferential joints. Joining of steel pipe shall meet the
requirements of AWWA C206, Standards for Field Welding Steel Water Pipe
Joints.
Pipe support piers shall be constructed in accordance with Standard Detail
536.03, as applicable. Upon completion of installation, paint the exterior of
the pipe with coal-tar enamel. See Section 2.1.C of this specification.
2)
ENCASEMENT PIPE:
Where required, steel encasement pipe shall meet the length as shown on
the plans and the thickness and diameter as shown on Standard Detail
517.01 OR AS DIRECTED BY THE ENGINEER OF RECORD WHICHEVER
IS MORE STRINGENT.
Construction shall be executed in such a manner as to prevent settlement of
the ground surface above the pipeline. The installation of the pipeline shall
follow the heading or tunneling excavation as closely as possible.
Installation shall be in accordance with AWWA.
The pipe shall be beveled and prepared for field welding at the
circumferential joints.
Joining of steel casing pipe shall meet the
requirements of AWWA C206, Standards for Field Welding Steel Water Pipe
Joints. Casing shall be installed by dry boring and jacking or open cut, as
indicated on the drawings.
Encasement ends shall be enclosed as shown on Standard Detail 517.01.
Manufactured Spiders: Refer to Standard Detail 517.01 for spider spacing.
All carrier piping shall be Restrained mechanical joint ductile iron pipe or
approved equal.
3.2
TUNNELING METHOD
A.
GENERAL:
All liner plates and ribs used in the tunnel shall be of one type.
All operations of the Contractor shall be subordinate to the free and unobstructed
use of the rights of way for passage of traffic without delay or danger to life,
equipment, or property. The Contractor shall provide all necessary bracing,
bulkheads, and shields to ensure safety to traffic at all times. The Contractor shall
provide all traffic control devices as necessary and as shown on the approved traffic
control plan.
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B.
TUNNELING (BORING METHOD):
Commence boring operation from a pit, with the bottom excavated to grade, and
sheeted or shored if necessary. A steel pipe shall be jacked in place as a casing
pipe. Boring through rock shall be oversized to allow installation of carrier pipe but
no casing pipe shall be required unless liner plate is necessary for safety reasons.
C.
TUNNELING (HAND MINING):
1)
Commence tunneling operation from a pit, with the bottom excavated to
grade, and sheeted or shored if necessary.
2)
Install the steel liner plates immediately after the excavated material has
been removed, and remove the material not more than 24 inches ahead of
the installed liner plates.
3)
Grout all voids between the soil and tunnel liner plates. The maximum
grouting pressure shall be 30 psi. Start grouting at the bottom of the tunnel
liner plates and proceed upward progressively and simultaneously on both
sides of the tunnel. Install liner plates no more than 6 feet ahead of grout
section. Prohibit traffic over ungrouted sections of tunnel unless this section
is in solid rock. Thoroughly dry-mix grout ingredients before adding water.
After adding water, mix the batch for 3 minutes. Batches shall be of size to
allow continuous placement of freshly mixed grout. Grout not used within 30
minutes after mixing shall be discarded. Placing shall be quick and
continuous. Placement shall be under pressure with a grout pump. The
period between installation of the tunnel liner plate and the placing of grout
shall not exceed 7 hours, without the approval of OWASA’s Engineer. Upon
completion of grouting, fill grout plugs with provided grout hole plugs.
4)
Smoothly pave the bottom of the tunnel with concrete. After installation of
the tunnel liner plates, the Contractor shall pour concrete pavement on the
bottom quadrant (invert) of the tunnel, the surface of the pavement being
parallel to the inner plate, with screed rails embedded in it, on line and grade
for the installation of pipe in the tunnel.
5)
The periphery of the tunnel shall be trimmed smooth to fit the outside of the
steel liner plate as nearly as is practical, so that the void outside the plates is
a minimum.
6)
After installation of the tunnel liner, pull the carrier pipe in place a joint at a
time. Each joint of the carrier pipe shall be supported by spiders strapped to
the carrier pipe.
7)
Close up tunnel liner ends to protect against entrance or foreign matter. The
open ends of the casing pipe or tunnel shall be closed off by an 8-inch grout
or masonry block wall prior to backfilling. A steel drain line to a 1 cubic yard
French drain or to daylight shall be provided.
8)
If installation is under railway tracks, all permits shall be obtained and
Railway Company shall be notified prior to such installation. The same shall
apply to contacting the applicable Municipality or NCDOT if installation is
under a roadway.
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3.3
MANHOLE CONSTRUCTION
A.
Standard Manholes: Manholes shall be constructed in accordance with
Standard Details 532.01 and 532.02. The Contractor shall exercise care in the
ordering of manholes so that the use of grade rings for leveling and adjustments
can be minimized. “O” Ring OR RAM NECK SHALL BE USED ALONG WITH
Infi-Shield® Gator Wrap external sealing systems, as manufactured by Sealing
Systems, Inc., are to be placed on the exterior joints of manholes. Infi-Shield®
Uniband shall be placed at the top of manholes where the iron casting mates with
the precast concrete cone section and/or grade rings. See Standard Details
532.01, 532.08, and 532.09.
Non-shrink grout shall be placed around pipe where pipe meets invert in manhole
to provide for a smooth transition for sewage flow.
Manholes shall be installed plumb.
When applicable, during installation of manhole, if frame and cover is near or
within wheel path in roadway, turn cone to place out of wheel path.
B.
Drop Manholes:
Invert elevations for drop connections in manhole shall be as shown on the
plans. ALL INVERTS 18” OR MORE SHALL BE CONSTRUCTED AS AN
OUTSIDE DROP.
Exterior drop connections shall consist of DIP and mechanical joint fittings.
Exterior drop manholes shall be installed per Standard Detail 532.03. Manholes
shall conform to PART 2 - PRODUCTS.
Interior drops are not permitted.
C.
Flexible Pipe-to-Manhole Connector: When it is necessary to field core a
manhole and install a flexible Pipe-to-Manhole connector. This applies to
Brick/Block and precast concrete sanitary sewer manholes, the connector shall
be installed per the manufacturer’s recommendations.
D.
Precast Concrete Doghouse Manholes: When it is necessary to install a
manhole over an existing sewer main, a precast concrete doghouse manhole
shall be installed over the main. A concrete base shall be poured and the
doghouse manhole set over the existing sewer. The joint between the precast
manhole and the base shall be sealed both inside and out with grout. The
annular space of the precast manhole, around the main, shall be filled with grout
and a shelf formed to the springline of the existing main. The crown/top of the
main shall be removed once the shelf has been formed and has set sufficiently.
See Standard Detail 532.08.
E.
Installation of Manhole frames and Covers: Frames and covers shall be
installed to manhole in accordance with Standard Details 532.01 and 532.06, as
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applicable.
Frame and covers shall be installed to finished elevation.
Adjustments shall be made as necessary to achieve finished elevation. On all
manholes, ½-inch grout is to be placed between the frame and concrete casting
or grade adjustment ring.
F.
Grade Rings/Adjustments: In street rehabilitation work, the combination of
grade rings and/or brick shall not exceed 12 VERTICAL INCHES before removal
of the cone is necessary to effect adjustment. When making adjustments to
manhole frames, place a ½-inch parge coat on interior of manhole from half
depth of the iron casting to a depth of 2 inches below the top of the precast cone.
See Standard Detail 532.06.
G.
Replacement/Rehabilitation of Existing Manholes:
Replacement of manholes: OWASA reserves the right to require replacement
of the existing manhole with a new manhole. OWASA will provide the manhole
but the Contractor shall pick up and install it. When a new manhole is necessary,
the old manhole must be completely removed and a new precast manhole
constructed in its place.
Any tie-in’s performed on sanitary sewer manholes must be machine-core drilled
with a neoprene flexible boot and adjustable band, except brick manholes. The
core shall be the size specified with a smooth finish. If connecting to existing
brick manhole, seal penetration WITH HYDRAULIC CEMENT on perimeter of
manhole. Coordinate with OWASA’s Engineer.
H.
3.4
Testing of Manholes: All Manholes are to be subjected to a vacuum test. This
includes all doghouse and rehabbed manholes. Manholes shall be vacuum
tested after construction in accordance with the manhole vacuum testing
procedures outlined in Section 3.9, paragraph B, item 7. Service connections
tied into manholes shall be tested in conjunction with the manhole.
ABANDONING SEWER LINES & MANHOLES
A.
Sewer lines: The following sewer pipes shall be abandoned by removal or by
filling with grout / flowable fill concrete (50 psi minimum/ 150 psi maximum) in
accordance with the following criteria (see Standard Detail 536.05):
1)
Pipes larger than 24-inches diameter
2)
Pipes located within roadway section and meeting one of the following
conditions:
a.
pipes that are 12-inches diameter up to and including pipes that are 24inches diameter and are buried less than 20 feet below finished grade
b.
pipes that are 6-inches diameter up to 12-inches diameter that are not
cast iron, ductile iron, PVC, or HDPE and are buried less than 12 feet
below finished grade
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3)
Pipes located below groundwater table that could become a conduit for water
movement
Optionally, sewer pipe may be excavated and removed subject to Engineers
approval and approval of controlling Right-of-Way agency.
B.
3.5
Manholes: When an existing manhole, either partially or wholly, is designated to
be abandoned and the sewer lines, either entering or exiting the manhole, have
been abandoned according to the preceding paragraph, the upper portion of the
manhole is to be removed to within 36 inches of the proposed finished grade, or
as determined by OWASA’s Engineer, #57 stone dumped into the manhole, the
stone vibrated to consolidate the stone. The remainder of void or space between
the top of the manhole and the finished subgrade is to be backfilled as follows.
Backfill with #57 stone and consolidate. Outside roadway right of ways, filter
fabric shall be placed over the stone and suitable material of a compactable
nature shall be placed over the concrete manhole pad (see Standard Detail
536.05) and tamped.
BYPASS PUMPING
Contractor is required to furnish all materials, equipment, labor, power, and
maintenance, etc. to affect a temporary pumping system for the purpose of diverting the
existing flow around the work area. The design, installation, and operation of the
temporary pumping system shall be the Contractor’s responsibility.
A.
Long-term Bypass Pumping: This section addresses bypass pumping
arrangements of greater than 24-hours duration.
1)
Bypass pumping arrangements shall consist of two pumps of equal size at
the diversion manhole. Each of the bypass pumps; that is, the primary and
secondary (redundant) pumps, shall be sized to:
a.
Accommodate maximum flow possible through the approaching pipeline
entering the manhole where the pump suction piping will be installed.
This volume of flow shall be based upon full circular pipe flow. The
minimum design criteria slope for the size pipe being replaced shall be
used for calculation, including the appropriate roughness coefficient for
the pipe material; and,
b.
Pump continuously without disruption or suspension of flow to the
discharge manhole. This requires that each pump be designed taking
into consideration the total dynamic head conditions of the pump system
including discharge piping and fittings.
The pump size for the redundant pump shall be the same as the primary
pump. The redundant equipment shall be staged and configured in a
fashion so that the redundant pump operates automatically in the event of
a failure of the primary system. The primary pump will be capable of
handling the flow completely without assistance from the secondary
pump.
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2)
Contractor shall provide the necessary labor and supervision to set up and
operate the pumping and bypassing system. Contactor shall comply with
local Town sound ordinance. If pumping is required between the hours of
8:00 PM and 6:00 AM, engines shall be equipped as specified in item 6)
below in order to keep noise to a minimum.
3)
Overflows from bypass operations will not be permitted to enter into any
streams or bodies of water. The Contractor will be solely responsible for any
legal actions taken by the state regulatory agencies if such overflows occur.
4)
Bypass pumping equipment shall include pumps, conduits, engines, and
related equipment necessary to divert the flow or sewage around the section
in which work is to be performed. In addition, the Contractor shall maintain at
the same location and in operable condition, duplicate equipment to be used
in case there is equipment failure. In the event of failure of any component of
the primary or secondary system, the Contractor shall promptly repair or
replace the failed equipment to the satisfaction of OWASA’s Engineer.
5)
The new sewer line may be used by the Contractor to carry the sanitary flows
after the new pipe has passed inspection and testing. Any “temporary”
connections to the new sewer line shall be approved by OWASA’s Engineer.
6)
Engine driven equipment for primary bypass pumping equipment shall have
“critical grade mufflers.” If equipment is operated between the hours of 8:00
PM and 6:00 AM, this equipment shall also be provided with sound
attenuation enclosure. It is not necessary that the secondary (redundant)
pump meet these requirements. The enclosure shall be portable in order to
allow the enclosure to be moved when bypass pumping equipment is moved.
These conditions are subject to any other additional stipulations that may be
required by local Town sound ordinances.
7)
If a bypass operation is located in a congested area with significant
pedestrian traffic or if the bypass operation will remain in one location for
greater than 3 days (72 hours) then adequate security fencing or other
means shall be provided to ensure that casual passersby are unable to
tamper with bypass equipment.
8)
Continuous (24 hours/day) monitoring is required for all bypass pumping
operations. Continuous manning of the operation by an individual that is
trained and able to respond in the event of equipment failure is preferred. In
those cases where continuously manning is not feasible/practical then
arrangements will be made to continuously monitor the operations remotely.
This remote monitoring will require that maintenance/repair personnel can be
notified and respond on site within 45 minutes. OWASA and the responsible
owner will be immediately contacted by telephone anytime an overflow
condition may occur.
9)
The Contractor shall submit to OWASA a detailed plan and description
outlining all provisions and precautions to be taken by the Contractor
regarding handling of existing wastewater flows. This plan must be specific
and complete, including flow calculations, pump sizing calculations, method
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of continuous monitoring of pumps (telemetry or manned), schedule for entire
duration of bypass pumping operations, contact name and telephone
numbers of responsible personnel. No bypass pumping shall begin until all
requirements have been reviewed and approved by OWASA.
10)
The plan shall include but not be limited to the details of the following:
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
l.
B.
Short-term Bypass Pumping: This section addresses bypass pumping
arrangement durations of 24 hours.
1)
3.6
Staging areas for the pumps.
Sewer plug method and type of plugs or gates to be used.
Number, size, material, locations, and method of installation of suction
piping.
Bypass pump sizes, capacity, number of each size to be on site, and
power requirements.
Calculations of static lift, friction loss, and flow velocity
Stand-by power.
Downstream discharge plan.
Method of noise control for each pump.
Temporary pipe supports and anchoring required.
Heavy equipment needed for installation of pumps and piping.
Stand-by/back-up pumpset for the bypass application.
Fueling of pumpsets on demand.
Bypass Operations for periods of 24 hours or less may be sized on the
expected peak flows during this period or, if applicable, the 10-year storm
frequency event. In all cases, of bypass operations of 24 hours or less, the
contractor shall provide for a qualified and competent attendant who shall be
onsite at all times during this period. Any bypass pumping arrangements for
24 hours or less must be approved in advance by OWASA personnel and
shall be on a case-by-case basis. Contactor must have an equivalent or
larger sized redundant pump onsite and in good working condition. This
pump must be available and ready to install immediately should the primary
pump fail. Requirement for noise attenuation will also be considered on a
case-by-case basis but may be subject to local governing jurisdictions’
ordinances and must be approved by those entities.
SERVICE CONNECTIONS
A.
New Services: Unless otherwise permitted by OWASA’s Engineer, all sewer
services shall be class 350 DIP slip joint pipe with mechanical joint fittings. See
Standard Detail 534.01. Sewer services are to be connected to main except at
manholes on cul-de-sacs. When connecting to manholes, services are to come
in at the bottom of the manhole.
B.
Bored Services: Where laterals are bored, the face of the bore cut shall be a
minimum distance of five feet from the edge of the pavement on either side
unless OWASA’s Engineer gives approval to the contrary.
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3.7
C.
4-inch sewer laterals shall be connected to the main by means of an in-line
monolithic wye or, if on an existing line, with a tap and saddle installed over a
hole cut in the top quadrant of the main at an angle of forty-five degrees (see
Standard Detail 534.01), with respect to flow direction. The hole shall be cut
with a mechanical circular type saw cutter designed for the particular use and
rendering a smooth uniform cut with no damage to the main and is one which
retrieves the plug. The cost for such cut-ins shall be included in the cost of the
lateral.
D.
A wye is to be provided at the cleanout set at the property line. All laterals are to
be left exposed until the inspectors can verify the installation of each service.
E.
Vertical stacks or standpipe services are not allowed.
F.
The cleanout shall be located at the right of way or easement line straddling the
easement line. A cleanout box and lid shall be set over the cleanout. The
cleanout is to be set between 4 and 6-inches from the top of the box.
G.
Grade: Minimum grade for services shall be ¼-inch per foot for 4-inch services.
Minimum grade for 6-inch services are to be laid preferably at a 1/8-inch per foot,
but no less than 0.6%.
H.
Service Saddles: Service saddles shall be constructed using Romac Industries,
Inc. sewer service saddles placed in the top quadrant of the pipe main. Backfill
under and around saddle with #67 stone. See Standard Detail 534.01.
I.
During service installation or line rehabilitation on existing mains, the Contractor
shall be responsible for the maintenance of all sewer house connections and the
proper treatment and/or by-pass of effluent sewer around work areas.
J.
Any services or utilities damaged by the Contractor shall be properly repaired.
K.
Sewer lines shall be air tested (low-pressure air test) after the complete
installation of all sewer services. Laterals shall be tested with the main line. THIS
APPLIES TO NEW SEWER SERVICES INSTALLED.
CONCRETE ENCASEMENTS
All concrete encasements shown on the plans shall be constructed per the details on
the plans.
The earth may be used for side and bottom forms provided such sides can be
excavated uniformly smooth and to the size and shape specified. Care must be
taken during the pouring operation to ensure that the pipe does not float or move
from the buoyant affects of the concrete. Misalignments of the crossings shall be
cause for total removal and replacement of the encasement by the Contractor.
Once the concrete is set, measures shall be taken to cure the concrete by covering it
with plastic. Water shall not be allowed to run over the concrete for at least 48
hours.
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Forms will be required if the subgrade and sides are not firm, or will not hold shape.
Exercise care to avoid spilling concrete into creek.
3.8
USE OF SLOPE ANCHORS ON STEEP LINES
All lines with slopes from 15 to 20 percent shall have concrete anchors placed on
the bell end of the sewer line. The anchors shall be spaced AS OUTLINED IN 15A
NCAC 2T REGULATIONS OR as shown on the plans (WHICHEVER IS MORE
STRINGENT) and constructed to the dimensions shown on Standard Detail
536.01. Anchors shall penetrate at least 6 inches into virgin soil. Concrete shall be
4000 psi concrete.
3.9
TESTING
A.
The following tests shall apply for the respective pipe materials as required by
the following specifications.
Material
DIP
Table 02530.2
Table of Testing Applications
Air Test
Vacuum TV Inspection (OWASA may require
Test
VISUAL INSPECTION ON a caseby-case basis)
X
X
Manholes
B.
X
TEST AND INSPECTION:
All sanitary sewer pipe shall be tested after backfilling has been completed and
before final acceptance by OWASA. Upon completion of entire pipe installation,
OWASA’s Engineer shall inspect the work in part or as a whole and make such
tests as necessary to verify that the work has been carried out in accordance
with the plans and specifications.
All manholes shall be of the specified size, shape, and material, and shall have
their tops set to the grade as furnished by the Design Engineer.
The Contractor shall provide all equipment, material, water, labor, etc. needed to
perform any and all tests in accordance with the procedures listed herein. All
equipment, materials, etc. used shall be checked and approved by OWASA’s
Engineer prior to its use. It shall be the responsibility of the Contractor to insure
pipe to be tested is clean before any tests are made. Frame and covers shall be
tested with manhole tests.
Test for leakage of gravity sewers shall be done as directed by OWASA’s
Engineer or as shown on the plans.
1)
General Requirements: Testing and inspection shall promptly follow
installation of wastewater pipe including services. Testing shall not be more
than 1000 feet behind sewer pipe laying operation.
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Furnish all pumps, gauges, instruments, test equipment and personnel
required for inspections and testing operations.
All final testing and inspections shall be performed in the presence of the
OWASA’s Engineer.
Flush all sand, dirt and debris from lines prior to inspection.
Clean and pretest prior to notifying the OWASA’s Engineer and arranging for
inspections and tests. FAILURE TO CLEAN AND PRE-TEST MAY RESULT
IN RE-INSPECTION FEES.
Inspect the system for conformance with line and grade shown on the plans
and provide record drawing measurements CERTIFIED BY PLS AND
ENGINEER OF RECORD on Record Drawings. THESE MEASUREMENTS
SHALL BE TIED TO NC PLANE COORDINANTES in 88/83 datum.
2)
Flushing: If during any of the inspections sewer lines and manholes are
found to contain mud and other debris, the Contractor shall be required to
flush or clean this material from the system by whatever means necessary.
Mud and other debris shall not be allowed to enter the existing sanitary sewer
system. The Contractor shall be responsible for the cost of water used to
flush the system AND PAY A RE-INSPECTION FEE
3)
Backfill Testing: Testing of backfill shall be performed in accordance with
the requirements of Section 02275 – Trenching, Backfilling, and Compaction
of Utilities.
4)
Visual Inspection: Visual inspections may be required by OWASA on a
case-by-case basis. When required, sewer lines shall be visually inspected
from every manhole by use of mirrors. The lines shall exhibit a fully circular
pattern when viewed from one manhole to the next. Lines, which do not
exhibit a true line and grade, have obstruction or structural defects, shall be
corrected to meet these specifications and the sewer barrel left clean for its
entire length.
5)
Primary test method – Low Pressure Air Test: Sewer lines shall be air
tested after the complete installation of all sewer services. Sewer laterals
are to be tested along with main. The Contractor shall be responsible for
furnishing all equipment and labor for the low pressure air test at no
additional cost to OWASA.
The portion of the line being tested shall be accepted if the portion under the
test meets or exceeds the requirements of ASTM F1417, Standard Test
Method for Installation Acceptance of Plastic Gravity Sewer Lines Using LowPressure Air. This requirement shall be accomplished by performing the test
as follows: the time required in minutes for the pressure to decrease from 3.5
to 2.5 psig greater than the average back pressure of any groundwater that
may be over the pipe shall not be less than the time shown for the given
diameters in Table I Line Pressure Air Test Table. If the system does not
meet the foregoing requirements, the Contractor will be required to locate and
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repair the leaks at no cost to OWASA and repeat the tests until the allowable
leakage is obtained.
Procedure:
It is imperative that proper plugs be installed on the laterals at the cleanout
stack. All plugs should be properly installed to withstand the test pressures
without requiring external bracing or blocking. Before tests are made, all
wyes, tees, or end of side sewer stubs shall be plugged with flexible-joint
caps, or acceptable alternate, securely fastened to withstand the internal test
pressures. Such plugs or caps shall be readily removable, and their removal
shall provide a socket suitable for making a flexible-jointed lateral connection
or extension.
Air leakage testing of installed system shall be performed with a continuous
monitoring gauge no less than 4 inches in diameter with minimum divisions of
0.10 psi and an accuracy of plus or minus 0.04 psi. All air used shall pass
through a single, above ground control panel visible to the OWASA’s
Engineer.
All air used shall pass through a single control panel. Individual air hoses
shall be used from control panel to pneumatic plugs, from control panel to
sealed line for introducing low pressure air, and from sealed line to control
panel for continually monitoring the air pressure rise in the sealed line. After
all pipes are cleaned, air shall be slowly supplied to the plugged pipe
installation until the internal air pressure reaches 4.0 psig (greater than
average groundwater backpressure that may submerge the pipe). Throttle
the air supply to maintain that constant pressure for at least 2 minutes. The
air pressure supply shall then be disconnected from the system or shut-off.
Do not enter manhole during test. Do not exceed 4.0 psig in the system.
Observe the continuous monitoring gauge while decreasing the pressure to
no less than 3.5 psig (greater than groundwater pressure). At a reading of
3.5 (adjusted), or any convenient observed pressure reading between 3.5
and 4.0 psig (adjusted), timing shall commence with a stopwatch or other
timing device that is at least 99.8% accurate. Regulate the pressure for at
least 2 minutes to permit the air/ground temperature to reach equilibrium
before commencing test.
Measure the time interval for pressure to drop 1.0 psig.
If the time, shown in Table I for the designated line size and length, elapses
before the air pressure drops 1.0 psig, the section undergoing the test may
be discontinued once the prescribed time has elapsed even though the 1.0psig drop has not occurred. Record all readings.
If the pressure drops 1.0 psig before the appropriate time shown in Table I
has elapsed, the air loss rate shall be considered excessive, and the section
of pipe has failed the test. Record all readings.
If service lateral sewers are included in the test section, their lengths may be
ignored for computing the required test times. The test will be slightly more
severe. In the event a test section, having a total surface area less than 625
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square feet, fails to pass the air test when lateral sewers have been ignored,
the test time shall be recomputed to include all lateral.
If the sections fail the air test, the Contractor shall determine the source or
sources of leakage and shall repair or replace all defective material and
workmanship.
No sealant shall be used in the newly installed sewers to correct the leaks.
The extent and type of repair that may be allowed shall be subject to the
approval of OWASA’s Engineer.
The repaired pipe installation shall be retested and required to meet the
requirements of this test.
Safety Note: The air pressure test may be dangerous if, because of
ignorance or carelessness, a line is improperly prepared. It is extremely
important that the various plugs be installed and braced in such a way as to
prevent blowouts. A force of 250 lbs is exerted on an 8-inch plug by an
internal pressure of 5 psi. It should therefore be realized that sudden
expulsion of a poorly installed plug, or a plug that is partially deflated before
the pressure is released, can be dangerous. As a safety precaution,
pressurizing equipment should include a pressure regulator set at, for
example, 5 psi to avoid over-pressurizing and damaging an otherwise
acceptable line. No one shall be permitted in the manholes during
testing.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02530-33
02530 – SANITARY SEWER
1
Pipe
Diameter
(in.)
4
6
8
10
12
15
18
24
TABLE I
Line Pressure Air Test Using Low-Pressure Air
SPECIFICATION TIME REQUIRED FOR A 1.0 PSIG PRESSURE DROP
FOR SIZE AND LENGTH OF PIPE INDICATED FOR Q = 0.0015
(Excerpted from ASTM F 1417)
2
Minimum
Time
(min:sec)
3
Length For
Minimum
Time (ft.)
4
Time For
Longer
Length
(sec.)
3:46
5:40
7:34
9:26
11:20
597
398
298
239
199
.380
.854
1.520
2.374
3.418
14:10
17:00
22:40
159
133
99
5.342 L
7.692 L
13.674 L
OWASA – Manual of Specifications, Standards and Design
April 2015
L
L
L
L
L
Specification Time for Length (L) Shown (min:sec)
100
ft.
150
ft.
200
ft.
250
ft.
300
ft.
350
ft.
400
ft.
450
ft.
3:46
3:46
3:46
3:46
3:46
3:46
3:46
3:46
5:40
7:34
9:26
11:20
14:10
5:40
7:34
9:26
11:20
14:10
5:40
7:34
9:26
11:24
17:48
5:40
7:34
9:53
14:15
22:15
5:40
7:36
11:52
17:05
26:42
5:40
8:52
13:51
19:56
31:09
5:42
10:08
15:49
22:47
35:36
6:24
11:24
17:48
25:38
40:04
17:00
22:47
19:13
34:11
25:38
45:34
32:03
56:58
38:27
68:22
44:52
79:46
51:16
91:10
57:41
102:33
Page 02530-34
6)
Manhole Vacuum Testing
Manholes shall be vacuum tested as indicated below unless otherwise
allowed by OWASA’s Engineer. Vacuum testing shall meet ASTM C1244
Standard Test Method for Concrete Sewer Manholes by the Negative Air
Pressure (Vacuum) Test Prior to Backfill. Only new manholes are to be
vacuum tested. Vacuum testing of existing manholes is not required.
The test shall be made using an inflatable compression band, vacuum pump,
and appurtenances specifically designed for vacuum testing manholes.
Equipment to be manufactured by Peter A Glazier & Associates, Worcester,
MA or approved equal. The Contractor shall be responsible for furnishing all
equipment and labor for the vacuum test at no additional cost to OWASA.
Manholes may be tested by vacuum test immediately after assembly of the
manhole, frames and connecting pipes, and before any backfill is placed
around the manholes. However, the final test and acceptance shall be based
only upon a test after the manhole is backfilled and the cover frame castings
are grouted in place. Testing devices shall be installed on the iron manhole
frame.
All lift holes shall be plugged with nonshrink grout and all pipes shall be
plugged, taking care to securely brace the plugs and pipe. Stubouts,
manhole boots, and pipe plugs shall be secured to prevent movement while
the vacuum is drawn.
Manholes shall be tested from the top of the casting, including the casting-tocone joint (adjusting ring).
Installation and operation of vacuum equipment and indicating devices shall
be in accordance with manufacturer’s recommendations.
After the testing equipment is in place, a measured vacuum of 10 inches of
mercury (Hg) shall be established in the manhole. The time for the vacuum
to drop to 9 inches of mercury shall be recorded.
Acceptance standards for leakage shall be established from the elapsed time
for a negative pressure change from 10 inches to 9 inches of mercury. See
Table II, Vacuum Test Table for Manholes.
If the manhole fails the test, the Contractor shall locate the leakage, make the
proper repairs, and the vacuum test shall be repeated until the manhole
passes the test. After the manholes have been backfilled and the cover
frame casting sealed in place, and prior to final acceptance of the project, any
signs of leaks or weeping visible from the inside of the manhole shall be
repaired and the manhole made watertight and tested. The extent and type
of repairs that may be allowed shall be subject to the approval of OWASA’s
Engineer. Leaks shall be repaired on the outside of the manhole unless
approved otherwise by OWASA.
If a manhole joint mastic material is completely pulled out during the vacuum
test, the manhole shall be disassembled and the mastic replaced.
7)
Televising of Sanitary Sewers
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02530-35
02530 – SANITARY SEWER
TV inspections ARE required by OWASA ON EACH NEW SEWER MAIN
INSTALLED. Following placement and compaction of backfill and completion
of other required testing, but prior to placing of pavement, the Contractor shall
televise all sewer lines for conformance to the project drawings and
specifications. The sewer main shall be cleaned prior to the TV inspection. A
tape and log of the televising shall be delivered to OWASA’s Engineer within
a week of televising. If defective pipe or conditions are discovered they shall
be corrected at no cost to OWASA.
The television camera used for the inspection shall be one specifically
designed and constructed for such inspection. Lighting for the camera shall
be suitable to allow a clear picture of the entire periphery of the pipe. The
camera shall be operative in 100% humidity conditions. The camera,
television monitor, and other components of the video system shall be
capable of producing picture quality IN COLOR to the satisfaction of the
OWASA’s Engineer.
The camera shall be moved through the line in either direction at a moderate
rate, stopping when necessary to permit proper documentation of the sewer’s
condition. In no case will the television camera be pulled at a speed greater
than 30 feet per minute. Manual winches, power winches, TV cable, and
powered rewinds or other devices that do not obstruct the camera view or
interfere with proper documentation of the sewer conditions shall be used to
move the camera through the sewer line.
OWASA WILL televise sewer lines prior to the expiration of the one-year
warranty. If a defective condition is found, it shall be, COMPARED TO THE
ORIGIANL VIDEO. IF EVIDENCE OF NO DEFECT IS FOUND IN ORIGINAL
VIDEO THEN IT WILL BE
presumed to be caused by defective
workmanship or materials. The Contractor shall be notified and shall correct
the work in a manner approved by OWASA’s Engineer.
Force mains
8)
a.
Order of Operations: Fill the system with water at a velocity of
approximately 1 foot per second while necessary measures are taken to
eliminate all air. Do not leave fill line connected to sewer line unless an
RPZ backflow preventer is placed between the potable water supply and
the line being filled. AS OUTLINED IN AWWA C651-05 4.3.9.
b.
Pressure Tests & Leakage: The Contractor shall test completed
sections of line, including fittings, with water. This testing, however, does
not relieve the Contractor of his responsibility to repair or replace any
cracked or defective pipe. All work necessary to secure a tight line shall
be performed by the Contractor. Testing shall be performed in the
presence of OWASA’s Engineer and the Contractor. Cost for testing shall
be incidental to line construction.
Pressure Test: The newly laid piping or any valved section of piping
shall, unless otherwise specified, be subjected for two hours to a leakage
test. Raise the pressure by pump to 200 psi, 150% of design working
pressure, or test pressure as shown on the drawings, whichever is
greater.
Measure the pressure at the low point on the system
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02530-36
02530 – SANITARY SEWER
compensating for gauge elevation. Maintain this pressure (+ or – 5psi) for
2 hours. If pressure cannot be maintained, determine cause, repair, and
repeat the test until successful. The allowable leakage shall be no
greater than allowances shown in Table 6A - Hydrostatic Testing, Section
5.2, of AWWA C 600-93, AWWA Standard for Installation of Ductile Iron
Water Mains and Their Appurtenances. A copy of this chart is located at
the rear of OWASA specification Section 02510 – Water Distribution.
Contactor shall be responsible for all costs, labor, materials, and
equipment to perform the testing. All visible leaks, broken or cracked
pipe, valves, etc. shall be repaired.
i.
3.10
Prerequisite conditions for testing shall be as follows:
a)
All pipe has been laid and the trench backfilled.
b)
Valves shall be properly located, operable and at correct
elevation.
c)
All reaction anchors have had sufficient set of 7 days. High early
strength concrete, 4500 psi or greater, may be used to reduce
number of days to 4.
d)
Lines shall be properly vented where entrapped air is a
consideration.
e)
All construction activities on the project, that requires trenching or
excavation within the limits of the line location, shall be completed
prior to pressure testing of line.
PUMP STATIONS AND FORCE MAINS
A.
Pump Stations: Pump stations and force mains will be allowed only with the
permission of OWASA’s Executive Director. Pump stations shall be either self
priming or submersible pumps and designed in accordance with the
requirements of the NC Department of Environment and Natural Resources,
Division of Water Quality, NCAC Title 15A 2T, latest revision. Typical Pump
station site layout shall conform to Standard Details 539.01 through 539.05.
Lift stations shall include the following as a minimum:
1)
2)
3)
4)
Service head, meter base, service connection, disconnect, and area light with
switch.
Audible and visual high water alarm and alarm silence. High water alarm
circuitry. Provide dual high water alarm floats. The first (lowest) high water
alarm float is to activate the telemetry only (not the alarm and light) to allow
maintenance personnel time to arrive at site and attempt to fix the problem.
The second (higher) high water alarm float shall activate the alarm horn and
light.
Auto-dialer (minimum 8 numbers, 4 channels). The automatic telephone
dialer shall be a solid state component capable of dialing up to 8 phone
numbers, each up to 24 digits in length. The dialer shall have solid state
voice message recording and playback, all implemented with permanent
nonvolatile solid state circuitry with no mechanical tape mechanism.
Automatic air release valves, as applicable.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02530-37
02530 – SANITARY SEWER
5)
6)
7)
8)
9)
10)
11)
12)
13)
14)
15)
16)
17)
18)
19)
20)
21)
22)
23)
a.
b.
c.
d.
For self-priming pumps, provide air bubbler type control system with handoff-automatic (H-O-A) switches and an automatic alternator. For submersible
pumps, provide mercury float switches for level control.
3-phase voltage monitor, if applicable. Indication of 3-phase power fail.
Suction and/or discharge gauges, as applicable.
Elapsed time indicators.
High pump temperature protection.
Pump run lights.
Motor overload resetter.
Surge suppressor.
Duplex service receptacles on GFCI installed external to the NEMA 4X
enclosure.
Surge relief valve and return piping to wetwell.
Start-up assistance and certification, including operational/witness/drawdown
test. Certified pump curves shall be provided as part of the project closeout
documents.
Dual power supply auto switch-over, etc.
Non-Freeze Yard Hydrant (Clayton Mark model 5451 Lever type frost proof
yard hydrant).
For self priming pump stations, provide heaters and fluorescent lighting.
Non-Freeze shower w/ eyewash and concrete pad.
10 ft x 10 ft x 8-inch concrete pad for water tank with drain and valve.
Emergency pump connection w/ blind flange and gate valve.
The lift station is to include back-up alarm system that operates off a 12-volt
battery connection in the event of power failure. The battery system is to
include a trickle charger to ensure battery integrity.
Provide auxiliary propane, natural gas or diesel fired automatically activated
stand-by power generator source with automatic reset, placed on site. Pump
manufacturer to provide power demand/ratings to Contractor before ordering
pump and the power demand appropriately marked on the pump shop
drawings. Generator shall have the capacity sufficient to sequentially start
and run all pumps in the pump station. The Contractor shall provide a
complete engine driven generator set. The generator set shall consist of
four-cycle, radiator-cooled, engine direct connected to an alternating current
generator, a unit-mounted control panel, all mounted on a common sub-base.
The control panel shall be complete with engine controls and instruments,
safety controls and panel lights including the following:
The generation unit shall be capable of powering the pump motors
starting current, electrical systems, instrumentation/controls and alarm
systems, and other auxiliary equipment as may be necessary to provide
for the safe and effective operation of the pump station. The generation
unit shall have the appropriate power rating to start and continuously
operate under all connected loads.
The generation unit shall be provided with special sequencing controls to
delay lead and lag pump starts unless the generating unit has the
capacity to start all pumps simultaneously while the auxiliary equipment is
operating.
The generation unit shall be capable of shutting down and activating the
audible and visual alarms and telemetry if a damaging operating condition
develops.
The generation unit shall be protected from damage when restoration of
power supply occurs.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02530-38
02530 – SANITARY SEWER
e.
The generator shall be equipped with an automatic transfer switch to start
generator and transfer load to emergency in case of utility undervoltage,
overvoltage, power loss, phase reversal, or phase loss.
The control panel shall be complete with run-stop-remote switch; remote
start-stop terminals; cranking limit; battery charge rate ammeter, oil
pressure gauge, temperature gauge; low oil pressure shutdown; high
engine temperature shutdown; over speed shutdown; AC voltmeter;
voltage adjustment; frequency meter; and running time meter. The
controls must indicate engine run, common engine fail, transfer switch
position, low fuel level, and fuel tank leak for remote telemetry purposes.
The generator shall be equipped with an automatic transfer switch to start
generator and transfer load to emergency in case of utility under voltage,
over voltage, power loss, phase reversal, or phase loss.
Circuit breakers shall be provided with a built in control panel.
The manufacturer of the unit shall completely assemble and test the unit
before shipment. He shall be one who is regularly engaged in the
production of such equipment, and who has spare parts and service
facilities. He must also provide 1 complete set of filters.
The controls must indicate engine run, common engine fail, transfer
switch position, low fuel level, and fuel tank leak for remote telemetry
purposes.
The automatic transfer switches must have a disconnect on the utility
service main side.
The generator shall comply with the following minimum requirements:
f.
g.
h.
i.
j.
k.
i.
ii.
iii.
iv.
v.
l.
m.
n.
o.
Engine: Four-cycle, 4 cylinder, radiator cooled, at 1800 RPM.
Starting shall be from batteries, with capability to start the unit at 32
degrees temperature.
Generator: Rating shall be continuous standby service at 0.8 power
factor, at 1800 RPM.
Voltage: Three-phase, 208. KW rating to match facility needs.
Engine shall be equipped with an isochronus governor as
manufactured by Woodall.
Frequency regulation shall be less than 3-cycles from no-load to full
load.
All accessories needed for the proper installation of the system shall be
furnished. Included should be batteries, battery cables, exhaust piping,
mufflers, vibration mounting, and three bound sets of detailed operation
and maintenance manuals with parts list. Batteries should be lead acid.
The generator set shall be enclosed with a factory-installed weatherprotective housing (sound abating enclosure to 68db @ 23 ft.) Housing
shall provide easy access to the engine-generator and instrument panel.
Muffler to be designed so exhaust is not blown or sucked across the set
by cooling air.
Included with the generator shall be a complete fuel system consisting of
a fuel tank, fuel gauge, fuel lines, fuel pumps, valves and any and all
other items incidental to a first-quality installation.
Provide integral sub-base double-walled diesel tank. The tank is to be UL
approved closed-top dike type. The tank shall also be fitted with a leak
sensor device. The tank must have a capacity to run the generator for a
minimum of 48 hours at 100% load.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02530-39
02530 – SANITARY SEWER
p.
q.
r.
s.
t.
u.
v.
w.
x.
Fuel tank shall consist of the fuel tank separate and contained within the
frame. No generator weight is to be supported by the tank. Provide a
drain plug at one end of the rupture basin. Provide vibration isolators
between generator set and tank assembly. Provide fuel low-level alarm
remote mounted.
Provide manufacturer’s recommended anti-freeze and engine block
heater, per manufacturer’s recommendations, with thermostatic controls
to maintain engine coolant at proper temperature to fulfill start-up
requirements, adjustable if possible. Provide suitable trickle battery
charger. All accessories shall be engine-mounted and within the
weatherproof sound attenuated housing.
Provide annunciator panels with visual and audible alarms to monitor and
warn of emergency operation conditions affecting line and generator
power sources.
Provide stainless steel super critical grade type exhaust silencer mounted
inside of the generator enclosure for corrosion protection.
Provide amp meter, voltmeter, and frequency meters with phase
switches.
Provide fuses or circuit breakers for battery charger and engine.
Provide an automatic battery charger, static type, magnetic amplifier
control with DC voltmeter, DC ammeter and potentiometer for voltage
adjustment. The charger is to be completely automatic and rated for the
type of battery use. The charging rate is to be determined by the state of
the battery and reducing to milliamp current on fully charged battery. The
charger shall be 120 V., single-phase, 60 cycle, AC input with 6-amp
maximum output.
Operation and Maintenance instructions. The Contractor shall provide a
minimum of 4 continuous hours of operation and maintenance
instructions for the Owner’s personnel.
OWASA must be furnished with one complete set of air, oil, and fuel
filters.
B.
Pump Certification: Contractor to provide a certified shop test of pump from
pump manufacturer. Manufacturer’s representative shall be present at pump
start-up. See paragraph H, Pump Station Operational/Witness Test/Start-up
requirements, below.
C.
Wetwell Coating: Wetwell interiors shall be coated with a two component
elastomeric, hydrophobic, corrosion resistant polyurea coating where the primer
can be applied to damp or dry surfaces. Primer coat film thickness shall be 1.5
to 3 mils. The top coat film range shall be from 8 to 12 mils. Shore hardness D
shall be minimum 75. Coating shall equal or exceed Duramer K-2002 by
Innovative Polymer Solutions, LLC. Contractor to follow all applicable safety
measures for handling and application as recommended by the Manufacturer of
the coating. Comply with applicable confined space safety requirements.
D.
Wetwell/Valve Vault Hatches: Provide access frames and covers meeting
Section 2.2.P of this specification with padlocked hasps.
E.
Force mains: Force mains shall be ductile iron pipe. PVC Force mains may be
approved by OWASA’s Engineer on a case by case basis. Pipe joints may be
push on (provided each joint is mechanically restrained), or mechanical joint type
with the appropriate restraining gland. All Fittings shall be mechanical joint with
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02530-40
02530 – SANITARY SEWER
appropriate blocking and/or rodding. Force mains shall be constructed in
accordance with the plans and in accordance with the requirements applicable to
OWASA water main construction.
F.
Manuals/Parts: OWASA must be furnished with 3 copies of the Operation and
Maintenance and Parts Manuals for the pumps/motors and/or station, pump
controls, the generator unit, and the automatic transfer switch. Also, provide a
spare impeller, key, nut, washer, and mechanical seal for each pump.
G.
Safety Placards: Provide safety placards as required for structure (e.g. confined
access entry) and equipment as required by OSHA shall be posted and readily
visible.
H.
Pump Station Operational/Witness Test/Start-up:
1)
Witnessed Testing: Witnessed testing shall be performed in the presence of
OWASA’s Engineer and the results of the testing maintained as part of the
construction record documentation. Witnessed testing shall include start-up
assistance by a qualified factory representative and certification. Prior to
acceptance by OWASA, an operational test of all pumps, drive, and control
systems shall be conducted to determine if the installed equipment meets the
purpose and intent of the specifications. Tests shall demonstrate that all
equipment is electrically, mechanically, structurally, and otherwise
acceptable; it is safe and in optimum working condition; and conforms to the
specified operating characteristics.
After construction debris and foreign material has been removed from the
wetwell, the Contractor shall supply an adequate amount of clear water
volume to operate station through several pumping cycles. Observe and
record operation of pumps, suction (if applicable) and discharge gage
readings, ampere draw, pump controls, and liquid level controls. Check
calibration of all instrumentation equipment, test manual control devices, and
automatic control systems. Be alert to any undue noise, vibration, or other
operational problems.
2)
Drawdown test: The Contractor shall conduct a drawdown test to confirm
that the pump is operating at or near the required design operating point and
to determine the actual pumping rate of each pump. This test shall be
conducted in the presence of OWASA’s Engineer, the Contractor and a
representative of the pump manufacturer. The rate shall be determined by
subtracting the starting static surface elevation of the water in the wetwell
from the “off” elevation and multiplying the difference by the volume per
vertical foot of wetwell. That number shall then be divided by the number of
minutes of pump run time to affect the drop measured. This test shall be
performed for each pump and the rates recorded for each pump and included
as part of the record in the certified pump test.
3)
Manufacturers Start-up Services: The manufacturer’s representative shall
be present at pump start up. Co-ordinate station start-up with manufacturer’s
technical representative. The representative or factory service technician
shall inspect the completed installation. He shall calibrate and adjust
instrumentation, correct or supervise correction of defects or malfunctions,
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02530-41
02530 – SANITARY SEWER
and instruct operating personnel in proper operation and maintenance
procedures.
3.11
PIPE DESIGN LIFE
In addition to the above noted specifications, the Contractor shall secure and the
manufacturer shall furnish and warrant that sanitary sewer pipe is designed for a 50year life.
3.12
CLEANUP AND RESTORATION OF SITE
After the backfill is completed, the contractor shall dispose of all surplus material, dirt
and rubbish from the site, and shall keep the site free of mud and dust to the satisfaction
of OWASA’s Engineer. The Contractor may be required to flush or sprinkle the street to
prevent dust nuisance. It is important that clean up and restoration of the site follows the
work closely. The Contractor shall dispose of surplus material and clean the street at
the end of each day for the portion of work completed that day unless additional cleaning
is required. After all work is completed, the Contractor shall remove all tools and other
equipment, leaving the site free, clean, and in good condition.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02530-42
02530 – SANITARY SEWER
TABLE II
VACUUM TEST TABLE FOR MANHOLES
BASED ON ASTM C1244
MINIMUM TEST TIMES FOR VARIOUS manhole DIAMETERS FOR PRESSURE
DROP FROM 10 INCHES TO 9 INCHES HG.
Depth
(FT)
DIAMETER (FEET)
4
4.5
5
5.5
6
TIME (SECONDS)
6
15
8
20
23
26
29
33
10
25
29
33
36
41
12
30
35
39
43
49
14
35
41
46
51
57
16
40
46
52
58
67
18
45
52
59
65
73
20
50
53
65
72
81
22
55
64
72
79
89
24
59
64
78
87
97
26
64
75
85
94
105
28
69
81
91
101
113
30
74
87
98
108
121
END OF SECTION 02530
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OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02530-43
02530 – SANITARY SEWER
Section No.
Rev
No.
Div 02530 – Sanitary Sewer
Revision Summary Sheet
Rev.
Date
By
Reason for change
OWASA – Manual of Specifications, Standards and Design
April 2015
What Changed
Page 02530-44
02530 – SANITARY SEWER
Section No.
Rev
No.
Div 02530 – Sanitary Sewer
Revision Summary Sheet
Rev.
Date
By
Reason for change
What Changed
OWASA.Revisions-Sewer.doc
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 02530-45
SECTION 3 – WATER & SEWER DESIGN
(Last revised 06-01-13)
SUGESTED SEARCH WORDS FOR THIS SECTION
Air Release Valves
Piping Material - Sewer
Bury of Pipes – Sewer
Piping Material - Water
Bury of Pipes - Water
Pressure/Pressure Zones
Combination Vaults
Public Easements
Dead end lines
Pump Stations
Design - Manholes
Sewer Service Connections
Design – Sewer System
Slopes – Sewer Pipes
Design – Water System
Stream Crossings - Sewer
Fire Hydrants
Water Services
Permits
Water/Sewer Crossings
1.1
GENERAL
A.
SPECIFICATION AND DESIGN MANUAL:
1)
All projects within the jurisdiction of the OWASA shall be designed and
constructed in accordance with OWASA’s Manual of Specifications and
Standards, latest revision.
2)
Public sanitary sewer gravity mains, force mains, and lift stations shall conform to
the design and construction requirements of the NC Department of Environment
and Natural Resources, Division of Water Quality, NCAC Title 15A 2T Waste not
Discharged to Surface Waters, latest revision.
3)
Public water distribution systems shall conform to the design and construction
requirements of the NC Department of Environment and Natural Resources,
NCAC Title 15A, Subchapter 18C, Rules Governing Public Water Systems, latest
revision.
B.
PROJECT OVERVIEW REPORT REQUIREMENTS:
1)
C.
Prior to proceeding with design, the developer’s Engineer shall be required to
provide a brief Project Overview Report satisfactory to OWASA’S Engineer which
shall include the information outlined in the “Procedure for Approval of Water
and/or Sewer Extension Projects” (located in this manual).
PERMITS:
1)
Plan approvals, Water & Sewer Permits: Prior to commencing construction, all
plan approvals and water and/or sewer permits shall be obtained.
A
preconstruction conference with OWASA’s Inspectors must also be held prior to
commencing any construction.
2)
Encroachment Permits: An encroachment permit will be required from any
Contractor or Developer wishing to excavate or place utilities on either a NCDOT
or Municipal public right-of-way.
OWASA – Manual of Specifications, Standards and Design
April 2015
Page 3-1
SECTION 3 – WATER AND SEWER DESIGN
3)
Pavement Cuts: Pavement cuts in streets shall be repaired in accordance with
the specific requirements of public agency on whose street or roadway the utility
is being placed, as well as any other applicable requirements dictated in the
approved encroachment permit. Open cut or bored crossings shall otherwise
adhere, as applicable, to Specification Section 02275 – Trenching, Backfilling &
Compaction of Utilities.
4)
Developer must obtain all other State and Local permits, as applicable (Noise,
Erosion and Sedimentation Control, Zoning, etc.)
5)
Certificate of Compliance.
D.
1.2
Plan Review and Observation Fees: All plan review and observation fees must be
paid prior to approval of project.
WATER SYSTEM DESIGN STANDARDS
The purpose of this module is to establish standard design procedures and criteria for
water system design on systems owned and maintained by OWASA.
A.
DISTRIBUTION SYSTEM
1)
General: Distribution systems shall meet the minimum requirements of the NC
Department of Environment and Natural Resources, NCAC Title 15A,
Subchapter 18C, Rules Governing Public Water Systems, latest revision.
a.
Water Supply System: The subdivider shall connect the subdivision or
development with the water system at his expense, and shall construct it in
such a manner as to serve adequately for both domestic use and for fire
protection.
b.
Individual meter services: Structures/Buildings shall be served by a single
meter capable of supplying the calculated fixture load. The use of multiple
meters to serve a single structure shall not be permitted.
c.
No new permanent structure or pond shall be constructed over water
mains or located within water easements.
2)
Design - System Design: As part of the design, the Engineer shall model all
new systems using WaterCAD, or compatible, software. The design data shall
include a sketch of the system showing assumed minor losses, pipe roughness
(“C” Constants assumed), line lengths, fixed grade node elevations, node
numbers, demands, pipe numbers, time of day of field test of hydrant (static
pressure converted to elevation head) for verification of starting elevation head,
the static water elevation in tank at the time a static pressure reading was taken,
and ground elevation of hydrant tested.
a.
Pipeline Velocity: 3 to 6-fps normal working conditions are preferred
although higher velocities in short lengths of pipe may be tolerated for brief
periods.
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SECTION 3 – WATER AND SEWER DESIGN
Main Size, Type and Restraint: Water mains shall be sized in accordance
with OWASA’s long-range water distribution system plans. Standard main
sizes in OWASA’s distribution system are 4, 6, 8, 12, 16, 24, and 30 inches.
On a case-by-case basis, 2-inch diameter mains may be approved by
OWASA for dead end lines with less than 20 services. The minimum
diameter of public water main is 2 inches.
b.
Fire hydrants shall not be installed on mains less than 6 inches in diameter.
However, the Town of Chapel Hill requires an 8” main or larger to supply fire
hydrants in all new developments.
All pipe shall be Ductile Iron. All joints shall be restrained by mechanical
means.
c.
Looping/Interconnectivity: Water mains shall be designed to be looped
and interconnected; OWASA’s Representative shall have final approval.
d.
Valving: Valve shall be fully accessible from ground surface by means of a
valve box or manhole. All valves 16 inches and larger shall be butterfly
valves unless gate valve is approved by OWASA Representative. The
installation of 16-inch and larger butterfly or gate valves in all areas shall be
rated for 250 psi working pressure. Valves shall be installed at all branches
from feeder mains and between mains and hydrants according to the
following schedule:
i.
One 6-inch valve shall be installed on each fire hydrant leg,
ii.
Three valves at tees (excluding fire hydrant tees),
iii.
Four valves at crosses,
iv.
An in-line valve shall be installed on the water line and shall not exceed
the distances given below:
Line size
4, 6 or 8-inch
mains
12-inch mains
16-inch
&
larger mains
Distance
450 feet
600 feet
1000 feet
If required when tapping an existing live main and inserting a main line
valve, the main being tapped must be shut off and a valve installed (cutin) on the existing main within close proximity to the new connection. In
lieu of shutting off the existing main and cutting in a valve, OWASA’s
Engineer may allow an “inserting” valve to be placed if the former is
undesirable or impractical.
e.
When downsizing a main, locate a valve after the reducer on the side with the
smaller diameter. However, the designer must evaluate thrust forces and
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SECTION 3 – WATER AND SEWER DESIGN
accommodate the forces by placement of a thrust collar (if required) on the
larger main.
f.
Manholes Valves: Unless approved otherwise by OWASA,
Valves 16
inches and larger shall be placed in a minimum 6-foot diameter precast
concrete doghouse manhole. The operating nut must be positioned under
the manhole opening. See Standard Details 513.06 and 513.08.
g.
Concrete Blocking under Valves: Provide concrete blocking behind and
beneath valves connected to tapping sleeves. See Standard Details 512.03
and 512.04.
3)
Piping Material Applications:
a.
General: Use pipe, fittings, and methods of joining in accordance with the
following:
MATERIAL
WATER
MAINS
WATER
SERVICES
UNDERGROUND APPLICATIONS
Ductile Iron
4-inch thru
2–inch and
48-inch
larger
Polyethylene
4-inch thru
Not allowed
12-inch
Type K
Not allowed
¾-inch and
Soft Copper
1-inch
Type K Hard Drawn
2-inch only
2-inch
Copper
PVC
2-inch
Not allowed
Brass Pipe
Not allowed
Short sections
of 2-inch
ABOVE GROUND APPLICATIONS
Ductile Iron
4-inch thru
2” DI allowed
48-inch
Brass Pipe
Not Allowed
2-inch only
4)
BACKFLOW
PREVENTION
BOXES/VAULTS
4-inch thru
48-inch
Not allowed
Not allowed
¾-inch thru 2inch
Not allowed
¾-inch thru
2-inch
4-inch thru
48-inch
¾-inch thru
2-inch
Joint applications:
PIPE
JOINT TYPE
COMMENT
UNDERGROUND APPLICATIONS
Ductile Iron Pipe
Restrained Joint
4-inch thru 48-inch
Ductile Iron Fittings
Restrained
4-inch thru 48-inch
Mechanical Joint
Polyethylene
Butt-Fused
4-inch thru 12-inch
Type K
Flare type brass
¾-inch and
Soft Copper
fittings
1-inch
Type K Hard Drawn
Sweat type with
2-inch
Copper
silver brazed joints
PVC
Bell end w/ gasket
2-inch only
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SECTION 3 – WATER AND SEWER DESIGN
Brass Pipe
Ductile Iron
Ductile Iron
Brass
Stainless Steel
NPT threaded
Short sections of 2-inch
NPT threaded
2-inch only
ABOVE GROUND APPLICATIONS
Flange Joint
4-inch thru 48-inch
NPT threaded
¾” thru 2-inch
NPT threaded
¾” thru 2-inch
a.
Galvanized pipe is not permitted in the OWASA water system.
b.
Provide transition couplings and special fittings with pressure equal to or
exceeding the pressure rating of the pipe or fitting to which they will be either
connected or fitted.
c.
Do not use flanges, unions, or keyed couplings for underground piping. With
the approval of OWASA’s Engineer, they may; however, be used in above
ground applications such as vaults.
5)
Location: Water mains shall be located within dedicated street rights-of-way or
publicly dedicated OWASA water easments (see Standard Detail 534.02).
6)
Fire Hydrants: Fire hydrants shall not be installed on mains less than 8 inches
in diameter in the Town of Chapel Hill or 6 inches in the Town of Carrboro.
a.
Fire Hydrant Location: The jurisdiction having authority, of the fire district,
shall be responsible for providing direction on the number and location of
hydrants.
b.
All hydrants are to be located in a street right-of-way or OWASA public utility
easement.
c.
Minimum Fire Flow at Hydrants: Chapel Hill: Meet local requirements of
section 7.5.2 thru 7.5.3 in the Town of Chapel Hill design manual. Carrboro:
Meet local requirements and NFPA Regulations. Orange County: Meet local
requirements and NFPA Regulations.
d.
Maximum Distances from Structures:
Residential: 500 by the pull of the hose method (not as the crow flies).
Commercial:
300 feet by the pull of the hose method.
e.
Minimum distances from a structure: No new hydrant shall be located
closer than 40 feet from a structure.
f.
Hydrant in relation to street: See Standard Details 514.02 and 514.03.
g.
Hydrant Requirements for uses other than residential single family:
Hydrant spacing and location shall be reviewed and approved by the Fire
Marshall and/or the local governing Municipality, as applicable.
h.
Hydrant Location in relation to Siamese connection: A hydrant shall be
placed on the “supply” side of the Siamese connection no more than 75 feet
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SECTION 3 – WATER AND SEWER DESIGN
from the Siamese connection to allow the fire suppression personnel to
charge the closed system. The hydrant must be completely accessible for
truck pumper connection.
i.
7)
Services on Fire Hydrant Branches: Services on fire hydrant branches are
not permitted.
Pressure:
a.
Minimum System Pressure: Water distribution mains shall be sized to
provide a minimum pressure at all points within the distribution system of not
less than 20 psi (gauge) during periods of peak demand (fire flow). Systems
not designed for fire flows shall have the capacity to maintain a pressure of at
least 30 psi (gauge) throughout the system during periods of peak flow.
b.
Pressure Zones: OWASA’s distribution system consists of two pressure
zones, 740 feet and 640 feet. Interconnection of pressure zones must be
approved by the Director of Engineering and Planning, and shall be
separated by a zone separation check valve assembly. Contact OWASA’s
Engineering Department to find out which pressure zone an existing or
proposed development is located in.
Connecting varying pressure zones: In the case where high and low
pressure systems are to be connected, as directed by OWASA’s Engineer, as
shown in detail # 513.03.An OWASA Engineer may require a sign to be
erected at or near the valve denoting the valve as a “Pressure Zone Division
Valve.”
c.
Limits of service based on pressure:
740-foot Pressure Zone: OWASA will not serve elevations above 700 feet,
based on United States Geological Survey (USGS) maps, in the 740-foot
pressure zone. Elevations below 565 feet (USGS) may require a pressurereducing valve on private service lines.
640-foot Pressure Zone: OWASA will not serve elevations above 600 feet
(USGS) in the 640-foot pressure zone. Elevations below 465 feet (USGS)
may require a pressure-reducing valve on private service lines.
d.
8)
Pressure Reducing Valves: When the maximum static pressure in a new
system exceeds 75 psi, businesses and/or residences shall be equipped with
a pressure-reducing valve. The valve shall be located on private service
lines. The installation of pressure reducing valves is covered by the NC State
Plumbing Code. The pressure reducing valves are neither owned by nor
maintained by OWASA.
Bury: Water mains shall be designed with a minimum bury of 42 inches cover
and a maximum of 72 inches of cover, as measured from the top of crown to the
finished grade. Under conditions which otherwise prevent 42 inch bury, such as
at crossings above shallow buried structures or rock, the minimum cover shall be
30 inches, as approved by OWASA’s Engineer. Lines which have no more than
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SECTION 3 – WATER AND SEWER DESIGN
18 inches of cover at ditch or culvert crossings shall be encased in concrete for a
length of 5 feet on each side the ditch or culvert or utilize a higher pressure class.
Such encasements or increase in pressure class shall require approval of
OWASA.
9)
Horizontal and Vertical Blocking: Restrained joint pipe, tie rods with restrainer
glands and/or other means of restraint shall be provided at all changes in pipe
direction. Concrete thrust blocking is not to be used as the primary restraining
method except when making connection or taps to existing in-service mains.
Caution should be exercised where the blocking may bear on other utilities or
where the area behind the block may be excavated in the future.
10)
Dead end lines: Blowoff assemblies shall be installed at the end of all water
mains and as required for flushing, as directed by OWASA’s Engineer.
Temporary blowoff assemblies shall be installed on lines that may be extended.
Permanent blowoff assemblies shall be installed on lines that will not be
extended. The following blowoff sizes shall apply for the applicable main size:
Main Line Size
4, 6, and 8-inch
mains
12-inch mains
16-inch mains and
larger
Blowoff Size
Blowoff Valve
Required
Size
Permanent Blowoff Assemblies
2-inch
2-inch
4-inch
6-inch
4-inch
6-inch
Standard Detail
Reference
514.04
514.06
514.06
Temporary Blowoff Assemblies
2-inch
Valve to match
514.05
a
main size
a
A temporary blowoff shall have a full 18-foot joint of pipe between the valve and
the standpipe.
4-inch thru 24-inch
The maximum length of a permanent dead end 6 and 8-inch main shall be 600
feet and 1200 feet, respectively, except as provided in cul-de-sac design. A fire
hydrant is required at the dead end.
11)
Sag Vertical- Sag Blowoffs: When directed by an OWASA Engineer, provide a
sag blow-off when lines have severe sag where sediment can accumulate and
retard flow in water line (such as when running beneath large streams, ditches or
culverts).
12)
Crest Vertical – Air Release Valves: Where water mains are subject to air
entrapment, provide an air release valve constructed in accordance with
Standard Details 513.04 and 513.05, as applicable, located at the highest
elevation on the main. Where the main undulates along its length and several
crests are encountered, a separate air release manhole will be required at each
crest. The OWASA Engineer, before placement, shall approve the final actual
location of all air release manholes. Typically, when the relative elevation
difference in a water main (from the main’s sag elevation to the crest elevation) is
greater than 25 feet, an air release valve will be needed.
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SECTION 3 – WATER AND SEWER DESIGN
A 1-inch air release valve shall be used on water mains from 2-inches to 12inches in diameter. A 2-inch air release valve shall be used on water mains 16
inches and larger in diameter. Refer to air release valve manufacturer’s
recommendations for air release sizing and quantity.
The valve shall be used to bleed air from the line as it is filled with water for
testing.
13)
Vertical upward thrust: Vertical upward thrust at fittings or vertically deflected
joints shall be restrained with the use of an approved mechanical means. Thrust
collars of adequate size and weight, pilings, or other alternative method approved
by OWASA.
14)
Relation of Water Mains to Sewers:
See Specification Section 02510 – Water Distribution, Part 1 - General,
paragraph 1.9, Project Conditions for separation requirements between water
mains and sewer mains/structures and between water mains and other
utilities/structures.
15)
Stream crossing:
Where possible, all stream crossings shall be made below water level. Stream
crossings shall be made as close to a 90-degree angle as possible. All stream
crossings shall be made with ductile iron pipe. A valve shall be placed on each
side of the crossing and restrained, in the event the line is lost, by anchor blocks.
Below streambed crossing: Underwater stream crossings shall be encased in
concrete (see Standard Detail 536.08).
Above stream crossing: Water mains crossing streams above normal water
level shall be placed above the 25-year storm elevation when practical and
otherwise meet DWQ requirements for stream crossings. Stream crossings
above water level shall be constructed with I-beam supports. Pier support shall
be avoided if possible. (see Standard Details 536.02 and 536.04) both methods
shall have the approval of OWASA’s Engineer.
Hanger Support from Bridges: In the design of the aerial system, provide both
details and calculations showing the hanger type, hanger capacity, hanger-tobridge attachment type (mechanical or chemical) capacity with a minimum safety
factor of 3. Assume the pipe is full. Provide lateral bracing of hanger to a girder
or to bottom of bridge deck. Two pipe hangers per pipe joint shall be required.
Provide plans showing the plan view and elevation of the water line crossing.
Thermal Protection, allowance for main expansion: Where aerial crossings
are approved by OWASA, install expansion devices as necessary to allow for
expansion and contraction movement in pipe, such as on aerial bridge or creek
crossings. Expansion joints are typically to be provided where the line transitions
from aerial to underground. Provide calculations showing expected differential
movement. To prevent freezing, provide either pipe insulation jackets that totally
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SECTION 3 – WATER AND SEWER DESIGN
cover the pipe (so that the pipe and insulation is placed inside the hanger
assembly) or an insulation system the covers both the pipe and hanger
assembly.
16)
Taps: taps shall be made in accordance with the following table:
Service Size
¾-inch and
1-inch
1 ½-inch
2-inch
3-inch
4-inch thru
12-inch
17)
Type Tap
Allowed
Single or
DoubleStrap
Bronze saddle
Not allowed
Standard Detail
Reference
515.01, 515.02,
& 512.06
Double strap
bronze saddle
Not allowed
515.04
Tapping sleeve &
valve
512.04
-
-
Comments
Direct taps are not
permitted
1 ½-inch water
meters shall be
served by 2-inch
taps with 2-inch
service lines.
None
3-inch water meters
shall be served by a
4-inch tap with 4inch service lines.
None
Water Services:
General: A water service shall be provided for each lot. The meter box shall be
located 1 foot from the back of the curb, within the public right of way (see
Standard Detail 515.01 and 515.02). Services shall be placed perpendicular to
the main and shall not meander or snake in such a manner as to offset the meter
from its main connection point (see schematic below). The meter box shall be
set flush with the finished grade and shall not be installed in a ditch slope. In
situations where the meter box is located outside of the public right-of-way, an
easement shall be provided to OWASA.
Meter
Service
Required
Prohibited
For multi-family housing, individual water meters are recommended.
Meter Location – double frontage lots: If a lot fronts on 2 or more streets, the
meter shall front the same street as the lot’s address.
18)
Combination Vaults: Vaults shall be designed and constructed to provide
minimum clearances between the pipe, fittings or vault walls per the dimensions
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SECTION 3 – WATER AND SEWER DESIGN
prescribed in the applicable OWASA vault detail(s). See the applicable detail for
the particular type application proposed.
19)
Multiple Feeds and Cross-connection prevention:
Buildings/Structures with multiple feeds shall be installed in accordance with OWASA’s CrossConnection Control Ordinance and Manual. See Standard Details 515.06 through 515.11.
20)
Testing:
General: OWASA will provide water for testing purposes on water mains. Refer
to technical Specification Section 02510 – Water Distribution, paragraph 3.4,
Testing and Disinfection for required testing requirements and methods. Testing
of completed water mains shall include the following:
a.
Hydrostatic Testing.
b.
Chlorination and Bacteriological Test; HPC Test.
1.3 GRAVITY COLLECTION SYSTEM DESIGN STANDARDS
The purpose of this module is to establish standard design procedures and criteria for sewer
system design on systems owned and maintained by OWASA.
A.
GENERAL
General: Gravity Collection systems shall generally meet the minimum requirements of
the State of North Carolina Department of Environment and Natural Resources, NCAC
Title 15A 02T Waste Not Discharged to Surface Waters, latest revision. Any additions,
deletions, or changes from the OWASA approved plan set must be submitted to
OWASA’s Engineer for approval, prior to making changes in the field.
B.
DEFINITIONS
Definitions: For the purposes of this specification, the following definitions
refer to sanitary sewer collection systems that come under the authority of
OWASA as specified within this section and other sections of this manual.
1)
a.
Main or Trunk Sanitary Sewer:
Exterior gravity sanitary sewer
systems receiving flow from one or
more lateral or mains.
b.
Sewer Service:
Exterior domestic sewer piping
serving a private residence,
business, commercial facility or
industrial user.
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SECTION 3 – WATER AND SEWER DESIGN
c.
2)
C.
Interceptor:
Sewer that receives flow from a
number of gravity mains or trunk
sewers, usually placed along a
stream or river.
The following are industry abbreviation for various pipe materials:
a.
DIP:
b.
PVC: Polyvinyl Chloride Plastic
Ductile Iron Pipe
COLLECTION SYSTEM DESIGN
1)
Minimum Size/Sizing: No public gravity sewer conveying wastewater shall
be less than 8 inches in diameter. No private gravity sewer conveying
wastewater shall be less than 4 inches in diameter.
2)
System Design: The system is to be designed taking into account the total
natural drainage basin, land use, ultimate population estimates, maximum
anticipated commercial and industrial contribution, infiltration and a 50-year
design period. The capability of the downstream sewers to accept the future
flow tributary to the collections system shall be evaluated by the design
engineer. Sewer size shall be based on an average daily flow of 100 gpcd
(gallons per capita per day) and a peak/average ratio of 2.5. The ratio
includes an allowance for infiltration but not inflow. The table below should
be used as a general guide for determining the equivalent persons per acre
and the peak flow for various zones.
Zoning
a
R-2
R-4
R-6
R-10
Shop Center
Bus/Commercial
O&I (light)
O&I (heavy)
Industrial
Equivalent
Person/Acre
5
8
14
21
18
25
13
30
50
Average Flow
(gal/acre/day)
500
800
1400
2100
1800
2500
1300
3000
5000
Table from the City of Raleigh Public Utilities Handbook
Peak Flow
(gal/acre/day)
1250
2000
3500
5250
4500
6250
3250
7500
12500
3)
Developments: Wastewater flows for developments with localized sewers
shall be determined in accordance with NCAC Title 15A 02T
4)
Design Flow Depth: It is customary to design sanitary sewers with some
reserve capacity. Generally, sanitary sewers through 15 inches in diameter
are designed to flow half full. Larger sanitary sewers are designed to flow
three-fourths full. These factors include infiltration but exclude inflow. If
inflow is anticipated or known to exist in upstream sewers, OWASA’s
Engineer may require that the design flow be increased accordingly and the
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SECTION 3 – WATER AND SEWER DESIGN
justification/computation/source referenced in the design calculations and
provided to the OWASA’s Engineer for review.
5)
Main Depths: The depth of sewer mains shall be great enough to serve
adjoining property, allowing for sufficient grade on service lines, but shall be
limited to a maximum depth of 20 feet. Main depth shall also take into
consideration potential conflicts with parallel pipe systems (such as water
mains and storm drainage lines), providing room for the service laterals to
pass either over or below lines.
6)
Extensions to Adjacent Property: Where tributary flow is expected from an
upstream natural drainage basin, designers shall provide easements for
future extensions of sewer mains to the farthest property line of the tract.
7)
Acceptable Pipe Material:
a.
Refer to Part 2 - PRODUCTS of Section 02530 – Sanitary Sewer for
detailed specifications for pipe and fittings listed below. Use pipe, fittings,
and joining methods according to the application indicated.
Allowable Materials for Gravity Sewer Pipe up to 18 inches
in diameter
Services
DIP, Class 350 in R/W or OWASA
easements
Gravity Mains
DIP, Class 350 (401 lined)
Allowable Materials for Gravity Sewer Pipe 21 to 48 inches
in diameter
Gravity Mains
DIP, Class 350 (401 lined)
Allowable Materials for Force Mains
Class 350 (401 lined)
4-inch and larger aC900 PVC, Class 150, DR18 w/
Ductile Iron Fittings
PVC
2-inch
ASTM D2241, SDR 21, Class 200
a
C900 PVC may be used with prior approval by OWASA’s Engineer.
DIP
b.
PVC sewer force mains are not permitted under paved surfaces.
c.
PVC, RCP, and VCP gravity pipe are not permitted.
Location: All sewer mains shall be installed within the street right-of-way or
within a dedicated OWASA sewer or utility easement (see Standard Detail
534.02). When located in street right-of-way, the sewer main shall be in the
center of the pavement or right-of-way, as practical.
8)
a.
Plan Requirements:
i. Manhole number and station.
ii. Manhole top and invert elevations.
iii. Benchmark reference (elevations must be tied to mean sea level
reference datum).
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SECTION 3 – WATER AND SEWER DESIGN
9)
Bury: A minimum of 36 inches of cover shall be provided for all sewers.
10)
Slope:
General: All sewers shall be designed and constructed to give mean
self-cleansing velocities of not less than 2.0 feet per second, based on
Manning’s formula using an “n” value of 0.013 – this includes evaluating
sewers flowing partly full. The following are the minimum slopes that
shall be provided; however, slopes greater than these are recommended.
a.
Minimum Slope
Sewer Size (inches)
Minimum Slope (%)
8
0.40
10
0.28
12
0.22
15
0.15
16
0.14
18
0.12
21
0.10
24
0.08
i.
Uniform slope between manholes: Sewers shall be designed with
uniform slope between manholes.
ii.
Slope Increase:
a) On upper reaches of small services and mains, due to water
saving fixtures now employed, the designer should give
consideration to increasing the slope of gravity services above the
minimum allowed in order to flush solids.
b) Special attention must be given to the early years that the new
public system is used, as initial flows may be substantially lower
than design flows and the velocities well below the minimum. The
designer or OWASA’s Engineer may direct usage of greater slope.
iii.
Pipe size increase: Sewers shall not be oversized to justify flatter
slopes. If the minimum scouring velocity cannot be maintained during
initial operation prior to the design flow capacities being reached, the
designer may be required to periodically flush the system until volume
has increased to affect a self-cleansing velocity.
iv.
Maximum Slope: Maximum grade for sanitary sewers is 20%.
v.
Steep Slope Protection: Any time the grade is 20%, concrete collars
shall be provided to prevent creep and/or to prevent water from
flowing along the pipe and causing trench scour. Manholes shall be
protected from corrosion generated by release of hydrogen sulfide
gas from high turbulence associated with line velocity. See Standard
Detail 536.01.
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SECTION 3 – WATER AND SEWER DESIGN
vi.
High Velocity Protection: Where design velocities are projected to
be greater than 10 fps, the sewers and manholes shall be protected
against internal erosion and impact by high velocity. Pipe shall
conform to ASTM, AWWA, ANSI, etc., which provide protection
against erosion. For velocities greater than 20 fps, erosion control
measures shall be documented on the “Record Drawings” and the
Engineer’s Certification.
vii.
Sewers placed in predominantly silty soils: The designer should
give consideration to placing either clay or concrete collars (dams)
periodically along sewers constructed in and backfilled predominantly
with silty soils – regardless of slope. A non-woven separation
geotextile fabric should be placed between the stone and the earthen
backfill.
11)
Alignment: All sewers shall have a straight alignment between manholes.
12)
Changes in Pipe Size or Material:
a.
Pipe Size Changes: Gravity sewer sizes shall remain constant between
manholes. Pipe size changes shall occur only at manholes. When a
smaller sewer joins a larger one, the inverts of the sewers shall be
arranged to maintain approximately the same energy gradient whenever
possible. 0.8 times the pipe diameter of the two lines shall match.
b.
Undersized or substandard downstream sewers: Sewer extensions
shall be designed for projected flows even when the diameter of the
receiving sewer is less than the diameter of the proposed extension at a
manhole, with special consideration of an appropriate flow channel to
minimize turbulence when there is a change in sewer size. Justification
shall be provided at the end of the project with the as-built drawings
indicating that the capacity of the downstream sewer will not be
overloaded by the proposed upstream installation. OWASA reserves the
right to prohibit additional flow into an undersized sewer for new growth.
c.
Pipe Material Changes: To avoid couplings of dissimilar material, pipe
material must remain consistent between manholes and may not be
changed. The manhole drop material should conform to Standard Detail
532.03.
13)
Uneven inverts of parallel pipe lines in same trench: Where more than
one pipe line is laid in the same trench and the invert elevations are not
identical, and where no concrete cradle or encasement is provided for the
support of the high pipe line, its foundation shall be considered to be yielding.
When bridging is required to support a portion of the pipeline over such
yielding trench bottom, it shall not be considered to provide bridging strength.
#57 stone shall be provided and used for this purpose.
14)
Buoyancy: Buoyancy of sewers shall be considered and flotation of the pipe
shall be prevented with appropriate construction where shallow cover and
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SECTION 3 – WATER AND SEWER DESIGN
high groundwater or flooding conditions are anticipated.
purposes, assume water to top of pipe and pipe is empty.
15)
16)
For design
Service Connections:
a.
Services connected to gravity sewers shall be connected using in line
wyes or saddles. Service saddles may be used only on existing sewer
mains. Tees/wyes shall be used for new construction. See Standard
Detail 534.01 for service tap detail.
b.
All 6-inch and larger sewer services shall be connected to a manhole.
c.
A cleanout will be installed on each house service. Unless topography
permits otherwise, services are to be placed at the low side of the lot.
The cleanout shall be located at the right-of-way or easement line on
the customer’s side of the right-of-way or easement line. An access
port is to be set over the cleanout.
d.
Minimum grade for 4-inch and 6-inch services shall be in accordance
with the North Carolina State Plumbing Code, latest revision.
e.
Service connections to manholes: A service connection may not
enter the cone or its joint. Service connections must enter the bottom of
the manhole only.
f.
Vertical stacks or standpipe services are not allowed.
g.
Services on Utility Easements:
Cleanouts, shall be located at the
easement line, must be at ground level and in a mini-manhole (See
Standard Detail 534.01).
Public Easements: The width of easements (except when adjacent and
parallel to right-of-way) shall be based on the following:
Sewer Lines
Sewer Easements
Combinations Easements
(Sewer with either Water or Storm Drainage)
Min. Easement Width
(feet)
30
40
Consideration shall be given for deeper cuts (generally greater than 12’) by
including an additional temporary construction easement (usually 10’ - 20’).
OWASA’s Engineer may require that the width of the permanent easement
increase with a depth of sewer as determined by OWASA’s Engineer for
maintenance purposes.
Easements shall be fully accessible by rubber-tired vehicles in their entirety,
with a maximum grade of 4:1.
OWASA may require stream fords for larger streams provided crossings are
consistent with NCDENR Division of Water Quality and USACOE
requirements.
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SECTION 3 – WATER AND SEWER DESIGN
All easements shall be acquired by the developer and dedicated to OWASA
by recorded map and by deed of easement prior to approval of the project for
construction.
17)
Testing: See Specification Section 02530 – Sanitary Sewer; paragraph 3.9
Testing for testing requirements.
18)
Allowable Leakage: 100 gallons per inch nominal diameter per mile of pipe
per 24 hours. A weir flow test will not be allowed in lieu of a pressure test.
D.
DESIGN – MANHOLES
Location
1)
a.
General: Manholes shall be installed on all mains 8 inches and larger.
Manholes shall be installed at the end of each line, at all changes in
grade, at changes in main size or alignment, at all intersections.
b.
Spacing: Manholes shall be placed at distances not greater than 400
feet for all public sewer mains.
c.
Cleanouts: Cleanouts may be used in lieu of manholes on 4 and 6-inch
private lines with distances between cleanouts not exceeding 75 feet.
DIAMETER:
2)
a.
Minimum Diameter: The minimum diameter of both standard and drop
manholes shall be 4 feet.
b.
Manhole Diameter Based on Pipe Size:
Line Size
8 through 12 inches
16 through 24 inches
c.
Minimum Diameter
4-foot in diameter
5-foot in diameter
Manhole Diameter Based on Depth:
Depth
Manholes 0 to 10’-0”
Manholes greater than 10’-0” deep
Minimum Diameter
4-foot in diameter
5 feet in diameter
5-foot diameter manholes below 10 feet in depth may have a 5 x 4
transition slab, transitioning to 4-foot diameter, after a minimum of 6’ of
riser (height) from invert of manhole.
d.
Extended Bases: Manholes over 12 feet in depth, as measured from top
of casting to effluent invert, shall have extended bases with appropriate
reinforcing.
e.
Cones: Eccentric cones are required to be used on all mains.
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SECTION 3 – WATER AND SEWER DESIGN
f.
Minimum drop across invert: The minimum drop between manhole
invert in and invert out is 0.10 feet on straight junctions. Other drops (H),
where there is no change in pipe size, can be computed by applying the
following headloss (K) coefficients to the velocity head:
V 2 
 , where
H  K 
 2g 
H = Vertical drop across invert of manhole (ft)
K = Headloss coefficient (from table below)
V = Average velocity in influent pipe (ft/sec)
g = Acceleration of gravity (32 ft/sec2)
Condition
For bends at junctions of 25 degrees
For bends at junctions of 45 degrees
For bends at junctions of 90 degrees
For junctions of 3 pipes
For junction of 4 or more pipes
(Reference: King’s handbook of Hydraulics)
K
0.30
0.40
0.60
0.80
1.00
DROP TYPE:
3)
a.
An outside drop shall be provided for a sewer entering a manhole at an
elevation greater than 18 inches above the invert of the manhole unless
sewer pipe crown elevations match. See Standard Detail 532.03.
b.
Inside Drops: Not permitted.
c.
Service taps in manholes: If a service is proposed in the manhole,
service must be installed at the bottom of the manhole.
WATER-TIGHTNESS:
4)
a.
Manholes shall be pre-cast concrete. Infi-Shield® Gator Wrap external
sealing systems, as manufactured by Sealing Systems, Inc. and a butyl
rubber seal, are to be placed on the exterior joints of manholes. InfiShield® Uniband and a buytl rubber seal shall be placed at the top of
manholes where the iron casting mates with the precast concrete cone
section and/or grade rings. See Standard Details 532.01, 532.03,
532.05, 532.06, and 532.08.
b.
Pipe connections to Manholes: Inlet and outlet pipes shall be joined to
the manhole with gasketed flexible watertight connections (rubber boots).
See Standard Details 532.01 and 532.03.
c.
Manholes in streets or adjacent to streets: Manholes subject to be
flooded by street water or located in flood prone areas shall have
watertight covers.
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SECTION 3 – WATER AND SEWER DESIGN
d.
All sanitary sewers in utility easements (other than those running
parallel to creeks and/or located in a flood plain): All manholes rims must
be a minimum of 12-inches above grade.
e.
Sanitary Sewer Easements running parallel to creeks and/or located
in flood plains:
i.
Manholes shall be designed for protection from the 100-year flood by
one of the two methods:
a)
b)
c)
Manholes shall be watertight and vented 24 inches above the 100year base flood elevation. Manholes shall be vented every 1000
feet or every 3rd manhole, whichever is lesser. Maximum vent
spacing shall not exceed 1000 feet on watertight sections of main.
See Standard Detail 532.05, or
Manholes rims shall be 24 inches above the 100-year base flood
elevation.
Odor control apparatuses may be required.
BUOYANCY:
5)
Buoyancy shall be considered and flotation of the manholes shall be prevented
with appropriate construction where high groundwater or flooded conditions are
anticipated. For design purposes, assume water to top of manhole and that the
manhole is empty.
CORROSION PROTECTION FOR MANHOLES:
6)
a.
Where corrosive conditions due to septicity or other causes are
anticipated, consideration shall be given to providing corrosion protection
on the interior of the manholes. Consequently, drops in interceptor lines
or drops into interceptor lines shall be avoided. Drop manholes, if
required, shall be provided upstream of interceptor line connection.
b.
Where high flow velocities are anticipated, the manholes shall be
protected against internal corrosive erosion and displacement from
impact.
INSPECTION AND TESTING:
7)
See technical Specification Section 02530 – Sanitary Sewer for manhole
testing requirements.
MANHOLE NUMBERING/ANNOTATION:
8)
a.
All Sanitary Sewers: All manholes located in utility easements shall be
labeled. OWASA will provide the number(s) to the Developer/Contractor.
b.
All manholes located in utility easements running parallel to creeks:
Where overgrowth is likely to occur in utility easements running parallel to
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SECTION 3 – WATER AND SEWER DESIGN
creeks, as determined by OWASA’s Engineer, the manholes located in
these easements shall have a sign marker. The sign marker is to be
provided by the Developer. The marker shall be comprised of a standard
steel signpost (3 lbs/ft) with a 3½” wide flange, 12 feet long. The post
shall extend 10-feet out of the ground with a minimum of 2-feet of the post
buried. The sign marker shall be a standard 18” x 24”, 0.080” aluminum
blank with the 24” dimension of the sign set horizontally.
c.
9)
For those manholes located in utility easements but not running
parallel to creeks: The number shall be stenciled on the manhole.
INSPECTION AND TESTING:
See technical Specification Section 02530 – Sanitary Sewer for manhole
testing requirements.
E.
SEWERS IN RELATION TO STREAMS AND OTHER BODIES
Creek crossings shall be in accordance with OWASA’s “Policy on Sewer Lines
Crossing Creeks and Easements.” All creek crossings, unless otherwise
approved by OWASA, shall be made with ductile iron pipe.
1)
Materials: Sewers entering or crossing streams shall be constructed of
ferrous material pipe with mechanical joints; otherwise they shall be
constructed so they will remain watertight and free from changes in alignment
of grade and tested to 150 psi. Material used to backfill the trench shall be
stone, coarse aggregate, washed gravel or other materials, which will not
readily erode, cause siltation, damage pipe during placement, or corrode the
pipe.
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SECTION 3 – WATER AND SEWER DESIGN
a.
Sewers Paralleling Creeks: Sewers paralleling creeks shall be below
the stream elevation, such that lateral connections will be below
streambed. In certain circumstances where rock is present, sections of
the main may be raised to allow lateral connections above the stream bed
provided the ability to serve the upstream property is not compromised
and the pipe crossing is designed sufficiently restrained to prevent line
breakage by the dynamic affects of the stream flow. Sewers shall be
placed outside of applicable Watershed and River Buffers.
b.
Perpendicular Crossings:
Creek crossings shall be as near to
perpendicular to the stream as possible. Sewers crossing creeks shall be
placed below the streambed such that there is a minimum of 3 feet bury
below the streambed. If the minimum 3-foot bury cannot be attained,
either encase the sewer in concrete in accordance with Standard Detail
536.08 or design the sewer as an aerial crossing in accordance with
Standard Details 536.02, 536.04 and 536.06, as applicable. Aerial
crossings require prior approval of OWASA.
Buried Pipe Cover Depth: The top of all sewers entering or crossing
streams shall be at a sufficient depth below natural bottom of the streambed
to protect the sewer line. The following cover requirements shall be met:
2)
a. One foot of cover where the sewer is located in rock:
b. Three feet of cover in other material unless ferrous pipe is specified. In
major streams or rivers, more than three feet may be required; and
c. With approval of OWASA’s Engineer, in paved stream channels, the
crown of the sewer line may be placed below the bottom of the channel
pavement.
d. With approval of OWASA’s Engineer, less covering will be considered if
the proposed sewer crossing is encased in concrete (see Standard
Detail 536.08) provided the encasement will not interfere with future
improvements to the stream channel.
Aerial Crossings:
3)
a.
Creek crossings above water level shall be constructed with I-beam
support carriage. If piers are necessary, approval shall be obtained from
OWASA. The bottom of the pipe should be placed no lower than the
elevation of the 25-year flood. Ductile iron pipe with mechanical joints
shall be required. In the event the 25-year flood elevation cannot be
determined or the proposed gravity sewer must be placed below the 25year elevation, the applicant (for both private and public sewers) will have
to issue a certification stating: “Regular and proper inspection and
maintenance of the aerial crossing shall be provided to insure that the
creek/stream flow is not impeded and that no damage will be caused to
upstream or adjacent properties.”
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SECTION 3 – WATER AND SEWER DESIGN
b.
Proper joint technology, such as flanged or restrained, adequate supports
to prevent excessive deflection and flexion or a combination of both shall
be provided for all aerial pipe crossings. Supports shall be designed to
prevent heave, overturning, uplift, and settlement. Supports shall be
designed to withstand the hydrodynamic effects of the stream flow
pressure using the following formula:
P  1.5KV 2
Where,
1.5 = safety factor against overturning (2.5 is recommended),
P = pressure, psf
V = velocity of water, fps
K = 4/3 for square ends, ½ for angle ends when angle is < 30 or less and
2/3 for circular piers.
If it is probable that the aerial pipe could be submerged by the stream
flow, the effects of the flow pressure on the pipe shall also be taken into
account when computing pier-overturning moments. For aerial stream
crossings, the impact of floodwaters and debris shall be considered. In
streams subject to flooding velocities greater than 5 fps, pipe crossing
shall be anchored in bank in such a way that if all supports are lost, the
pipe system will not separate and will be restrained by anchor blocking of
appropriate size in the bank. Provide applicable blocking computations
and details.
c.
Precautions against freezing, such as insulation and increased slope,
shall be provided.
d.
Expansion jointing shall be provided between above ground and below
ground sewers. Where buried sewers change to aerial sewers, special
construction techniques shall be used to minimize heaving. Similarly,
special details may be required between above ground and below ground
sewer transition to account for seismic forces.
e.
Computations:
i.
Provide structural calculations for any elevated main and pier system
where span of the main exceeds the joint length. Provide calculations
for all aerial mains, and their supporting structures that are subject to
hydrodynamic forces. Calculations are to provide for a minimum
safety factor of 2.5 against overturning and 1.5 for uplift. Calculations
shall also address applicable seismic loads if applicable. Where
stream is subject to floating debris such that the pipe system could be
broken or separated by the impact forces, pipe joints shall be flexible
restrained joints. Pipe crossing shall be anchored in bank in such a
way that if all supports are lost, the pipe system will not separate and
will be restrained by anchor blocking in the bank. Provide applicable
blocking computations and details for review.
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SECTION 3 – WATER AND SEWER DESIGN
f.
See Standard Details 536.02, 536.03, 536.04, and 536.06.
4)
Structures: The sewer interceptors, manholes, or other structures shall be
located so they do not interfere with free discharge of flood flows of the
stream. Portions of manholes above grade subject to hydrodynamic forces of
flooding shall be designed to resist the flood forces with a safety factor of 2.5
considerations shall be given for impact from debris. See paragraph C
above.
5)
Anti-Seepage Collars – wetland areas: In areas where the sewer trench
has the potential to drain wetlands, anti-seepage collars shall be installed. In
these areas, a US Army Corps of Engineers 404 Wetland Permit and/or a
NCDENR 401 Water Quality Permit may be required.
6)
Environmental - Buffer Requirements: A minimum buffer separation of 50
feet shall be maintained between sewers and streams/waters classified as
nutrient sensitive streams or watershed buffers (from normal high water).
See also NCDENR NCAC Title 15A 02T for other requirements regarding
minimum separation with streams, lakes and impoundments. Before crossing
streams or ditches, working within 100 feet of private or public water supply
sources or 50 feet of non-water supply ponds, lakes, or rivers, the Designer
shall verify whether either the line is exempt or obtain a permit to encroach
into a watershed or nutrient sensitive river basin buffer. Unless otherwise
permitted, water or sewer mains crossing a stream, river, pond, or lake
buffers are to be as near perpendicular as possible (the crossing is
considered to be perpendicular if it intersects the stream or surface water
between an angle of 75 and 105 degrees). Do not disturb more than 40
linear feet (longitudinal) of a riparian buffer. Adhere to all of the following
Best Management Practices in Zone 1 (the lower 30 feet beside the stream or
water) during design/construction.
a. Woody vegetation is to be cleared by hand. No grading allowed.
b. Stumps to remain except in trench where trees are cut. Minimize
disturbance to roots in buffer zone.
c. Backfill trench with the excavated soil immediately following installation.
d. Do not use fertilizer except for the one-time application to reestablish
vegetation.
e. Minimize removal of woody vegetation, the amount of disturbed area, and
the time the disturbed area remains disturbed.
f. Take measures to ensure diffuse flow of water through the buffer after
construction.
g. In wetland areas, use mats to minimize soil disturbance.
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SECTION 3 – WATER AND SEWER DESIGN
PROTECTION OF POTABLE WATER SUPPLIES AND STORM SEWERS
F.
1)
General: See Specification Section 02530 – Sanitary Sewer, Part 1 General, paragraph 1.10, Project Conditions for separation requirements
between water mains and sewer mains/manholes and water mains and
drainage structures/streams.
2)
Sewer/Well Conflict: If a sewer main must be placed closer than 100 feet of
the well, ferrous sewer pipe with joints equivalent to NCDENR water main
standards shall be used; however, no gravity sewer, force main, or manhole
structure shall pass or be placed within 25 ft of a private well or 50 feet of a
public water supply well, source or structure. If the sewer line must be
installed within 25 feet of a well, the well shall be capped and the property
shall be required either to connect to OWASA’s water system, if available, or
the existing well must be abandoned according to NCAC Title 15A 2C .0100
Well Construction Standards, latest revision, regarding guidelines for well
abandonment and construction of a new well drilled meeting the setback
requirements.
G.
PUMP STATIONS
1)
GENERAL:
Pump stations and force mains will be allowed only with the permission of
OWASA’s Executive Director.
Pump stations shall be OWASA standard. Pumps may be either self-priming or
submersible grinder pumps with electro-mechanical controls. Pumps shall be
designed for continuous duty pumping raw, unscreened wastewater.
Self-priming pumps: USE OF THESE PUMPS MUST BE APPROVED BY
THE OWASA REPRESENTIVE. Self-priming pumps shall have bubble system
switches. Pumps and related controls shall be enclosed in a rollback “Quonset”
style fiberglass enclosure. Pumps shall be capable of handling a 3-inch solid and
any trash or stringy material that can pass through a 4-inch hose unless
mechanical means of solids reduction is installed at the pump. Pumps shall be
made non-clog by passing solids, trash, and stringy material through a non-clog
impeller. Impellers shall have blades that are generally forward rounded or
otherwise configured to avoid catching solids, trash, and stringy material.
Submersible Pumps: Submersible pumps shall have mercury float control
switches with electro-mechanical controls. See Standard Detail 539.01 for
typical pump stations site layout. Pumps shall be capable of handling a 3-inch
solid and any trash or stringy material that can pass through a 4-inch hose unless
mechanical means of solids reduction is installed at the pump. Pumps shall be
made non-clog either by passing solids, trash, and stringy material through a
non-clog or vortex-type impeller or by grinding, chopping, or cutting them prior to
passing them through the impeller. Impellers shall have blades that are generally
forward rounded or otherwise configured to avoid catching solids, trash, and
stringy material.
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SECTION 3 – WATER AND SEWER DESIGN
Lift stations shall include the following as a minimum:
a. Service head, meter base, service connection, disconnect, and area light with
switch.
b. Audible and visual high water alarm and alarm silence.
c. Auto-dialer (minimum 8 number, 4 channel). The automatic telephone dialer
shall be a solid-state component capable of dialing up to 8 phone numbers,
each up to 24 digits in length. The dialer shall have solid-state voice
message recording and playback, all implemented with permanent
nonvolatile solid-state circuitry with no mechanical tape mechanism.
d. Automatic air release valves, as applicable.
e. For self-priming pumps, provide air bubbler type control system with hand-offautomatic (H-O-A) switches and an automatic alternator. For submersible
pumps, provide mercury float switches for level control.
f. High water alarm circuitry.
g. 3-phase voltage monitor, if applicable. Indication of 3-phase power fail.
h. Suction and/or discharge gauges, as applicable.
i. Elapsed time indicators.
j. High pump temperature protection.
k. Pump run lights.
l. Motor overload resetter
m. Surge suppressor.
n. Duplex service receptacles on GFCI.
o. Surge relief valve and return piping to wetwell.
p. Start-up assistance and certification, including operational/witness/drawdown
test. Certified pump curves shall be provided as part of the project closeout
documents.
q. Dual power supply auto switchover, etc.
r. For self-priming pump stations, provide heaters and fluorescent lighting.
s. The lift station is to include back-up alarm system that operates off a 12-volt
battery connection in the event of power failure. The battery system is to
include a trickle charger to ensure battery integrity.
t. Provide auxiliary, natural gas or diesel fired automatically activated stand-by
power generator source with automatic reset, placed on site. Pump
manufacturer to provide power demand/ratings to Contractor before ordering
pump and the power demand appropriately marked on the pump shop
drawings. Generator shall have the capacity sufficient to sequentially start
and run all pumps in the pump station. The Contractor shall provide a
complete engine driven generator set. The generator set shall consist of
four-cycle, radiator-cooled, engine direct connected to an alternating current
generator, a unit-mounted control panel, all mounted on a common sub-base.
The control panel shall be complete with engine controls and instruments,
safety controls and panel lights including the following:
i.
ii.
The generation unit shall be capable of powering the pump motors
starting current, electrical systems, instrumentation /controls and alarm
systems, and other auxiliary equipment as may be necessary to provide
for the safe and effective operation of the pump station. The generation
unit shall have the appropriate power rating to start and continuously
operate under all connected loads.
The generation unit shall be provided with special sequencing controls to
delay lead and lag pump starts unless the generating unit has the
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SECTION 3 – WATER AND SEWER DESIGN
capacity to start all pumps simultaneously while the auxiliary equipment is
operating.
iii. The generation unit shall be capable of shutting down and activating the
audible and visual alarms and telemetry if a damaging operating condition
develops.
iv. The generation unit shall be protected from damage when restoration of
power supply occurs.
v. The generator shall be equipped with an automatic transfer switch to start
generator and transfer load to emergency in case of utility under voltage,
over voltage, power loss, phase reversal, or phase loss.
vi. The control panel shall be complete with run-stop-remote switch; remote
start-stop terminals; cranking limit; battery charge rate ammeter, oil
pressure gauge, temperature gauge; low oil pressure shutdown; high
engine temperature shutdown; over speed shutdown; AC voltmeter;
voltage adjustment; frequency meter; and running time meter.
vii. Circuit breakers shall be provided with a built in control panel.
viii. Provide manufacturer’s recommended anti-freeze, engine heaters, and
suitable trickle battery charger. All accessories shall be engine-mounted
and within the weatherproof sound attenuated housing.
ix. The manufacturer of the unit shall completely assemble and test the unit
before shipment. He shall be one who is regularly engaged in the
production of such equipment, and who has spare parts and service
facilities. He must also provide 1 complete set of filters.
x. The controls must indicate engine run, common engine fail, transfer
switch position, low fuel level, and fuel tank leak for remote telemetry
purposes.
xi. The automatic transfer switches must have a disconnect on the utility
service main side.
xii. The generator shall comply with the following minimum requirements:
a) Engine: Four-cycle, 4 cylinder, radiator cooled, at 1800 RPM.
Starting shall be from batteries, with capability to start the unit at 32
degrees temperature.
b) Generator: Rating shall be continuous standby service at 0.8 power
factor, at 1800 RPM.
c) Voltage: Three-phase, 480 V. KW rating to match facility needs.
d) Engine shall be equipped with an isochronus governor as
manufactured by Woodall.
e) Frequency regulation shall be less than 3-cycles from no-load to full
load.
xiii.
All accessories needed for the proper installation of the system shall be
furnished. Included should be batteries, battery cables, exhaust piping,
mufflers, vibration mounting, and three bound sets of detailed operation
and maintenance manuals with parts list. Batteries should be lead acid.
xiv.
The generator set shall be enclosed with a factory-installed weatherprotective housing (sound abating enclosure to 68db @ 23 ft.) Housing
shall provide easy access to the engine-generator and instrument panel.
Muffler to be designed so exhaust is not blown or sucked across the set
by cooling air.
xv.
Included with the generator shall be a complete fuel system consisting of
a fuel tank, fuel gauge, fuel lines, fuel pumps, valves and any and all
other items incidental to a first-quality installation.
xvi.
Provide integral sub-base double-walled diesel tank. The tank is to be UL
approved closed-top dike type. The tank shall also be fitted with a leak
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SECTION 3 – WATER AND SEWER DESIGN
xvii.
xviii.
xix.
xx.
xxi.
xxii.
xxiii.
xxiv.
xxv.
2)
sensor device. The tank must have a capacity to run the generator for a
minimum of 48 hours at 100% load.
Tank shall consist of the fuel tank separate and contained within the
frame. No generator weight is to be supported by the tank. Provide a
drain plug at one end of the rupture basin. Provide vibration isolators
between generator set and tank assembly. Provide fuel low-level alarm
remote mounted.
Provide manufacturer’s recommended anti-freeze and engine block
heater, per manufacturer’s recommendations, with thermostatic controls
to maintain engine coolant at proper temperature to fulfill start-up
requirements, adjustable if possible. Provide suitable trickle battery
charger. All accessories shall be engine-mounted and within the
weatherproof sound attenuated housing.
Provide annunciator panels with visual and audible alarms to monitor and
warn of emergency operation conditions affecting line and generator
power sources.
Provide stainless steel super critical grade type exhaust silencer mounted
inside of the generator enclosure for corrosion protection.
Provide amp meter, voltmeter, and frequency meters with phase
switches.
Provide fuses or circuit breakers for battery charger and engine.
Provide an automatic battery charger, static type, magnetic amplifier
control with DC voltmeter, DC ammeter and potentiometer for voltage
adjustment. The charger is to be completely automatic and rated for the
type of battery use. The charging rate is to be determined by the state of
the battery and reducing to milliamp current on fully charged battery. The
charger shall be 120 V., single-phase, 60 cycle, AC input with 6-amp
maximum output.
Operation and Maintenance instructions. The Contractor shall provide a
minimum of 4 continuous hours of operation and maintenance
instructions for the Owner’s personnel.
OWASA must be furnished with one complete set of air, oil, and fuel
filters.
STATION DESIGN:
a. Design of station shall be according to the provisions of NCDENR, Division of
Environmental Management NCAC Section 15A 02T – Waste Not Discharged to
Surface Waters.
b. The pump station shall have a 100% reserve peak pumping capacity (dual pumps)
and be capable of pumping at a rate of 2.5 times the average daily flow rate with
any one pump out of service. Pump on/off elevations shall be set to achieve 2 to 8
pumping cycles per hour at the average flow rate.
c. The power source, voltage and phasing shall be verified before ordering pumps.
d. Evaluate the capacity of the receiving sewer main at the point of discharge and
downstream to determine that the line can handle the pumped sewer flow.
e. The pump station and force main must be sized to accommodate the total basin
area that could gravity flow into it.
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SECTION 3 – WATER AND SEWER DESIGN
f. OWASA reserves the right to require odor control facilities at pump stations.
g. All control panels must be weatherproofed and have weatherproof identifying labels
attached with stainless steel screws. An acceptable enclosure is RACO Guard-It
system.
h. The use of metal rigid conduit is required THROUGHOUT THE ENTIRE STATION.
3)
WETWELLS:
a. Wetwells shall have the interior walls painted in accordance with the technical
Specifications Section 02530 – Sanitary Sewer.
b. Buoyancy shall be considered and flotation of the wetwells shall be prevented with
appropriate construction where high groundwater conditions are anticipated.
i. Computations: Provide buoyancy calculations to OWASA’s Engineer. Assume
water to top of structure and structure is empty except that you may include the
weight of the liquid below pump off elevation.
c. Surface water shall be directed away from the station pad in all directions.
d. Wetwells, and the access road to the site, shall be located a minimum of 3 foot
above the 100 year base flood elevation.
e. Provide a screened vent to prevent gas entry to either the panel or pump house
enclosure.
f.
Wetwell components shall be located such that normal maintenance and operation
of the components can be performed without having to enter the wetwell.
g. Seal the electrical conduit running from the wetwell to the control panel to prevent
gas entry into panel or pump house enclosure.
h. All bolts, mounting brackets, pump lift chains, etc. must be of proper corrosion
resistance, sized to support the applicable static and dynamic loads imposed by the
equipment.
4)
SITE (See Standard Details 539.01 through 539.05):
a.
Provide a service head, meter base, service connection, disconnect, area
light with photocell.
b.
A 12-foot wide all weather access road consisting of 8 inches of ABC is to be
provided to the station with a turn-a-round area of sufficient size to
accommodate turning of OWASA maintenance vehicles. There shall be a 10
foot maintenance area around the perimeter of the station fence. If the lift
station easement does not directly abut a publicly dedicated road, a 30 ft.
access easement shall be provided.
c.
Provide an 8-inch thick concrete generator pad (see Standard Detail
539.01).
d.
Unless otherwise allowed by OWASA’s Engineer, all stations shall be fenced
with an 8-foot high, GREEN COMMERCIAL GRADE PVC COATED
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SECTION 3 – WATER AND SEWER DESIGN
galvanized chain link fence with 3 strands of razor wire across the top. A
minimum of either two 6-foot long gates or one 12 foot wide hinged gate,
WITH A LOCKING MECHONISIM CAPABLE HANDLING MUTLIPLY
LOCKS, shall be provided. Green privacy fence slats shall be installed on all
installations.
e.
A photocell controlled area light, on a separate circuit from the pumps, shall
be provided at the station. The light shall be a minimum of 138-watt LED,
medium 350 mA, 9500 lumens area light, with a minimum clear mounting
height (ground to fixture) of 15 feet.
f.
Emergency pump connection with quick connect flange and gate valves.
g.
A metered potable water source with an approved RPZ with enclosure and
non-freeze yard hydrant is required, unless approved otherwise by OWASA’s
Engineer. The Non-Freeze Yard Hydrant shall be Clayton Mark model 5451
Lever type frost proof yard hydrant or approved equal.
h.
Provide a non-freeze shower w/ eyewash and concrete pad.
5)
FORCE MAINS:
a.
Force main materials shall minimum conform to the table in Section 1.3.,
section C paragraph 7, Collection System Design.
b.
Provide combination air vacuum air release valves at all high points with
differential grade separation of 15 feet or more between high and low points.
See Standard Detail 538.01. If not provided in the design, the Designer
shall provide calculations to prove that a surge relief valve is not needed.
c.
A plug valve or valve vault shall be placed outside of the pump station.
d.
Sewer force main valve boxes shall have the valve cap marked SEWER.
END OF SECTION 3
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SECTION 3 – WATER AND SEWER DESIGN
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SECTION 4 - PROCEDURE FOR APPROVAL OF
WATER AND/OR SEWER EXTENSION PROJECTS
(REVISED 06-01-13)
SUGESTED SEARCH WORDS FOR THIS SECTION
Attachments – Standard Forms
Plan Requirements – General
Close-out Documents
Sewer Line Extension Plans
Construction
Tentative Acceptance - Warranty
Design and Plan Approval
Tests
Final Acceptance
Water Line Extension Plans
Payment of Fees & Setting of Meters
WATER AND SEWER PLAN APPROVAL
1.1
INTRODUCTION
This document establishes the procedure for obtaining State of North Carolina (State)
and Orange Water and Sewer Authority (OWASA) approvals for extending OWASA's
water distribution and/or wastewater collection systems.
Approvals from OWASA and certain state regulatory agencies are required in order to
construct water and/or sewer extensions. Additional approvals from these agencies are
required in order to discharge wastewater into a new sanitary sewer line or withdraw
water from a new water main. Approvals from the local government with jurisdiction over
the area in which the project is located may also be required.
Design and construction of public water and sewer mains must conform to the
requirements of the Orange Water and Sewer Authority. All design and construction
within the service area shall incorporate OWASA’s long range planning objectives and
shall provide for the orderly expansion of the system to adjacent properties. This shall
include but not be limited to installation of public water and sewer mains in an alignment
and of a size and length to adequately provide for development build-out and the
provision of easements to allow for extension of water or sewer to adjacent or upstream
properties. Costs incurred are entirely at the Applicant/Developer’s expense, However,
under our current guidelines (May, 2007) OWASA may reimburse the cost for over sized
mains under certain circumstances.
In addition, the North Carolina Department of Environment and Natural Resources
(NCDENR) regulates public water and sewer main extensions. Water and sewer line
extensions require approval from NCDENR's Division of Environmental Health (DEH)
and Division of Water Quality (DWQ), respectively. See Section 3 – Water & Sewer
Design of this manual for more information.
Approval from the Town of Chapel Hill, Carrboro, or the North Carolina Department of
Transportation (NCDOT) will be required for any project that will have work performed
within that municipality or agency’s right-of-way. Additionally, construction of water and
sewer improvements within other utility or agency easements or rights of way must be
approved, in writing, by that entity in addition to acquiring OWASA approval for same.
The guidelines and procedures in this document apply to any party proposing to
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April 2015
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
undertake a water and/or sewer extension project in OWASA's service area. Such
parties include, but are not limited to: builders, developers, property owners, Town of
Carrboro, Town of Chapel Hill, Orange County, University of North Carolina at Chapel
Hill, and UNC Hospitals.
1.2
PLAN REQUIREMENTS
Detailed plans shall be prepared by a professional engineer licensed to practice in the
state of North Carolina. All plan sheets shall bear the registration seal of the engineer,
signature, and date. The plans shall be clear and legible and drawn to a scale that
permits all information to be clearly depicted and reviewed. Plans that are not legible or
information that is unclear or incomplete shall be returned without review.
A.
GENERAL
Submitted plans shall be on 24"x36" or other suitable size paper and shall
include all relevant sheets pertaining to public water and/or sewer main
installation or any proposed work that may have an impact on the public water
and sewer system. In addition, all drawings indicating landscaping or plantings
shall be submitted and are to clearly identify existing and proposed water and
sewer mains and easements.
Commercial development projects that include food handling or preparation
facilities must also include provisions for grease and oil control interceptors.
Relevant plan sheets shall be submitted to OWASA for review. This shall include
kitchen plumbing plan and plumbing plan including grease interceptor. In
accordance with Section 5.4 of the OWASA’s Administrative Policy for Grease
and Oil Control, the following documentation regarding proposed grease
interceptors to OWASA shall be submitted for review and approval:
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A site plan showing the location of the interceptor, lines, and cleanout or
manhole;
Details of the interceptor, lines, and cleanout or manhole;
Formula and calculations used to determine the interceptor capacity.
For specific projects that require installation of backflow assemblies (RPZ or
DDC) to be located inside buildings or facilities, a plan must be submitted
indicating model, type, and location. Fire Lines require the installation of detector
assembly (RPDA). The location of the ERT\Remote readout device shall also be
shown. This device cannot be installed more than 200 linear feet from the
backflow assembly.
General plan set submittal requirements are as follows:
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Cover Sheet with vicinity map,
Index Sheet (if necessary),
Overall Plan ,
Plan/Profile,
Landscaping plan with water and sewer easements designated,
Any relevant plumbing drawings, and
Details.
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
Digital Drawing Submittal: Plans shall be submitted in an AutoCAD format
suitable to OWASA. These requirements for this submittal shall be as specified
in Section 1.5, Close-out Documents.
Cover Sheet
Submitted plans shall have a cover sheet, which contains the following:
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Project Name,
Engineer's Name and Address,
Owner's Name and Address,
Area Map,
Vicinity Map with North Arrow,
Index of Plan Sheets,
Revision Block, and
Index Sheet.
Overall Plan
Submitted plans shall have an overall map which shall contain all water and
sewer lines, water and sewer services, valves, hydrants, manholes, lot lines,
phase lines, right-of-way limits, and easements. Note: If the intent of the
developer or engineer is to phase the project in order to initiate service to a
select group of buildings or facilities in advance of other units, a separate water
and sewer phasing plan will be required to demonstrate feasibility. This plan
must include and depict water and sewer phasing lines and be acceptable and
suitable to OWASA. Any additional valves or valves required to construct,
temporary blow-offs for water mains, or manholes for sewer lines shall be
installed at the applicant’s expense. Sewer line pipes may not be stubbed to a
dead-end but must terminate at a manhole.
Plan/Profile Sheets
All public water and sewer line extensions shall be shown on both plan and
profile sheets. Plan and profile drawings shall be at a horizontal scale of 1" = 40'
and a vertical scale of 1" = 4' or horizontal scale of 1" = 50' and vertical scale of
1" = 5' or other such scale that is clearly legible and allows for proper review.
The scale shall be identified on all sheets.
All sheets shall have a title, a north arrow, a revision block, and show NC State
Plane grid coordinates in North American Datum, NAD 1983 feet. Assumed
base coordinate systems (i.e. N10,000, E10,000) are not to be used. Assumed
elevations may not be used in preparation of profile or topography information.
Elevations must be correlated to the NC State Plane Coordinate System, NAVD
88 feet vertical datum. Elevations must be to a hundredth of a foot (0.01’). The
design engineer's professional seal, signature, and date shall be imprinted on all
sheets.
Plan/Profile Sheets shall show:

Plan and profile of water and sewer extensions, all above and below ground
utility crossings shall be shown with stationing,
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
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B.
Water service lines and meters and sewer service laterals and clean-outs,
Contour lines at no greater than 2-foot contour intervals and elevations of low
and high points,
Property lines, all public utility easements (OWASA and non-OWASA), public
rights-of-way limits,
Existing and proposed streets,
Structures, plumbing plans,
Streams and water surfaces,
One hundred year flood elevations,
Supplemental drawings which may be needed to provide all information and
additional details necessary to review the project, and
Any other miscellaneous information relevant to the design.
WATER LINE EXTENSION PLANS
All water mains and appurtenances shall be located within public right-of-way or
a dedicated OWASA water easement. If, in the opinion of OWASA’s staff, there
is inadequate distance from the water main to the edge of the right-of-way for
operation and maintenance of the line, OWASA water easement beyond the
right-of-way may be required.
A comprehensive plan of the existing and proposed water system shall be
submitted for review and approval. In addition to items identified in Section 1.2.A
above, the plan shall include the following:
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C.
Services,
Backflow prevention devices: type, size, model, location,
Diameter and material of water mains,
Water meter size and location,
Vault dimensions,
Depth of cover,
Supplemental fire protection lines (pipe size and material),
Irrigation lines - pipe size and material,
Method and location of connection to existing line,
Valves,
Fire hydrants,
Siamese connections,
Air release valves,
Pressure zone separators, and
Any other water main appurtenance not otherwise identified above.
SEWER LINE EXTENSION PLANS
All sewer mains and appurtenances shall be located within public right-of-way or
a dedicated OWASA water easement. If, in the opinion of OWASA’s staff, there
is inadequate distance from the sewer main to the edge of the right-of-way for
operation and maintenance of the line, OWASA sewer easement beyond the
right-of-way may be required.
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
A comprehensive plan of the existing and proposed sewer system shall be
submitted for review and approval. In addition to items identified in Section 1.2.A
above, the plan shall contain the following:
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1.3
Ground surface elevations,
Pipe diameter and material,
Distance between manholes,
Percent grade of sewer between two consecutive manholes,
Invert elevations (both in and out),
Manhole rim elevations,
Manhole numbers,
Depth of cover,
Concrete encasement location and dimensions,
Carrier pipes,
All known existing and proposed structures and utilities, identify all
clearances between crossings and horizontal spacing,
Stream crossings (normal water level, 25 year flood, 100 year flood) and
aerial sewers, and
Any other sewer main appurtenance not otherwise identified above.
DESIGN AND PLAN APPROVAL
A.
DISCUSS PRELIMINARY DESIGN REQUIREMENTS WITH OWASA
The Applicant should meet with OWASA's Director of Engineering or his
designated representative to determine the availability of water service and
sewer service and the feasibility of extending water service and sewer service to
the proposed project. OWASA design requirements and long-range system
planning considerations will be discussed including line sizes, line routes, and
easement requirements. The Applicant's design must consider both existing and
planned features of OWASA's water distribution and wastewater collection
systems, incorporate OWASA long-range planning considerations, and be in
accordance with State and OWASA design guidelines.
If application is for non-residential, commercial establishment, a statement
indicating the intended use of potable water and type of establishment will be
required. Additionally, a statement will be required indicating the nature of
wastewater discharge to be released must be submitted. If any food handling or
preparation will occur, acknowledgement must be included in this statement.
B.
DISCUSS AVAILABILITY FEES WITH OWASA
The Applicant is encouraged to discuss OWASA Availability and Connection
Fees in the early stages of project planning to determine project budget
implications. Estimates of water and sewer connection fees can be calculated for
the project if the following information is provided to OWASA:
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Tax map identification number,
Pin Number,
Plat with property lines,
Site plan indicating proposed method of water and sewer service,
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS

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Size and number of water meters,
Meter size and number of Commercial, Non-Residential Units, or
Number and square footages of residential structures.
Estimates are based on the project information available at that time and are not
to be considered final. Estimates are based on the Schedule of Rates and Fees
in effect at the time. Should the proposed method of connecting to the OWASA
water system and sewer system change, conditions relevant to the proposed
connection change, or the Schedule of Rates and Fees change, the estimate will
require recalculation.
C.
SUBMIT PRELIMINARY PROJECT PLANS TO LOCAL PLANNING UNIT
AND OWASA
When evaluating development proposals, the Local Planning Unit will usually
consult with OWASA about the availability of water and sewer service and utility
design requirements for the approval of the project. However, if preliminary
plans are not forwarded from the Local Planning Unit to OWASA for review, it is
the responsibility of the Applicant or Applicant’s representative (Engineer or
Architect) to submit plans directly to OWASA for review. Preliminary drawings
should show all existing and proposed water and sewer lines, water and sewer
services, fire hydrants, lot lines, building footprints, easements, right-of-ways,
other utilities, and any other information necessary for OWASA to review the
proposed development.
D.
REVIEW OF PRELIMINARY (ZONING COMPLIANCE) PLANS BY OWASA
OWASA will review the preliminary drawings for compliance with OWASA
extension policies, service policies, design requirements, standards, and
specifications. OWASA will return comments to the Local Planning Unit and
Project Engineer.
E.
PRELIMINARY DESIGN APPROVAL BY OWASA
OWASA will review revised preliminary drawings for compliance with OWASA
Standards and Specifications and changes requested from the previous OWASA
review comment letter.
If preliminary design is approved by OWASA, applicant may request a
conceptual approval letter to be written to the Local Planning Unit. However,
conceptual approval does not constitute approval for construction.
F.
SUBMIT CONSTRUCTION DRAWINGS TO OWASA
To obtain OWASA approval of any project, the Project Engineer shall submit one
set of construction drawings with plan and profile for public water and sewer
extension to OWASA for review and approval. Construction drawings shall be in
accordance with State and OWASA design standards. Failure to comply with
these standards will result in return of the Applicant's drawings without OWASA
review. Upon completion of the review by OWASA, comments will be returned to
the Project Engineer for revisions to the construction drawings.
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
At this time a Project Fact Sheet, Certification of Compliance, and a
NCDENR/DWQ Fast-track sewer application (if applicable) will be sent to the
Project Engineer for completion.
G.
CONSTRUCTION DESIGN APPROVAL BY OWASA
OWASA will review the revised construction drawings for compliance with
OWASA Standards and Specifications and changes requested from the previous
OWASA comment letter. All changes or modifications to construction drawings
resubmitted to OWASA shall be clearly indicated or the submittal will be returned.
Plans submitted with modifications or changes other than those required by
OWASA are subject to a complete second review and payment of additional plan
review fees.
H.
SUBMIT PROJECT FACT SHEET
The project fact sheet must be completed and returned to OWASA upon
completion of the water and sewer design. OWASA will calculate the plan review
and construction observation fees, which must be paid before construction
drawings are approved.
I.
RECORDED ON-SITE and OFF-SITE DEEDS OF EASEMENT
Occasionally, to serve a project, water and sewer line extensions must be
constructed across properties not owned by the project Owner. Deeds of
easement are required for all water and sewer lines and appurtenances not
located within a public right-of-way. The acquisition of all on-site and off-site
easements by the Applicant should start as early in the planning process as
possible. Prior to recordation all easements documents shall be submitted to
OWASA for review. All on-site and off-site plats and deeds of easement for the
project shall be recorded and submitted to OWASA prior to construction
approval. OWASA cannot approve development plans without recorded on-site
and off-site easements. Contact the OWASA Engineering Department to obtain a
copy of the OWASA deed of easement. OWASA standard deed of easement
forms must be used.
J.
PROJECT CONSTRUCTION DRAWINGS APPROVAL
Upon receipt of four sets of construction drawings (and one reduced size set)
with only those changes required by OWASA modified, payment of the plan
review and construction observation fees, return of the Certification of
Compliance, three plan sets for NCDENR/DEH water permit, return of the
completed NCDENR/DWQ Fast-track sewer application with an approved
NCDENR Watershed Classification Attachment, and check payable to NCDENR
in the amount of $480.00, an approval letter will be written by OWASA. The
letter will outline conditions of approval specific to the project.
OWASA will prepare the NCDENR/DEH water permits, when required, and
submit to the State with the three provided plan sets and a check in the amount
of the fee as appropriate. OWASA will also submit the NCDENR DWQ Fasttrack sewer application with the Watershed Classification and $480.00 check.
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
K.
PROJECT DRAWINGS, APPLICATIONS, AND APPLICATION FEES ARE
SUBMITTED TO STATE REGULATORY AGENCIES BY OWASA
OWASA will submit the water and/or sewer line extension applications to DEH
and DWQ. A copy of the OWASA letter of transmittal that accompanies the
applications will be provided to the Project Engineer by OWASA.
L.
NCDOT RIGHT OF WAY ENCROACHMENT
An NCDOT Three Party Encroachment Agreement (A-2) is required for all water
and sewer lines that encroach within a NCDOT right-of-way. Applicant shall
determine proper number of originals/copies required by NCDOT. The Owner
shall complete and execute under Second Party to the Agreement and will
forward to OWASA for execution. OWASA will sign the agreements as the third
party and return them to the Applicant for submittal to NCDOT.
The Owner must post the required Bond with NCDOT. OWASA must have a
completely executed copy of the encroachment agreement prior to any
work being performed within a NCDOT right-of-way.
If a Town of Chapel Hill or Carrboro road will be disturbed, approval by the Town
is required prior to beginning construction.
M.
DESIGN APPROVAL BY STATE REGULATORY AGENCIES (DWQ, DEH)
The State agencies will notify OWASA in writing of project approval and permit
number. The State will mail a copy of the water and/or sewer line extension
permit to the Project Engineer. Project Engineer is responsible for any additional
information required by the State. All additional required information shall be
copied to OWASA.
N.
FINAL DESIGN APPROVAL BY OWASA
Upon receiving State Regulatory Permits, OWASA will issue water and/or sewer
extension permits with conditions of approval. These permits are valid for one
year. Should water and sewer utility construction not begin within the one-year
period, the Applicant must resubmit the plans and acquire re-approval from
OWASA. All re-submitted plans shall be required to meet current Standard and
Specification at time of re-submittal, additionally; all appropriate review fees must
be paid again. If the State permits have expired, new permits must be issued
before water and sewer construction may begin.
1.4
CONSTRUCTION
A. PRECONSTRUCTION CONFERENCE
A preconstruction conference must be held with an OWASA Inspector before
construction may begin. The Applicant shall contact an OWASA Inspector to
schedule a preconstruction conference.
The Owner/Developer, Project
Engineer, Contractor, and appropriate Town personnel shall attend the
preconstruction conference.
The OWASA Inspector will discuss what is
expected of the Contractor and inspection procedure and answer questions
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
pertaining to construction. The Inspector shall provide a list of preconstruction
comments that the Owner or Owner’s Representative, Project Engineer, and
Contractor are to acknowledge receipt of by signature.
B. BEGIN CONSTRUCTION
Work on the project shall not begin until final design approval is granted and a
preconstruction conference is held. Any work completed prior to OWASA final
design approval is subject to rejection by OWASA.
Following the preconstruction meeting, OWASA’s Inspector shall be notified at
least 72 hours before the project's utility work commences. If notification is not
provided, the Contractor shall be responsible for uncovering and/or removing
lines installed prior to OWASA inspection. The Applicant will be responsible for
all costs associated with verifying compliance with OWASA standards.
All permits required for the project must be kept valid. If construction is not
started within the timeframe provided on the permits, the Applicant shall resubmit
plans to OWASA for approval.
Only OWASA personnel shall make taps to public water lines and sewer lines.
Taps will be made by OWASA after the OWASA Customer Service Department
has received payment of the tap fees. Contact the OWASA Engineering
Department to have a fee schedule calculated. Tap fees will not be accepted
until final design approval is granted by OWASA and a preconstruction
conference is held with an OWASA Inspector. Notice of 48 hours shall be given
to OWASA's Operations Department in order to schedule the tap. The trench
must be open and dewatered with shoring in-place, materials on-site, and traffic
control devices in-place for OWASA personnel to perform the tap.
C. CONSTRUCTION INSPECTION
The Project Engineer is responsible for conducting all necessary inspection of
utility construction to ensure compliance with the approved plans. An OWASA
Inspector will make periodic inspections of the utility construction to verify
compliance with OWASA Standards and Specifications and the approved project
drawings. OWASA Inspector will not provide any engineer’s certification of
project. It is the responsibility of the Applicant’s engineer to provide proper
observation of construction.
If any conflicts arise, they will be brought to the attention of the OWASA
Inspector and Engineer’s on-site representative. These issues will be discussed
and resolved between these parties to the satisfaction of OWASA. If the conflicts
cannot be resolved in this manner, the Project Engineer will be so advised and
will be required to submit a proposal to OWASA for resolution of any conflicts.
OWASA’s Director of Engineering or authorized representative must approve any
proposal or changes to the approved plans before making any changes in the
field.
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
D. PRESSURE, VACUUM, AND BACTERIOLOGICAL TESTS
Water mains must pass pressure and purity tests. Contractor shall be
responsible for providing dechlorinating devices at his expense prior to any
flushing or sampling. Sewer lines must pass pressure tests and be flashed to
ensure the lines are not deflected. Manholes must pass a vacuum test. The
Contractor shall provide all materials for and perform pressure and vacuum tests.
An OWASA Inspector shall be present to verify all tests. Detailed descriptions of
the testing procedures and requirements can be found in OWASA's "Standard
Specifications for Water Distribution and Wastewater Collection Systems.”
E. PRELIMINARY FINAL INSPECTION
The OWASA Inspector will perform inspections with assistance from the
Contractor. Any items to be completed or changed will be discussed with the
Contractor's representative on the job and, if requested, a written "punch-list" will
be provided to the Contractor.
F. PROVISION OF CONSTRUCTION METERS BY OWASA
Temporary water service for construction may be provided through a one-inch
(1"), two-inch (2”) or three-inch (3") hydrant meter connected to a fire hydrant.
Application for this service must be made to the OWASA Engineering
Department and fees paid to the OWASA Customer Service Department.
Hydrant Meters are subject to priority use and are restricted to a 60-day period.
Service will be provided in accordance with the established policy for temporary
hydrant meters and the OWASA "Schedule of Rates and Fees." Charges for
service related to the provision of temporary hydrant meters and water for
construction purposes will begin when the meter is set.
G. FINAL INSPECTION BY OWASA
The OWASA Inspector will field verify that the water and sewer extensions and
appurtenances have not been damaged or covered during landscaping and
paving. The Inspector will also check to see that all deficiencies listed on the
punch-list have been corrected. The Owner or Owner’s Representative is
responsible for any damage to the water and sewer extensions and
appurtenances throughout the construction process.
1.5
CLOSE-OUT DOCUMENTS
All close-out documents must be submitted in a manner that allows OWASA’s staff
sufficient time to review the documents. OWASA’s staff will return documents that
require revision. Contact the OWASA Engineering Department with questions regarding
close-out document submittals.
Below are close-out submittal requirements
necessary prior to OWASA initiating service to any site:
A.
SUBMIT ENGINEER'S CERTIFICATION OF PUBLIC WATER LINES TO OWASA
Public water mains shall not be placed in service until a letter of “FINAL
ACCEPTANCE” from NCDENR Department of Public Water Supply has been
received by OWASA.The Project Engineer must certify to DEH that the water
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
mains were installed in accordance with the approved plans. The certification
containing the permit number, the Project Engineer's original seal and signature,
and the date must be submitted to OWASA. OWASA will submit the certification
to DEH. OWASA's Standard Engineer's Certification of Public Water System (A7) shall be used (See Forms Section).
B.
SUBMIT ENGINEER'S CERTIFICATION OF PUBLIC SEWER LINES TO OWASA
Public sewer lines shall not be placed in service until the following documents
have been submitted, accepted by OWASA and submitted to DWQ.
The Project Engineer must certify to DWQ that the sewer lines were installed in
accordance with the approved plans. The certification containing the permit
number and the Project Engineer's original seal and signature, and the date must
be submitted to OWASA. OWASA will submit the engineer's certification along
with the record drawings to DWQ. DWQ's certification issued with the permit
shall be used.
C.
SUBMIT RECORDED FINAL PLAT TO OWASA
Plats shall be submitted to OWASA for review prior to recordation. The recorded
final plat shall identify all OWASA easements. This plat will be used to establish
water and sewer accounts for billing purposes and shall include street addresses
and subdivision lot numbers.
D.
SUBMIT ORIGINAL RECORDED DEED OF EASEMENT TO OWASA
The deed of easement shall be submitted to OWASA for review prior to
recordation. This document must be provided before approval of project is
granted. The deed of easement sets forth the conditions of use and rights of the
water and sewer easement.
OWASA's Standard Deed of Easement shall be
recorded for all water and sewer easements. Contact OWASA's Engineering
Department for a copy of OWASA's Standard Deed of Easement or for
assistance in completing the document. This document must include a metes
and bounds description of the relevant water and/or sewer easements and must
be accompanied by an easement exhibit graphically depicting or representing the
surveyed description.
OWASA will review recorded easements to verify the water lines, sewer lines,
and appurtenances were constructed within the boundaries of the recorded
easements.
E.
SUBMIT LETTER OF DEDICATION TO OWASA
The letter of dedication transfers ownership of the water and sewer lines
constructed for the project from the Owner to OWASA. The dedication letter
must reference the recorded plat, approved construction plan title and date, and
the Project Engineer. OWASA's Standard Dedication Form (A-5) shall be used
(see Forms Section). OWASA will not assume ownership and initiate service to
any system constructed that has not been legally dedicated and rights of
ownership conveyed to OWASA.
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
F.
SUBMIT ASSET EVALUATION FORM TO OWASA
The asset evaluation form provides information on the value of the water and
sewer utilities dedicated to OWASA. The asset evaluation from should include
only the value of the lines and appurtenances dedicated to OWASA. The cost of
water service lines beyond the meters, private fire lines, and sewer service
laterals should not be included on the asset evaluation form. OWASA's Standard
Asset Evaluation Form (A-6) shall be used (see Forms Section) for reporting this
information.
G.
SUBMIT RECORD DRAWINGS TO OWASA FOR REVIEW
Record or "as-built" drawings provide information regarding location and
attributes of the water and sewer systems installed. This information is essential
for the maintenance, repair, and operation of the water distribution and
wastewater collection systems. Prior to placing sewer lines in-service, a set of
record drawings must be submitted to DWQ, along with the engineer's
certification of public sewer. OWASA will submit record drawings to DWQ. Blue
line or similar prints should be submitted for review prior to submitting
reproducible mylar drawings. Record drawings must be submitted with sufficient
lead-time to allow OWASA to review the drawings.
Record Drawings
Record drawings shall have a cover sheet with a vicinity map showing the project
location. If the project was developed in phases, all phase lines shall be clearly
indicated.
Record drawings shall show street names, right-of-way limits and easements,
pipe material, pipe diameter, slope, manhole rim elevations, and invert
elevations.
Record drawings shall include a seal, signature, and statement by the Project
Engineer attesting to the accuracy of the drawings.
Record drawings shall have all bends, fittings, valves, and appurtenances tied to
two fixed objects.
H.
SUBMIT ELECTRONIC FILES TO OWASA
Electronic files of all drawings shall be submitted to OWASA. These files shall be
delivered on a diskette or a CD and shall be in an AutoCAD format suitable to
OWASA with a .dwg extension.
I.
SUBMIT MANHOLE DATABASE TO OWASA
The manhole database provides information about the location and attributes of
sanitary sewer manholes. Manhole database shall be submitted for all new
manholes and all existing manholes modified for the project. Surveys for
manhole database shall use State Plane NAD 1983 feet horizontal datum.
Elevations shall use State Plane NAVD 1988 to the hundredth of a foot. All
survey information must be performed by a licensed surveyor. OWASA’s
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
standard database can be obtained from the engineering department or on line at
www.owasa.org
J.
SUBMIT OPERATION AND MAINTENANCE MANUALS TO OWASA
The operation, maintenance, and service manuals (O&M) for each piece of
equipment shall be provided to OWASA prior to startup. Three copies of the
O&M manuals shall be submitted. The manuals shall be specific to the
equipment supplied.
The manuals shall include: parts list (including
recommended spare parts list), guaranties, recommended maintenance
instructions, recommended lubricants and lubrication instructions, detailed
description of operating procedures for the item of equipment written specifically
for this installation (including start-up and shut-down procedures), equipment
performance specifications (including pump curves), and results of start-up and
any further recommendations resulting from start-up. The O&M manual shall
include a summary of all preventive maintenance and lubrication.
K.
SUBMIT LETTER OF CREDIT TO OWASA
The letter of credit ensures any warranty work required within the one-year
warranty period will be completed. If the Contractor does not correct any
deficiencies that develop within the warranty period, the letter of credit will be
used by OWASA to correct the problems. OWASA's Standard Letter of Credit
(A-9) shall be used.
1.6
TENTATIVE ACCEPTANCE AND BEGINNING OF ONE-YEAR WARRANTY
Upon acceptance of all documents by OWASA and completion of a final inspection,
OWASA will grant tentative acceptance of the water and/or sewer lines constructed for
the project. OWASA will write a letter of tentative acceptance to the Project Engineer.
This letter will begin the one-year warranty period. Any emergency repair of the lines by
OWASA during the one-year warranty period will be billed to the Owner.
1.7
PAYMENT OF FEES AND SETTING OF METERS
A.
CALCULATION OF AVAILABILITY FEES BY OWASA
The following information must be provided to the OWASA Engineering
Department for availability fees to be calculated:
Applicant's Name
Telephone Number
Complete Service Address
Complete Billing Address
Tax Map Identification Number
(TMBL)
Parcel Identification Number (PIN)
Building Permit or plans showing
square
footage
of
residential
structures.
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April 2015
County
Subdivision Name
Subdivision Lot Number
Water Meter Size
Residential/Nonresidential
Single Family/Duplex/Multi-Family
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
B.
PAY AVAILABILITY FEES TO OWASA CUSTOMER SERVICE DEPARTMENT
FOR SERVICE INITIATION
Fees for service initiation are to be paid to OWASA Customer Service
Department. Fees will be accepted only after all above items are completed.
If the Applicant does not request meter installation within six (6) months of
payment, the fees will be refunded without interest.
C.
SETTING OF WATER METERS
.
All water meters are to be purchased from OWASA. The water meter is
purchased at the time availability fees are paid by the Applicant. Meters that are
2-inches and smaller shall be delivered and set by OWASA. . Depending on
workload and schedule, the water meters will be set within three (3) working days
of fee payment for ‘meter only’ installations. A complete water service installation
for a 5/8" or 1" meter requires ten (10) working days from the date of receipt of
payment for OWASA to install the service and set the meter.
A water meter can only be installed in an undamaged clean water meter box.
The water meter box and setter must be free of debris, undamaged, and at the
proper grade. Any damage and/or modification to the water meter box or setter
will be the responsibility of the Applicant.
For meters 3-inches and larger, Contractor shall pick up and install under
supervision of OWASA. Appropriate lead-time for supplying meters shall be
given to OWASA by the Contractor or Owner requesting the water meter.
Meters are tested for accuracy by OWASA and are to be promptly installed by
the Contractor. The Contractor is responsible for providing a meter vault in
accordance with OWASA Standards and Specifications. OWASA will inspect the
water meter installation prior to placing the meter in-service.
No meters will be installed until “Tentative Acceptance” of the lines has been
granted and the appropriate fees paid.
1.8
FINAL ACCEPTANCE
A.
WARRANTY CHECKS AND REPAIRS
The Owner will be responsible for all repairs required on the new water and/or
sewer lines and appurtenances for a period of one year from the date of tentative
acceptance. During this period, written notification of all deficiencies will be
provided to the Owner and the Contractor by OWASA. The Contractor shall
notify an OWASA Inspector when warranty repairs will be made so that
inspections can be made during repairs. If OWASA determines that an
emergency repair must be made, OWASA may make the repair and bill the
Owner.
B.
EXPIRATION OF WARRANTY
Prior to expiration of the one-year warranty period and final acceptance of the
lines by OWASA, an OWASA Inspector will make a warranty inspection. Any
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SECTION 4 – PROCEDURE FOR APPROVAL OF WATER AND/OR SEWER PROJECTS
deficiencies found during this inspection will be noted and a letter sent to the
Owner and Contractor. After the deficiencies have been corrected, the
Contractor should contact an OWASA Inspector to schedule an inspection.
C.
LETTER OF FINAL ACCEPTANCE
If the OWASA Inspector finds that the Contractor has corrected all the
deficiencies identified from the warranty inspection, OWASA will issue final
acceptance. OWASA will write a letter of final acceptance to the Project
Engineer.
END OF SECTION 4
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Section 4 – Procedures for Approval of Water and/or Sewer
Extension Projects - Revision Summary Sheet
Section
No.
Rev
No.
Rev.
Date
By
Reason for change
What Changed
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