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USACE / NAVFAC / AFCEC / NASA
UFGS-26 42 17.00 10 (November 2008)
----------------------------------Preparing Activity: USACE
Superseding
UFGS-26 42 17.00 10 (April 2006)
UNIFIED FACILITIES GUIDE SPECIFICATIONS
References are in agreement with UMRL dated January 2016
**************************************************************************
SECTION TABLE OF CONTENTS
DIVISION 26 - ELECTRICAL
SECTION 26 42 17.00 10
CATHODIC PROTECTION SYSTEM (IMPRESSED CURRENT)
11/08
PART 1
GENERAL
1.1
REFERENCES
1.2
SYSTEM DESCRIPTION
1.2.1
General Requirements
1.2.2
Contractor's Modifications
1.3
SUBMITTALS
1.4
QUALITY ASSURANCE
1.4.1
Services of "Corrosion Expert"
1.4.2
Isolators
1.4.3
Anodes and Bond Wires
1.4.4
Surge Protection
1.4.5
Sacrificial Anodes
1.4.6
Nonmetallic Pipe Systems
1.4.6.1
Coatings
1.4.6.2
Tracer Wire
1.5
DELIVERY, STORAGE, AND HANDLING
1.6
EXTRA MATERIALS
PART 2
PRODUCTS
2.1
IMPRESSED CURRENT ANODES
2.1.1
Bare High Silicon Cast-Iron Anodes
2.1.1.1
Chemical Composition (Nominal)
2.1.1.2
Electrical Resistivity
2.1.1.3
Physical Properties (Nominal)
2.1.2
Bare Graphite Anodes
2.1.3
Canister Contained Anodes
2.1.4
Anode Connecting Cables
2.1.5
Mixed Metal Oxide Anodes
2.1.5.1
Conductive Material
2.1.5.2
Anode Life Test
2.1.5.3
Canister Contained Mixed Metal Oxide Anodes
2.1.5.4
Anode Connecting Cables
2.1.5.5
Canister Connection Cables
2.1.5.6
Deep Anode Connection Cables
SECTION 26 42 17.00 10
Page 1
2.2
RECTIFIERS AND ASSOCIATED EQUIPMENT
2.2.1
Rectifier Unit
2.2.1.1
Transformer
2.2.1.2
Rectifiers
2.2.1.3
Meters
2.2.1.4
Circuit Breaker
2.2.1.5
Fuses
2.2.2
Cabinet Construction
2.2.2.1
Wiring Diagram
2.2.2.2
Grounding Provisions
2.2.2.3
Resistance to Ground
2.2.2.4
Cabinet Paint System
2.2.3
Wiring
2.2.4
Oil Immersed Enclosures
2.3
COKE BREEZE
2.3.1
Calcined Petroleum Coke Breeze (Dry)
2.3.1.1
Electrical Resistivity
2.3.1.2
General Backfill Specifications
2.3.2
Metallurgical Coke Breeze (Processed)
2.3.2.1
Electrical Resistivity (Nominal)
2.3.2.2
General Backfill Specifications
2.4
MISCELLANEOUS MATERIALS
2.4.1
Electrical Wire
2.4.1.1
Anode Connecting Wire
2.4.1.2
Anode Header Cable
2.4.1.3
Test Wires
2.4.1.4
Resistance Wire
2.4.2
Deep Anode Ground Bed Casing
2.4.3
Anode Centering Device for Deep Anode Ground Beds
2.4.4
Conduit
2.4.5
Test Boxes and Junction Boxes
2.4.6
Vent Pipes
2.4.7
Polyethylene Insulation
2.4.7.1
High Molecular Weight Polyethylene
2.4.7.2
High Density Polyethylene
2.4.8
Test Stations
2.4.9
Calibrated Shunts
2.4.10
Sealing and Dielectric Compound
2.4.11
Protective Covering
2.4.11.1
Pipeline Metallic Components
2.4.11.2
Field Joints
2.4.11.3
Inspection of Pipe Coatings
2.4.11.4
Above Ground Piping System
2.4.12
Preformed Sheaths
2.4.13
Epoxy Potting Compound
2.4.14
Backfill Shields
2.4.15
Electrical Tape
2.4.16
Cable Marker Tape
2.4.17
Electrically Isolating Pipe Joints
2.4.17.1
Threaded Fittings
2.4.17.2
Electrically Isolating Pipe Joints
2.4.18
Electrically Conductive Couplings
2.4.19
Joint and Continuity Bonds
2.4.19.1
Resistance Bonds
2.4.19.2
Stray Current Measurements
2.4.20
Electrical Isolation of Structures
2.5
MAGNESIUM ANODES
2.5.1
Composition
2.5.2
Packaged Anodes
SECTION 26 42 17.00 10
Page 2
2.5.3
Lead Wires
2.5.4
Connection Wires
2.5.5
Insulation
2.5.6
Conduit Steel
2.5.7
Tape
2.5.8
Backfill Shields
2.5.9
Electrical Connections
2.5.10
Anode Installation
2.6
LEAD WIRE CONNECTIONS
PART 3
EXECUTION
3.1
CRITERIA OF PROTECTION
3.1.1
Iron and Steel
3.1.2
Aluminum
3.1.3
Copper Piping
3.2
GROUND BED INSTALLATION
3.2.1
Shallow Ground Beds
3.2.1.1
Horizontally Buried Bare Anodes
3.2.1.2
Vertically Buried Bare Anodes
3.2.1.3
Horizontally Buried Canister-Contained Anodes
3.2.1.4
Vertically Buried Canister-Contained Anodes
3.2.1.5
Cable Protection
3.2.1.6
Multiple Anode Systems
3.2.1.7
Distributed Anode Systems
3.2.2
Deep Anode Ground Beds
3.2.2.1
Anode Centering
3.2.2.2
Casing
3.2.2.3
Casing Insulation
3.2.2.4
Anode Requirements
3.2.2.5
Anode Lead Wire
3.2.2.6
Anode Cables
3.2.2.7
Anode and Cable Installation
3.2.2.8
Backfill
3.2.2.9
Cable Marker Tape
3.2.2.10
Pavement Inserts
3.3
MAGNESIUM ANODE INSTALLATION
3.3.1
Installation of Packaged Anodes
3.3.2
Underground Metal Pipe Line
3.3.3
Lead and Resistance Wire Splices
3.3.4
Magnesium Anodes for Metallic Components
3.4
MISCELLANEOUS INSTALLATION
3.4.1
Rectifier Installation
3.4.2
Wire Connections
3.4.2.1
Wire Splicing
3.4.2.2
Steel Surfaces
3.4.3
Pipe Joints
3.4.3.1
Electrical Continuity
3.4.3.2
Electrical Isolation of Structures
3.4.3.2.1
Isolating Fittings
3.4.3.2.2
Gas Distribution Piping
3.4.3.2.3
[Steam] [High Temperature] [Chilled] [Water] [Line
Supply and Return Piping] [Line Conduit]
3.4.3.2.4
[Fuel] [Gasoline] [Storage Tanks] [Fire Suppression]
[_____]
3.4.3.2.5
Copper Piping
3.4.3.2.6
Underground Storage Tanks (UST)
3.4.4
Dissimilar Metals
3.4.5
Ferrous Valves
SECTION 26 42 17.00 10
Page 3
3.4.6
Brass or Bronze Valves
3.4.7
Metal Pipe Junction
3.4.8
Casing
3.4.9
Test Stations
3.5
TRAINING COURSE
3.6
TESTS AND MEASUREMENTS
3.6.1
Baseline Potentials
3.6.2
Isolation Testing
3.6.2.1
Insulation Checker
3.6.2.2
Cathodic Protection Meter
3.6.3
Anode Output
3.6.4
Electrode Potential Measurements
3.6.5
Location of Measurements
3.6.5.1
Coated Piping or Conduit
3.6.5.2
Underground Tanks
3.6.6
Casing Tests
3.6.7
Interference Testing
3.6.8
Holiday Test
3.6.9
Recording Measurements
-- End of Section Table of Contents --
SECTION 26 42 17.00 10
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**************************************************************************
USACE / NAVFAC / AFCEC / NASA
UFGS-26 42 17.00 10 (November 2008)
----------------------------------Preparing Activity: USACE
Superseding
UFGS-26 42 17.00 10 (April 2006)
UNIFIED FACILITIES GUIDE SPECIFICATIONS
References are in agreement with UMRL dated January 2016
**************************************************************************
SECTION 26 42 17.00 10
CATHODIC PROTECTION SYSTEM (IMPRESSED CURRENT)
11/08
**************************************************************************
NOTE: This guide specification covers the
requirements for a cathodic protection system using
impressed current anodes.
Adhere to UFC 1-300-02 Unified Facilities Guide
Specifications (UFGS) Format Standard when editing
this guide specification or preparing new project
specification sections. Edit this guide
specification for project specific requirements by
adding, deleting, or revising text. For bracketed
items, choose applicable items(s) or insert
appropriate information.
Remove information and requirements not required in
respective project, whether or not brackets are
present.
Comments, suggestions and recommended changes for
this guide specification are welcome and should be
submitted as a Criteria Change Request (CCR).
**************************************************************************
PART 1
1.1
GENERAL
REFERENCES
**************************************************************************
NOTE: This paragraph is used to list the
publications cited in the text of the guide
specification. The publications are referred to in
the text by basic designation only and listed in
this paragraph by organization, designation, date,
and title.
Use the Reference Wizard's Check Reference feature
when you add a RID outside of the Section's
Reference Article to automatically place the
reference in the Reference Article. Also use the
Reference Wizard's Check Reference feature to update
the issue dates.
SECTION 26 42 17.00 10
Page 5
NEMA TC 2
(2013) Standard for Electrical Polyvinyl
Chloride (PVC) Conduit
NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)
NFPA 70
(2014; AMD 1 2013; Errata 1 2013; AMD 2
2013; Errata 2 2013; AMD 3 2014; Errata
3-4 2014; AMD 4-6 2014) National
Electrical Code
U.S. NATIONAL ARCHIVES AND RECORDS ADMINISTRATION (NARA)
40 CFR 280
Technical Standards and Corrective Action
Requirements for Owners and Operators of
Underground Storage Tanks (UST)
49 CFR 192
Transportation of Natural and Other Gas by
Pipeline: Minimum Federal Safety Standards
49 CFR 195
Transportation of Hazardous Liquids by
Pipeline
UNDERWRITERS LABORATORIES (UL)
UL 467
(2007) Grounding and Bonding Equipment
UL 506
(2008; Reprint Oct 2013) Specialty
Transformers
UL 510
(2005; Reprint Jul 2013) Polyvinyl
Chloride, Polyethylene and Rubber
Insulating Tape
UL 514A
(2013) Metallic Outlet Boxes
UL 6
(2007; Reprint Nov 2014) Electrical Rigid
Metal Conduit-Steel
1.2
SYSTEM DESCRIPTION
Submit proof that the materials and equipment furnished under this section
conform to the specified requirements contained in the referenced standards
or publications. The label or listing by the specified agency will be
acceptable evidence of such compliance.
1.2.1
a.
General Requirements
Provide a complete, operating impressed current cathodic protection
system in accordance with NFPA 70, the applicable federal, state and
local regulations, and the requirements of this contract. In addition
to the minimum requirements of these specifications, [construction of
gas pipelines and associated cathodic protection systems shall be in
compliance with 49 CFR 192] [and] [construction of hazardous liquid
pipelines, and associated cathodic protection system shall be in
compliance with 49 CFR 195] [and] [construction and installation of
underground fuel storage tanks and associated cathodic protection
system shall be in compliance with 40 CFR 280].
SECTION 26 42 17.00 10
Page 7
NEMA TC 2
(2013) Standard for Electrical Polyvinyl
Chloride (PVC) Conduit
NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)
NFPA 70
(2014; AMD 1 2013; Errata 1 2013; AMD 2
2013; Errata 2 2013; AMD 3 2014; Errata
3-4 2014; AMD 4-6 2014) National
Electrical Code
U.S. NATIONAL ARCHIVES AND RECORDS ADMINISTRATION (NARA)
40 CFR 280
Technical Standards and Corrective Action
Requirements for Owners and Operators of
Underground Storage Tanks (UST)
49 CFR 192
Transportation of Natural and Other Gas by
Pipeline: Minimum Federal Safety Standards
49 CFR 195
Transportation of Hazardous Liquids by
Pipeline
UNDERWRITERS LABORATORIES (UL)
UL 467
(2007) Grounding and Bonding Equipment
UL 506
(2008; Reprint Oct 2013) Specialty
Transformers
UL 510
(2005; Reprint Jul 2013) Polyvinyl
Chloride, Polyethylene and Rubber
Insulating Tape
UL 514A
(2013) Metallic Outlet Boxes
UL 6
(2007; Reprint Nov 2014) Electrical Rigid
Metal Conduit-Steel
1.2
SYSTEM DESCRIPTION
Submit proof that the materials and equipment furnished under this section
conform to the specified requirements contained in the referenced standards
or publications. The label or listing by the specified agency will be
acceptable evidence of such compliance.
1.2.1
a.
General Requirements
Provide a complete, operating impressed current cathodic protection
system in accordance with NFPA 70, the applicable federal, state and
local regulations, and the requirements of this contract. In addition
to the minimum requirements of these specifications, [construction of
gas pipelines and associated cathodic protection systems shall be in
compliance with 49 CFR 192] [and] [construction of hazardous liquid
pipelines, and associated cathodic protection system shall be in
compliance with 49 CFR 195] [and] [construction and installation of
underground fuel storage tanks and associated cathodic protection
system shall be in compliance with 40 CFR 280].
SECTION 26 42 17.00 10
Page 7
b.
The system includes planning, inspecting the installation, adjusting
and testing cathodic protection and test system using rectifiers and
impressed current anodes, supplemented with sacrificial anodes as
needed, for utilities and equipment shown. The cathodic protection
system shall also include cables, connectors, splices, corrosion
protection test stations, ace power panels, and any other equipment
required for a complete operating system providing the specified
protection. The cathodic protection system includes (a) calculations
for rectifier, anodes, and any recommendations for supplementing or
changing the minimum design criteria to provide the specified
potentials and (b) equipment, wiring, and wiring devices necessary to
produce a continuous flow of direct current from anodes in the soil
electrolyte to the pipe surfaces.
c. Submit [6] [_____] copies of Detail Drawings consisting of a
complete list of equipment and material including manufacturer's
descriptive and technical literature, catalog cuts, results of system
design calculations including soil resistivity, installation
instructions and certified test data stating the maximum recommended
anode current output density and the rate of gaseous production, if
any, at that current density. Detail drawings shall contain complete
wiring and schematic diagrams and any other details required to
demonstrate that the system has been coordinated and will function
properly as a unit. The installation shall meet the specified
protection criteria for a 25 year life.
d. Submit [6] [_____] copies of operating manual outlining the
step-by-step procedures required for system startup, operation,
adjustment of current flow, and shutdown. The manuals shall include
the manufacturer's name, model number, service manual, parts list, and
brief description of all equipment and their basic operating features.
e Submit [6] [_____] copies of maintenance manual listing routine
maintenance procedures, recommendation for maintenance testing,
possible breakdowns and repairs, and troubleshooting guides. The
manuals shall include single line diagrams for the system as installed;
instructions in making [pipe-] [tank-] to-reference cell potential
measurements and frequency of monitoring; instructions for dielectric
connections, interference and sacrificial anode bonds; instructions
shall include precautions to ensure safe conditions during repair of
pipe system.
1.2.2
Contractor's Modifications
The specified system is based on an impressed current system supplemented
with magnesium anodes. The Contractor may modify the cathodic protection
system after review of the project, site verification and analysis if the
proposed modifications include the impressed current anodes and rectifiers
and will provide better overall system performance.
a.
Submit [6] [_____] copies of detail drawings showing proposed changes
in location, scope or performance indicating any variations from,
additions to, or clarifications of contract drawings. The drawings
shall show proposed changes in anode arrangement, anode size and
number, anode materials and layout details, conduit size, wire size,
mounting details, wiring diagram, method for electrically isolating
each pipe, and any other pertinent information to the proper
installation and performance of the system.
SECTION 26 42 17.00 10
Page 8
b.
The modifications shall be fully described, shall be approved by the
Contracting Officer and shall meet the following criteria. The
proposed system shall achieve a minimum pipe-to-soil "Instant Off"
potential of minus 850 millivolts with reference to a saturated
copper-copper sulfate reference cell on the underground metallic
components of the [piping] [tanks] [_____].
c.
Take resistivity measurements of the soil in the vicinity of the
[pipes] [tanks] [_____] and ground bed sites; based upon the
measurements taken, adjust current and voltage of the rectifier as
required to produce a minimum of minus 850 millivolts "Instant Off"
potential between the structure being tested and the reference cell.
This potential shall be obtained over 95 percent of the metallic area
without the "Instant Off" potential exceeding 1200 millivolts.
d.
Submit final report regarding supplemental magnesium anode
installation. The report shall include pipe-to-soil measurements
throughout the affected area, indicating that the additions corrected
the conditions which made the additional anodes necessary, and current
measurements for the additional anodes. The following special
materials and information are required: Calculations on current and
voltage for [100 V] [40 V] [_____] rectifier plus rectifier and meter
specifications; taping materials and conductors; zinc grounding cell,
installation and testing procedures, and equipment; coating material;
system design calculations for rectifier, anode number, life, and
parameters to achieve protective potential; backfill shield material
and installation details showing waterproofing; bonding and
waterproofing details; insulated resistance wire; exothermic weld
equipment and material.
1.3
SUBMITTALS
**************************************************************************
NOTE: Review submittal description (SD) definitions
in Section 01 33 00 SUBMITTAL PROCEDURES and edit
the following list to reflect only the submittals
required for the project.
The Guide Specification technical editors have
designated those items that require Government
approval, due to their complexity or criticality,
with a "G." Generally, other submittal items can be
reviewed by the Contractor's Quality Control
System. Only add a “G” to an item, if the submittal
is sufficiently important or complex in context of
the project.
For submittals requiring Government approval on Army
projects, a code of up to three characters within
the submittal tags may be used following the "G"
designation to indicate the approving authority.
Codes for Army projects using the Resident
Management System (RMS) are: "AE" for
Architect-Engineer; "DO" for District Office
(Engineering Division or other organization in the
District Office); "AO" for Area Office; "RO" for
Resident Office; and "PO" for Project Office. Codes
following the "G" typically are not used for Navy,
Air Force, and NASA projects.
SECTION 26 42 17.00 10
Page 9
An "S" following a submittal item indicates that the
submittal is required for the Sustainability
Notebook to fulfill federally mandated sustainable
requirements in accordance with Section 01 33 29
SUSTAINABILITY REPORTING.
Choose the first bracketed item for Navy, Air Force
and NASA projects, or choose the second bracketed
item for Army projects.
**************************************************************************
Government approval is required for submittals with a "G" designation;
submittals not having a "G" designation are for [Contractor Quality Control
approval.] [information only. When used, a designation following the "G"
designation identifies the office that will review the submittal for the
Government.] Submittals with an "S" are for inclusion in the
Sustainability Notebook, in conformance to Section 01 33 29 SUSTAINABILITY
REPORTING. Submit the following in accordance with Section 01 33 00
SUBMITTAL PROCEDURES:
SD-02 Shop Drawings
Detail Drawings; G[, [_____]]
Contractor's Modifications; G[, [_____]]
SD-03 Product Data
Miscellaneous Materials; G[, [_____]]
Spare Parts
SD-06 Test Reports
Tests and Measurements
Contractor's Modifications; G[, [_____]]
SD-07 Certificates
Tests and Measurements
Cathodic Protection System
Services of "Corrosion Expert"; G[, [_____]]
SD-10 Operation and Maintenance Data
Cathodic Protection System; G[, [_____]]
Training Course; G[, [_____]]
1.4
1.4.1
QUALITY ASSURANCE
Services of "Corrosion Expert"
Obtain the services of a "corrosion expert" to supervise, inspect, and test
the installation and performance of the cathodic protection system.
"Corrosion expert" refers to a person, who, by reason of thorough knowledge
of the physical sciences and the principles of engineering and mathematics,
acquired by professional education and related practical experience, is
qualified to engage in the practice of corrosion control of buried metallic
piping and tank systems.
SECTION 26 42 17.00 10
Page 10
a.
Such a person shall be accredited or certified by the National
Association of Corrosion Engineers (NACE) as a NACE Accredited
Corrosion Specialist or a NACE certified Cathodic Protection (CP)
Specialist or be a registered professional engineer who has
certification or licensing that includes education and experience in
corrosion control of buried or submerged metallic piping and tank
systems, if such certification or licensing includes 5 years experience
in corrosion control on underground metallic surfaces of the type under
this contract.
b.
Submit the "corrosion expert's" name and qualifications certified in
writing to the Contracting Officer prior to the start of construction,
including the name of the firm, the number of years of experience, and
a list of not less than five of the firm's installations three or more
years old that have been tested and found satisfactory.
c.
The "corrosion expert" shall make at least 3 visits to the project
site. The first of these visits shall include obtaining soil
resistivity data, acknowledging the type of pipeline coatings to be
used and reporting to the Contractor the type of cathodic protection
required. Once the submittals are approved and the materials
delivered, the "corrosion expert" shall revisit the site to ensure the
Contractor understands installation practices and laying out the
components. The third visit shall involve testing the installed
cathodic protection systems and training applicable personnel on proper
maintenance techniques. The "corrosion expert" shall supervise
installation and testing of all cathodic protection.
1.4.2
Isolators
Isolators are required to isolate the indicated pipes from any other
structure. Isolators shall be provided with lightning protection and a
test station as shown.
1.4.3
Anodes and Bond Wires
Install anodes in sufficient number and of the required type, size and
spacing to obtain a uniform current distribution of 2.5 milliamperes per
0.09 square meters square foot minimum to underground metal surfaces. For
each cathodic protection system, the metallic components and structures to
be protected shall be made electrically continuous. This shall be
accomplished by installing bond wires between the various structures.
Bonding of existing buried structures may also be required to preclude
detrimental stray current effects and safety hazards. Provisions shall be
included to return stray current to its source without damaging structures
intercepting the stray current. The electrical isolation of underground
facilities in accordance with acceptable industry practice shall be
included under this section.
1.4.4
Surge Protection
Install approved zinc grounding cells or sealed weatherproof lightning
arrestor devices across insulated flanges or fittings installed in
underground piping as indicated on the drawings. The arrestor shall be
gapless, self-healing, solid state type. Zinc anode composition shall
conform to ASTM B418, Type II. Lead wires shall be number 6 AWG copper
with high molecular weight polyethylene (HMWPE) insulation. The zinc
grounding cells shall not be prepackaged in backfill but shall be installed
as detailed on the drawings. Lightning arrestors or zinc grounding cells
SECTION 26 42 17.00 10
Page 11
explosion-proof or dust-ignition-proof housing, as
appropriate. Transformer tap adjusters will be
provided in cases where an automatic system is not
provided.
**************************************************************************
Rectifier unit shall consist of a transformer, rectifying elements,
transformer tap adjuster, terminal block, [one dc output voltmeter, one dc
output ammeter,] [one combination volt-ammeter,] one toggle switch for each
meter, fuse holders with fuses for each dc circuit, variable resistors, an
ac power-supply circuit breaker, lightning arresters for both input and
output, all wired and assembled in a weatherproof cabinet. The overall
efficiency of the rectifier shall be not less than 65 percent when operated
at nameplate rating and shall be capable of supplying continuous full rated
output at an ambient temperature of 44 degrees C 112 degrees F in full
sunlight with expected life in excess of 10 years.
2.2.1.1
Transformer
Transformer shall conform to UL 506.
2.2.1.2
Rectifiers
**************************************************************************
NOTE: Below about 500 volt-amperes of dc rating
output, single phase selenium rectifiers cost less
to acquire and operate than silicon rectifiers.
Above 1000 volt-amperes silicon rectifiers are more
economical for both single phase and three phase.
Silicon rectifiers are more economical to repair.
**************************************************************************
Rectifying elements shall be [silicon diodes] [selenium cells] connected to
provide full-wave rectification. Silicon diodes shall be protected by
selenium surge cells or varistors against over-voltage surges and by
current-limiting devices against over-current surges.
2.2.1.3
Meters
Meters shall be accurate to within plus or minus 2 percent of full scale at
27 degrees C 80 degrees F, and shall possess temperature stability above
and below 27 degrees C 80 degrees F and shall possess temperature stability
above and below 27 degrees C 80 degrees F of at least 1 percent per 5
degrees C 10 degrees F. Separate meters shall be 63.5 mm 2-1/2 inch
nominal size or larger.
2.2.1.4
Circuit Breaker
A [single] [double] [three]-pole, flush-mounted, fully magnetic, properly
rated non-terminal type circuit breaker shall be installed in the primary
circuit of the rectifier supply transformer.
2.2.1.5
Fuses
Cartridge-type fuses with suitable fuse holders shall be provided in each
leg of the dc circuit.
SECTION 26 42 17.00 10
Page 16
2.2.2
Cabinet Construction
Cabinet shall be constructed of [not lighter than 1.56 mm 16 gauge [steel]
[hot dipped galvanized steel] [stainless steel] [aluminum]] [molded
fiberglass reinforced polyester], and shall be provided with a full door.
The enclosure shall have oil-resistant gasket. The door shall be hinged
and have a hasp that will permit the use of a padlock. The cabinet shall
be fitted with screened openings of the proper size to provide for adequate
cooling. Holes, conduit knockouts, or threaded hubs of sufficient size and
number shall be conveniently located.
2.2.2.1
Wiring Diagram
A complete wiring diagram of the power unit showing both the ac supply and
the dc connections to anodes shall be on the inside of the cabinet door.
All components shall be shown and labeled.
2.2.2.2
Grounding Provisions
Grounding provisions shall [be as specified in Section 26 20 00 INTERIOR
DISTRIBUTION SYSTEM.] [comply with NFPA 70 and UL 467 including a ground
terminal in the cabinet.] The grounding conductor from the terminal to the
earth grounding system shall be solid or stranded copper not smaller than
No. 6 AWG. The earth grounding system shall consist of one or more ground
rods. Ground rods shall be of [copper-clad steel conforming to UL 467]
[zinc-coated steel conforming to IEEE C135.30] [solid stainless steel] not
less than [16] [19] mm [5/8] [3/4] inch in diameter by [2.4] [3.1] m [8]
[10] feet in length. Rods shall be driven full length into the earth.
Sectional type rods may be used.
2.2.2.3
Resistance to Ground
**************************************************************************
NOTE: Remove this paragraph if not required in the
project.
**************************************************************************
The resistance to ground shall be measured using the fall-of-potential
method described in IEEE 81. The maximum resistance of driven ground shall
not exceed 25 ohms under normally dry conditions. If this resistance
cannot be obtained with a single rod, [_____] additional rods not less than
1.8 m 6 feet on centers, or if sectional type rods are used, [_____]
additional sections may be coupled and driven with the first rod. In
high-ground-resistance, UL listed chemically charged ground rods may be
used. If the resultant resistance exceeds 25 ohms measured not less than
48 hours after rainfall, the Contracting Officer shall be notified
immediately. Connections below grade shall be fusion welded. Connections
above grade shall be fusion welded or shall use UL 467 approved connectors.
2.2.2.4
Cabinet Paint System
[The cabinet and mounting support shall be [painted] [hot dipped
galvanized] [aluminum] [stainless steel] with the manufacturer's standard
painting system.] [The mounting support for the fiberglass cabinet shall
be [painted] [hot dipped galvanized] [aluminum] [stainless steel] with the
manufacturer's standard painting system.]
SECTION 26 42 17.00 10
Page 17
environments.
**************************************************************************
Cable for anode header and distribution shall be No. [_____] AWG stranded
copper wire with type [CP high molecular weight polyethylene, 2.8 mm 7/64
inch thick insulation] [HMWPE protective jacketed cable with a
fluorocopolymer inner or primary insulation], 600-volt rating.
2.4.1.3
Test Wires
Test wires shall be No. 12 AWG stranded copper wire with NFPA 70 Type TW or
RHW or polyethylene insulation.
2.4.1.4
Resistance Wire
Resistance wire shall be AWG No. [16 or No. 22] [_____] nickel-chromium
wire.
2.4.2
Deep Anode Ground Bed Casing
**************************************************************************
NOTE: A metal casing should not be used except for
a maximum of 1.5 meter 5 feet at the top for a well
cap which also serves as a support for the
suspension ropes. The drilling mud on the sides of
the hole will usually keep the hole open until the
anodes and coke breeze are installed. If a casing
must be used, it should be fiberglass reinforced
plastic (nonmetallic) and should be located above
the anode string.
**************************************************************************
Casing shall be [_____] mm inch outside diameter, 3 mm 1/8 inch minimum
wall thickness black steel pipe, conforming to ASTM A53/A53M, Type E or S,
Grade B. The top casing shall be [_____] mm inch outside diameter, 3 mm
1/8 inch minimum wall thickness black steel pipe, conforming to
ASTM A53/A53M, Type E or S, Grade B. The metal casing shall extend no more
than [1.5] [_____] m [5] [_____] feet below the top of a well cap.
2.4.3
Anode Centering Device for Deep Anode Ground Beds
Anode centering device shall be nonmetallic and capable of maintaining
centering in the hole without interfering with other anode lead wiring,
until coke breeze is packed in place.
2.4.4
Conduit
Nonmetallic conduit shall conform to NEMA TC 2.
2.4.5
Test Boxes and Junction Boxes
Boxes shall be outdoor type conforming to UL 514A.
2.4.6
Vent Pipes
All deep wells shall be vented in anode zones.
not be larger than 0.1524 mm 0.006 inch.
SECTION 26 42 17.00 10
Openings in the vent shall
Page 20
2.4.7
Polyethylene Insulation
Polyethylene insulation shall comply with the requirements of ASTM D1248
and of the following types, classes, and grades:
2.4.7.1
High Molecular Weight Polyethylene
High molecular weight polyethylene shall be Type I, Class C, Grade E5.
2.4.7.2
High Density Polyethylene
High density polyethylene shall be Type III, Class C, Grade E3.
2.4.8
Test Stations
Provide test stations complete with an insulated terminal block having the
indicated number of terminals; provided with a lockable cover and have a
cast-in legend, "C.P. Test" and complete with an insulated terminal block
having the required number of terminals. (One terminal required for each
conductor). Provide sufficient test stations to monitor underground
isolation points. Test-bond stations (potential measurement and stray
current control) shall be provided to monitor pipe to soil potential of
proposed underground pipes or existing underground metallic structures
which may conduct stray current from the new cathodic protection system.
The location of the test-bond stations shall ensure that the pipe to soil
potential of metallic pipe not designated to be protected is not made less
negative by the energization of the cathodic protection system. Test
station terminal connections and the terminal conductor shall be
permanently tagged to identify each termination of the conductors (e.g.
identify the conductors connected to the protected structures). Conductors
shall be permanently identified in the station by means of plastic or metal
tags, or plastic sleeves to indicate termination. Each conductor shall be
color coded in accordance with the drawings. The station test facility,
including permanent Cu-Cu S04 reference cells and test returns shall be
installed as indicated. Pavement inserts shall be nonmetallic and shall
allow Cu-Cu S04 reference electrode to contact the electrolyte beneath the
pavement surface. Abbreviations shall not be used. Welding of electrical
connections shall be as follows: Exothermic welds shall be "CADweld",
"Thermo-weld", or approved equal. Use and selection of these materials and
welding equipment shall be in accordance with the manufacturer's
recommendations.
2.4.9
Calibrated Shunts
Install shunts calibrated in current per potential (e.g. mA/V) between the
lead or header wire connected to the anode and the current collector lead
connected to the structure. The calibration of the shunt shall be clearly
marked and installed to be visible.
2.4.10
Sealing and Dielectric Compound
Sealing and dielectric compound shall be a black, rubber based compound
that is soft, permanently pliable, tacky, moldable, and unbacked. Apply
compound as recommended by the manufacturer, but not less than 3 mm 1/8 inch
thick.
2.4.11
Protective Covering
Except as otherwise specified, protective covering for underground metallic
SECTION 26 42 17.00 10
Page 21
explosion-proof or dust-ignition-proof housing, as
appropriate. Transformer tap adjusters will be
provided in cases where an automatic system is not
provided.
**************************************************************************
Rectifier unit shall consist of a transformer, rectifying elements,
transformer tap adjuster, terminal block, [one dc output voltmeter, one dc
output ammeter,] [one combination volt-ammeter,] one toggle switch for each
meter, fuse holders with fuses for each dc circuit, variable resistors, an
ac power-supply circuit breaker, lightning arresters for both input and
output, all wired and assembled in a weatherproof cabinet. The overall
efficiency of the rectifier shall be not less than 65 percent when operated
at nameplate rating and shall be capable of supplying continuous full rated
output at an ambient temperature of 44 degrees C 112 degrees F in full
sunlight with expected life in excess of 10 years.
2.2.1.1
Transformer
Transformer shall conform to UL 506.
2.2.1.2
Rectifiers
**************************************************************************
NOTE: Below about 500 volt-amperes of dc rating
output, single phase selenium rectifiers cost less
to acquire and operate than silicon rectifiers.
Above 1000 volt-amperes silicon rectifiers are more
economical for both single phase and three phase.
Silicon rectifiers are more economical to repair.
**************************************************************************
Rectifying elements shall be [silicon diodes] [selenium cells] connected to
provide full-wave rectification. Silicon diodes shall be protected by
selenium surge cells or varistors against over-voltage surges and by
current-limiting devices against over-current surges.
2.2.1.3
Meters
Meters shall be accurate to within plus or minus 2 percent of full scale at
27 degrees C 80 degrees F, and shall possess temperature stability above
and below 27 degrees C 80 degrees F and shall possess temperature stability
above and below 27 degrees C 80 degrees F of at least 1 percent per 5
degrees C 10 degrees F. Separate meters shall be 63.5 mm 2-1/2 inch
nominal size or larger.
2.2.1.4
Circuit Breaker
A [single] [double] [three]-pole, flush-mounted, fully magnetic, properly
rated non-terminal type circuit breaker shall be installed in the primary
circuit of the rectifier supply transformer.
2.2.1.5
Fuses
Cartridge-type fuses with suitable fuse holders shall be provided in each
leg of the dc circuit.
SECTION 26 42 17.00 10
Page 16
2.2.2
Cabinet Construction
Cabinet shall be constructed of [not lighter than 1.56 mm 16 gauge [steel]
[hot dipped galvanized steel] [stainless steel] [aluminum]] [molded
fiberglass reinforced polyester], and shall be provided with a full door.
The enclosure shall have oil-resistant gasket. The door shall be hinged
and have a hasp that will permit the use of a padlock. The cabinet shall
be fitted with screened openings of the proper size to provide for adequate
cooling. Holes, conduit knockouts, or threaded hubs of sufficient size and
number shall be conveniently located.
2.2.2.1
Wiring Diagram
A complete wiring diagram of the power unit showing both the ac supply and
the dc connections to anodes shall be on the inside of the cabinet door.
All components shall be shown and labeled.
2.2.2.2
Grounding Provisions
Grounding provisions shall [be as specified in Section 26 20 00 INTERIOR
DISTRIBUTION SYSTEM.] [comply with NFPA 70 and UL 467 including a ground
terminal in the cabinet.] The grounding conductor from the terminal to the
earth grounding system shall be solid or stranded copper not smaller than
No. 6 AWG. The earth grounding system shall consist of one or more ground
rods. Ground rods shall be of [copper-clad steel conforming to UL 467]
[zinc-coated steel conforming to IEEE C135.30] [solid stainless steel] not
less than [16] [19] mm [5/8] [3/4] inch in diameter by [2.4] [3.1] m [8]
[10] feet in length. Rods shall be driven full length into the earth.
Sectional type rods may be used.
2.2.2.3
Resistance to Ground
**************************************************************************
NOTE: Remove this paragraph if not required in the
project.
**************************************************************************
The resistance to ground shall be measured using the fall-of-potential
method described in IEEE 81. The maximum resistance of driven ground shall
not exceed 25 ohms under normally dry conditions. If this resistance
cannot be obtained with a single rod, [_____] additional rods not less than
1.8 m 6 feet on centers, or if sectional type rods are used, [_____]
additional sections may be coupled and driven with the first rod. In
high-ground-resistance, UL listed chemically charged ground rods may be
used. If the resultant resistance exceeds 25 ohms measured not less than
48 hours after rainfall, the Contracting Officer shall be notified
immediately. Connections below grade shall be fusion welded. Connections
above grade shall be fusion welded or shall use UL 467 approved connectors.
2.2.2.4
Cabinet Paint System
[The cabinet and mounting support shall be [painted] [hot dipped
galvanized] [aluminum] [stainless steel] with the manufacturer's standard
painting system.] [The mounting support for the fiberglass cabinet shall
be [painted] [hot dipped galvanized] [aluminum] [stainless steel] with the
manufacturer's standard painting system.]
SECTION 26 42 17.00 10
Page 17
2.2.3
Wiring
Wiring shall be installed in accordance with NFPA 70 utilizing type TW or
RHW or polyethylene insulation. Fittings for conduit and cable work shall
conform to UL 514A. Outlets shall be of the threaded hub type with
gasketed covers. Conduit shall be hub type with gasketed covers. Conduit
shall be securely fastened at 2.4 m 8 foot intervals or less. Splices
shall be made in outlet fittings only. Conductors shall be color coded for
identification. Cable for anode header and distribution shall be No. [2]
[_____] AWG stranded copper wire with type [cathodic protection high
molecular weight polyethylene] [Dular/Halar] insulation.
2.2.4
Oil Immersed Enclosures
**************************************************************************
NOTE: The enclosure should not be used in areas
prone to flooding unless required for hazardous
locations. Provisions should be made for flooding.
**************************************************************************
Enclosures shall be of 3.1 mm 11 gauge steel or heavier, with an accessible
drain plug. The oil level shall be clearly marked. The lid shall be
hinged and have quick release clamps to secure it in closed position. A
stop shall limit the swing of the lid when opened. A compressible, oil
resistant, positive sealing gasket shall be provided. The gasket shall
return to its original shape upon release of lid pressure. The gasket shall
be attached to the tank or lid and joints shall be free of gaps. Base
mounting using 102 mm 4 inch high channels shall be provided. Conduits
entering the enclosure shall be internally sealed and shall enter or exit
above the oil fill line.
2.3
COKE BREEZE
2.3.1
Calcined Petroleum Coke Breeze (Dry)
Breeze shall conform to the following requirements:
2.3.1.1
Electrical Resistivity
Resistivity shall not exceed 1 milliohm-meter (0.1 ohm-cm) Great Lake
Carbon C 12 A Test Method.
2.3.1.2
General Backfill Specifications
Bulk Density - 1044 to 1204 kg/cubic meter 65 to 75 lbs/cubic foot
Fixed Carbon - 99.0 percent or greater
Volatiles - 0.2 percent or less
Sizing - 100 percent less than 13 mm 1/2 inch
2.3.2
Metallurgical Coke Breeze (Processed)
Breeze shall conform to the following requirements:
2.3.2.1
Electrical Resistivity (Nominal)
Nominal electrical resistivity shall be:
a.
100 milliohm-meter (10 ohm-centimeter) Max., tightly compacted.
SECTION 26 42 17.00 10
Page 18
b.
100 milliohm-meter to 150 milliohm-meter, (10 to 15 ohm-centimeter,)
lightly compacted.
c.
150 to 200 milliohm-meter, (15 to 20 ohm-centimeter,) loose.
2.3.2.2
General Backfill Specifications
Bulk density - 608 to 672 kg per cubic meter 38 to 42 pounds per cubic foot
Fixed Carbon - 80 percent or greater
Sizing - 100 percent less than 10 mm 3/8 inch
2.4
MISCELLANEOUS MATERIALS
Within [30] [45] [_____] days after receipt of notice to proceed, submit an
itemized list of equipment and materials including item number, quantity,
and manufacturer of each item. The list shall be accompanied by a
description of procedures for each type of testing and adjustment,
including testing of coating for thickness and holidays. Installation of
materials and equipment shall not commence until this submittal is approved.
2.4.1
2.4.1.1
Electrical Wire
Anode Connecting Wire
**************************************************************************
NOTE: Any pinhole, cut, scratch or other damage to
the anode cable exposing bare copper to the
electrolyte will result in early failure of the
cathodic protection system. For this reason,
special, extra heavy insulation is used on anode
cable. While it is often expedient to use the same
type wire for the cathodic (negative) cable in order
to avoid a mix-up in the field, the cathode cable is
not subject to anodic failure and lesser insulation
can be used.
**************************************************************************
Anode connecting wire shall be No. [8] [_____] AWG stranded copper wire
with type CP high molecular weight polyethylene insulation, 2.8 mm 7/64 inch
thick, 600 volt rating. Cable-to-anode contact resistance shall be 0.003
ohms maximum. Deep anode ground bed connecting wire shall be No. 8 AWG,
stranded copper wire with an inner jacket of 1 mm 40 mils of Halar
insulation covered by an outer jacket of 1.6 mm 65 mils CP high molecular
weight polyethylene insulation, 600 volt rating. Cable-to-anode contact
resistance shall be 0.02 ohms maximum.
2.4.1.2
Anode Header Cable
**************************************************************************
NOTE: The double insulated fluorocopolymer cable is
intended for use in very harsh environments such as
deep anode bed installations where chlorine and
hydrogen gases are generated. This cable can be
installed directly in soil or submerged in fresh,
brackish, or salt waters. The CP high molecular
weight polyethylene cable is also a direct buried
and submergible type cable suitable for harsh
environments, but not as quiet as durable as the
double insulated cable would be in the toughest of
SECTION 26 42 17.00 10
Page 19
entire structure, pipe, tank, or other metallic component to verify and
record achievement of minus 850 millivolts "instant off". This
potential shall be obtained over 95 percent of the total metallic area
without the "instant off" potential exceeding 1200 millivolts.
b.
A minimum polarization voltage shift of 100 millivolts as measured
between the [pipe] [tank] and a saturated copper-copper sulphate
reference electrode contacting the earth directly over the [pipe]
[tank]. This polarization voltage shift shall be determined by
interrupting the protective current and measuring the polarization
decay. When the protective current is interrupted, an immediate
voltage shift will occur. The voltage reading, after the immediate
shift, shall be used as the base reading from which to measure
polarization decay. Measurements achieving 100 millivolts shall be
made over 95 percent of the metallic surface.
3.1.2
Aluminum
Aluminum [pipes] [tanks] shall not be protected to a potential more
negative than minus 1200 millivolts, measured between the [pipe] [tank] and
a saturated copper-copper sulphate reference electrode contacting the
earth, directly over the [pipe] [tank] [metallic component]. Resistance,
if required, shall be inserted in the anode circuit within the test station
to reduce the potential of the aluminum [pipe] [tank] to a value which will
not exceed a potential more negative than minus 1200 millivolts. Voltage
shift criterion shall be a minimum negative polarization shift of 100
millivolts measured between the [pipe] [tank] [metallic component] and a
saturated copper-copper sulphate reference electrode contacting the earth,
directly over the [pipe] [tank]. The polarization voltage shift shall be
determined as outlined for iron and steel.
3.1.3
Copper Piping
For copper piping the following criteria shall apply. A minimum of 100
millivolts of cathodic polarization between the structure surface and a
stable reference electrode contacting the electrolyte. The polarization
voltage shift shall be determined as outlined for iron and steel.
3.2
GROUND BED INSTALLATION
3.2.1
Shallow Ground Beds
Shallow ground beds shall contain size and quantity of anodes designed to
meet performance criteria of the cathodic protection system at an initial
operating current output density not exceeding [40] [50] [70] percent of
maximum recommended current output density.
3.2.1.1
Horizontally Buried Bare Anodes
Horizontally buried bare anodes shall be bedded on and covered with
metallurgical coke breeze in a trench excavated for the purpose at depths,
spacing and locations as shown. Anodes shall be completely surrounded by
the backfill at bottom, sides, and top for a distance of not less than 100
mm 4 inch. Backfill shall be compacted.
3.2.1.2
Vertically Buried Bare Anodes
Vertically buried bare anodes shall be installed in vertical holes in the
ground having a depth, spacing, and location shown. The holes in the
SECTION 26 42 17.00 10
Page 28
3.2.2.4
Anode Requirements
Anode sizes, spacing, number of anodes, depth of well, and other details
shall be as shown.
3.2.2.5
Anode Lead Wire
Each anode shall have a separate, continuous wire extending from the anode
to the junction box at the well head.
3.2.2.6
Anode Cables
Anode cables shall terminate in a nearby junction box, equipped with
individual anode current shunts. Where full length casing is used, two
wire connections from casing shall terminate in the junction box.
3.2.2.7
Anode and Cable Installation
If the method of installation utilizes backfill support for anodes and
cable, provide slack in the cable near each anode and increase the cable
insulation in thickness from 2.8 to 4.0 mm 7/64 to 5/32 inch utilizing an
approved composite of plastic and elastomeric materials.
3.2.2.8
Backfill
Backfill the well with calcined petroleum coke breeze or metallurgical coke
breeze surrounding the anodes by a method that does not leave voids or
bridging. The recommended method is to pump the backfill from the bottom
upward. The well shall be over-filled with coke breeze allowing for
settlement so that the settled level after a number of days is as high as
the level shown. The number of days allowed for settling of the coke
breeze will be determined by the Contracting Officer. If the top level of
coke breeze is below the level shown after settlement, put additional coke
breeze in the well. The backfill used shall not require tamping. The top
portion of the well shall be sealed for 8 m 25 feet to prevent surface
water run-off. All vents shall be vented above the high water mark and at
a safe height.
3.2.2.9
Cable Marker Tape
Locate traceable marker tape in the same trench above cathodic protection
cables including structure leads, anode leads, anode header cables, test
station leads, bonding cables, and rectifier electrical power cables.
3.2.2.10
Pavement Inserts
Install pavement inserts at a minimum of 30 m 100 foot intervals for
pipelines. The pavement inserts shall be installed directly over the
structure being protected and tested.
3.3
MAGNESIUM ANODE INSTALLATION
Installation shall not proceed without the presence of the Contracting
Officer, unless otherwise authorized. Anode locations may be changed to
clear obstructions when approved. Install anodes in sufficient number and
of the required type, size, and spacing to obtain a uniform current
distribution surface on the structure. Prepackaged anodes shall be
installed as shown on the drawings.
SECTION 26 42 17.00 10
Page 30
3.3.1
Installation of Packaged Anodes
Install packaged anodes completely dry, lower them into holes by rope sling
or by grasping the cloth gather. The anode lead wire shall not be used in
lowering the anodes. Backfill the hole with fine soil in 150 mm 6 inch
layers and each layer shall be hand-tamped around the anode. The tamper
shall not strike the anode or lead wire. If immediate testing is to be
performed, add water only after backfilling and tamping has been completed
to a point 150 mm 6 inch above the anode. Approximately 8 L 2 gallons of
water shall be poured into the hole; after the water is absorbed by the
soil, backfilling and tamping shall be completed to the top of the hole.
Anodes shall be installed as shown. When rock is found prior to achieving
specified depth, anode may be installed horizontally to a depth at least as
deep as the bottom of the pipe, with the approval of the Contracting
Officer.
3.3.2
Underground Metal Pipe Line
Install anodes 610 mm 2 feet below the line to be protected unless
otherwise noted on the drawings. To facilitate periodic electrical
measurements during the life of the sacrificial anode system and to reduce
the output current of the anodes if required, anode lead wires in a single
group of anodes shall be buried a minimum of 610 mm 2 feet and each anode
lead wire shall be connected to an individual terminal in a test station.
The anode lead cable shall make contact with the structure only through a
test station. Resistance wire shall be installed between the anode lead
cable and the pipe cable in the test station to reduce the current output,
if required.
3.3.3
Lead and Resistance Wire Splices
Lead wire splicing, when necessary, shall be made with copper split bolt
connectors of proper size. The joint shall be carefully wrapped with at
least 3 layers of electrical tape. Resistance wire connections shall be
done with silver solder and the solder joints wrapped with a minimum of 3
layers of pressure-sensitive tape.
3.3.4
Magnesium Anodes for Metallic Components
As a minimum, each metallic component shall be protected with [2] [_____]
[4.1] [7.7] [_____] kg [9] [17] [_____] lb magnesium anodes located on each
side of the metallic component and routed through a test station. Fire
hydrant pipe component shall have a minimum of [2] [3] [_____] [4.1] [7.7]
[_____] kg [9] [17] [_____] lb magnesium anodes routed through a test
station for each hydrant. Pipe under concrete slab shall have a minimum of
[5] [_____] [7.7] [_____] kg [17] [_____] lb anodes for each location where
metal pipe enters the building under the slab. A permanent reference cell
shall be provided adjacent to the pipe entrance to the slab. Conductors
shall be routed to a test station. Each valve shall have a minimum of [2]
[_____] [4.1] [_____] kg [9] [_____] lb magnesium anodes routed through a
test station. Sections of metallic pipe 6.1 m 20 foot long, when used
where force mains are within 3 m 10 feet of the water pipe, shall have a
minimum of [4] [_____] 7.7 kg 17 lb anodes.
3.4
MISCELLANEOUS INSTALLATION
**************************************************************************
NOTE: The cathodic protection system will fail
SECTION 26 42 17.00 10
Page 31
2.4.12
Preformed Sheaths
Preformed sheaths for encapsulating electrical wire splices to be buried
underground shall fit the insulated wires entering the spliced joint.
2.4.13
Epoxy Potting Compound
Epoxy potting compound for encapsulating electrical wire splices to be
buried underground shall be a two package system made for the purpose.
2.4.14
Backfill Shields
Backfill shields shall consist of approved pipeline wrapping or fiberglass
reinforced, coal-tar impregnated tape, or plastic weld caps, specifically
made for the purpose.
2.4.15
Electrical Tape
Pressure-sensitive vinyl plastic electrical tape shall conform to UL 510.
2.4.16
Cable Marker Tape
Traceable marker tape shall be manufactured for the purpose and clearly
labeled "Cathodic Protection Cable Buried Below".
2.4.17
Electrically Isolating Pipe Joints
**************************************************************************
NOTE: The cathodic protection system will fail
unless full consideration is given to specifications
for electrically isolating pipe joints, electrically
conductive pipe joints, and casing cradles and
seals. Mechanical and electrical specifications
should reference this paragraph and paragraph
"Electrically Conductive Couplings."
**************************************************************************
Electrically isolating pipe joints for above or below ground use shall be
[flexible, mechanical pipe couplings of an electrically isolating type
consisting of bolted or compression design provided with electrically
isolating joint harness if required to provide pull-out strength]
[flexible, integral electrically isolating pipe couplings designed for
field installation by means of a swaging system and providing pull-out
strength with a factor of safety] [nonflexible flanged type electrically
isolating pipe joints to be field assembled] [nonflexible factory assembled
electrically isolating pipe joints designed with stub ends for installation
by welding and providing pull-out strength with a factor of safety].
2.4.17.1
Threaded Fittings
Threaded type electrically isolating pipe joints shall have molded plastic
screw threads and be used above ground only. Machined plastic screw
threads shall not be used.
2.4.17.2
Electrically Isolating Pipe Joints
Electrically isolating pipe joints shall be of a type that is in regular
factory production.
SECTION 26 42 17.00 10
Page 23
2.4.18
Electrically Conductive Couplings
Electrically conductive couplings shall be of a type that has a published
maximum electrical resistance rating given in the manufacturer's
literature. Cradles and seals shall be of a type that is in regular
factory production made for the purpose of electrically isolating the
carrier pipe from the casing and preventing the incursion of water into the
annular space.
2.4.19
Joint and Continuity Bonds
Provide bonds across joints or any electrically discontinuous connections
in the piping, and other pipes and structures with other than welded or
threaded joints included in this cathodic protection system. Unless
otherwise specified, bonds between structures and across joints in pipe
with other than welded or threaded joints shall be with No. 4 AWG stranded
copper cable with polyethylene insulation. Bonds between structures shall
contain sufficient slack for any anticipated movement between structures.
Bonds across pipe joints shall contain a minimum of 100 mm 4 inch of slack
to allow for pipe movement and soil stress. Bonds shall be attached by
exothermic welding. Exothermic weld areas shall be insulated with coating
compound and approved by the Contracting Officer. Continuity bonds shall
be installed as necessary to reduce stray current interference. Additional
joint bonding shall be done where determined during construction or testing
or as directed. Joint bonding shall include excavation and backfilling.
There shall be a minimum of 2 continuity bonds between each structure and
other than welded or threaded joints. Electrical continuity shall be
tested across joints with other than welded or threaded joints and across
metallic portions of sewage lift stations and water booster stations.
2.4.19.1
Resistance Bonds
Resistance bonds shall be adjusted for minimum interference while achieving
the criteria of protection. Alternate methods may be used when approved.
2.4.19.2
Stray Current Measurements
Perform stray current measurements as indicated. Alternate methods may be
used when approved. The stray current test report shall indicate location
of test, type of pipes tested, method of testing, [_____].
2.4.20
Electrical Isolation of Structures
Isolating fittings, including isolating flanges and couplings, shall be
installed above ground or in a concrete hand hole. As a minimum, isolating
flanges or unions shall be provided at the following locations:
a.
Connection of new piping to existing pipes.
b.
Pressure piping under floor slab to a building.
Additionally, isolation shall be provided between new pipe lines and
foreign pipes that cross the new lines within 3 m 10 feet.
2.5
MAGNESIUM ANODES
Weights and dimensions of magnesium anodes shall be approximately as
follows:
SECTION 26 42 17.00 10
Page 24
TYPICAL MAGNESIUM ANODE SIZE
(Cross sections may be round, square, or D shaped)
Nominal Weight
(kg) (lbs)
Approx. Size (mm)
(inch)
1.43
76 X 76 X 1273 X 3 X 5
3.68
133 X 133 X 2035-1/4 X
5-1/4 X 8
2.35
76 X 76 X 2033 X 3 X 8
5.913
133 X 133 X 2865-1/4 X
5-1/4 X 11-1/4
4.19
76 X 76 X 3563 X 3 X 14
12.327
133 X 5085-1/4 X 20
5.512
102 X 102 X 3054 X 4 X
12
14.532
191 X 4577-1/2 X 18
7.717
102 X 102 X 4324 X 4 X
17
20.545
191 X 6107-1/2 X 24
14.532
127 X 127 X 5215 X 5 X
20-1/2
30.968
216 X 7118-1/2 X 28
22.750
178 X 178 X 4067 X 7 X
16
45.5100
254 X 61010 X 24
2.5.1
Nominal Gross Weight Nominal Package Dimensions
(kg) (lbs) Packaged
(mm) (inch)
in Backfill
Composition
Anode shall be of high potential magnesium alloy, made of primary magnesium
obtained from sea water or brine, and not from scrap metal. Magnesium
anodes shall conform to ASTM B843 and to the following analysis unless
otherwise indicated:
Element
Percent by Weight
Aluminum
0.02 maximum
Manganese
1.50 maximum
Zinc
0.05
Silicon
0.10 maximum
Copper
0.02 maximum
Nickel
0.002 maximum
Iron
0.03 maximum
Impurities
0.30 maximum
Magnesium
Remainder
Furnish spectrographic analyses on samples from each heat or batch of
anodes used on this project.
SECTION 26 42 17.00 10
Page 25
2.5.2
Packaged Anodes
Provide anodes in packaged form with the anode surrounded by specially
prepared quick-wetting backfill and contained in a cloth or paper sack.
Anodes shall be centered in the backfill material. The backfill material
shall have the following composition, unless otherwise indicated.
Material
2.5.3
Percent by Weight
Gypsum
75
Bentonite
20
Sodium Sulfate
5
Lead Wires
Anode lead wires shall consist of No. 10 solid copper wire, with TW
insulation. Lead wires shall be not less than 3 m 10 feet in length,
without splices.
2.5.4
Connection Wires
Wires shall consist of No. 10 solid copper wire with RHW-USE or
polyethylene insulation.
2.5.5
Insulation
Type RHW-USE insulation shall comply with NFPA 70. Polyethylene insulation
shall comply with ASTM D1248; high molecular weight polyethylene shall be
Type I, Class C, Grade E5; high density polyethylene shall be Type III,
Class C, Grade E3.
2.5.6
Conduit Steel
Conduit steel shall conform to UL 6 and ANSI C80.1.
2.5.7
Tape
Pressure-sensitive vinyl plastic electrical tape shall conform to UL 510.
2.5.8
Backfill Shields
Provide shields consisting of approved wrapping of reinforced fiberglass
coal-tar impregnated tape, or plastic weld caps specifically made for the
purpose and installed in accordance with the manufacturer's
recommendations. When joint bonds are required, due to the use of
mechanical joints, the entire joint shall be protected with kraft paper
joint cover. The joint cover shall be filled with poured hot coal-tar
enamel.
2.5.9
Electrical Connections
Electrical connections shall be done as follows:
a.
Exothermic welds shall be "Cadweld" or Burndy "Thermo-Weld" or approved
equal. Use of these materials shall be in accordance with the
SECTION 26 42 17.00 10
Page 26
manufacturer's recommendations.
b.
Electrical shielded arc welds on steel pipe shall be approved via shop
drawing action.
c.
Other methods of welding shall be specifically approved for use by the
pipe manufacturer.
2.5.10
Anode Installation
Anode configuration and size shall be as indicated. A minimum of [one]
[two] [three] [ten] [15] [_____] anodes are required to achieve minus 850
millivolts "instant off" potential and shall be required on the [_____]
components or structure. Details shown are indicative of the general type
of material required and are not intended to restrict selection of
materials or of any particular manufacturer. The anode system shall be
designed for a life of 25 years of continuous operation.
2.6
LEAD WIRE CONNECTIONS
Lead wire to structure connections shall be by exothermic welding process.
Weld charges made specifically for use on cast iron shall be used on cast
iron pipe. A backfill shield filled with a pipeline mastic sealant or
material compatible with the coating shall be placed over the weld
connection and shall cover the exposed metal adequately.
PART 3
3.1
EXECUTION
CRITERIA OF PROTECTION
Acceptance criteria for determining the adequacy of protection on a buried
[pipe] [tank] shall be in accordance with [NACE SP0169,] [and] [NACE RP0193,]
and as specified below.
3.1.1
Iron and Steel
**************************************************************************
NOTE: If the second method is used, the requirement
for obtaining measurements over 95 percent of the
entire metallic area is required as in the first
method. Verification of the 100 millivolts decay of
polarization should be achieved at points over 95
percent of the entire metallic area.
**************************************************************************
Use the following method a. for testing cathodic protection voltages.
more than one method is required, use method b.
a.
If
A negative voltage of at least minus 850 millivolts as measured between
the [pipe] [tank] [specified underground component] and a saturated
copper-copper sulphate reference electrode contacting the (electrolyte)
earth directly over the [pipe] [tank] [specified underground
component]. Determination of this voltage shall be made with the
cathodic protection system in operation. Voltage drops shall be
considered for valid interpretation of this voltage measurement. A
minimum of minus 850 millivolts "instant off" potential between the
[structure] [pipe] [tank] [specified underground component] being
tested and the reference cell shall be achieved over 95 percent of the
area of the structure. Obtain adequate number of measurements over the
SECTION 26 42 17.00 10
Page 27
entire structure, pipe, tank, or other metallic component to verify and
record achievement of minus 850 millivolts "instant off". This
potential shall be obtained over 95 percent of the total metallic area
without the "instant off" potential exceeding 1200 millivolts.
b.
A minimum polarization voltage shift of 100 millivolts as measured
between the [pipe] [tank] and a saturated copper-copper sulphate
reference electrode contacting the earth directly over the [pipe]
[tank]. This polarization voltage shift shall be determined by
interrupting the protective current and measuring the polarization
decay. When the protective current is interrupted, an immediate
voltage shift will occur. The voltage reading, after the immediate
shift, shall be used as the base reading from which to measure
polarization decay. Measurements achieving 100 millivolts shall be
made over 95 percent of the metallic surface.
3.1.2
Aluminum
Aluminum [pipes] [tanks] shall not be protected to a potential more
negative than minus 1200 millivolts, measured between the [pipe] [tank] and
a saturated copper-copper sulphate reference electrode contacting the
earth, directly over the [pipe] [tank] [metallic component]. Resistance,
if required, shall be inserted in the anode circuit within the test station
to reduce the potential of the aluminum [pipe] [tank] to a value which will
not exceed a potential more negative than minus 1200 millivolts. Voltage
shift criterion shall be a minimum negative polarization shift of 100
millivolts measured between the [pipe] [tank] [metallic component] and a
saturated copper-copper sulphate reference electrode contacting the earth,
directly over the [pipe] [tank]. The polarization voltage shift shall be
determined as outlined for iron and steel.
3.1.3
Copper Piping
For copper piping the following criteria shall apply. A minimum of 100
millivolts of cathodic polarization between the structure surface and a
stable reference electrode contacting the electrolyte. The polarization
voltage shift shall be determined as outlined for iron and steel.
3.2
GROUND BED INSTALLATION
3.2.1
Shallow Ground Beds
Shallow ground beds shall contain size and quantity of anodes designed to
meet performance criteria of the cathodic protection system at an initial
operating current output density not exceeding [40] [50] [70] percent of
maximum recommended current output density.
3.2.1.1
Horizontally Buried Bare Anodes
Horizontally buried bare anodes shall be bedded on and covered with
metallurgical coke breeze in a trench excavated for the purpose at depths,
spacing and locations as shown. Anodes shall be completely surrounded by
the backfill at bottom, sides, and top for a distance of not less than 100
mm 4 inch. Backfill shall be compacted.
3.2.1.2
Vertically Buried Bare Anodes
Vertically buried bare anodes shall be installed in vertical holes in the
ground having a depth, spacing, and location shown. The holes in the
SECTION 26 42 17.00 10
Page 28
**************************************************************************
USACE / NAVFAC / AFCEC / NASA
UFGS-26 42 17.00 10 (November 2008)
----------------------------------Preparing Activity: USACE
Superseding
UFGS-26 42 17.00 10 (April 2006)
UNIFIED FACILITIES GUIDE SPECIFICATIONS
References are in agreement with UMRL dated January 2016
**************************************************************************
SECTION TABLE OF CONTENTS
DIVISION 26 - ELECTRICAL
SECTION 26 42 17.00 10
CATHODIC PROTECTION SYSTEM (IMPRESSED CURRENT)
11/08
PART 1
GENERAL
1.1
REFERENCES
1.2
SYSTEM DESCRIPTION
1.2.1
General Requirements
1.2.2
Contractor's Modifications
1.3
SUBMITTALS
1.4
QUALITY ASSURANCE
1.4.1
Services of "Corrosion Expert"
1.4.2
Isolators
1.4.3
Anodes and Bond Wires
1.4.4
Surge Protection
1.4.5
Sacrificial Anodes
1.4.6
Nonmetallic Pipe Systems
1.4.6.1
Coatings
1.4.6.2
Tracer Wire
1.5
DELIVERY, STORAGE, AND HANDLING
1.6
EXTRA MATERIALS
PART 2
PRODUCTS
2.1
IMPRESSED CURRENT ANODES
2.1.1
Bare High Silicon Cast-Iron Anodes
2.1.1.1
Chemical Composition (Nominal)
2.1.1.2
Electrical Resistivity
2.1.1.3
Physical Properties (Nominal)
2.1.2
Bare Graphite Anodes
2.1.3
Canister Contained Anodes
2.1.4
Anode Connecting Cables
2.1.5
Mixed Metal Oxide Anodes
2.1.5.1
Conductive Material
2.1.5.2
Anode Life Test
2.1.5.3
Canister Contained Mixed Metal Oxide Anodes
2.1.5.4
Anode Connecting Cables
2.1.5.5
Canister Connection Cables
2.1.5.6
Deep Anode Connection Cables
SECTION 26 42 17.00 10
Page 1
3.2.2.4
Anode Requirements
Anode sizes, spacing, number of anodes, depth of well, and other details
shall be as shown.
3.2.2.5
Anode Lead Wire
Each anode shall have a separate, continuous wire extending from the anode
to the junction box at the well head.
3.2.2.6
Anode Cables
Anode cables shall terminate in a nearby junction box, equipped with
individual anode current shunts. Where full length casing is used, two
wire connections from casing shall terminate in the junction box.
3.2.2.7
Anode and Cable Installation
If the method of installation utilizes backfill support for anodes and
cable, provide slack in the cable near each anode and increase the cable
insulation in thickness from 2.8 to 4.0 mm 7/64 to 5/32 inch utilizing an
approved composite of plastic and elastomeric materials.
3.2.2.8
Backfill
Backfill the well with calcined petroleum coke breeze or metallurgical coke
breeze surrounding the anodes by a method that does not leave voids or
bridging. The recommended method is to pump the backfill from the bottom
upward. The well shall be over-filled with coke breeze allowing for
settlement so that the settled level after a number of days is as high as
the level shown. The number of days allowed for settling of the coke
breeze will be determined by the Contracting Officer. If the top level of
coke breeze is below the level shown after settlement, put additional coke
breeze in the well. The backfill used shall not require tamping. The top
portion of the well shall be sealed for 8 m 25 feet to prevent surface
water run-off. All vents shall be vented above the high water mark and at
a safe height.
3.2.2.9
Cable Marker Tape
Locate traceable marker tape in the same trench above cathodic protection
cables including structure leads, anode leads, anode header cables, test
station leads, bonding cables, and rectifier electrical power cables.
3.2.2.10
Pavement Inserts
Install pavement inserts at a minimum of 30 m 100 foot intervals for
pipelines. The pavement inserts shall be installed directly over the
structure being protected and tested.
3.3
MAGNESIUM ANODE INSTALLATION
Installation shall not proceed without the presence of the Contracting
Officer, unless otherwise authorized. Anode locations may be changed to
clear obstructions when approved. Install anodes in sufficient number and
of the required type, size, and spacing to obtain a uniform current
distribution surface on the structure. Prepackaged anodes shall be
installed as shown on the drawings.
SECTION 26 42 17.00 10
Page 30
3.3.1
Installation of Packaged Anodes
Install packaged anodes completely dry, lower them into holes by rope sling
or by grasping the cloth gather. The anode lead wire shall not be used in
lowering the anodes. Backfill the hole with fine soil in 150 mm 6 inch
layers and each layer shall be hand-tamped around the anode. The tamper
shall not strike the anode or lead wire. If immediate testing is to be
performed, add water only after backfilling and tamping has been completed
to a point 150 mm 6 inch above the anode. Approximately 8 L 2 gallons of
water shall be poured into the hole; after the water is absorbed by the
soil, backfilling and tamping shall be completed to the top of the hole.
Anodes shall be installed as shown. When rock is found prior to achieving
specified depth, anode may be installed horizontally to a depth at least as
deep as the bottom of the pipe, with the approval of the Contracting
Officer.
3.3.2
Underground Metal Pipe Line
Install anodes 610 mm 2 feet below the line to be protected unless
otherwise noted on the drawings. To facilitate periodic electrical
measurements during the life of the sacrificial anode system and to reduce
the output current of the anodes if required, anode lead wires in a single
group of anodes shall be buried a minimum of 610 mm 2 feet and each anode
lead wire shall be connected to an individual terminal in a test station.
The anode lead cable shall make contact with the structure only through a
test station. Resistance wire shall be installed between the anode lead
cable and the pipe cable in the test station to reduce the current output,
if required.
3.3.3
Lead and Resistance Wire Splices
Lead wire splicing, when necessary, shall be made with copper split bolt
connectors of proper size. The joint shall be carefully wrapped with at
least 3 layers of electrical tape. Resistance wire connections shall be
done with silver solder and the solder joints wrapped with a minimum of 3
layers of pressure-sensitive tape.
3.3.4
Magnesium Anodes for Metallic Components
As a minimum, each metallic component shall be protected with [2] [_____]
[4.1] [7.7] [_____] kg [9] [17] [_____] lb magnesium anodes located on each
side of the metallic component and routed through a test station. Fire
hydrant pipe component shall have a minimum of [2] [3] [_____] [4.1] [7.7]
[_____] kg [9] [17] [_____] lb magnesium anodes routed through a test
station for each hydrant. Pipe under concrete slab shall have a minimum of
[5] [_____] [7.7] [_____] kg [17] [_____] lb anodes for each location where
metal pipe enters the building under the slab. A permanent reference cell
shall be provided adjacent to the pipe entrance to the slab. Conductors
shall be routed to a test station. Each valve shall have a minimum of [2]
[_____] [4.1] [_____] kg [9] [_____] lb magnesium anodes routed through a
test station. Sections of metallic pipe 6.1 m 20 foot long, when used
where force mains are within 3 m 10 feet of the water pipe, shall have a
minimum of [4] [_____] 7.7 kg 17 lb anodes.
3.4
MISCELLANEOUS INSTALLATION
**************************************************************************
NOTE: The cathodic protection system will fail
SECTION 26 42 17.00 10
Page 31
unless full engineering considerations are applied
to selection, location and installation of
electrically conductive joints and electrically
isolating joints including the use of underground
type dielectric coatings (not paint).
Adequate electrical conductivity of a pipe joint
made by means other than welding should be
determined by the "corrosion expert". Allowable
electrical resistance depends on the cross sectional
area of the pipe metal, the resistivity of the pipe
metal, and the effectiveness of the coating on the
pipe. Effectively coated pipe underground requires
only a fraction of the electrical conductivity at
joints needed for bare pipe. Shop painted pipe is
considered to be the same as bare pipe and is not to
be confused with pipe coated with an underground
type dielectric coating.
The type of electrical isolating pipe joint to be
used requires engineering design consideration. In
general, the dielectric parts of an isolating joint
will not withstand structural or environmental
stresses as well as an all-metal type of joint. If
the pipe on the cathodic protected side of the
underground electrically isolating pipe joint,
including the joint, is not effectively coated,
interference type corrosion may occur unless other
measures are taken. Factors to be considered
include:
a.
Deflection stresses
b.
Pull-out stresses
c.
Expansion-contraction due to temperature changes
d.
Is function as a union necessary?
e.
Is field assembly of critical parts practical?
f.
Hazardous locations to be avoided
g.
Accessibility if above ground
h.
Location of test box if below ground
i. Importance of coating the adjacent pipe if below
ground
j.
Vulnerability to short circuiting
Factor of safety on pull-out strength required has
to be engineered for the specific conditions
involved since no blanket provisions are fully
applicable to all cases. The requirement for
isolating flanges or couplings should be based on a
study of the conditions. If the new piping is a
short extension to an existing old piping system not
SECTION 26 42 17.00 10
Page 32
under cathodic protection, an isolating fitting
should be installed at the point of connection,
since the new piping will be anodic to the older
system. If the older system is under cathodic
protection, no isolating fitting should be used.
**************************************************************************
3.4.1
Rectifier Installation
Mounting shall be as shown. [Pole or wall mounting shall be equipped with
a channel bracket, lifting eyes, and a keyhole at the top.] [Cross-arm
brackets shall accommodate a 102 by 102 mm 4 by 4 inch cross-arm.]
3.4.2
Wire Connections
3.4.2.1
Wire Splicing
**************************************************************************
NOTE: In water tanks, split bolts are used (above
the water line only) because working space is
limited and the hydraulic or mechanical compression
tools may be cumbersome and hazardous to use; since
a single split-bolt will work loose when the wires
it connects are moved, a minimum of two split bolts
should be used. At ground level or in trenches,
compression tools can be used conveniently, and the
swaged sleeve connection produced by such tools is
more reliable than split bolts.
**************************************************************************
Connecting wire splicing shall be made with copper compression connectors
or exothermic welds, following instructions of the manufacturer.
Split-bolt type connectors shall not be used.
3.4.2.2
Steel Surfaces
Connections to [ferrous pipe] [metal tanks] shall be made by exothermic
weld methods as manufactured by an approved manufacturer for the type of
[pipe] [tank]. Electric arc welded connections and other types of welded
connections to ferrous pipe and structures shall be approved before use.
3.4.3
Pipe Joints
**************************************************************************
NOTE: This paragraph will be coordinated with and
referenced in mechanical and electrical
specifications.
**************************************************************************
3.4.3.1
Electrical Continuity
Underground pipe shall be electrically continuous except at places where
electrically isolating joints are specified. Pipe joined by means other
than welding shall meet the following electrical continuity requirements:
a.
Mechanical joints that are not factory designed to provide electrical
continuity shall be bonded by installing a metallic bond across the
joint. The bonding connections shall be made by the exothermic welding
process.
SECTION 26 42 17.00 10
Page 33
b.
Mechanical joints designed to provide electrical continuity may be used.
3.4.3.2
Electrical Isolation of Structures
Perform electrical isolation of structures as follows:
3.4.3.2.1
Isolating Fittings
Install isolating flanges and couplings aboveground, or within manholes,
wherever possible, but an isolating device that electrically separates a
pipeline shall not be installed in a confined area where a combustible
atmosphere may collect unless precautions are taken to prevent arcing such
as by means of externally located surge arresters, grounding cells, or
other means. Isolating flanges and couplings in lines entering buildings
shall be located at least 300 mm 12 inch above grade or floor level.
Pipelines entering buildings either below or above ground shall be
electrically isolated from the structure wall with an electrically
isolating [gas tight wall sleeve.] [wall sleeve.]
3.4.3.2.2
Gas Distribution Piping
Provide electrical isolation at each building riser pipe to the pressure
regulator, at all points where a short circuit to another structure or to a
foreign structure may occur, and at other locations as indicated.
3.4.3.2.3
[Steam] [High Temperature] [Chilled] [Water] [Line Supply and
Return Piping] [Line Conduit]
Provide electrical isolation at each building entrance, and at other
locations as indicated.
3.4.3.2.4
[Fuel] [Gasoline] [Storage Tanks] [Fire Suppression] [_____]
Provide electrical isolation in each pipe [at the building] [at the tank] as
indicated.
3.4.3.2.5
Copper Piping
Copper piping shall be [electrically isolated at both ends of the pipe run]
[wrapped with pipeline tape and electrically isolated at both ends].
3.4.3.2.6
Underground Storage Tanks (UST)
Electrically isolate tanks from other metallic structures. Bond components
protected with the tank such as pipes, vents, anchors, and fill pipes to
the tank.
3.4.4
Dissimilar Metals
**************************************************************************
NOTE: This paragraph will be coordinated with and
referenced in mechanical and electrical
specifications.
**************************************************************************
Buried piping of dissimilar metals including new and old steel piping,
excepting valves, shall be electrically separated by means of electrically
insulating joints at every place of connection. The insulating joint,
SECTION 26 42 17.00 10
Page 34
including the pipes, shall be coated with an underground type dielectric
coating for a minimum distance of 10 diameters on each side of the joint.
3.4.5
Ferrous Valves
Dissimilar ferrous valves in a buried ferrous pipeline, including the pipe,
shall be coated with an underground type dielectric coating for a minimum
distance of 10 diameters on each side of the valve.
3.4.6
Brass or Bronze Valves
Brass or bronze valves shall not be used in a buried ferrous pipeline.
3.4.7
Metal Pipe Junction
If the dissimilar metal pipe junction, including valves, is not buried and
is exposed to atmosphere only, the connection or valve, including the pipe,
shall be coated with an underground type dielectric coating for a minimum
distance of 3 diameters on each side of the junction.
3.4.8
Casing
**************************************************************************
NOTE: This paragraph will be deleted if mechanical
and electrical specifications include these
requirements.
**************************************************************************
Where a pipeline is installed in a casing under a roadway or railway, the
pipeline shall be electrically isolated from the casing, and the annular
space sealed against incursion of water.
3.4.9
Test Stations
Test stations shall be of the type and location shown and shall be [curb
box] [post] mounted. Buried electrically isolating joints shall be
provided with test wire connections brought to a test station. Changes in
designated location shall have prior approval. Unless otherwise shown,
other test stations shall be located as follows:
a.
At 300 m 1,000 foot intervals or less.
b.
Where the pipe or conduit crosses any other metal pipe.
c.
At both ends of casings under roadways and railways.
d.
Where both ends of an insulating joint are not accessible above ground
for testing purposes.
3.5
TRAINING COURSE
Conduct a training course for the operating staff as designated by the
Contracting Officer. The training period shall consist of a total of [16]
[_____] hours of normal working time and shall start after the system is
functionally completed but prior to final acceptance tests. Submit the
proposed Training Course Curriculum (including topics and dates of
discussion) indicating that all of the items contained in the operating and
maintenance instructions, as well as demonstrations of routine maintenance
operations, including testing procedures included in the maintenance
SECTION 26 42 17.00 10
Page 35
instructions, are to be covered. The field instructions shall cover all of
the items contained in the operating and maintenance instructions, as well
as demonstrations of routine maintenance operations, including testing
procedures included in the maintenance instructions. At least 14 days
prior to date of proposed conduction of the training course, submit the
training course curriculum for approval, along with the proposed training
date. Training shall consist of demonstration of test equipment, providing
forms for test data and the tolerances which indicate that the system works
satisfactorily.
3.6
TESTS AND MEASUREMENTS
Submit test reports in booklet form tabulating field tests and measurements
performed, upon completion and testing of the installed system and
including close interval potential survey, casing and interference tests,
final system test verifying protection, insulated joint and bond tests, and
holiday coating test. Submit a certified test report showing that the
connecting method has passed a 120-day laboratory test without failure at
the place of connection, wherein the anode is subjected to maximum
recommended current output while immersed in a 3 percent sodium chloride
solution. Each test report shall indicate the final position of controls.
3.6.1
Baseline Potentials
Each test and measurement will be witnessed by the Contracting Officer.
Notify the Contracting Officer a minimum of 5 working days prior to each
test. After backfill of the [pipe] [tank] [_____] and anodes is completed,
but before the anodes are connected to the [pipe] [tank] [_____], the
static potential-to-soil of the [pipe] [tank] [_____] shall be measured.
The locations of these measurements shall be identical to the locations
specified for [pipe-] [tank-] [_____] to-reference electrode potential
measurements.
3.6.2
Isolation Testing
Before the anode system is connected to the [pipe] [tank] [_____], an
isolation test shall be made at each isolating joint or fitting. This test
shall demonstrate that no metallic contact, or short circuit exists between
the two isolated sections of the [pipe] [tank]. Any isolating fittings
installed and found to be defective shall be reported to the Contracting
Officer.
3.6.2.1
Insulation Checker
Use a Model 601 insulation checker, as manufactured by ["Gas Electronics"]
[_____] [or] [an approved equal], for isolating joint (flange) electrical
testing in accordance with manufacturer's operating instructions. An
isolating joint that is good will read full scale on the meter; if an
isolating joint is shorted, the meter pointer will be deflected at near
zero on the meter scale. Location of the fault shall be determined from
the instructions and the joint shall be repaired. If an isolating joint is
located inside a vault, the pipe shall be sleeved with insulator when
entering and leaving the vault.
3.6.2.2
Cathodic Protection Meter
Use a Model B3A2 cathodic protection meter, as manufactured by ["M. C.
Miller"] [_____] [or] [an approved equal] using the continuity check
circuit for isolating joint (flange) electrical testing. Perform this test
SECTION 26 42 17.00 10
Page 36
in addition to the Model 601 insulation checker. Continuity is checked
across the isolated joint after the test lead wire is shorted together and
the meter adjusted to scale. A full scale deflection indicates the system
is shorted at some location. The Model 601 verifies that the particular
insulation under test is good and the Model B3A2 verifies that the system
is isolated. If the system is shorted, further testing shall be performed
to isolate the location of the short.
3.6.3
Anode Output
After the rectifier is energized, the current output of the individual
anode leads shall be measured by using an approved method. This may be
done with a shunt and MV meter, a low-resistance ammeter, or a clamp-on
milliammeter. The total current shall be measured and compared to the sum
of all anode currents and to the rectifier output current. If an
individual anode output current meets or exceeds the recommended output for
that anode, the system shall be turned down or balancing resistors
installed. Calculation of the wattage of the resistors shall be sufficient
to handle the maximum load which will be encountered on the anode lead.
All measurements obtained, the date, time, and locations of all
measurements shall be recorded.
3.6.4
Electrode Potential Measurements
Upon completion of the installation and with the entire cathodic protection
system in operation, electrode potential measurements shall be made using a
copper-copper sulphate reference electrode and a potentiometer-voltmeter,
or a direct current voltmeter having an internal resistance (sensitivity)
of not less than 10 megohms per volt and a full scale of 10 volts. The
locations of these measurements shall be identical to the locations used
for baseline potentials. The values obtained and the date, time, and
locations of measurements shall be recorded. No less than 8 measurements
shall be made over any length of line or component. Additional
measurements shall be made at each distribution service riser, with the
reference electrode placed directly over the service line.
3.6.5
3.6.5.1
Location of Measurements
Coated Piping or Conduit
For coated piping or conduit, take measurements from the reference
electrode located in contact with the earth, directly over the pipe.
Connection to the pipe shall be made at service risers, valves, test leads,
or by other means suitable for test purposes. Pipe to soil potential
measurements shall be made at intervals not exceeding [0.75] [1.5] [122]
[_____] m [2.5] [5] [400] [_____] feet. The Contractor may use a
continuous pipe to soil potential profile in lieu of 0.75 m 2.5 ft interval
pipe to soil potential measurements. Additional measurements shall be made
at each distribution service riser, with the reference electrode placed
directly over the service line adjacent to the riser. Potentials shall be
plotted versus distance to an approved scale. Locations where potentials
do not meet or exceed the criteria shall be identified and reported to the
Contracting Officer.
3.6.5.2
Underground Tanks
For underground tanks, make a minimum of three measurements taken from the
reference electrode located:
SECTION 26 42 17.00 10
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a.
Directly over the center of the tank.
b.
At a point directly over the tank and midway between each pair of
anodes.
c.
At each end of the tank.
3.6.6
Casing Tests
Before final acceptance of the installation, the electrical separation of
carrier pipe from casings shall be tested and any short circuits corrected.
3.6.7
Interference Testing
**************************************************************************
NOTE: Adverse effects may be caused by the foreign
pipeline.
**************************************************************************
Before final acceptance of the installation, interference tests shall be
made with respect to any foreign [pipes] [tanks] in cooperation with the
owner of the foreign [pipes] [tanks]. A full report of the tests giving
all details shall be made.
3.6.8
Holiday Test
Repair any damage to the protective covering, during transit and handling,
before installation. After field coating and wrapping has been applied,
inspect the entire pipe by an electric holiday detector with impressed
current in accordance with NACE SP0188 using a full ring, spring type coil
electrode. The holiday detector shall be equipped with a bell, buzzer, or
other type of audible signal which sounds when a holiday is detected.
Holidays in the protective covering shall be repaired upon detection.
Occasional checks of holiday detector potential will be made by the
Contracting Officer to determine suitability of the detector. Furnish
labor, materials, and equipment necessary for conducting the inspection.
Inspect the coating system for holes, voids, cracks, and other damage
during installation.
3.6.9
Recording Measurements
Record all [pipe-] [tank-] to-soil potential measurements including initial
potentials where required. Locate, correct and report to Contracting
Officer any short circuits to foreign [pipes] [tanks] [_____] encountered
during checkout of the installed cathodic protection system. [Pipe-]
[Tank-] [_____] to-soil potential measurements are required on as many
[pipes] [tanks] [_____] as necessary to determine the extent of protection
or to locate short-circuits.
-- End of Section --
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