ufc_3_190_06
UFC 3-190-06
16 January 2004
UNIFIED FACILITIES CRITERIA (UFC)
PROTECTIVE COATINGS AND
PAINTS
APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED
UFC 3-190-06
16 January 2004
UNIFIED FACILITIES CRITERIA (UFC)
PROTECTIVE COATINGS AND PAINTS
Any copyrighted material included in this UFC is identified at its point of use.
Use of the copyrighted material apart from this UFC must have the permission of the
copyright holder.
U.S. ARMY CORPS OF ENGINEERS
NAVAL FACILITIES ENGINEERING COMMAND (Preparing Activity)
AIR FORCE CIVIL ENGINEER SUPPORT AGENCY
Record of Changes (changes are indicated by \1\ ... /1/)
Change No.
1
Date
Dec 2005
Location
FOREWORD
This UFC supersedes Military Handbook 1110, dated 30 September 1996.
UFC 3-190-06
16 January 2004
FOREWORD
\1\
The Unified Facilities Criteria (UFC) system is prescribed by MIL-STD 3007 and provides
planning, design, construction, sustainment, restoration, and modernization criteria, and applies
to the Military Departments, the Defense Agencies, and the DoD Field Activities in accordance
with USD(AT&L) Memorandum dated 29 May 2002. UFC will be used for all DoD projects and
work for other customers where appropriate. All construction outside of the United States is
also governed by Status of forces Agreements (SOFA), Host Nation Funded Construction
Agreements (HNFA), and in some instances, Bilateral Infrastructure Agreements (BIA.)
Therefore, the acquisition team must ensure compliance with the more stringent of the UFC, the
SOFA, the HNFA, and the BIA, as applicable.
UFC are living documents and will be periodically reviewed, updated, and made available to
users as part of the Services’ responsibility for providing technical criteria for military
construction. Headquarters, U.S. Army Corps of Engineers (HQUSACE), Naval Facilities
Engineering Command (NAVFAC), and Air Force Civil Engineer Support Agency (AFCESA) are
responsible for administration of the UFC system. Defense agencies should contact the
preparing service for document interpretation and improvements. Technical content of UFC is
the responsibility of the cognizant DoD working group. Recommended changes with supporting
rationale should be sent to the respective service proponent office by the following electronic
form: Criteria Change Request (CCR). The form is also accessible from the Internet sites listed
below.
UFC are effective upon issuance and are distributed only in electronic media from the following
source:
•
Whole Building Design Guide web site http://dod.wbdg.org/.
Hard copies of UFC printed from electronic media should be checked against the current
electronic version prior to use to ensure that they are current. /1/
AUTHORIZED BY:
______________________________________
DONALD L. BASHAM, P.E.
Chief, Engineering and Construction
U.S. Army Corps of Engineers
______________________________________
DR. JAMES W WRIGHT, P.E.
Chief Engineer
Naval Facilities Engineering Command
______________________________________
KATHLEEN I. FERGUSON, P.E.
The Deputy Civil Engineer
DCS/Installations & Logistics
Department of the Air Force
______________________________________
Dr. GET W. MOY, P.E.
Director, Installations Requirements and
Management
Office of the Deputy Under Secretary of Defense
(Installations and Environment)
UFC 3-190-06
16 January 2004
CONTENTS
Page
CHAPTER 1 INTRODUCTION
Paragraph
1-1
1-2
1-2.1
1-2.2
1-2.3
1-2.4
1-3
APPENDIX A
PURPOSE AND SCOPE ....................................................... 1-1
APPLICABILITY..................................................................... 1-1
General Building Requirements ............................................. 1-1
Safety .................................................................................... 1-1
Fire Protection ....................................................................... 1-1
Antiterrorism/Force Protection ............................................... 1-1
REFERENCES ...................................................................... 1-1
MIL-HDBK 1110……...…………...................…………………… A-1
i
UFC 3-190-06
16 January 2004
CHAPTER 1
INTRODUCTION
1-1
PURPOSE AND SCOPE. This UFC is comprised of two sections.
Chapter 1 introduces this UFC and provides a listing of references to other Tri-Service
documents closely related to the subject. Appendix A contains the full text copy of the
previously released Military Handbook (MIL-HDBK) on this subject. This UFC serves as
criteria until such time as the full text UFC is developed from the MIL-HDBK and other
sources.
This UFC provides general criteria for protective coatings and paints.
Note that this document does not constitute a detailed technical design,
maintenance or operations manual, and is issued as a general guide to the
considerations associated with protective coatings and paints.
1-2
APPLICABILITY. This UFC applies to all Navy and Air Force service
elements and contractors; Army service elements should use the references cited in
paragraph 1-3 below; all other DoD agencies may use either document unless explicitly
directed otherwise.
1-2.1
GENERAL BUILDING REQUIREMENTS. All DoD facilities must comply
with UFC 1-200-01, Design: General Building Requirements. If any conflict occurs
between this UFC and UFC 1-200-01, the requirements of UFC 1-200-01 take
precedence.
1-2.2
SAFETY. All DoD facilities must comply with DODINST 6055.1 and
applicable Occupational Safety and Health Administration (OSHA) safety and health
standards.
NOTE: All NAVY projects, must comply with OPNAVINST 5100.23 (series), Navy
Occupational Safety and Health Program Manual. The most recent publication in this
series can be accessed at the NAVFAC Safety web site:
www.navfac.navy.mil/safety/pub.htm. If any conflict occurs between this UFC and
OPNAVINST 5100.23, the requirements of OPNAVINST 5100.23 take precedence.
1-2.3
FIRE PROTECTION. All DoD facilities must comply with UFC 3-600-01,
Design: Fire Protection Engineering for Facilities. If any conflict occurs between this
UFC and UFC 3-600-01, the requirements of UFC 3-600-01 take precedence.
1-2.4
ANTITERRORISM/FORCE PROTECTION. All DoD facilities must
comply with UFC 4-010-01, Design: DoD Minimum Antiterrorism Standards for
Buildings. If any conflict occurs between this UFC and UFC 4-010-01, the requirements
of UFC 4-010-01 take precedence.
1-3
REFERENCES. The following Tri-Service publications have valuable
information on the subject of this UFC. When the full text UFC is developed for this
subject, applicable portions of these documents will be incorporated into the text. The
1-1
UFC 3-190-06
16 January 2004
designer is encouraged to access and review these documents as well as the
references cited in Appendix A.
1.
US Army Corps of Engineers
AFETL 96-5, Hangar Concrete Floor
Commander
Reflective Coating Criteria, 26 August
USACE Publication Depot
1996
ATTN: CEIM-IM-PD
USACE EM 1110-2-3400, Painting:
2803 52nd Avenue
New Construction and Maintenance
Hyattsville, MD 20781-1102
USACE TM 5-618, Paints and
(301) 394-0081 fax: 0084
Protective Coatings, 15 June 1981
[email protected]
http://www.usace.army.mil/inet/usace-docs/
1-1
UFC 3-190-06
16 January 2004
APPENDIX A
MIL-HDBK 1110
PROTECTIVE COATINGS AND PAINTS
A-1
1.
NOT MEASUREMENT
SENSITIVE
MIL-HDBK-1110
17 JANUARY 1995
SUPERSEDING
NAVFAC MO-110
JUNE 1981
MILITARY HANDBOOK
HANDBOOK FOR PAINTS AND PROTECTIVE COATINGS
FOR FACILITIES
AMSC N/A
AREA FACR
DISTRIBUTION STATEMENT A. Approved for public release; distribution
is unlimited.
MIL-HDBK-1110
ABSTRACT
This handbook is provided as guidance for DOD personnel wishing
to apply architectural paints or protective coatings to military
structures fixed in place. It is not for use with ships,
aircraft, or automotive vehicles. It is written for general use
by both those with much and with little knowledge of the use of
paint and coating materials. It contains information on the
composition of coatings, their mechanisms of curing,
environmental and safety concerns, necessary surface preparation,
selection for different substrates and structures, application,
inspection, and failure analysis.
ii
MIL-HDBK-1110
FOREWORD
This handbook identifies criteria and procedures for applying
architectural paints or protective coatings to military
structures fixed in place.
Recommendations for improvements are encouraged from Government
agencies and the private sector and should be furnished on the DD
Form 1426 provided inside the back cover to Commanding Officer,
Northern Division, Naval Facilities Engineering Command, Code
164, 10 Industrial Highway, Mail Stop 82, Lester, PA 19113-2090;
Telephone: Commercial (610) 595-0661/DSN 443-0661.
THIS HANDBOOK SHALL NOT BE USED AS A REFERENCE DOCUMENT FOR
PROCUREMENT OF FACILITIES CONSTRUCTION. IT IS TO BE USED AS A
MAINTENANCE MANAGEMENT TOOL BY PUBLIC WORKS DEPARTMENTS, PUBLIC
WORKS CENTERS, BASE CIVIL ENGINEERS, AND FACILITIES ENGINEERS.
DO NOT REFERENCE IT IN MILITARY OR FEDERAL SPECIFICATIONS OR
OTHER PROCUREMENT DOCUMENTS.
iii
MIL-HDBK-1110
THIS PAGE INTENTIONALLY LEFT BLANK
iv
MIL-HDBK-1110
HANDBOOK FOR PAINTS AND PROTECTIVE COATINGS FOR FACILITIES
CONTENTS
Section 1
1.1
1.2
1.3
1.3.1
1.3.2
1.3.3
1.3.4
1.3.4.1
1.3.4.2
1.3.4.3
1.3.4.4
1.3.4.5
1.3.4.6
1.4
1.4.1
1.4.1.1
1.4.1.2
1.4.1.3
1.5
1.5.1
1.5.2
1.5.3
1.5.4
1.5.5
1.5.6
Section 2
2.1
2.1.1
2.1.2
2.1.3
2.1.4
2.1.5
2.2
2.2.1
2.2.2
2.2.3
2.3
2.3.1
2.3.2
2.3.3
2.3.4
Page
INTRODUCTION
Purpose.................................... 1
Scope...................................... 1
Deterioration of Facilities................ 1
Corrosion of Metals........................ 1
Deterioration of Wood...................... 2
Deterioration of Concrete.................. 2
Design Factors Affecting Deterioration..... 2
Water Traps................................ 2
Crevices................................... 3
Rough and Sharp Surfaces................... 3
Limited Access to Work..................... 3
Incompatible Environment................... 3
Contact of Dissimilar Metals............... 3
Control of Facilities Deterioration........ 4
Corrosion Control by Coatings.............. 4
Barrier Protection......................... 4
Inhibitive Pigments........................ 4
Cathodic Protection........................ 4
Painting for Purposes Other Than Protection 5
Cosmetic Appearance........................ 5
Marking Paints............................. 5
Safety Colors and Designs.................. 5
Reflective Finishes........................ 5
Nonskid Surfaces........................... 5
Antifouling Coatings....................... 6
COATING COMPOSITIONS AND CURING MECHANISMS
Coating Composition........................
Solvent....................................
Resin......................................
Pigment....................................
Other Components...........................
Spreading Rate.............................
Mechanisms of Curing of Coatings...........
Air Oxidation of Drying Oils...............
Solvent of Water Evaporation...............
Chemical Reaction..........................
Properties of Different Generic Types
of Coatings................................
Alkyds and Other Oil-Containing Coatings...
Water Emulsion (Latex) Coatings............
Lacquers...................................
Epoxy Coatings.............................
v
7
7
7
8
10
10
10
11
12
13
14
14
15
16
17
MIL-HDBK-1110
2.3.5
2.3.6
2.3.7
2.3.8
2.3.9
2.4
2.4.1
2.4.2
2.4.3
2.4.4
2.4.5
Section 3
3.1
3.2
3.2.1
3.2.1.1
3.2.1.2
3.2.1.3
3.2.2
3.2.3
3.2.4
3.2.5
3.2.6
3.3
3.3.1
3.3.2
3.4
3.4.1
3.4.1.1
3.4.1.2
3.4.1.3
3.4.1.4
3.4.2
3.4.3
3.4.3.1
3.4.3.2
3.4.4
3.4.4.1
3.4.4.2
3.4.4.3
3.4.4.4
3.4.5
3.4.6
3.4.7
Page
Coal-Tar Epoxy Coatings..................... 18
Polyurethane Coatings....................... 18
Polyester Coating........................... 19
Inorganic Zinc Coatings..................... 19
Zinc-Rich Organic Coatings.................. 20
Coating Compatibility....................... 20
Bleeding.................................... 21
Disbonding of Old Paint..................... 21
Topcoat Checking............................ 21
Poor Adhesion of Latex Topcoats to Enamels.. 21
Oil-Based Paints Applied to Alkaline
Surfaces.................................... 21
ENVIRONMENTAL, OCCUPATIONAL, AND SAFETY ISSUES
Introduction................................ 23
Material Composition Issues................. 23
VOC Restrictions............................ 23
Definition of VOC........................... 23
Types of Regulations........................ 23
Effect on Coatings.......................... 24
Application Issues.......................... 25
Toxic Solvents.............................. 25
Hazardous Air Pollutants.................... 26
Binders - Polyurethanes, Coal Tars, Asphalts 26
Heavy Metal-Containing Pigments and
Additives................................... 26
Issues Affecting Surface Preparation........ 28
Regulations................................. 28
Waste....................................... 29
Surfaces Coated With Leaded Paint........... 29
Background.................................. 29
Use of Lead in Paint........................ 29
Effects of Lead Exposure on Health.......... 30
Environmental Issues........................ 30
Occupational Safety Issues.................. 30
Definitions................................. 31
DOD Policy/Instruction...................... 31
Residential Structures...................... 31
Non-Residential............................. 32
General Description of Lead-Based Paint
Procedures.................................. 33
Inspection/Assessment....................... 33
In-Place Management (IPM)................... 33
Removal..................................... 34
Operations and Maintenance.................. 34
Waste Disposal.............................. 35
Demolition of Buildings Containing
Lead-Based Paint............................ 35
Sources of Detailed Information............. 35
vi
MIL-HDBK-lll0
Section 4
4.1
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
4.3
4.4
4.4.1
4.4.1.1
4.4.1.2
4.4.1.3
4.4.1.4
4.4.2
4.4.2.1
4.4.2.2
4.4.2.3
4.4.2.4
4.4.3
4.4.3.1
4.4.3.2
4.4.3.3
4.4.4
4.4.4.1
4.4.4.2
4.4.5
Section 5
5.1
5.2
5.3
5.3.1
5.3.2
5.4
5.4.1
5.4.2
5.5
5.5.1
5.5.2
5.6
5.6.1
5.6.1.1
5.6.1.2
5.6.1.3
Page
SELECTION OF COATINGS
Available Guidance......................... 36
Selection Criteria......................... 36
Desired Film Properties.................... 36
Work Requirements or Limitations........... 36
Safety and Environmental Restrictions...... 37
Compatibilities............................ 37
Costs...................................... 37
Specifications for Lead- and Chromate-Free
Coatings With VOC Limits................... 38
Recommendations for Different Substrates... 39
Recommendations for Wood................... 40
Oil-Based Paints........................... 40
Water-Emulsion Paints...................... 40
Semi-Transparent Stains.................... 41
Clear Floor Finishes....................... 41
Recommendations for Concrete and Masonry
Surfaces................................... 41
Waterborne Coatings........................ 41
Elastomeric Coatings....................... 42
Textured Coatings.......................... 42
Epoxy Coatings............................. 43
Recommendations for Steel.................. 43
Alkyd Systems.............................. 44
Epoxy Coating Systems...................... 44
Zinc-Rich Coatings......................... 45
Recommendations for Galvanized Steel....... 45
Epoxy Systems.............................. 46
Waterborne System for Galvanizing.......... 46
Recommendations for Aluminum............... 46
COATING SYSTEMS FOR SPECIFIC USES
General....................................
Painting New Construction..................
Fuel Storage Tanks.........................
Interiors of Steel Fuel Tanks..............
Exteriors of Steel Fuel Tanks..............
Steel Water Tanks..........................
Interiors of Steel Water Tanks.............
Exteriors of Steel Water Tanks.............
Other Steel Tanks..........................
Interiors of Other Steel Tanks.............
Exteriors of Other Steel Tanks.............
Steel Distribution Lines...................
Steel Fuel Lines...........................
Buried Steel Fuel Lines....................
Immersed Steel Fuel Lines..................
Aboveground Fuel Lines.....................
vii
48
48
48
49
50
50
51
51
51
51
51
51
51
51
53
53
MIL-HDBK-1110
5.6.2
5.7
5.7.1
5.7.1.1
5.7.1.2
5.7.1.3
5.7.2
5.7.2.1
5.7.2.2
5.7.2.3
5.7.3
5.8
5.9
5.10
5.11
5.12
5.13
5.14
5.15
5.16
5.17
5.18
5.19
5.19.1
5.19.2
5.19.3
5.20
5.20.1
5.20.1.1
5.20.1.2
5.20.1.3
5.20.1.4
5.20.2
5.21
Section 6
6.1
6.1.1
6.1.2
6.1.3
6.2
6.2.1
Page
Steel Water Distribution Lines.............. 53
Communication Towers and Other Tall
Structures.................................. 53
New Towers.................................. 54
New Galvanized Steel Towers................. 54
New Thermally Sprayed Steel Towers.......... 55
New Steel Towers............................ 55
Existing Towers............................. 55
Towers With Only Cosmetic Coating Defects... 56
Zinc-Coated Steel Tower Components With
Deteriorated Organic Coatings............... 57
Steel Tower Components (With No Zinc
Coating) With Damaged Organic Coating....... 57
Galvanized Steel Guy Lines for Towers....... 58
Waterfront Structures....................... 58
Hydraulic Structures and Appurtenant Works.. 58
Factory Finished Metal Siding............... 59
Chain Link Fences........................... 59
Hot Steel Surfaces.......................... 59
Concrete Fuel Tanks......................... 59
Concrete Swimming Pools..................... 60
Concrete Catchment Basins................... 61
Chemically Resistant Finishes for Concrete
Floors...................................... 61
Slip-Resistant Floors....................... 62
Fouling-Resistant Coatings.................. 62
Mildew-Resistant Coatings................... 62
Factors Affecting Mildew Growth............. 62
Use of Mildewcides in Paints................ 63
Removal of Mildew........................... 63
Pavement Markings........................... 63
Painted Markings............................ 64
Specifications for Marking Paints........... 64
Specification for Reflective Glass Beads.... 65
Application of Painted Markings............. 65
Inspection of Marking Operation............. 66
Alternative Markings........................ 71
Wooden Floors............................... 71
SURFACE PREPARATION
Introduction................................
Selection Factors...........................
Specification Procedure.....................
Section Organization........................
Repair of Surfaces..........................
Joints, Cracks, Holes, or Other Surface
Defects.....................................
viii
72
72
72
72
73
73
MIL-HDBK-lll0
6.2.2
6.3
6.3.1
6.3.2
6.3.3
6.3.3.1
6.3.4
6.3.5
6.4
6.4.1
6.4.2
6.5
6.5.1
6.5.1.1
6.5.1.2
6.5.1.3
6.5.2
6.5.3
6.6
6.7
6.7.1
6.7.1.1
6.7.1.2
6.7.1.3
6.7.1.4
6.7.1.5
6.7.1.6
6.7.1.7
6.7.2
6.7.2.1
6.7.3
6.7.4
6.7.5
6.7.6
6.7.7
6.7.8
6.7.9
6.7.10
6.7.10.1
Section 7
7.1
7.2
7.3
7.3.1
7.3.1.1
Page
Cementitious Surfaces....................... 74
Recommendations By Substrate................ 74
Wood........................................ 74
Concrete/Masonry............................ 76
Steel....................................... 76
Specific Surface Preparation Requirements
for Coatings for Steel...................... 77
Galvanized and Inorganic-Zinc Primed Steel.. 77
Aluminum and Other Soft Metals.............. 78
Standards for Condition of Substrates....... 78
Unpainted Steel............................. 78
Nonferrous Unpainted Substrates............. 79
Standards for Cleanliness of Substrates..... 79
Standards for Cleaned Steel Surfaces........ 79
SSPC and NACE Definitions and Standards..... 79
Job-Prepared Standard....................... 79
Pictorial Standards for Previously Painted
Steel....................................... 79
Standards for Cleaned Nonferrous Metals..... 80
Previously Coated Surfaces.................. 80
Recommendations for Paint Removal........... 81
Methods of Surface Preparation.............. 81
Abrasive Blasting........................... 81
Types of Abrasive Blasting.................. 82
Conventional Abrasive Blasting Equipment.... 84
Abrasive Properties......................... 87
Abrasive Types.............................. 88
Selection................................... 91
Inspection.................................. 91
Procedures/General Information.............. 92
Acid Cleaning............................... 92
Concrete.................................... 94
Chemical Removal of Paint................... 94
Detergent Washing........................... 95
Hand Tool Cleaning.......................... 95
Heat........................................ 95
Organic Solvent Washing..................... 96
Power Tool Cleaning......................... 96
Steam Cleaning.............................. 97
Water Blast Cleaning........................ 97
Equipment................................... 98
APPLICATION
Introduction................................ 99
Paint Storage Prior to Application.......... 99
Preparing Paint for Application............. 99
Mixing...................................... 99
Mixing Two-Component Coatings...............100
ix
MIL-HDBK-lll0
7.3.2
7.3.3
7.3.4
7.4
7.4.1
7.4.2
7.4.3
7.4.4
7.5
7.5.1
7.5.2
7.5.2.1
7.5.3
7.5.3.1
7.5.4
7.5.4.1
7.5.4.2
7.5.4.3
7.5.4.4
7.5.4.5
7.5.4.6
7.5.4.7
7.5.4.8
7.5.4.9
Section 8
8.1
8.2
8.3
8.3.1
8.3.1.1
8.3.1.2
8.3.1.3
8.3.1.4
8.3.1.5
8.3.1.6
8.3.1.7
8.3.2
8.3.3
8.3.3.1
8.3.3.2
8.3.3.3
8.3.3.4
8.4
8.4.1
8.5
Page
Thinning...................................103
Tinting....................................103
Straining..................................103
Weather Conditions Affecting Application
of Paints..................................103
Temperature................................104
Humidity...................................104
Wind.......................................104
Moisture...................................104
Methods of Application.....................105
Selection of Application Method............105
Brush Application..........................105
Procedure for Brush Application............106
Roller Application.........................107
Procedures for Roller Application..........108
Spray Application..........................109
Conventional or Air Spray Equipment........109
Airless Spray..............................115
Air-Assisted Airless Spray.................117
High-Volume, Low-Pressure Spray............117
Multi-Component Spray......................117
Electrostatic Spray........................118
Powder Spraying............................118
Thermal Spraying...........................118
Application Technique......................119
PREPARATION OF A PAINTING CONTRACT
SPECIFICATION
General....................................128
Background.................................128
The CSI Format.............................129
General Information Part...................129
Summary Section............................130
Reference Section..........................130
Definition Section.........................131
Submittals Section.........................131
Quality Assurance Section..................133
Delivery, Storage, Handling, and Disposal..133
Site Conditions............................134
Products Part..............................134
Execution Part.............................135
Work Conditions............................135
Surface Preparation........................136
Coating Application........................136
Inspection.................................136
Language to be Used in Specification.......137
Concise Words..............................137
Construction Criteria Base.................138
x
MIL-HDBK-lll0
Section 9
9.1
9.2
9.3
9.4
9.4.1
9.5
9.6
9.6.1
9.6.2
9.6.3
9.6.4
9.6.5
9.6.6
9.6.6.1
9.6.6.2
9.6.7
9.6.7.1
9.6.7.2
9.6.7.3
9.6.7.4
9.6.7.5
9.6.8
9.9.8.1
9.6.8.2
9.6.8.3
9.6.8.4
9.6.8.5
9.6.9
9.6.10
Section 10
10.1
10.2
10.3
10.3.1
10.3.2
10.3.3
10.3.4
10.3.4.1
10.3.4.2
10.3.4.3
10.3.5
10.3.6
Page
INSPECTION OF PAINTING OPERATIONS
Scope of Section.......................... .139
Importance of Inspection....................139
Contractor Quality Control Inspection.......139
Duties of an Inspector......................139
Record Keeping..............................140
Inspection Equipment........................140
Inspection Steps........................... 141
Review Specification and Correct
Deficiencies, If Any........................141
Visit Job Site..............................141
Conduct Pre-Construction Conference.........146
Inspect Job Site After Pre-Surface
Preparation.................................146
Inspect Coating Materials...................146
Measure Ambient Conditions..................147
Relative Humidity and Dew Point.............149
Surface Temperature.........................149
Inspect Surface Preparation.................149
Abrasive-Blasting Surface Preparation
Equipment and Supplies......................149
Water Blasting..............................150
Frequency of Inspecting Cleaned Surfaces....151
Inspecting Prepared Steel Surfaces..........151
Inspecting Concrete, Masonry, Wood, Plaster,
Wallboard, Old Paint........................152
Inspect Coating Application.................152
Application Equipment.......................152
Ventilation.................................153
Mixing/Thinning.............................153
Film Thickness..............................153
Drying......................................154
Final Approval Procedures...................154
Year Warranty Inspection....................155
FIELD INSPECTION INSTRUMENTS
Introduction................................156
Illuminated Microscope......................156
Instruments for Use with Abrasive Blasting..156
Gage for Determining Nozzle Pressure........156
Wedge for Determining Diameter of Nozzle
Orifice.....................................156
Surface Contamination Detection Kit.........156
Profile of Blasted Steel....................157
Comparators.................................157
Surface Profile Gages.......................157
Testex Press-O-Film Replicate Tape..........157
Thermometers................................157
Psychrometers...............................157
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10.3.7
10.3.8
10.3.9
10.3.9.1
10.3.9.2
10.3.10
10.3.11
10.3.11.1
10.3.11.2
10.3.12
10.3.13
10.3.13.1
10.3.13.2
10.3.14
10.3.14.1
10.3.14.2
10.3.15
10.3.16
Section 11
11.1
11.2
11.3
11.3.1
11.3.2
11.3.3
11.3.4
11.3.5
11.3.6
11.3.6.1
11.3.6.2
11.3.6.3
11.3.6.4
11.3.7
11.4
11.4.1
11.4.1.1
11.4.1.2
11.4.1.3
11.4.1.4
11.4.1.5
11.4.1.6
11.4.1.7
11.4.1.8
Page
Wind Meter..................................158
Moisture Meter..............................158
Wet Film Gage...............................158
Notched Metal Gage..........................158
Cylindrical Gage............................159
Dry Film Thickness Gages for Coatings on
Aluminum, Copper, and Stainless Steel.......159
Magnetic Dry Film Thickness Gages for
Coatings on Steel...........................159
Pull-Off Gages..............................160
Flux Gages..................................160
Destructive (Nonmagnetic Dry Film Thickness
Gage).......................................161
Holiday Detector............................161
Low Voltage Holiday Detectors...............161
High Voltage Holiday Detectors..............162
Adhesion Tester.............................162
Tape Adhesion Test..........................162
Pull-Off Adhesion Test......................162
Portable Glossmeter.........................163
Hardness Tester.............................163
ANALYSIS OF PAINT FAILURES
Definition..................................164
Documentation of Findings...................164
Scope of Failure Analysis...................164
Review of Specification for Coating Work....165
Review of Supplier’s Data...................165
Review of Inspector’s Daily Reports.........165
On-Site Inspection..........................165
On-Site Inspection Techniques...............166
Laboratory Testing..........................167
Microscopic Examination.....................167
Spot Tests..................................167
Infrared Spectrophotometric Analysis........167
Other Specialized Instrumentation...........168
Forming Conclusions and Preparing Reports...169
Expert System for Failure Analysis..........169
Cosmetic Defects............................170
Chalking....................................170
Mildew......................................170
Dirt........................................170
Uneven Gloss................................170
Blushing....................................170
Bleeding....................................170
Fading......................................171
Discoloration...............................171
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11.4.1.9
11.4.1.10
11.4.1.11
11.4.1.12
11.4.1.13
11.4.1.14
11.4.2
11.4.2.1
11.4.2.2
11.4.2.3
11.4.2.4
11.4.2.5
11.4.2.6
11.4.2.7
11.4.2.8
11.4.2.9
11.4.3
11.4.3.1
11.4.3.2
Section 12
12.1
12.2
12.2.1
12.2.1.1
12.2.1.2
12.2.2
12.2.2.1
12.2.2.2
12.2.2.3
12.2.3
12.2.4
12.2.4.1
12.2.4.2
12.2.4.3
12.2.4.4
12.2.5
Section 13
13.1
13.2
Page
Pigment Overload............................171
Checking....................................171
Dry Spray...................................171
Sagging.....................................171
Orange Peel.................................171
Wrinkling...................................171
Film Failures...............................172
Crawling....................................172
Alligatoring................................172
Intercoat Delamination......................172
Intercoat Blistering........................172
Pinpoint Rusting............................172
Cracking....................................172
Blistering to Substrate.....................173
Peeling.....................................173
Flaking (Scaling)...........................173
Examples of Using Decision Trees............173
Example of Surface Defect...................173
Example of a Film Defect....................173
PROGRAMMING MAINTENANCE PAINTING
Definitions of Programmed Painting and
Maintenance Painting........................176
Components of Programmed Painting...........176
Initial Design..............................176
Structural Design...........................176
Design of Coating System....................177
Plan for Monitoring Conditions of
Structures and Their Protective Coatings....177
Determining the Type of Coating Failure.....177
Determining the Extent of Coating Failure...177
Determining the Generic Type of the Finish
Coat........................................178
Types of Maintenance Painting...............178
Plan for Maintenance Painting...............180
Selecting Materials for Maintenance
Painting....................................180
Surface Preparation for Maintenance
Painting....................................180
Application for Maintenance Painting........181
Inspection of Maintenance Painting..........181
Scheduling the Work.........................181
GENERAL SAFETY PRACTICES DURING PAINTING
OPERATIONS
Introduction................................182
Standard Operation and Safety Plans.........182
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MIL-HDBK-1110
13.3
13.3.1
13.3.2
13.4
13.4.1
13.4.1.1
13.4.1.2
13.4.1.3
13.4.2
13.5
13.6
13.6.1
13.6.1.1
13.6.1.2
13.6.1.3
13.6.1.4
13.6.2
13.6.2.1
13.6.2.2
13.6.3
13.6.3.1
13.6.3.2
13.6.4
13.7
13.7.1
13.7.1
13.7.2
13.7.2.1
13.7.2.2
13.7.2.3
13.7.3
13.7.3.1
13.7.3.2
13.7.3.3
13.7.4
13.7.4.1
13.7.4.2
13.7.4.3
13.7.5
13.7.6
13.8
Page
Hazard Communication........................182
Labels......................................183
Material Safety Data Sheets.................183
Toxicity Hazards............................183
Entrance of Toxic Materials Into Body.......183
Inhalation..................................185
Ingestion...................................185
Skin Absorption.............................185
Types of Toxic Materials....................185
Respiratory Hazards.........................185
Hazards in Different Painting Operations....186
Surface Preparation.........................186
Abrasive and Water Blasting.................186
Mechanical Cleaning.........................186
Chemical Cleaning...........................186
High Temperature Operations.................186
Painting Operations.........................187
Storage of Paints...........................187
Mixing and Applying Paints..................188
Work in High, Confined, and Remote Places...189
Work in High Places.........................189
Confined Areas..............................190
Remote Areas................................191
Personal Protective Equipment...............191
Clothing....................................191
Gloves......................................192
Protective Headwear.........................192
Hard Hats...................................192
Bump Hats...................................193
Hair Covers.................................193
Eye Protection..............................193
Safety Glasses..............................193
Safety Goggles..............................193
Safety Shields..............................193
Hearing Protection..........................193
Ear Muffs...................................194
Ear Plugs...................................194
Canal Cups..................................194
Safety Shoes................................194
Respirators/Ventilation.....................194
Safety Program..............................195
FIGURES
Figure 1
Schematic Drawing Illustrating Components
of Conventional Abrasive Blasting Equipment. 83
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MIL-HDBK-lll0
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
Figure 17
Figure 18
Figure 19
Figure 20
Figure 21
Figure 22
Figure 23
Figure 24
Page
Schematic Drawing of Cross Section of
Typical Water-Injected Wet Abrasive
Blasting Nozzle............................. 84
Cross-Sectional Drawing of Nozzles.......... 86
Drawing Illustrating Effect of Shape of
Abrasive Particle on Contour of BlastCleaned Metallic Substrate.................. 88
Schematic Illustrating Typical Cleaning
Angles for Various Surface Conditions....... 93
Illustration of Proper Stroke Pattern for
Blast Cleaning.............................. 93
Illustration of Mixing and “Boxing” OneComponent Paint: A - Pouring Off PigmentPoor Vehicle, B and C - Mixing Pigment to
Form Smooth Paste, D - Pouring in Vehicle
and Mixing, E - Boxing Paint................101
Illustration of Parts of Paint Brush........107
Equipment Used in Applying Paint by Roller..108
Schematic Drawing Illustrating Basic Parts
of Conventional Air Spray Application
Equipment...................................111
Drawing of Air-Spray Gun....................113
Cross-Sectional Drawing of Nozzle of AirSpray Gun...................................113
Illustration of Proper Spray Patterns.......114
Illustration of Improper Movement of Spray
Gun When Applying Paint.....................120
Illustration of Proper Procedure for Spray
Painting Large Flat Surfaces............... 121
Schematic to Illustrate Proper Painting of
Large Vertical Surfaces.....................122
Illustration of Proper “Triggering” of
Spray Guns..................................123
Proper Spray Painting of Inside Corners.....124
Proper Spray Painting of Outside Corners....125
Schematic Illustrating Importance of
Spraying Surfaces With Protruding Parts
From All Directions to Avoid “Shadowing
Effect”.....................................126
Sample Inspector’s Contract Summary Form....144
Sample Daily Project Reports for Painting
Inspectors..................................145
Nomograph for Estimating Quantities of
Paint Required for a Job....................148
Decision Tree 1: Support for Analysis of
Coating Failures That Do Not Penetrate
the Finish Coat.............................174
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MIL-HDBK-1110
Figure 25
Figure 26
Page
Decision Tree 2: Support for Analysis
of Coating Defects That Penetrate the
Finish Coat................................175
Coating Condition and Identification Form..179
TABLES
Table 1
Table 2
Table 3
Table 16
Compatibility of Commonly Used Paints...... 22
Problems Encountered With Low VOC Coatings. 25
TLV and Other Safety Data on Paint and
Cleaning Solvents.......................... 27
DOD and Military Component’s Policy
Documents on Lead-Based Paint.............. 32
Lead- and Chromate-Free Coating
Specifications With VOC Limits............. 38
Commonly Used Methods of Surface
Preparation for Coatings................... 75
SSPC and NACE Standards for Cleaned Steel
Surfaces................................... 80
Procedures for Coating Removal............. 81
Typical Physical Characteristics of
Abrasives.................................. 89
Approximate Rates of Paint Application.....105
Comparison of Conventional Air and Airless
Spray......................................110
Common Conventional Air-Spray Problems and
Their Causes and Remedies..................114
Common Airless-Spray Problems and Their
Causes and Remedies........................116
Spray Painting Errors......................127
Equipment for Inspecting Painting
Operations.................................142
Inspection Steps...........................143
REFERENCES
...........................................196
GLOSSARY
...........................................184
Table 4
Table 5
Table 6
Table 7
Table 8
Table 9
Table 10
Table 11
Table 12
Table 13
Table 14
Table 15
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Section 1:
INTRODUCTION
1.1
Purpose. This handbook presents information on the
effective use of paint-type coatings to protect metal, concrete,
and wooden structures at military activities from deterioration.
In this handbook, the words "paint" and "coating" are used
interchangeably. Sometimes, the word "paint" is used to describe
an architectural rather than protective material, but this is not
the case in this handbook.
1.2
Scope. This handbook covers virtually all aspects of
coating fixed structures. These include surface preparation for
painting; selection, application, and inspection of coatings for
both original and maintenance painting; quality control methods
and equipment; and painting different substrates and facilities.
It does not cover painting of ships, aircraft, or motor vehicles.
The coatings covered are limited to organic paint-type materials,
with a few exceptions. Inorganic zinc, thermal spray metal, and
powder coatings are included, because they are most commonly used
as alternatives to conventional organic coatings and, like
organic coatings, are usually applied by spray.
1.3
Deterioration of Facilities. The main purpose of
painting military facilities is to protect them from
deterioration. These structures comprise a vital resource in the
defense of our nation. They must be kept in a state of
operational readiness by efficient use of the limited funds
available for this purpose. Unfortunately, these facilities are
frequently subject to environments and uses that accelerate their
natural deterioration and require costly repairs and maintenance.
Metals corrode in aggressive soil, industrial or chemical
atmospheres, or immersion environments; woods swell, warp, and
crack during weathering; concrete and masonry structures crack
and spall in severe environments; and organic polymeric materials
suffer degradation in sunlight. To adequately meet the
challenges of protecting constructed facilities, it is necessary
to have a general understanding of the common ways in which
materials deteriorate and the procedures used to control the
deterioration.
1.3.1
Corrosion of Metals. Metals corrode because they exist
in chemically unstable states. Thus, iron ore is a corrosion
product in its natural, stable state. Energy must be used in
blast furnaces to reduce iron to its metallic state. Iron and
steel products are then slowly oxidized by corrosion to their
previous stable lower energy states. Four conditions must be
present for corrosion to occur:
a)
Anodic areas where corrosion occurs
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MIL-HDBK-1110
b)
Cathodic areas where the metal is protected
c)
An electrolyte (conductive medium such as soil or
d)
A metallic path between the anode and cathode
water)
In atmospheric corrosion, surface moisture and
contamination serve as the electrolyte. Dissimilar metals are
anodic and cathodic to each other; also, the same metal
components have anodic and cathodic areas because of slight
chemical or physical differences.
1.3.2
Deterioration of Wood. The chief causes of
deterioration of wood are effects of ultraviolet light, and
swelling and contracting. These adversely affect the physical
properties of the wood.
1.3.3
Deterioration of Concrete. The chief cause of concrete
deterioration is moisture and electrolyte penetration. This may
result in deterioration of the concrete itself or in corrosion of
reinforcing steel which causes spalling of the concrete.
1.3.4
Design Factors Affecting Deterioration. Poor design of
structures may accelerate their deterioration or interfere with
their protection by coatings. Examples of poor designs are
listed below:
a)
Water traps
b)
Crevices
c)
Rough and sharp surfaces
d)
Limited access
e)
Incompatible environment
f)
Contact of dissimilar metals
1.3.4.1
Water Traps. Since water greatly accelerates
deterioration, structures should be designed so that water is not
collected. For example, angle irons and other configurations
that can collect water should be oriented downward rather than
upward. Weep holes of sufficient size should be placed where
water collection cannot be otherwise avoided. Condensate water
from air conditioners should not be allowed to run or drip on
surfaces and steam or other vapors should not be allowed to
impinge on surfaces.
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MIL-HDBK-1110
1.3.4.2
Crevices. Crevices should be avoided in structures,
because these oxygen-deficient areas accelerate metal corrosion.
Thus, continuous welds should be used rather than skip welds.
Back-to-back angles should also be avoided for this reason.
1.3.4.3
Rough and Sharp Surfaces. To obtain protection of a
surface, a painter must be able to apply a uniformly thick,
continuous film. Thus, irregular surfaces such as welds and other
projections should be ground smooth to eliminate projections
through the paint film. Weld-spatter, which is loosely-bonded to
the steel, must be removed for two reasons. First, it creates
crevices which lead to crevice corrosion and, second, as the mill
scale becomes disbonded, the barrier film will be broken.
Sharp edges should be rounded (1/8 inch or more radius
is ideal) because a uniformly thick coating cannot be applied
over the edge. This is because wet coatings draw thin on them.
Sharp interior corners should be avoided, since they may receive
an excessive coating thickness.
1.3.4.4
Limited Access to Work. Areas to be protected should
be readily accessible for inspection and maintenance. Difficultto-reach areas are not only difficult to prepare and coat, but
reaching them may also constitute a safety hazard.
1.3.4.5
Incompatible Environment. Materials must be compatible
with the environment in which they are located. Thus, aluminum
should not come into direct contact with concrete, because the
alkalinity of the concrete will attack the aluminum.
1.3.4.6
Contact of Dissimilar Metals. Dissimilar metals
probably present the biggest design problem. Because they have
different corrosion potentials, they may corrode rapidly when in
contact with each other. Examples of dissimilar metal (galvanic)
corrosion are:
a)
Steel pipe passing through an aluminum deck
b)
Steel nut on a copper valve
c)
Aluminum stanchion with a bronze lifeline
d) Aluminum plate with steel or different alloy
aluminum rivets
e)
Mild steel attached to stainless steel
Dissimilar surface conditions (e.g., threads,
scratches, etc.) may also cause galvanic corrosion.
3
MIL-HDBK-1110
1.4
Control of Facilities Deterioration. While coating of
surfaces is the most commonly used method of protecting them, it
can be used most effectively in conjunction with other control
methods. These include but are not limited to proper design of
components, proper selection of materials and components,
cathodic protection, controlling the environment, and use of
corrosion inhibitors.
1.4.1
Corrosion Control by Coatings. Coatings protect metals
from corrosion by interfering with one or more of the conditions
necessary for corrosion to occur. The three protective
mechanisms of coatings are:
a)
Barrier
b)
Inhibitors
c)
Cathodic protection
Regardless of the mechanism(s) of protection imparted
by coatings, a multiple coat system is normally recommended for
maximum protection of metals. The primer is formulated to bond
well to the substrate and provide a good surface for adhesion of
additional coats. Zinc or inhibitive primer pigments can provide
corrosion control, as described above. Intermediate coats
provide additional barrier protection and unite the primer and
finish coats. The finish coat provides additional barrier
protection as well as resistance to weathering, and color,
texture, and gloss.
1.4.1.1
Barrier Protection. Most coatings provide corrosion
protection by forming a barrier that is relatively impermeable to
moisture and electrolytes (usually salts) necessary for
corrosion. No organic coating is completely impermeable, but
some are much more so than others. Obviously, the coating film
must be thick enough and free of discontinuities (holidays) to
achieve maximum barrier protection.
1.4.1.2
Inhibitive Pigments. Some pigments are used in primers
for metals to inhibit the corrosion reaction at the metal/primer
interface. Red lead and zinc chromate pigments, used for this
purpose for many years, are seldom used today because of health
and environmental concerns. Acceptable alternate corrosion
control pigments are available.
1.4.1.3
Cathodic Protection. Some coatings have a high loading
of fine zinc particles to provide cathodic protection to steel
surfaces. They convert anodic areas on the steel to cathodic
areas. The zinc particles must be in electrical contact with
4
MIL-HDBK-1110
each other and with the steel to provide this protection. The
two basic types of zinc-rich coatings, organic and inorganic
zinc, will be described later in this handbook.
A film of inorganic zinc silicate coating is unique
because the film is relatively porous. Initially, the coating
protects steel by cathodic protection, but its corrosion products
gradually fill the porosity, so that it becomes a barrier
coating. Should this barrier coat become scratched to expose the
steel substrate, cathodic protection will begin again until the
damage is healed. An inorganic zinc silicate coating is also
unique in that it reacts with the steel to form a chemical bond.
Many organic coatings rely on physical rather than chemical
bonding to steel.
1.5
Painting for Purposes Other Than Protection.
Facilities are often painted for other purposes than, or in
addition to, protection. These include appearance, marking, and
safety.
1.5.1
Cosmetic Appearance. Painting is an important factor
in promoting morale and productivity. NAVFAC P-309, Colors for
Navy Shore Facilities, and Army TM5-807-7, Color for Buildings,
present scientific approaches to the use of color to improve
working and living environments.
FED-STD-595, Colors Used in Government Procurement,
presents standard colors currently used by the Government. The
colors are identified by five-digit numbers, and defined by
fundamental color data. The standard, also available as a
fandeck, includes reference chips of each color.
1.5.2
Marking Paints. Marking paints are used on airfield
runways, streets, and parking lots. Their chief function is to
provide safety for personnel and equipment.
1.5.3
Safety Colors and Designs. Safety colors and designs
are used on military installations for rapid identification of
hazards or safety equipment. They are also described in NAVFAC
P-309.
1.5.4
Reflective Finishes. Reflective finishes on concrete
floors of hangars and shops may increase the lighting for
workmen, particularly in sheltered areas such as under the wings
of aircraft. Such smooth floors are easier to keep clean.
1.5.5
Nonskid Surfaces. Nonskid surfaces are frequently made
by adding grit to coatings on floors, ramps, and other walking
surfaces to provide slip resistance.
5
MIL-HDBK-1110
1.5.6
Antifouling Coatings. Antifouling coatings prevent the
attachment and growth of marine fouling organisms by the
controlled release of toxic materials.
6
MIL-HDBK-1110
Section 2:
COATING COMPOSITIONS AND CURING MECHANISMS
2.1
Coating Composition. The primary ingredients used to
formulate coatings can be placed into one of three basic
categories - solvent, resin, and pigment. Each of these
categories has a special function in the formulation of coatings.
The resin (also called binder) and the solvent comprise the
liquid portion, sometimes called the vehicle. Since the solvent
evaporates as a coating cures, it is sometimes called the
volatile vehicle, and the resin the nonvolatile vehicle. The
resin and pigment which comprise the solid film after evaporation
of the solvent are sometimes called the total solids or film
solids.
Historically, the first paints utilized fish or
vegetable (e.g., linseed) oils as binders and natural earth
pigments. The first solvents were from trees (e.g., turpentine).
Now most resins and solvents are derived from petroleum, and many
pigments are derived from organic synthesis or modification of
natural minerals.
2.1.1
Solvent. Organic solvents are used to dissolve the
resin material and reduce the viscosity of the product to permit
easier application. They also control leveling, drying,
durability, and adhesion. Because the different organic polymers
in different formulations vary greatly in their solubilities,
some resins require much stronger solvents and/or greater amounts
than others to dissolve them. In most water-based coatings, the
water is a dispersing rather than a dissolving agent.
A blend of solvents is generally used in paint to
achieve all the properties desired from them. The blend must
completely dissolve the total binder system and be balanced to
ensure compatibility and stability during all stages of curing.
Improper blends may result in cloudy films, pigment float to the
wet film surface, or reduced film durability.
Paint solvents evaporate into the air and contribute to
the production of photochemical smog. Thus, there is a great
pressure to reformulate coatings to reduce the solvent content of
paints.
2.1.2
Resin. Resins, also called binders, are the filmforming portions of coatings. They are usually high molecular
weight solid polymers (large molecules with repeating units) in
the cured film. In some cases, lower molecular weight units in
two liquid components react with each other upon mixing to
polymerize into the higher molecular weight solid.
7
MIL-HDBK-1110
The resin is responsible for many of the properties of
the coating. Thus, coatings are usually identified generically
by the types of their resins. Important film properties related
to the resin chemistry are:
a)
Mechanism and time of curing
b)
Performance in different environments
c)
Performance on different substrates
d)
Compatibility with other coatings
e)
Flexibility and toughness
f)
Weather resistance
g)
Adhesion
h)
Ease of topcoating and repair
i)
Application properties (wetting, build, pot life,
etc.)
2.1.3
Pigment. The pigment constitutes the solid portion of
a wet paint. Pigments are insoluble in the vehicle and are
generally heavier than the liquid vehicle portion. They may
settle to the bottom of a container upon prolonged standing.
Natural earth pigments are generally much more stable to light
than synthetic organic pigments.
a) The pigment portion of coatings contributes to the
following desirable properties:
(1)
Opacity (hiding)
(2)
Color
(3)
Corrosion inhibition
(4)
Weather resistance
(5)
Moisture resistance
(6)
Level of gloss and hardness
(7)
Film build and reinforcement
8
MIL-HDBK-1110
b) The chief function of the pigment is to provide
opacity (hiding) to obscure the substrate and protect the organic
resin from degradation by the sun's ultraviolet light. Organic
resins degrade to some extent in sunlight, some much more than
others. Titanium dioxide is the pigment most frequently used to
impart opacity to white paints and light tints, because it has
high opacity. If a coat of paint does not completely obscure a
surface, it is usually necessary to apply an additional coat.
c) Another important function of some pigments has
already been mentioned - corrosion control. Inhibitive pigments
can be very effective in reducing the corrosion that would
otherwise occur. Lead and chromate inhibitive pigments were
commonly used in paints in the past but are now restricted
because of adverse health effects. Examples of lead- and
chromate-containing pigments, and of those presently used,
environmentally acceptable corrosion-inhibitive pigments are
listed below:
Common Inhibitive Pigments
Relatively Hazardous
Relatively Nonhazardous
Red Lead
White Lead
Zinc Chromate
Strontium Chromate
Basic Lead-Silico-Chromate
Zinc Oxide
Zinc Phosphate
Zinc Molybdate
Calcium Borosilicate
Calcium Phosphosilicate
Zinc Phosphosilicate
Barium Metaborate
d) Pigments also may improve adhesion and decrease
moisture permeability. Leafing pigments such as aluminum tend to
align themselves as parallel plates in the film to effectively
increase film thickness by increasing the path that moisture must
take to reach the substrate.
e) Other things being equal, the greater the resin-topigment ratio, the glossier will be the coating. The size of
pigment particles (fineness of dispersion or grind) of the
pigment in the vehicle also affects gloss. Other things being
equal, the finer the dispersion, the glossier the cured film.
Secondary or filler pigments (talc, silica, etc.) are used to
control viscosity, wet film build and leveling, and settling.
These cheaper pigments provide very little hiding. The pigment
to resin ratio, generally expressed as pigment volume
concentration (PVC), can vary widely. There can be no pigment,
or the pigment content can approach a value called the critical
pigment volume concentration (CPVC). As this point is
approached, there is insufficient binder to wet the individual
9
MIL-HDBK-1110
pigment particles and bond them to the substrate. This may
result in a poorly bonded or porous film or one with a mottled
appearance.
2.1.4
Other Components. There are also many additives used
in small amounts in coatings to provide some special function.
These include antifoam agents, flattening agents to reduce gloss,
mildewcides, adhesion promoters, viscosity modifiers, and
ultraviolet stabilizers.
2.1.5
Spreading Rate. If the percent solids by volume of a
coating is known, the dry film thickness of a coating can be
determined from its wet film thickness by the relationship:
Dry Film
Thickness = Wet Film Thickness x Percent Solids by Volume
100
Also, it can be shown mathematically that if 1 gallon
of coating is uniformly applied to a flat surface at 1 mil (0.001
inch) wet film thickness, it will cover an area of 1600 square
feet. Thus, if the percent solids by volume of a paint is
provided by the supplier, its spreading rate at any dry film
thickness (dft) can be determined, as shown below:
a)
0 Percent Solvent - 1600 square feet at 1-mil dft
(100 Percent Solids) 800 square feet at 2-mil dft
400 square feet at 4-mil dft
b)
50 Percent Solvent (50 Percent Solids)
by volume
600 square feet at 1-mil dft
400 square feet at 2-mil dft
200 square feet at 4-mil dft
Obviously, this relationship is only true for coatings
as received from the supplier without thinning. Thinning will
reduce the percent solids by volume reported by the supplier and
require calculating a new value before the above relationship can
be used.
2.2
Mechanisms of Curing of Coatings.
one of three basic ways:
a)
drying oils
b)
Coatings cure from
Air oxidation (polymerization) of unsaturated
Evaporation of solvent from lacquers or water from
emulsions
c) Chemical reaction of components or chemical
reaction with water in air
10
MIL-HDBK-1110
Coatings that cure by solvent or water evaporation are
unchanged chemically during curing. They are said to be
thermoplastic, because they can be softened by heat or by
solvent. Chemically curing coatings are said to be
thermosetting, because they are not softened by heating or by
solvent. Air-oxidizing coatings (oil-based paints) are
thermoplastic after initial curing. Upon further curing (e.g.,
6 months or more), the additional polymerization (cross-linking
of polymers) slowly converts them to thermosetting coatings.
This is shown below:
Thermoplastic Coatings
Thermosetting
Lacquers
Chemically Reacting Products
Latex Products
Oil-Based Products (After Aging)
Oil-Based Products (Initially)
2.2.1
Air Oxidation of Drying Oils. For coatings that cure
by air oxidation of drying oils (usually vegetable), oxygen from
the air reacts with unsaturated fatty acids in their drying oils.
By this reaction, liquid resins are converted to solid films.
Metal driers are usually incorporated into formulations of drying
oil coatings to accelerate their normally slow curing.
a) Examples of coatings that are cured by this
mechanism are:
(1)
Unmodified drying oils
(2)
Alkyds
(3)
Silicone alkyds
(4)
Epoxy esters
(5)
Oleoresinous phenolics
b) Such coatings wet surfaces very well and generally
perform well in mild atmospheric environments, but they have
limited durability in chemical environments, particularly
alkaline environments. Epoxy esters provide some additional
chemical resistance. They should not be confused with higher
performance, two-component, chemically reacting epoxies.
Oleoresinous phenolic coatings are the only oil-based coatings
that can be used successfully in water immersion service.
11
MIL-HDBK-1110
c) Formulating oil-based coatings with low-solvent
content presents difficulties and requires major formulation
changes from those used for high-solvent coatings. Thus,
attempts are also being made to develop waterborne alkyd
products.
2.2.2
Solvent of Water Evaporation. Coatings that cure by
simple evaporation of organic solvent are sometimes called
lacquers. They are made by dissolving solid resins in an
appropriate solvent. After application of a lacquer, the solvent
evaporates to deposit the resin in a thin film. No chemical
change occurs in the resin.
a)
Examples of coatings that cure by this mechanism
are:
(1)
Shellacs
(2)
Vinyls (polyvinyl chlorides)
(3)
Chlorinated rubber
(4)
Acrylics
(5)
Bituminous coatings (coal tars and asphaltics)
b) Coatings of this type have poor solvent resistance,
since they are deposited from a solvent, but are easy to topcoat
and repair because the topcoat solvent bites into the undercoat
to bond tightly. Because lacquers are high in solvent content,
that is, volatile organic compounds (VOC), their use has been
greatly curtailed.
c) Latex and many other waterborne coatings also cure
by simple water evaporation. Emulsified particles of solid resin
coalesce to form a film as the water is lost. These coatings
usually contain some organic solvent to control curing and
improve application properties. Latex films are quite flexible
and tend to be more permeable than oil and alkyd films. Examples
of latex coatings are:
(1)
Acrylics
(2)
Vinyls (polyvinyl acetates)
d) At this time, it is important to point out that
there are other types of waterborne coatings that cure by
mechanisms other than simple water evaporation. The three basic
types of waterborne coatings are:
12
MIL-HDBK-1110
(1)
Water soluble (of limited value)
(2)
Water reducible
(3)
Emulsions
e) Water soluble coatings are not durable enough for
general use. The other two types of waterborne coatings find use
on military facilities, although they may be somewhat less
durable in some environments than corresponding solvent-based
types. Water-reducible coatings contain a solvent blend that can
be thinned with water. Alkyd and epoxy formulations are
available in either water-reducible or emulsion forms. Such
alkyd films are cured by air oxidation, and two-component epoxy
films by chemical reaction.
2.2.3
Chemical Reaction. Coatings that cure by chemical
reaction are usually the most durable. They are generally
packaged in two separate containers that are mixed to initiate
the reaction. Components must be combined in the specified
proportions in the manner specified by the supplier to achieve a
film with optimum properties. Sometimes, an "induction period"
is required after mixing and before application to permit the
reaction to get started. After mixing, there is always a "pot
life" during which the coating must be applied, before the
reaction has advanced so far that the coating cannot be properly
applied.
a)
Examples of coatings that cure by chemical reaction
are:
(1)
Epoxies
(2)
Coal tar epoxies
(3)
Polyurethanes
(4)
Polyesters
b) Because these coatings are thermosetting, they have
excellent chemical and solvent resistance. They are difficult to
topcoat when fully cured, because topcoat solvent cannot bite
into the films. Thus, a topcoat is best applied while the
undercoat still has some residual tack. If a completely cured
thermosetting coating is to be topcoated, it is necessary to
first spray a thin (e.g., 2 mil wet film thickness) tie coat
(tack coat) of the topcoat and allow it to cure to a tacky state.
13
MIL-HDBK-1110
c) Another example of a chemically curing coating is
an inorganic zinc coating. Different formulations may cure by
different types of reaction. Usually the cure reaction involves
the hydrolysis (reaction with water vapor from the atmosphere) of
the silicate binder. Some cure by reaction with water from the
air, and thus cure slowly in dry environments. A one-package
water-based inorganic zinc coating cures by chemical reaction
after evaporation of the water.
d) Zinc-rich organic coatings, on the other hand, cure
by the mechanism of curing of their organic binders. Thus, zincrich epoxies cure by chemical reaction and zinc-rich vinyls, by
solvent evaporation.
2.3
Properties of Different Generic Types of Coatings. The
properties of coatings commonly used on military facilities will
be discussed individually below and then their properties will be
summarized in a series of tables. Special mention will be made
of the ease of formulating each generic type with a low VOC
(solvent) content, since new restrictions on VOC content may
limit or eliminate their use.
2.3.1
Alkyds and Other Oil-Containing Coatings. The
unmodified drying oil coatings initially developed were very
easily applied, did not require a high level of surface
preparation, and had good flexibility; they could readily expand
and contract with the substrate. They did, however, have several
drawbacks: they were slow to dry, had residual tack, and
provided a limited period of protection. They cannot be used in
sea water immersion service or on alkaline substrates (e.g.,
concrete), because they are easily hydrolyzed (deteriorated by
reaction with water) by alkalinity. They are used most on wood
and steel surfaces.
a) Alkyd coatings, prepared by chemically modifying
drying oil formulations, cured much faster than the unmodified
ones and did not have residual tack. They retained the good
application properties, but lost some flexibility. Silicone
alkyds were developed by incorporating silicone into the resin to
provide greater gloss retention. Epoxy esters were another
modification of drying oils that improved some performance
properties, particularly their chemical resistance, but worsened
others, such as gloss retention. Still, none of these were
suitable for a severe environment such as sea water.
Oleoresinous phenolic drying oil formulations could be
successfully used in water immersion.
14
MIL-HDBK-1110
b) Air-oxidizing coatings have limited solvent
resistance. They continue to oxidize and cross-link after
initial drying and curing. Thus, with time, they become harder,
more brittle, and less soluble in solvent. That is, they become
more like thermosetting coatings and are harder to recoat and
maintain.
c) Although alkyds have long been the most widely used
type of protective coating, their use is dropping rapidly because
of difficulties in preparing formulations with: low VOC content,
a brushable viscosity, and good film properties. Exempted
halogenated hydrocarbons are presently being used to produce
limited low-VOC alkyd formulations, but this exemption is
expected to be withdrawn in the near future.
Alkyd and Most Other Air-Oxidizing Coatings
Advantages
Easy
Good
Good
Good
Limitations
to apply/repair/topcoat
initial flexibility possible
surface wetting/adhesion
gloss retention
Relatively inexpensive
Based on renewable source
Relatively high in VOCs
Poor performance in severe
environment
Poor chemical/solvent
resistance
Poor immersion resistance
Poor alkali resistance
Poor heat resistance
Become brittle with extended
aging
2.3.2
Water Emulsion (Latex) Coatings. Water emulsion
coatings, commonly called latex coatings, have been successfully
used for many years to coat wood and masonry structures. The
porous nature of their films allows water vapor to pass through
them, i.e., they are breathing. This porosity reduces their
durability on steel. Thus, much effort is being made to develop
more durable products because of the great advantages of their
low VOC contents and ease of application and clean-up. In
addition, water-emulsion coatings have excellent flexibility and
low cost, and are easily topcoated and repaired. Drawbacks
include poor solvent and heat resistance (as with all
thermoplastics), poor immersion resistance, and difficulty in
bonding to smooth oil/alkyd coatings and chalky surfaces. The
poor bonding is due to insufficient content of organic solvents
to soften and wet the binder in the existing paint film. Because
of this limited adhesion, it is necessary to sand smooth enamels
and/or use a surface conditioner before topcoating with latex
15
MIL-HDBK-1110
coatings. Also, latex paints do not cure well at temperatures
below 50 degrees F, as the emulsion does not coalesce to form a
good film.
Water Emulsion (Latex) Coatings
Advantages
Limitations
Environmental acceptability
Easy to apply/repair/topcoat
Limited durability
Poor chemical/solvent
resistance
Poor wetting of surfaces
Poor immersion service
Must cure above 50 degrees F
Excellent flexibility
and color and gloss retention
Low cost
Available in wide range of
color and gloss
2.3.3
Lacquers. Lacquers (e.g., vinyls, chlorinated rubbers,
and acrylics) form durable films that have good water and
chemical resistance but, being thermoplastics, poor solvent and
heat resistance. They have a low film build but dry so fast that
they can be quickly topcoated. When used on steel, they require
a blast-cleaned surface, and in some cases wash priming, for good
adhesion. They are easy to topcoat and repair and can be
formulated for good gloss retention. The good weathering of
acrylic lacquers is duplicated in acrylic water emulsion
coatings.
a) The chief disadvantage of lacquers is their high
VOC content. Because of their uniquely excellent performance on
exterior concrete swimming pools, chlorinated rubber coatings
have been granted temporary exemptions in some localities for
this use despite their high VOCs.
Lacquers (Vinyls, Chlorinated Rubbers, and Acrylics)
Advantages
Limitations
Rapid drying and recoating
Good chemical resistance
Good in water immersion
Good gloss retention possible
Good durability
Easy to topcoat and repair
Can be applied at low temperatures
High in VOCs
Poor solvent/heat resistance
Low film build
Blasted surface necessary
Occasional poor adhesion
b) Bituminous (asphalt and coal tar) coatings are also
lacquers, but they are discussed separately because of their
unique film properties. Bituminous coatings have found much use
16
MIL-HDBK-1110
in the past because they were inexpensive and easy to use. They
have good water resistance but weather poorly in sunlight. They
are used much less now because of toxicity concerns and their
limited durability.
Bituminous Coatings
Advantages
Limitations
Low cost
Easy to apply/repair/topcoat
Good water resistance
Good film build
Low level of surface preparation
High in VOCs
Poor solvent/heat resistance
Poor weathering
Black color only
2.3.4
Epoxy Coatings. Epoxy coatings are two-component
thermosetting products. (Epoxy-ester coatings are modified oil
coatings, refer to par. 2.3.1.) One part is commonly called the
base and the other, the catalyst component, although they are
both best described as coreactants. Epoxies are available in a
variety of formulations. Those most commonly used in general
service are the epoxy polyamide (which has better water
resistance) and the amine-cured epoxy (which has better chemical
resistance). Epoxies and polyurethanes provide the best overall
combinations of film properties of any organic coatings.
a) Epoxy films are tough and relatively inflexible.
Thus, they cannot expand or contract much without cracking.
However, they bond well and are very durable in most
environments. They require a blasted steel surface, and they
chalk freely in sunlight. An aliphatic polyurethane finish coat
is usually applied when the coating is exposed to sunlight.
Epoxies can be formulated to be low in VOCs, some actually
solvent-free.
b) Epoxies, as do all thermosetting coatings, have
topcoating problems. Solvent from a topcoat cannot penetrate a
fully cured epoxy to bond tightly to it. Thus, a topcoat of a
multiple coat system is applied when the undercoat is still
somewhat tacky (e.g., within 4 days). If this is not possible, a
fog coat (thin coat of about 2 mils wet film thickness) is first
applied by spray and allowed to cure to a tacky state (e.g., 4
hours) before a full coat is applied.
17
MIL-HDBK-1110
Epoxy Coatings
Advantages
Limitations
Low in VOCs
Good solvent/water resistance
Tough, hard, smooth film
Good adhesion
Good abrasion resistance
Limited pot life
Chalk in sunlight
Cure best above 50 degrees F
Topcoating is a problem
Blasted surface needed
2.3.5
Coal-Tar Epoxy Coatings. Coal-tar epoxy coatings are
basically epoxies (with all properties of epoxies) to which coal
tar has been incorporated. The coal tar reduces cost, improves
water resistance, and provides for greater film builds. Because
of the coal tar, coatings tend to become brittle in sunlight, and
there is great concern about toxic effects of the coal tar. They
are used primarily on steel piling and other buried structures.
The catalyst component is usually either a polyamide or an amine.
Coal-Tar Epoxy Coatings
Advantages
Low in VOCs
Good water/chemical resistance
Good film build
Good abrasion resistance
Limitations
Toxic; personal protection needed
Limited pot life
Blasted surface needed
Topcoating is a problem
Available only in black, dark
red, or aluminum
2.3.6
Polyurethane Coatings. Polyurethane coatings are oneor two-package systems. For two-package systems, one component
is an isocyanate and the other a polyol component. Because of
the reactivity of the isocyanate, polyurethanes are moisture
sensitive, and the gloss may drop when the wet film is exposed to
high humidity. One component types cure with moisture supplied
from the atmosphere. The toxicity of the isocyanate component is
of great concern, and personal protection, including respirators,
must be used when applying them. They require skilled
applicators. Polyurethane coatings are available in a variety of
formulations, giving rise to a variety of properties (e.g., may
be tough or elastomeric). They perform well in most
environments. Aliphatic polyurethanes have excellent weathering
in sunlight; aromatic polyurethanes do not, but they have better
chemical resistance. Both types can readily be formulated to be
low in VOCs.
18
MIL-HDBK-1110
Polyurethane Coatings
Advantages
Limitations
Low in VOCs
Good solvent resistance
Good hardness or flexibility
May have excellent gloss
Good durability
Good abrasion resistance
Highly toxic; need personal
protection
Moisture sensitive; gloss may
drop
Skilled applicator needed
Limited pot life
Blasted surface required
High cost
2.3.7
Polyester Coating. Polyester coatings are used most
with fiberglass or glass flake reinforcement. They can be very
tough and durable but are seldom used today on military
facilities except with glass reinforcement.
2.3.8
Inorganic Zinc Coatings. Inorganic zinc coatings
usually have a silicate resin and may cure by several different
mechanisms. They can be formulated to be acceptably low in VOCs,
particularly the water-based products. The silicate film is very
hard and abrasion resistant. When applied too thickly, they may
mud crack. Thus, they are generally applied at less than 5 mils
dft, although some products can successfully be applied at
greater thicknesses. They provide cathodic protection to steel,
but as the zinc corrosion products fill the natural film
porosity, they begin to provide barrier protection. If this
barrier is broken by impact, cathodic protection will again take
over until the break is healed by again filling with zinc
corrosion products. They require greater steel surface
cleanliness than do other coating types. They must be applied by
a skilled applicator using a constantly agitated pot to keep the
heavy zinc particles suspended. Inorganic zinc silicate coatings
frequently do not bond well to each other, and it is safest to
repair them using a zinc-rich organic coating. Problems may
occur when topcoating them with organic coatings. Small bubbles
of air or solvent vapors escaping from the porous silicate film
may create holidays. Because of this concern, and their good
performances without topcoating in a variety of services, it is
often best not to topcoat them.
Zinc-rich organic coatings require less surface
preparation and are easier to topcoat than inorganic zinc
products. However, if properly applied, inorganic zinc coatings
are extremely durable in an atmospheric environment, the steel
preferentially receiving cathodic protection from the zinc. The
zinc is attacked, however, by acid and alkali (i.e., is
19
MIL-HDBK-1110
amphoteric). Inorganic zinc coatings have not been used often in
continuous water immersion because of concern for their limited
period of protection.
Inorganic Zinc Coatings
Advantages
Limitations
Can be low in VOCs
Excellent abrasion resistance
Excellent heat resistance
Good atmospheric durability
Useful as shop primer
Costly
Needs clean, blasted surface
Requires skilled applicator
Constant agitation needed
Difficult to topcoat
Attacked by acid and alkali
2.3.9
Zinc-Rich Organic Coatings. Zinc-rich organic coatings
utilize an organic resin rather than an inorganic silicate
binder. Zinc-rich organic coating films can be of the
thermoplastic (e.g., utilize vinyl or chlorinated rubber resins)
or the thermosetting type (e.g., utilize epoxy or polyurethane
resins). Film properties of zinc-rich organic coatings are
similar in most respects to those of zinc-free organic coatings
using the same resin. Organic zinc-rich coatings do not require
as high a level of blast-cleaned steel surface as do zinc-rich
inorganic coatings, and they are easier to topcoat.
Zinc-Rich Organic Coatings
Advantages
Limitations
Can be low in VOCs
Good durability
Relatively easily topcoated
Moderate surface preparation
needed
equires skilled operator
Constant agitation necessary
Unsuitable for acid or alkali
Costly
2.4
Coating Compatibility. Because of their different
chemical and physical properties, coatings of different generic
types or with different curing mechanisms are generally
incompatible with each other. Those of the same generic type or
with similar curing mechanisms are generally compatible with each
other. Table 1 lists compatibilities and incompatibilities of
different generic types of coating.
Another way to check solvent compatibility is to
determine its solvent solubility. To do this, soak a cloth in
methylethyl ketone or acetone, rub it against the existing paint,
and visually check for pickup of paint. The paint is classified
as "solvent soluble," if paint is picked up and as "solvent
20
MIL-HDBK-1110
insoluble," if not. Solvent soluble coatings are generally not
compatible with coatings having strong solvents such as epoxies
and polyurethanes.
A more system-specific way to determine compatibility
of a new coating with an existing one is to apply a small patch
of the new paint over the old one. If any of the
incompatibilities described below exist, it will become visually
apparent on the patch within a few days. Incompatibilities
associated with differing mechanical properties (e.g., a more
rigid coating over a more flexible one) or sensitivity to
alkaline conditions occur in a longer timeframe and are also
discussed below.
2.4.1
Bleeding. Bleeding (staining) may occur when a coating
with a solvent is applied over an existing bituminous (coal tar
or asphalt) paint or pavement. The solvent dissolves the
bituminous material and permits it to spread through the topcoat
to cause a brown surface discoloration. This normally does not
adversely affect the film properties but produces an unsightly
appearance.
2.4.2
Disbonding of Old Paint. Strong solvents in a topcoat
may penetrate the existing undercoat and reduce its adhesion to
the substrate. This may then result in disbonding of the total
coating system from the substrate.
2.4.3
Topcoat Checking. An incompatibility may occur when a
relatively rigid topcoat is applied over an existing flexible
coating. If the topcoat checks (cracks in the topcoat only) to
relieve the stress.
2.4.4
Poor Adhesion of Latex Topcoats to Enamels. Problems
are frequently encountered in obtaining good bonding of latex
topcoats to chalky surfaces or smooth fully-cured alkyd enamels.
There is usually insufficient organic solvent in the latex
topcoat to dissolve sufficient enamel to bond tightly to it. It
may be necessary to first lightly sand the enamel to provide more
texture for adhesion and/or apply an oil-based primer as a tack
coat, before applying the latex topcoat.
2.4.5
Oil-Based Paints Applied to Alkaline Surfaces. Moist
alkaline conditions cause a slow breakdown of oil-based paint
films. The chemical reaction is called hydrolysis or
saponification. The rate at which this occurs and the resulting
rate of coating deterioration depend upon the environmental
conditions and the specific formulation of the materials.
However, in time oil-based coatings applied to alkaline surfaces
will delaminate and peel.
21
Table 1
Compatibility of Commonly Used Paints
(Primer or existing coating less than 6 months old.)
Primer
or Existing
Coating
Topcoat
Latex
Solvent Drying
Chemically Reacting
Coal Tar
Polyvinyl
Acrylic Acetate
ChlorinatedEpoxy Epoxy Urethane Polyester
Silicone
Vinyl
Rubber
Oleoresinous Alkyd Alkyd
Oil Drying
Oil Drying
Oleoresinous
Alkyd
Silicone Alkyd
C
C
C
C
C
C
C
C
C
CT
CT
CT
CT
CT
CT
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
Latex
Acrylic
Polyvinyl Acetate
C
C
C
C
C
C
CT
CT
CT
CT
C
C
C
C
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
Solvent Drying
Vinyl
Chlorinated
Rubber
Bituminous
C
C
C
C
C
C
CT
CT
CT
CT
C
NR
C
C
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
CT
CT
NR
NR
NR
NR
NR
NR
Chemically
Reacting
Epoxy
Coal Tar Epoxy
Zinc Rich Epoxy
Urethane
Polyester
Inorganic Zinc
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
CT
NR
NR
NR
NR
NR
NR
CT
NR
CT
NR
NR
CT
CT
CT
CT
NR
CT
CT
CT
CT
NR
NR
NR
CT
CT
NR
P
CT
CT
P
CT
NR
NR
C
CT
C = Normally Compatible.
CT = Compatible when special preparation
application conditions are met.
NR = Not recommended because of known or
problems.
P = A urethane may be used as a topcoat
coreactant is polyether or acrylic,
NR
NR
CT
NR
NR
NR
and/or
suspected
if its
but not if it is polyester.
NR
MIL-HDBK-1110
Section 3:
ENVIRONMENTAL, OCCUPATIONAL, AND SAFETY ISSUES
3.1
Introduction. Environmental and health concerns have
led to increased restrictions on coating operations. Material
composition, surface preparation procedures, and application
techniques have been affected. This chapter summarizes these
restrictions and concerns. Detailed information on specific
regulations related to these issues can be obtained from
installation offices responsible for environmental, occupational,
and safety issues.
3.2
Material Composition Issues
3.2.1
VOC Restrictions. VOCs make up the solvent portion of
coatings. When emitted into the atmosphere, they may combine
with oxides of nitrogen to form ozone, a major component of smog.
The Clean Air Act of 1970 (amended in 1977 and 1990) requires
states to develop and implement plans to ensure that the
Environmental Protection Agency's (EPA) National Ozone Standard
(less than 0.12 parts ozone/million parts air (ppm), by volume)
is met (National Ambient Air Quality Standard, 40 Code of Federal
Regulations (CFR) 50). To help meet this requirement, some states
and regions have placed limits on the VOC content of paints and
coatings.
3.2.1.1
Definition of VOC. For paints and coatings, VOC is
defined as the amount of volatile organic material measured in a
specific test procedure. The test procedure used in most regions
is EPA Method 24 (40 CFR 60, Appendix A). The VOC content that
is measured following such a procedure may be different from that
calculated based upon the coating formulation. For field applied
coatings, the VOC is determined on the coating as it is applied.
That is, if the coating was thinned for application, the thinner
contributes to the VOC level.
3.2.1.2
Types of Regulations. VOC regulations may place a
limit on the VOC content of liquid coatings or the amount of VOC
that a coating shop can release into the atmosphere, or may
require a minimum transfer efficiency, depending upon the local
regulations. VOC-content regulations vary from region to region
within states and between states, depending upon the ability of a
region or state to maintain compliance with the National Ambient
Air Quality Standard for ozone. VOC-content regulations may
apply to either or both shop-applied coatings and field-applied
coatings (architectural). Many regions of the country have
restrictions on shop-applied coatings, but only a few have
restrictions on architectural coatings. (However, a national
rule for architectural coatings is expected to become effective
in 1996.) For military facilities, rules affecting shop-applied
coatings (e.g., the miscellaneous metal parts rule) are of
23
MIL-HDBK-1110
greatest concern to the facility. The VOC limit for
miscellaneous metal parts is 340 grams per liter (g/L) in most
parts of the country. This limit is the result of a 1978 Federal
EPA guideline for shop-applied coatings for metals (commonly
called miscellaneous metal parts) which 35 states adopted as part
of their state implementation plans for VOC control. Regulations
that limit the total amount of organic materials released into
the air by a coatings shop are also in effect in some areas of
the country. Architectural coatings are regulated in California
and some other regions of the country. In California, the
acceptable limits are based on the type of structure to be coated
(e.g., residential versus industrial) and coating type. For
example, for most coatings for residential use, the limit is 250
g/L and for steel in corrosive environments, the limit is usually
420 g/L. Some special use coatings have higher or unrestricted
VOC limits. Since these regulations are subject to change and
since they vary from region to region, a general listing of which
paints comply with local regulations is not presented.
3.2.1.3
Effect on Coatings. Traditional solvent-borne
coatings, such as alkyds and epoxies, have been reformulated to
meet the VOC regulations by using binders with lower viscosities,
modifying the solvents or using other techniques to lower the VOC
content. As examples, an epoxy, MIL-P-24441 has been
reformulated to have a VOC content less than 350 g/L. New lower
VOC content coating types have also been developed by using other
coating technologies such as waterborne or powder. VOC-induced
trends in coating selection are summarized below:
a)
Greater use of water-based paints
b)
Greater use of high-solids paints
c)
Less use of oil-based paints
d)
Elimination of lacquers (vinyls and chlorinated
e)
Increased use of powder coatings
rubbers)
In general, to obtain an acceptable service life, a
cleaner, better prepared surface is required for low-VOC content
coatings than for traditional higher VOC content coatings.
Application of low-VOC content field-applied coatings may also be
more difficult than higher VOC content coatings.
Problems have been encountered with the use of some
low-VOC content paints. They are summarized in Table 2.
24
MIL-HDBK-1110
Table 2
Problems Encountered With Low-VOC Coatings
Generic Coating Type
Oil-based
Two-component epoxies
Polyurethanes
Problems Observed
Longer drying time
Residual tack or softness
Poor leveling
Wrinkling
Reduced pot life
Shortened drying time
Settling
Sagging
Poor application properties
Reduced pot life
Inability to apply thin films
Reduced gloss
3.2.2
Application Issues. In some regions of the country,
VOC emissions into the air have been further reduced by
regulations restricting the methods of application of coatings to
those with a minimum transfer efficiency of 65 percent. Transfer
efficiency is defined as the percent of the mass or volume of
solid coating that is actually deposited on the item being
coated, as shown in the following formulas:
Transfer Efficiency
(Percent)
Transfer Efficiency
(Percent)
= Mass of Solid Coating on Item x 100
Mass of Solid Coating Consumed
= Volume of Solid Coating on Item x 100
Volume of Solid Coating Consumed
3.2.3
Toxic Solvents. Paints and coatings often contain
solvents that are toxic at some level. While a person can
withstand nominal quantities of most of these ingredients for
relatively short periods of time, continuous or overexposure to
them may have harmful effects. The potential severity of hazards
is greatly magnified when operations are performed in enclosed or
confined spaces where toxic solvent concentrations can quickly
build up to levels which could produce disability and death. The
threshold limit values (TLV) for several commonly used paint and
cleaning solvents are given in Table 3. The TLV is a measure of
the maximum concentration of solvent vapor in the air which can
be tolerated during an 8-hour working day. Since these
25
MIL-HDBK-1110
concentrations are very low, they are expressed as parts of vapor
per million parts of air by volume (ppm). The higher the value,
the safer the solvent.
3.2.4
Hazardous Air Pollutants. Some solvents currently used
in coatings are on the list of hazardous air pollutants of the
Clean Air Act. Restrictions on the use of some of these solvents
in coatings are expected. Also, halogenated solvents currently
exempted from VOC restrictions because of their photo-chemical
inactivity, may be eliminated from use in coatings in the near
future because they deplete the upper atmosphere ozone layer. In
addition, halogenated solvents can become explosive when in
contact with aluminum spray guns.
3.2.5
Binders - Polyurethanes, Coal Tars, Asphalts. Coatings
formulated with these resins may required special worker safety
measures. Respirators and protective clothing may be needed.
The material safety data sheet and the installations health and
safety office should be consulted.
3.2.6
Heavy Metal-Containing Pigments and Additives. Leadand chromate-containing pigments have been used in paints to
provide color and corrosion control. Because of health concerns,
a Federal regulation limits lead concentration in new consumer
paints to less than 0.06 percent of the weight of the paint
solids. Although chromium, as chromate, is not specifically
excluded from paints by Federal regulation, the military guide
specifications for painting facilities (NFGS-09900, Paints and
Coatings and CEGS 09900, Painting, General) exclude chromatecontaining coatings. Chromate is also on the ACGIH list of
suspected carcinogens. Mercury-containing additives have been
used to provide in-can bacteria control and paint-film mildew
control. Because of health concerns, mercury can no longer be
used in paints for residential use. Organic materials are used
to control bacterial growth in the can and mildew growth on
films.
Organo-tins have been used to control fouling on paints
exposed to sea water. Because of the toxic effects of these
materials, they have been restricted by the EPA. Coppercontaining and some organic materials are being used to provide
this protection.
26
MIL-HDBK-1110
Table 3
TLV and Other Safety Data on Paint and Cleaning Solvents
Relative
Evaporation
Time (1)
Solvent
Acetone
Benzene (suspected carcinogen)
Butyl Alcohol (Butanol) - skin
Carbon Tetrachloride - skin
(suspected carcinogen)
Diisobutyl Ketone (DIBK)
Ethyl Acetate
Ethyl (Grain) Alcohol (Ethanol)
Ethyl Ether
Ethylene Dichloride
(1,2,dichloroethane)
Ethylene Glycol Monoethyl Ether
(Cellosolve) - skin
Ethylenediamine - skin
Ethylene Glycol Monoethyl Ether Acetate
(Cellosolve Acetate) - skin
Hi-Flash Naptha (Aromatic)
Isopropyl Acetate
Isopropyl Alcohol (Isopropanol)
- skin
Methyl (Wood) Alcohol (Methanol) - skin
Methylene Chloride (Dichloromethane)
(suspected carcinogen)
Methyl Ethyl Ketone (MEK)
Methyl Isobutyl Ketone (MIBK)
Mineral Spirits (Petroleum Thinner)
Refined Kerosene
Trichloroethylene
Toluene (Toluol) - skin
Turpentine
VM & P Naptha
Water
Xylene - skin
27
4
8
70
8
150
8
20
1
Flash
Point
(2)
(deg F)
Evaporative
Limits (3)
(% by volume)
(min)
(max)
10 2.6 12.8
10 1.4
7.1
105 1.4 11.2
not flammable
140
40
60
0.8
2.5
4.3
6.2
9.0
19.0
Threshold
Limit Values
(4)
TWA
STEL
750
10
50
5
1000
32
25
400
1000
10
100
110
2.6
15.7
5
32
130
1.7
no
10
5
1.0
1.8
2.5
data
7.0
7.8
12.0
200
200
250
250
55 5.5 36.5
not flammable
200
50
250
30
65
105
150
200
50
300
75
50
50
100
100
105
10
25
10
4
8
20
150
800
105
50
65
1.8
1.4
0.8
0.7
1.3
0.8
10.0
7.5
7.0
5.0
15
100
45
105
7.0
no
20
100
35
data
50 1.1
5.9
not flammable
85 1.0
6.0
300
100
150
MIL-HDBK-1110
Table 3 (Continued)
TLV and Other Safety Data on Paint and Cleaning Solvents
________________________________________________________________
NOTES: (1) Relative evaporation time is the relative time
required for the solvent to completely evaporate, based on an
arbitrary value of 1.0 for ethyl ether. The higher the number,
the longer the time required for evaporation.
(2) Flash point is the temperature of the solvent in
degrees F at which the solvent releases sufficient vapor to
ignite in the presence of a flame. The higher the value, the
safer the solvent with respect to flash point.
(3) Explosive limits define the range of solvent vapor
concentration in air for which the vapor could explode or ignite.
Below the minimum concentration and above the maximum
concentration, the vapor will not ignite. These values are
expressed as the percentage of the solvent vapor in the total
volume of vapor plus air. They are also called flammable limits.
(4) Threshold limit values (TLV) were obtained from the
American Conference of Governmental Industrial Hygienists
(ACGIH), Threshold Limit Values for Chemical Substances and
Physical Agents in the Workroom Environment. TWA is the time
weighted average exposure limit for an 8-hour workday or a 40
hour week. STEL is the short-term exposure limit for a maximum
15-minute exposure. Both values are expressed as parts per
million (ppm) of vapor per volume of air. The higher the value,
the safer the solvent. These TLV's are ACGIH's recommendations;
Occupational Safety and Health Administration (OSHA) limits may
be lower.
_________________________________________________________________
3.3
Issues Affecting Surface Preparation
3.3.1
Regulations. This section is aimed at environmental
issues. Worker safety issues are discussed in Section 13.
Environmental concerns and regulations affecting surface
preparation activities involve contamination of the environment
and waste disposal. Air regulations (National Ambient Air
Quality Standards described in 40 CFR 50-99) that are closely
associated with surface preparation and paint removal are the
ones for air particulate matter (PM 10) and lead. Air
particulate matter is defined as particles with an aerodynamic
diameter less than a nominal 10 micrometers. The allowable limit
is 150 milligrams per cubic meter, based on a 24-hour average
concentration. For lead, the criterion is 1.5 milligrams per
cubic meter, based on a 90-day average. Exceeding the PM 10
criterion is more likely during abrasive blasting than other
coating operations.
28
MIL-HDBK-1110
To meet the air regulations described above,
containment of work areas may be required. More extensive
containment may be needed when removing lead-based paint. The
Steel Structures Painting Council (SSPC) SSPC Guide 6I,
Containing Debris Generated During Paint Removal Operations,
describes five categories of containment. Worker protection must
also be considered in designing containment and ventilation
systems. Protecting both the environment and the workers is a
challenging task.
3.3.2
Waste. Debris resulting from surface preparation may
be hazardous waste as defined by Federal solid waste regulations
(40 CFR 240-280). Waste may be classified as hazardous if it
exhibits any of the following characteristics: ignitability,
corrosivity, reactivity, or toxicity, or if it is on a special
EPA list. For paint debris, wastes are most likely to be
hazardous because of their toxicity (e.g., exceeds limits for
lead, cadmium, chromium or mercury) or because of their
corrosivity (e.g., pH greater than or equal to 12.5 or pH less
than or equal to 2). For toxicity, waste is tested using the
toxic characteristic leaching procedure (TCLP) test, described in
Appendix II of 40 CFR 261. Waste is classified as hazardous
because of toxicity if lead concentration in the leachate exceeds
5 mg/kg, cadmium concentration exceeds 1 mg/kg, chromium
concentration exceeds 5 mg/kg, or mercury concentration exceeds
0.2 mg/kg. Paint debris wastes fail most often because of lead.
Some industrial paint wastes have also been reported to fail
because of chromium or cadmium. Although paint debris may
contain low concentrations of mercury from old films in which
mercury additives were used to control fungal or bacterial
growth, experience indicates that paint waste is unlikely to fail
because of mercury toxicity.
3.4
Surfaces Coated With Leaded Paint. The presence of
lead in paint films causes health, environmental, and worker
safety concerns. This section describes the DOD policy for
dealing with leaded-paint associated problems and summarizes DOD
guidance. References for specific guidance are given in the
References section.
3.4.1
Background
3.4.1.1
Use of Lead in Paint. Most oil-based residential
paints contained lead pigments prior to 1940. Lead pigments
provided hiding and color (tints of orange, yellow, green, and
red). Lead driers were used in both pigmented oil-based paints
and varnishes. The concentrations of lead in white or lightcolored paints sometimes exceeded 50 percent of the mass of the
dry film. Concentrations of lead in paints colored using lead
pigments ranged from 1 to about 10 percent of mass of the dry
29
MIL-HDBK-1110
film. Lead driers were used in concentrations of a few tenths of
a percent of the mass of the dry film. The use of lead hiding
pigments decreased when titanium dioxide became available in the
1940's, but it was not until 1972 that a Federal regulation set
the maximum allowable level of lead in residential paint
transported interstate at 0.5 percent. This level was reduced to
0.06 percent for all residential paints in 1978. Thus, leadbased paint abatement is directed primarily at housing built
prior to 1978. For steel structures, lead-containing primers
(e.g., those pigmented with red lead) have been used on military
facilities until recently to control corrosion. Yellow traffic
marking paints also may contain lead.
3.4.1.2
Effects of Lead Exposure on Health. Lead can cause a
variety of serious adverse health effects. These are detailed in
the Strategic Plan for Elimination of Childhood Lead Poisoning,
Center for Disease Control, 1991. In children, even low levels
of lead increase a child's risk of developing permanent learning
disabilities, reduced concentration and attentiveness spans, and
behavior problems. Adverse health effects may occur before the
appearance of any symptoms. Symptoms include loss of appetite,
difficulty sleeping, irritability, fatigue, headache, moodiness,
joint and muscle aches, and metallic taste in the mouth. High
levels of lead concentrations can result in severe damage to the
blood forming, nervous, urinary, and reproductive systems of the
body. Lead poisoning from leaded paint typically occurs due to
the ingestion of leaded paint or lead-contaminated dust into the
body through the digestive system or inhalation. Peeling and
chipping of leaded paint or abrasion of surfaces of leaded paint
are primary pathways for lead poisoning.
3.4.1.3
Environmental Issues. Lead containing materials are a
potential hazard to the environment when released in an
uncontrolled manner. Proper containment of painting operations
involving leaded paint and proper disposal of the debris are
required to prevent contamination of soil, water and air. Debris
generated during a maintenance painting job involving leaded
paint may contain enough lead to be classified as a hazardous
waste. If so, storage, transportation, treatment, and disposal
of waste is governed by Federal regulations and applicable local
and State regulations.
3.4.1.4
Occupational Safety Issues. Workers involved in
leaded-paint removal are at risk for lead poisoning. Poisoning
can result when the leaded paint is disturbed in a way that
creates uncontrolled dust or small particles such as in sanding,
open-abrasive blasting, chipping, grinding, and burning. The
lead dust makes its way into an individual in many ways,
including eating dust-contaminated food, hand-to-mouth activity,
smoking cigarettes, and breathing dust-contaminated air. This
30
MIL-HDBK-1110
hazard was addressed by in a rule published May 4, 1993 in the
Federal Register, 29 CFR Part 1926.62. This rule amended their
regulations for construction workers. It reduced the permitted
level of exposure to lead for construction workers from 200
micrograms per cubic meter of air as an 8-hour TWA to 50
micrograms per cubic meter of air. Special worker-protection
requirements are mandated when surfaces coated with leaded paint
are disturbed, unless existing data show that the requirements
are not needed. Training for workers aimed at both residential
and non-residential activities is available from EPA-sponsored
training centers and other private training groups.
3.4.2
Definitions. For the purposes of this discussion,
residential structures are Government owned or leased family
housing, child development centers, family child care homes,
schools, playgrounds, and similar facilities. Target residential
facilities are those constructed prior to 1978. Facilities
constructed or included in whole-house revitalization or similar
major rehabilitation projects since 1978, if paint coatings were
removed or replaced, are considered free of lead-based paint.
Non-residential structures include office buildings, warehouses,
water towers, and the like. Lead-in-paint terms are defined in
the following way:
a) Leaded paint - paint containing lead compounds as
an ingredient at potentially hazardous concentrations.
b) Lead-based paint - a legislative term, defined by
the U.S. Lead-Based Paint Poisoning Prevention Act as existing
paint in residential structures having lead concentrations of
1 milligram per square centimeter or greater.
c) Lead-containing paint - a regulatory term, defined
by the Consumer Product Safety Commission as residential paint
(wet) offered for sale having a lead concentration greater than
0.06 percent by weight of the film solids.
3.4.3
DOD Policy/Instruction. The following sections
summarize policy documents issued by DOD and military components
for residential and non-residential structures (Table 4).
3.4.3.1
Residential Structures. DOD's policy memorandum, LeadBased Paint (LBP) - Risk Assessment, Associated Health Risk in
Children, and Control of Hazards in DOD Housing and Related
Structures, describes the DOD policy for residential structures.
A DOD instruction will also be developed. The DOD policy is to
provide occupants of DOD residential structures (to include
leased structures) a safe and healthful environment. The
memorandum covers 1) assessing health risk from LBP and 2)
controlling LBP hazards in DOD housing and related structures.
31
MIL-HDBK-1110
The memorandum states that DOD will assess and correct all
recognized health-hazards in DOD residential structures and will
negotiate for assessment and control of LBP in DOD-leased
facilities. Control of LBP will be by either in-place management
(IPM) or removal. Removal is to be performed when IPM cannot
reliably control the lead hazard, or when removal is cost
effective during renovation or upgrade. Specific procedures for
carrying out the DOD policy are described in each of the military
component's documents shown in Table 4. The information is
summarized in par. 3.4.4.
Table 4
DOD and Military Component's Policy Documents on Lead-Based Paint
Document No.
Document Name
Scope
Point of Contact
DOD Memorandum, 24 Nov
1992
Lead-Based Paint (LBP) - Risk
Assessment, Associated Health
Risk in Children and Control
of Hazards in DOD Housing and
Related Structures
Residential
ODASD (Env/Sfty &
Occ Hlth)
U.S. Army,
Memorandum
28 April,
1993
Lead-Based Paint Policy
Guidance
Residential
CEHSC-FB-S,
Bryan J. Nix
U.S. Air
Force,
24 May 1993,
HQ USAF/CC
Air Force Policy & Guidance
on Lead-Based Paint in
Facilities
Residential
and
Industrial
HQ AFCESA\ENE,
Barry Kollme
U.S. Navy, 9 Navy Family Housing Lead-Based Residential
Nov 1992
Paint/Asbestos Inventory
Memorandum
Program
11101
FAC 08/T1822B
NAVFAC (Fam Hsg),
Richard Hibbert
U.S. Navy,
Lead-Containing Paint on NonDesign Policy Residential Structures
Letter, DPL09B-0001
NAVFAC Code 1004,
Bruce Bell
NonResidential
3.4.3.2
Non-Residential. Although there is no corresponding
DOD memorandum for non-residential structures, the Air Force,
Army and Navy have policy documents, referenced above, which
prohibit the use of lead-containing paint on non-residential
structures. (The Navy allows a slightly higher amount of lead in
coatings for corrosion control - less than 0.3 percent by mass of
the dry film - to account for possible contamination of zinc
pigments by lead.) The Navy policy also states that surfaces
covered with intact leaded paint do not represent a hazard until
there is a need to remove or physically disturb the existing
paint. Whenever surfaces covered with leaded paint are
32
MIL-HDBK-1110
disturbed, for example during repair or as part of an operations
and maintenance activity, special precautions may be required to
ensure the safety of the workers and prevent contamination of the
surroundings.
3.4.4
General Description of Lead-Based Paint Procedures.
Identification, risk assessment, and abatement procedures for
lead-based paint in residential and non-residential structures
may not be the same because of the differences in the way the
structures are used and maintained.
3.4.4.1
Inspection/Assessment. The first step of
inspection/assessment is to prioritize facilities to ensure that
those most likely to have the worst lead-based paint problems are
inspected first. Next, painted surfaces (using the Department of
Housing and Urban Development (HUD) guidelines list of components
and surfaces) are inspected to identify lead-based paint, leadcontaining dust or lead-based paint hazards. For paint, portable
x-ray fluorescence devices are used in conjunction with limited
sampling of surfaces for laboratory atomic absorption
spectrometric analysis. The data are analyzed to determine which
surfaces present a high risk (e.g., peeling, chipping) to
occupants. Both IPM and removal are part of all the strategies.
The objective of the IPM is to reduce excessive exposure to lead
and protect occupants from lead poisoning in facilities pending
total removal of lead-based paint.
For non-residential structures, there are no written procedures
for choosing surfaces for testing for leaded paint. The primary
circumstance in which paint is tested on non-residential
structures is just prior to preparing a contract for maintenance
painting. At that time it is important that samples be taken for
laboratory analyses to determine whether the paint contains lead.
This is because special worker safety and environmental controls
may be needed during coating maintenance to protect workers and
the environment. Environmental controls include containment of
debris to prevent it from polluting air, soil, or water.
Although there are no standard procedures for this inspection, it
is important that enough samples be taken to obtain a
representative lead concentration of the paint. All layers of
the paint film must be included in the samples. Testing should
also be undertaken prior to maintenance and operation activities
that will cause significant amounts of leaded paint to enter the
environment. Both worker safety and local containment of debris
are of concern.
3.4.4.2
In-Place Management (IPM). IPM refers to a broad range
of strategies and methods for controlling exposures to lead and
preventing poisonings from lead in paint pending permanent
removal. Because of the high number of facilities with lead33
MIL-HDBK-1110
based paint, immediate removal of all lead-based paint will not
be possible. IPM includes cleaning up lead-contaminated dust,
chipping, and peeling paint, and taking steps to stabilize leadbased paint to prevent additional peeling paint. IPM also
includes monitoring surfaces painted with lead-based paint and
appropriate periodic clean up of lead-contaminated dusty
surfaces. It also requires maintenance and repair work be
carried out with attention to the potential for creating lead
hazards.
3.4.4.3
Removal. The Navy Guide Specification, NFGS-13283,
Removal and Disposal of Lead-Containing Paint, and the Army Corps
of Engineers Guide Specification (CEGS) 02090, Removal of LeadBased Paint, provide guidance for removal of leaded paint in both
residential and non-residential structures. The following issues
must be considered for both types of structures:
a)
Occupant safety
b)
Building contents
c)
Worker safety
d)
Environmental protection (containment of debris)
e)
Cleanup
f)
Waste disposal
Detailed guidance for paint removal from residential
structures can be found in the HUD guidelines. The SSPC has
prepared three documents dealing with issues pertaining to
removal of lead-containing paint from industrial structures:
SSPC Guide 6I; SSPC Guide 7I, Disposal of Lead-Contaminated
Surface Preparation Debris, and SSPC QP2, Evaluating the
Qualifications of Painting Contractors to Remove Hazardous Paint.
3.4.4.4
Operations and Maintenance. Special operations and
maintenance activities may disturb lead-containing paint, for
example repairing a light fixture. In these situations, special
precautions are needed to:
a)
Protect the worker
b)
Control the spread of the dust that is generated
c) Ensure that debris is collected, handled, and
disposed of properly
34
MIL-HDBK-1110
3.4.5
Waste Disposal. Wastes from some painting operations
involving leaded paint may be classified as hazardous waste under
the Resource Conservation and Recovery Act (RCRA). Regulations
resulting from this act can be found in 40 CFR 240-280. For
lead-containing wastes, these regulations require that a
representative sample of the waste be tested using a standard
procedure, the TCLP. If the amount of lead that is leached from
the waste exceeds 5 mg/kg (ppm), the waste is classified as
hazardous. In addition, if alkaline chemical strippers are used
for removal, the waste may fail because of its alkalinity. If
the debris is classified as a hazardous waste, special procedures
are required for handling, transporting, treating and disposal.
These requirements are described in detail in 40 CFR 260-268.
The cost for disposing of hazardous waste is many times greater
than for non-hazardous waste.
3.4.6
Demolition of Buildings Containing Lead-Based Paint.
Maintenance painting is not directly involved in demolition of
buildings containing leaded paint. However, sampling and testing
procedures to determine whether debris is hazardous due to the
presence of lead are similar. In addition, restrictions on
sorting the waste into hazardous and non-hazardous groups are
similar. Information on disposing of demolition debris is
available in guide specification (Sampling Protocol - Building
Demolition Debris and Buildings Painted With Lead-Based Paint)
prepared by HSHB-ME-SH, U.S. Army Environmental Hygiene Agency,
Waste Disposal Engineering Division, Aberdeen Proving Ground, MD
21010-5422.
3.4.7
Sources of Detailed Information. Details of procedures
for removing, abating, and managing existing lead-based paint on
surfaces can be found in the references listed below:
a) Lead-Based Paint: HUD Interim Guidelines for
Hazard Identification and Abatement in Public and Indian Housing
(can be obtained by calling 1-800-245-2691)
b)
Air Force policy and guidance
c)
Army policy and guidance
d)
Navy policy and guidance
35
MIL-HDBK-1110
Section 4:
SELECTION OF COATINGS
4.1
Available Guidance. Guidance for specifying coating
systems for original or maintenance painting of shore facilities
is found in specialized guide specifications such as NFGS-13283
or CEGS 09900 or in Air Force Engineering Technical Letters. In
these documents, surface preparation for the primer is usually
considered a part of the system because of its importance in
system performance and is included in the guidance.
Recommendations for coating systems are also available from an
Army, Navy, or Air Force coatings specialist. These specialists
are particularly helpful when criteria for a specialized job are
not available or when guidance documents are out of date.
4.2
Selection Criteria. The best selection of a coating
system for a particular service is determined by a variety of
factors. These include desired properties, work requirements and
limitations, safety and environmental restrictions,
compatibilities, and costs.
4.2.1
Desired Film Properties. In selecting a coating
system, the first consideration is the desired properties of the
system for the particular service. Desired properties may
include one or more of the following aspects:
a) Resistance to exterior weathering (chalking; color
and gloss retention)
b)
Water, fuel, or chemical resistance
c)
Abrasion, heat or mildew resistance
d)
Appearance (color, gloss, and texture)
e)
Drying time
f)
Ease of application and maintenance
4.2.2
Work Requirements or Limitations. The following work
requirements or limitations may have to be considered:
a)
Type of surface preparation
b)
Access to work
c)
Drying times
d)
Necessary applicator skills
e)
Necessary equipment
36
MIL-HDBK-1110
f)
Scaffolding for access to work
4.2.3
Safety and Environmental Restrictions.
necessary to conform to all prevailing safety and
regulations concerning materials and processes to
surface preparation and for coating application.
regulations are discussed more fully in Section 3
handbook.
It will be
environmental
be used for
These
of this
4.2.4
Compatibilities. Coating systems must be compatible
with the surfaces to which they are applied. Coating
incompatibility can cause failures at or just after application
or after a much longer time. Failures occurring just after
application are due to solvent incompatibility or wetting
problems. Failures associated with slow chemical reactions, such
as those occurring between alkaline surfaces (e.g., concrete and
galvanized steel) and oil-based paints or mechanical property
mismatches (e.g., a rigid coating applied over a more flexible
one) cause failure in a longer timeframe. The failure more often
is peeling. For existing coatings being repainted, compatibility
generally means that topcoats should be of the same generic type
or curing mechanism as undercoats. One exception to this rule is
inorganic zinc coatings. Since inorganic zinc coatings
frequently do not bond well to themselves, it is safest to repair
them with zinc-rich organic coatings.
A simple test to classify coatings is to determine
solvent sensitivity using an methylethyl ketone (MEK) or acetone
rub test. To do this, soak a cloth in MEK or acetone, rub it
against the existing paint, and visually check for pick up of
paint. The paint is classified as "solvent soluble" if paint is
picked up, and as "solvent insoluble" if not.
Another practical method of ensuring topcoat solvent
compatibility is to coat a small test area of the existing
coating with the paint selected for the work. If situations
permit, this test is preferred over the MEK rub test because it
is specific for the surface to be repainted. The test area
should be visually inspected the following day (or preferably
after 3 or more days) for bleeding of undercoat, wrinkling, loss
of adhesion, or other coating defects. Although most
incompatibility problems are apparent in a couple of days, some
types of incompatibility may not become apparent for several
months or until after a change of seasons. These types are
usually associated with mechanical film properties.
4.2.5
Costs. Life cycle cost has always been one of the most
important considerations in selection of coating systems. Life
cycle costs include original surface preparation, materials, and
application and necessary maintenance throughout the life of the
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MIL-HDBK-1110
coating system. Today, the expense of containment of old paint
during its removal and disposal of debris that is often
considered to constitute hazardous waste must be included. This
usually means that the system with the maximum maintainable life
is the best choice.
4.3
Specifications for Lead- and Chromate-Free Coatings
With VOC Limits. The coating specifications listed below in
Table 5 are lead- and chromate-free and have limitations on their
contents of VOC.
Table 5
Lead- and Chromate-Free Coating Specifications With VOC Limits
Latex Coatings
Listed latex coatings are available with a VOC content of no more than 250
grams per liter unless otherwise specified
TT-P-19
Exterior acrylic emulsion coating, available in a wide
variety of colors and flat gloss finishes
TT-P-29
Interior latex paint, flat, available in white and tints
TT-P-650
Interior latex primer coating for gypsum board or plaster
TT-P-1510
Latex exterior flat finish coating, available in a variety
of colors
TT-P-1511
Latex interior coating, available in gloss and semigloss
in white and tints
TT-P-1728
Latex, interior, flat, deep-tone coating
TT-P-001984
Primer, latex, for wood
TT-P-002119
Latex high-traffic coating, available in flat and eggshell
and a variety of colors
TT-E-2784
Acrylic emulsion exterior enamel, gloss and semigloss,
available in a wide variety of colors
MIL-E-24763
Acrylic water-emulsion coating intended for shipboard use,
available in 275 and 340 grams per liter VOC classes;
high, medium, low, and flat glosses; and a limited number
of colors
MIL-P-28577
Corrosion-resistant latex primer for metals
Stains
MIL-P-28578
Waterborne acrylic semigloss finish, available in a wide
variety of colors
TT-S-001992
Exterior latex stain, semi-transparent and opaque,
available in a variety of colors
Clear Floor Finishes
A variety of clear floor finishes are available from the Maple Flooring
Manufacturers Association (MFMA) specifications, Heavy-Duty and Gymnasium
Finishes forMaple, Beech, and Birch Floors. Suppliers on the attached
list must be contacted to determine VOC content.
Oil and Alkyd Coatings
SSPC PAINT-25
Corrosion-resistant raw linseed oil and alkyd primer,
usually available at 300 grams per liter VOC but no
requirement listed
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MIL-HDBK-1110
Table 5 (Continued)
Lead- and Chromate-Free Coating Specifications With VOC Limits
TT-P-25
Oil-based primer for wood, normally available with a VOC
content less than 350 grams per liter
TT-P-31
Red and brown oil ("roof and barn") paint, usually
available with 250 grams per liter VOC content but no
requirement specified
Alkyd enamel, with 420 grams per liter VOC limitation,
available only in gloss, but in a wide variety of colors
Corrosion-resistant alkyd primer, with a 340 VOC
limitation
Corrosion-inhibiting alkyd quick-dry primer, with a 420
grams per liter VOC limitation
Silicone alkyd enamel, available in limited colors, 275,
340, and 420 grams per liter VOC types, and high, medium,
low, and flat gloss classes
Alkyd primer normally available at less than 350 grams per
liter
Epoxy Coatings
Epoxy-polyamide, two- and three-coat systems, available in
types with 340 VOC and limited colors
Fast-dry epoxy primer with 420 grams per liter maximum VOC
content
Waterborne epoxy primer with 340 grams per liter maximum
VOC content
Textured Coatings
Waterborne or oil- or rubber-based textured coating
available at 250 grams per liter
Urethane Coatings
High-solids aliphatic urethane coating, with 340 and 420
grams per liter VOC types, available in a variety of
colors and in glass and semigloss
Zinc-Rich Coatings
Zinc-rich coating, aqueous and organic solvent types,
self-curing and post-curing classes, organic and inorganic
vehicles, with 340 grams per liter maximum VOC content
TT-E-489
TT-P-645
TT-P-664
MIL-E-24635
MIL-P-28582
MIL-P-24441
MIL-P-53022
MIL-P-85582
TT-C-555
MIL-C-85285
MIL-P-24648
4.4
Recommendations for Different Substrates. This portion
of Section 4 provides general recommendations for wood, concrete
and masonry, steel, galvanized steel, and aluminum surfaces. The
recommended dft in mils is provided for coating specification
recommended for a particular substrate. More detailed
recommendations for coating particular structures are presented
in Section 5 of this handbook. Referenced standards for coatings
provide for lead- and chromate-free products that are low in
VOCs. Although such requirements may not be necessary at all
activities, such requirements may occur in the near future.
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MIL-HDBK-1110
In making local repairs of damaged coatings, loose
paint should be removed by scraping with a putty knife before
lightly sanding or abrasive blasting any exposed substrate and
feather-edging existing sound paint to obtain a smooth transition
with the repaired area. Coats of repair material should be
extended 1 inch onto the surrounding sound coating.
4.4.1
Recommendations for Wood. Oil-based and waterborne
coatings and stains (frequently called latex) perform quite well
on new wood. A two-coat system, paint or stain, is normally
applied. However, as additional coats are applied to resurface
or repair weathered paint, the film thickness may become
sufficient to reduce the total flexibility to the point that
results in disbonding of the total paint system from the surface.
Thus, when topcoating or making localized repairs, no more
coating should be applied than necessary to accomplish the
desired goal.
Surface preparation of new wood normally consists of
lightly hand sanding or power sanding, carefully controlled so
that it does not damage the wood. Sanding is also appropriate
for preparing weathered surfaces for refinishing and for spot
repairing areas of localized damage.
4.4.1.1
Oil-Based Paints. Historically, wood has been
successfully painted with oil-based products that penetrate the
surface well. These coatings are very easy to apply.
Oil-Based Paint System for Wood
Surface
Preparation
Sand
Primer
Topcoat
one coat TT-P-25 or
MIL-P-28582
2 mils dft
one-two coats MIL-E-24635
or TT-P-102
2 mils dft per coat
4.4.1.2
Water-Emulsion Paints. More recently, latex coatings
have been found to be very effective in providing attractive,
protective finishes. They are also less affected by moisture
than are oil-based finishes and are generally more flexible and
thus less susceptible to cracking as the wood swells and
contracts with moisture changes.
A problem sometimes arises when repairing or topcoating
existing smooth alkyd coatings with latex paints. To obtain good
intercoat adhesion, it may be necessary to lightly sand the
existing paint and/or apply a surface conditioner containing tung
oil or some other oil that wets surfaces well before applying the
first coat of latex paint.
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MIL-HDBK-1110
Waterborne Paint System for Wood
Surface
Preparation
Primer
Topcoat
Sand
one coat TT-P-001984
1.5 mils dft
one-two coats TT-E-2784
or other appropriate
latex paint in Table 5
1.5 mils dft per coat
4.4.1.3
Semi-Transparent Stains. Because oil-based and
waterborne paints form continuous films, they may form blisters
or disbond because of moisture in the wood attempting to escape.
Semi-transparent stains do not form continuous films on wood and
so do not have this problem. Thus, they are a good alternative
on new wood. Additional coats applied over the years or heavybodied stains will, however, form continuous films.
Stains for Wood
Surface
Preparation
Primer
Topcoat
Sand
one coat TT-S-001992
1.5 mils dft
one coat TT-S-001992
1.5 mils dft
4.4.1.4
Clear Floor Finishes. A variety of clear floor
finishes are available from MFMA Heavy-Duty and Gymnasium
Finishes for Maple, Beech, and Birch Floors. Suppliers on the
attached list must be contacted to determine VOC content.
Surface preparation for hard wood floors is described in detail
in NFGS-13283 or CEGS 09900.
4.4.2
Recommendations for Concrete and Masonry Surfaces.
Concrete and masonry surfaces, as well as those of stucco,
plaster, wallboard, and brick, can be coated with a variety of
systems depending upon the desired purpose and appearance.
Surface preparation is usually accomplished by power
washing with aqueous detergent solution to remove dirt and other
loose materials. Any oil or grease will have to be removed by
solvent or steam cleaning; any mildew, by scrubbing with bleach;
and any efflorescence or laitance, by brushing, followed by acid
treatment. These techniques are described more fully in
Section 6.
4.4.2.1
Waterborne Coatings. A two-coat waterborne (latex)
system provides an attractive breathing film that is normally
less affected by moisture in the concrete than non-breathing
systems. The latex material is a self-primer in this service,
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MIL-HDBK-1110
unless otherwise stated. Alkyd and other oil-based coatings
should not be applied directly to concrete or masonry surfaces,
because the alkalinity in the concrete will hydrolyze the oil in
the binder and cause the coating to peel. However, they can be
applied over concrete or masonry surfaces primed with waterborne
coatings to produce a tougher, more washable finish.
Waterborne Coating System for Concrete/Masonry
Surface
Preparation
Primer/Topcoat
Power wash
two coats of TT-E-2784 or other
appropriate* waterborne coating
1.5 mils dft each coat
*Interior or exterior product, desired gloss and color available.
TT-P-29 is less expensive and normally used on interior surfaces.
4.4.2.2
Elastomeric Coatings. Elastomeric, waterborne acrylic
coating systems also perform well to seal and protect
concrete/masonry surfaces and are normally very low in VOCs.
They can successfully bridge fine or larger caulked cracks.
There are no Government or military specifications for them.
Elastomeric Waterborne Acrylic System for Concrete or Masonry
Surface
Preparation
Power wash
Primer
Topcoat
one coat primer recommended
by supplier of elastomeric
coating dft varies with
supplier
one coat
elastomeric
acrylic coating
10 - 20 mils dft
4.4.2.3
Textured Coatings. Textured coatings system can bridge
fine cracks and waterproof from wind-driven rain. They are
normally applied over a primer recommended by the supplier to
insure good adhesion. They are available in a variety of
textures and may be waterborne or oil or rubber-based products
with a VOC limit of 250 grams per liter.
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MIL-HDBK-1110
Textured Coating System for Concrete or Masonry
Surface
Preparation
Power wash
Primer
Topcoat
one coat primer recommended
by supplier of textured
coating dft varies with
supplier
one coat TT-C-555
20 - 30 mils dft
4.4.2.4
Epoxy Coatings. A two-coat epoxy system will seal and
protect concrete/masonry surfaces well. An aliphatic urethane
finish coat should be used rather than the second epoxy coat on
exterior surfaces to improve the weatherability.
Exterior Epoxy/Urethane System for Concrete or Masonry
Surface
Preparation
Power wash
Primer
Topcoat
one coat MIL-P-24441
Formula 15
3 mils dft
MIL-C-85285
Type II
2 mils dft
Interior Epoxy System for Concrete or Masonry
Surface
Preparation
Power wash
Primer
Topcoat
one coat MIL-P-24441
Formula 150
3 mils dft
one coat MIL-P-24441
of another color
2 mils dft
4.4.3
Recommendations for Steel. Presently, a highperformance coating system is recommended to prolong the service
before it becomes necessary to remove and replace it. Costs in
coating removal, especially where there are restrictions on
abrasive blasting, are very high.
Abrasive blasting is always preferred to alternative
methods of preparing steel surfaces for painting. It cleans the
steel and provides a textured surface to promote good primer
adhesion. A commercial blast (SSPC SP 6) is normally adequate
for alkyd and epoxy primers for a moderate environment. A nearwhite blast (SSPC SP 10) is required for epoxies, including zincrich epoxies, exposed to a severe environment such as marine
atmospheric or water or fuel immersion. Some manufacturers may
specify a white metal blast (SSPC SP 5) for particular coatings
for special applications. It is important that a contract
specification does not conflict with the coating manufacturer's
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MIL-HDBK-1110
written directions. A white metal blast (SSPC SP 5) is
recommended for zinc-rich inorganic primers. If abrasive
blasting cannot be done, then power tool cleaning to bare metal
(SSPC SP 11) is recommended. It provides a surface cleanliness
and texture comparable to those of a commercial blast (SSPC
SP 6). Hand tool cleaning (SSPC SP 2) or power tool cleaning,
however, may be adequate in making localized repairs.
4.4.3.1
Alkyd Systems. In the past, most military steel
structures with atmospheric exposures were coated with an alkyd
or other oil-based system. Three-coat alkyd systems provided
adequate protection in moderate atmospheric service. On new
painting, they are being replaced in significant part by epoxy
systems that provide longer protection. Alkyd systems, however,
will still be used in large volume for repairing old deteriorated
alkyd systems.
Alkyd Coating System for Steel
Surface
Preparation
SSPC SP 6
Primer
one coat TT-P-645 or
SSPC PAINT 25
2 mils dft
Topcoat
two coats MIL-E-24635
or TT-E-489
2 mils dft
4.4.3.2
Epoxy Coating Systems. A three-coat epoxy system
provides good interior service in harsh as well as moderate
environments. An aliphatic urethane finish system is used in
place of the third epoxy coat in exterior service to provide
greater resistance to deterioration by ultraviolet light.
Several different epoxy mastic systems, some aluminum-filled,have
been used successfully on steel structures. However, there is no
specification for one at this time.
Epoxy System for Exterior Steel
Surface
Preparation
SSPC SP 6 or 10
Primer/Mid Coat
Topcoat
one coat each MIL-P-24441
Formulas 150 and 151
3 mils dft per coat
one coat
MIL-C-85285 Type II
2 mils dft
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MIL-HDBK-1110
Epoxy System for Interior Steel
Surface
Preparation
SSPC SP 6 or 10
Primer/Mid Coat
Topcoat
one coat each MIL-P-24441
Formulas 150 and 151
3 mils dft per coat
one coat
MIL-P-24441
of desired color
3 mils dft
4.4.3.3
Zinc-Rich Coatings. Good protection from corrosion and
abrasion can be provided by zinc-rich inorganic coatings. They
perform well untopcoated in a variety of environments except
acidic or alkaline. They may be topcoated with an acrylic latex
finish coat to provide a variety of color finishes. Epoxy (for
interior) or epoxy and aliphatic urethane (for exterior)
topcoats may also be used. Localized repair of inorganic zinc
systems is usually accomplished with a zinc-rich organic coating
to permit good bonding to any exposed steel, inorganic coating,
or organic topcoats.
Zinc-Rich System for Steel
Surface
Preparation
SSPC SP 5
Primer
Topcoat
1-MIL-P-24648
None, or one or
Composition B
more coats of
(inorganic), 3 mil dft
acrylic or latex,
(Composition A (organic) epoxy, etc.
can be used when a more
"forgiving" system is needed,
refer to pars. 2.3.8 and 2.3.9)
4.4.4
Recommendations for Galvanized Steel. Galvanized steel
corrodes very slowly in moderate environments but may be painted
with organic coating systems to provide color or additional
corrosion protection, particularly in severe environments. It
should never be coated directly with an alkyd paint, because the
alkalinity on the surface of the galvanizing will hydrolyze the
oil in the binder, degrading the binder, and cause paint peeling.
New galvanizing should be solvent or steam cleaned
(SSPC SP 1, Solvent Cleaning) to remove any grease or oil before
coating. Older, untopcoated galvanizing should be power washed
to remove any dirt or loose zinc corrosion products. Any loose
coatings should also be removed by power washing or scraping and
sanding to produce a clean, sound surface. Rust should be
removed by waterblasting or careful abrasive blasting to limit
the removal of galvanizing.
45
MIL-HDBK-1110
4.4.4.1
Epoxy Systems. Two coats of epoxy will provide longterm protection to galvanizing in interior service, as will one
coat of epoxy and one coat of aliphatic urethane to galvanizing
in exterior service.
Epoxy Coating System for Exterior Galvanizing
Surface
Preparation
SSPC SP 1
Primer
Topcoat
one coat MIL-P-24441
Formula 150
3 mils dft
one coat MIL-C-85285
Type II
2 mils dft
Epoxy Coating System for Interior Galvanizing
Surface
Preparation
SSPC SP 1
Primer
Topcoat
one coat MIL-P-24441
Formula 150
3 mils dft
one coat MIL-P-24441
of desired color
3 mils dft
4.4.4.2
Waterborne System for Galvanizing. Two coats of latex
paint will provide a pleasing appearance and good protection to
galvanized steel in moderate environments. They are easy to
apply.
Waterborne Coating System for Galvanizing in Moderate Environment
Surface
Preparation
Primer
Topcoat
SSPC SP 1
one coat TT-E-2784
1.5 mils dft
one coat TT-E-2784 *
1.5 mils dft
* Other commercially available acrylic latex systems will also
perform well.
4.4.5
Recommendations for Aluminum. Aluminum surfaces
corrode very slowly in moderate environments. They may be coated
to provide color or additional protection, particularly in severe
environments. Epoxy and epoxy/urethane systems perform well in
interior or exterior service, respectively. Alkyd systems
usually require surface pretreatments containing toxic materials.
Because aluminum surfaces are relatively soft, they
should not be cleaned by blasting with conventional abrasives or
grinding to avoid damage. Any grease or oil should be removed by
solvent or steam cleaning (SSPC SP 1). Dirt and other loose
46
MIL-HDBK-1110
contaminants should be removed by power washing. Existing
coatings are best removed by careful blasting with a soft
abrasive (e.g., plastic). Alkaline strippers should never be
used, because they will attack the aluminum.
Coating System for Aluminum
Surface
Preparation
See above
Primer
Topcoat
one coat MIL-P-24441
Formula 150 or
MIL-P-53022
3 mils
one-two coats
MIL-C-85285 Type II
2 mils per coat
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MIL-HDBK-1110
Section 5:
COATING SYSTEMS FOR SPECIFIC USES
5.1
General. Section 4 of this document provides general
guidance for the selection of coating systems for wood,
concrete/masonry, steel, galvanized steel, and aluminum surfaces.
This section provides more detailed information on systems for
specific structures or components of structures. These
structures include metal storage tanks, pipe lines, towers,
waterfront structures, siding, fences, and hot surfaces; concrete
storage tanks, swimming pools, catchment basins, pavements, and
floors; and wood floors. This section also describes problems
associated with mildew on painted surfaces.
5.2
Painting New Construction. The designer of the first
coating system for a new fuel tank, pipe line or other
constructed facility has the unique opportunity to specify a
system that can provide the best service. Much of the coating
system - surface preparation, priming and in some cases
application of the complete coating system - can be carried out
in a shop environment where the environmental and application
parameters can be controlled. By controlling these conditions,
the surface can be very well prepared and the film properties
obtained after curing are optimum. Further, worker safety and
environmental controls may be more easily accomplished. Since
the cost difference of a white metal blast as compared to a nearwhite blast may be small for new steel, and since the cost of the
"best" materials may not be much greater than the cost of "poor"
materials, the use of these procedures and materials should be
considered when selecting the coating system. Maintenance
painting is always more difficult than shop painting and frequent
maintenance painting on constructed facilities may interfere
unacceptably with the mission of the structure. Thus, in
summary, it is recommended that high-performance systems be
specified on new construction.
5.3
Fuel Storage Tanks. Steel fuel tanks are coated to
keep the fuel clean and prevent leaks resulting from corrosion.
Leaks can cause fires or serious contamination of soils or ground
waters. Underground steel fuel tanks should also be cathodically
protected or double walled to meet Department of Transportation
requirements directed at environmental protection from fuel
leaks.
For new tanks in most environments, effective
performance of most chemically cured (e.g., epoxies and
polyurethanes) has been obtained with a near-white finish (SSPC
SP 10) before coating. However, it is essential that the surface
preparation specified for a coating not be in conflict with that
provided by the coating manufacturer on the written coating data
48
MIL-HDBK-1110
sheet. In some cases, a coating manufacturer may state that a
coating should only be used over a white-metal finish (SSPC
SP 5). After application of the total system, it should be
checked for holidays with a low-voltage holiday detector as
described in the National Association of Corrosion Engineers
(NACE) RPO188, Standard Recommended Practice, Discontinuity
(Holiday) Testing of Protective Coatings. Any holidays that are
located should be repaired.
Repair of damaged coatings will vary somewhat with the
existing coating system. Normally, repairs are made with the
type of coatings already on the tanks. If these are not
available, another compatible coating system must be used.
Compatibility of coatings can be determined as described in par.
5.6.2. Localized exposed steel should be spot abrasively blasted
to an SSPC SP 10 condition and the intact coating surrounding
these areas should be brush-off blasted (SSPC SP 7) to a 2-inch
width. The patch of the same or a compatible coating system
should be applied to steel and extend 2 inches onto the cleaned
intact coating.
5.3.1
Interiors of Steel Fuel Tanks. Interiors of steel
storage tanks should be cleaned as described in NFGS-13219,
Cleaning Petroleum Storage Tanks, and inspected regularly.
Because it may not be possible to do this conveniently, it is
critical that they receive long-lasting, high-performance
interior coating systems. Corrosion occurs most frequently on
the floors of the tanks, where water is always present despite
its frequent removal from sumps. Thus, the bottoms of steel tank
interiors should be measured for adequate thickness before
blasting and recoating is initiated. It may be necessary to fill
pits with weld metal, apply a false bottom of fiberglassreinforced plastic as described in NFGS-13217, Fiberglass-Plastic
Lining for Steel Tank Bottoms (for Petroleum), or install a new
replacement steel bottom. All steel storage tank interiors
should be given a near-white blast (SSPC SP 10) immediately prior
to priming.
For many years, fuel tank interiors have been
successfully lined with a three-coat epoxy system with a total
dry film thickness of 9 mils. Coats of epoxy-polyamide
conforming to Formulas 150, 151, and 152 of MIL-P-24441 have been
the epoxy system most frequently used to line military steel fuel
tanks. It is described in NFGS-09973, Interior Coating System
for Welded Steel Petroleum Storage Tanks.
More recently, a urethane system was developed for
lining steel fuel tanks. As described in NFGS-09970, Interior
Coatings for Welded Steel Tanks (for Petroleum Fuels), it
consists of a pretreatment wash primer, a polyurethane primer, a
polyurethane intermediate coat, and a finish coat. The finish
49
MIL-HDBK-1110
coat may be a polyurethane or a special fluorinated polyurethane.
These coatings currently exceed the VOC limit of 340 grams per
liter that exists in many locations, the fluorinated polyurethane
coating is very expensive, and the pretreatment wash primer and
the primer contain chromate. However, because of the reported
much longer life of the system with the fluorinated polyurethane
finish, it is recommended for Navy fuel tanks, wherever it is
legal to use it.
After application of each coat of interior paint, tank
interiors must be thoroughly ventilated to remove organic solvent
vapors and to assist in curing (solvent release) of coatings.
Ventilation requirements vary with tank size, shape, and number
of openings. Safety requirements and instructions of coating
manufacturers should be followed. Heated air can also be used to
accelerate curing of coatings. Blasting and painting hoses, as
well as other electrical equipment, should be grounded and
sparkproof. The local industrial hygienist can provide
information on health and safety requirements for the lining
operation. It is especially important to require holiday testing
of the interior tank coatings. In this way, small defects can be
found and repaired, preventing sites for premature initiation of
corrosion.
5.3.2
Exteriors of Steel Fuel Tanks. The exterior coating of
steel fuel tanks is described in NFGS-09971, Exterior Coating
System for Welded Steel Petroleum Storage Tanks. For new tanks,
a system that has performed well is two coats of epoxy-polyamide
(e.g., MIL-P-24441 Formulas 159 and 151) and a finish coat of
aliphatic polyurethane (e.g., MIL-C-85285) to a total dry film
thickness of at least 8 mils. The recommended surface
preparation is an SSPC SP 10 near-white blast. Refer to
par. 4.4.3 for maintenance painting of exterior tanks.
5.4
Steel Water Tanks. Newer steel water storage tanks
have welded sections. Older riveted or bolted tanks are still
used, however, at some activities. The seam areas of such tanks
are much harder to completely coat. Cathodic protection, as
described in NFGS-13112, Cathodic Protection System (Steel Water
Tanks), CEGS 16641, Cathodic Protection System (Steel Water
Tanks), and MIL-HDBK-1004/10, Electrical Engineering Cathodic
Protection, is recommended for water tank interiors to supplement
the protection afforded by coatings. Corrosion of cathodically
protected water tanks generally is usually concentrated at the
top of the tank along sharp edges, crevices, and beams supporting
the roof, where cathodic protection does not occur. Thus, it is
important to coat and inspect these areas especially well.
50
MIL-HDBK-1110
5.4.1
Interiors of Steel Water Tanks. Most states presently
require or are expected to require the use of coating systems
approved by the National Sanitation Foundation (ANSI/NSF
Standards 60 and 61) for the lining of potable water tanks.
Coating approval is based on tests (NSF Standards 60 and 61) for
leaching of toxic materials. The tests do not address durability
of the coatings for water immersion service. The coatings are
usually epoxies. In states that have no requirements, the threecoat epoxy-polyamide system described in par. 5.3.1.1 for the
interiors of steel fuel tanks can also be used, except that
Formula 156 (red) is used in place of Formula 151 (gray) as the
intermediate coat. Metal and coating repairs for water tanks can
be made in the same manner as described for fuel tanks, but those
for potable water tanks must be covered with an NSF-approved
coating system, where these requirements prevail.
5.4.2
Exteriors of Steel Water Tanks. Exteriors of water
tanks should be coated in the same manner as described in
par. 5.3.2 for the exteriors of fuel tanks.
5.5
Other Steel Tanks. Steel tanks may contain waste
water, chemicals, or other corrosive materials. Cathodic
protection is also recommended for these tanks. Refer to
par. 5.4.
5.5.1
Interiors of Other Steel Tanks. Interiors of steel
tanks containing waste water, chemicals, or other corrosive
liquids should be coated with a suitable corrosion-resistant
lining (e.g., fiberglass-reinforced polyester) to protect the
steel from corrosion. Since there are no Federal specifications
for such products, specialty coating suppliers should be
consulted about them.
5.5.2
Exteriors of Other Steel Tanks. Exteriors of steel
tanks containing wastewater, chemicals, and other corrosive
liquids should be coated with the system described for steel fuel
tank exteriors in par. 5.2.2.
5.6
Steel Distribution Lines. Steel distribution lines
containing water, fuel, or other liquids are coated to prevent
loss of product from corrosion and contamination of soils and
groundwater.
5.6.1
Steel Fuel Lines
5.6.1.1
Buried Steel Fuel Lines. Buried steel fuel lines must
be coated and cathodically protected to meet Department of
Transportation regulations and to provide their most economical
protection.
51
MIL-HDBK-1110
a) The desired properties of coatings for buried,
cathodically protected pipelines are:
(1)
Good electrical insulation
(2)
Good moisture resistance
(3)
Good adhesion
(4)
Resistance to cathodic disbonding
(5)
Resistance to damage during handling
(6)
Ease of repair
b) Coatings for piping to be buried should
in a shop under controlled conditions. Blasting with
equipment that recycles the abrasive should provide a
of cleanliness (SSPC SP 5 or 10). Coatings that have
commonly used on buried piping include:
(1) Coal Tar Enamels - Coal tar enamels
different combinations of fiberglass and felt wraps to
mechanical strength and thickness (1/8 inch or more).
has greatly declined because of environmental concerns
tar.
be applied
automatic
high level
been
use
provide
Their use
about coal
(2) Asphalt Mastics - Asphalt mastics are
combinations of asphalt, sand, and other materials that are
extruded over pipes at thicknesses up to 1/2 inch. They are
quite moisture-resistant but lack resistance to both hydrocarbons
and sunlight and, like coal tar enamels, are a health concern.
(3) Extruded Coatings - Extruded coatings
typically have a 10 to 15 mil mastic base covered with a
polyethylene or polypropylene outer jacket. They are sensitive
to sunlight and must be covered if they are to be exposed to it
for long periods of time.
(4) Fusion-Bonded Powder Coatings - Fusion-bonded
powder coatings are usually applied by electrostatic spray to
pre-heated pipe (400 to 500 degrees F) cleaned to a near-white
surface (SSPC SP 10). The 10 to 30 mil coating is water-cooled
before storage and subsequent use.
(5) Plastic Tapes - Polyethylene, vinyl, and coal
tar tapes are available with different adhesives and thicknesses.
Because they are relatively easily damaged, they are often
installed with a secondary rock shield. Portable wrapping
machines are also available for over-the-ditch application.
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MIL-HDBK-1110
(6) Heat-Shrinkable Tapes - Heat-shrinkable tapes of
polyolefin provide tight bonding to pipes. They are shrunk in
place by heating at 300 to 400 degrees F. Their relatively high
cost limits their use to special areas such as joints.
5.6.1.2
Immersed Steel Fuel Lines. Immersed pipes lines can be
in fresh or salt water, near the surface where they are exposed
to ultraviolet (UV) light or deep where UV light is not of
concern. Further, some pipe lines are exposed to abrasion from
particulates and debris in the water. A coating that has been
successful in some applications is the three-coat epoxy system
described for steel fuel tank interiors in par. 5.3.1. Vinyl
coatings are effective where there is abrasion. The pipe lines
can also be cathodically protected.
5.6.1.3
Aboveground Fuel Lines. Aboveground fuel lines can be
coated much the same as fuel tank exteriors described in
par. 5.3.2. A petrolatum paste/tape system has also been used
very effectively in protecting fuel lines under piers. The
system can be applied by hand over wire-brushed steel. It is
very easy to repair when damaged.
5.6.2
Steel Water Distribution Lines. Steel water
distribution lines should be coated as described for steel fuel
distribution lines in pars. 5.6.1.1, 5.6.1.2, and 5.6.1.3,
depending upon the environment, buried, immersed, or aboveground.
Although buried steel water distribution lines do not present the
same level of environmental hazard as do buried steel fuel lines,
it is recommended that they be cathodically protected, as well as
coated. For steel water distribution lines that are buried but
not cathodically protected, use the three-coat epoxy-polyamide
system described for steel fuel tank interiors in par. 5.3.1.
5.7
Communication Towers and Other Tall Structures. The
military has thousands of communication towers of various sizes
and configurations in many geographical and climatic regions.
The tower designs and initial treatments of the steel
construction materials often vary from site to site and within
the same site. These variable factors often cause problems in
obtaining cost-effective painting of the towers.
Many towers require either a painted pattern of
alternate aviation orange and white markings for daytime
visibility, or lighting (strobe for high towers). Requirements
for marking and lighting are described in detail in Federal
Aviation Administration (FAA) Advisory Circular 70/7460-1G.
Compatibility of coatings can be determined as described in par.
5.6.2. The use of painted patterns over zinc-coated structures
is a better choice over lighting for long-term use and operation
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of towers. While lighting may be less expensive in initial
construction and maintenance, an unprotected bare zinc surface
will erode and require more expensive repairs than a bare
surface. Further, some studies have shown that the lifetime of
the zinc plus organic coating system is significantly greater
than the sum of just the zinc coating and of an organic coating.
While painting automatically brings maintenance problems, these
are normally much less than those occurring to unpainted towers.
The orange and white colors required by the FAA are available in
aliphatic polyurethane, alkyd, and latex formulations.
5.7.1
New Towers. Today, new tower components are usually
built with galvanized structural steel or steel thermally sprayed
with zinc metal, if too large to be placed in a dipping tank.
5.7.1.1
New Galvanized Steel Towers. Galvanizing applications
for steel tower components are typically heavy (e.g., 4 to 7 mils
of zinc) and accomplished by hot dipping. Whether thermally
sprayed or hot dipped, the zinc coating can provide several years
of protection by itself. However, it will subsequently be
necessary to apply a paint system to extend this corrosion
protection, after the zinc is consumed. Because quality painting
of towers after erection is both difficult and expensive, it is
always best to apply organic coatings beforehand, preferably in a
shop setting. Surface preparation and painting of tower
components in a shop can be accomplished under controlled
conditions to provide optimum protection of the metal. Shop
cleaning of zinc-coated surfaces is normally limited to detergent
washing to remove loose contaminants and/or solvent cleaning
(SSPC SP 1) to remove grease or oil. Sometimes, a thin film of
grease or oil is applied at the factory to protect galvanizing
from corrosion during exterior storage. Also, new galvanizing is
sometimes treated with chromate corrosion inhibitors for
corrosion protection during storage. Such treatment should
specifically be excluded in specifications for galvanized steel
components to be coated.
Galvanized steel components are best protected with one coat each
of epoxy-polyamide (e.g., MIL-P-24441 Formula 150) and aliphatic
polyurethane (e.g., MIL-C-85285) coatings as described above. If
a delay of over 4 days occurs before topcoating, the finish coat
of polyurethane may not adhere because of the solvent resistance
of the nearly fully cured epoxy coat. A thin (2-mil wet film
thickness) film of the epoxy primer applied and allowed to cure
to a tacky finish (e.g., 4 hours) will provide a suitable surface
for the polyurethane finish coat. Epoxy and urethane coatings
must have at least a 6-hour pot life for practical coating of
towers in place. Oil-based paints (including oil/alkyds) are not
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MIL-HDBK-1110
recommended because of the inherent incompatibility of oil-based
paints with the alkaline surface of galvanizing. Premature
failure by peeling is predictable.
A two-coat latex system (e.g., 1-1/2 mils dry film
thickness each of MIL-P-28577 primer and MIL-P-28578 topcoat or
SSPC PAINT 24) can also be used on galvanizing, but the
protection and gloss and color retention may not be quite as good
as with the epoxy/polyurethane system. The corrosivity of the
exposure environment should be considered when choosing between
the two systems.
5.7.1.2
New Thermally Sprayed Steel Towers. Thermally sprayed
zinc is relatively porous and protects steel by cathodic
protection. It should be sealed to provide maximum protection.
Application of epoxy polyamide MIL-P-24441, Formula 150 thinned
50/50 has been very effective in sealing of thermally sprayed
ship components. Where restrictions on the solvent (VOC) content
prevail, sealing can be accomplished with a mist coat. Sealing
should be followed with a full coat of Formula 150 applied at the
usual 3-mil dry film thickness and a finish coat of aliphatic
polyurethane (e.g., 2 mils dry film thickness of MIL-C-85285).
Some private companies have successfully coated
thermally sprayed steel components with a single, heavy (e.g., 6
to 8 mils dry film thickness) coat of commercially available
aluminum-filled epoxy mastic. Such a product is not covered by
Government or industry specifications.
5.7.1.3
New Steel Towers. If new steel tower legs are not
galvanized or thermally sprayed with a zinc coating, use of an
inorganic zinc coating should be considered if the coating can be
applied in the shop. A controlled shop environment can provide
the proper conditions for obtaining a very corrosion-protective
inorganic-zinc coating. These coatings (e.g., SSPC SP 5 surface
preparation and MIL-P-24648, inorganic zinc) have been shown to
provide long-term service with minimal maintenance requirements.
If the coating must be applied in the field, an organic zinc-rich
coating is probably preferred since they are more forgiving of
surface preparation lapses and can be applied and cured over a
wider range of environmental conditions. For either system, an
intermediate coat of epoxy polyamide (e.g., MIL-P-24441, Formula
150) and a finish coat of aliphatic polyurethane (e.g.,
MIL-C-85285) can complete the system.
5.7.2
Existing Towers. It is best to repair damaged tower
coatings on existing towers on a regular schedule before the
damage becomes significant. To repair or topcoat existing
coatings, it is necessary to know the generic type of the present
coating. The same or another compatible coating must be used.
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MIL-HDBK-1110
In some cases (e.g., with vinyl or chlorinated rubber coatings),
another generic type coating may have to be used, because the old
one is no longer permitted by many local environmental
regulations.
Before contracting any tower painting, it is necessary
to determine if any existing paint on the tower contains lead.
Lead may be present as one or more components of alkyd paints or
as pigmentation for the aviation orange color. Unless the
absence of lead is definitely known, samples should be taken and
submitted to a laboratory for analysis. Refer to NFGS-13283 or
CEGS 02090 for information on removal, containment, and disposal
of lead-containing paint. If the generic type of the existing
finish coat is not known, a compatible coating may be selected by
merely determining its solvent solubility. To do this, soak a
cloth in methyl ethyl ketone or acetone, rub it against the
existing paint, and visually check for pickup of paint. The
paint is classified as "solvent soluble" if paint is picked up,
and as "solvent insoluble" if not.
The common practice of applying paint by glove is not
recommended. It produces neither a continuous nor a uniformly
thick paint film. Roller application is also not recommended
because of difficulties in coating irregular surfaces. Spray
application by portable equipment produces the most attractive
finish but generally produces much overspray. Electrostatic
spraying can eliminate overspray, if it is available on high
platforms.
Spray cans can provide a quick cosmetic touch-up for
small damaged areas. Brushing is generally the most practical
application method to coat sharp edges, crevices, and corners.
It also can produce a relatively uniform, continuous film.
5.7.2.1
Towers With Only Cosmetic Coating Defects. Maintenance
painting to correct fading, discoloration, or limited intercoat
peeling should be undertaken when the existing aviation orange on
the upper portion of the tower fails to meet the requirement of
the color tolerance chart of the FAA (refer to Advisory Circular
70/7460-1G). Whatever the construction material, the only
surface preparation that is required is removal of loose
contaminants with a bristle brush or by washing. One or two
coats of acrylic latex finish (e.g., TT-E-2784), as required for
complete hiding of the existing paint, should be applied to the
cleaned surfaces. Normally, weathered exterior coatings are
sufficiently textured for good adhesion and general compatibility
of latex topcoats. However, severe chalking of the old coating
may present an adhesion problem for latex coatings.
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MIL-HDBK-1110
5.7.2.2
Zinc-Coated Steel Tower Components With Deteriorated
Organic Coatings. Zinc-coated steel (either galvanized or
thermally sprayed) with damaged organic coatings should be
scrubbed with a bristle brush to clean the exposed metal surface
and remove loose coatings. The coatings should also be lightly
sanded, if necessary, to feather edge the damaged areas. If the
old paint is oil, alkyd, latex, vinyl or solvent soluble, apply
one coat each of latex primer and finish to the exposed zinc
coating and overlay it 1 inch onto the surrounding tight coating.
If the repaired area matches the intact paint, it will not be
necessary to topcoat the undamaged areas.
If the existing finish coat is polyurethane, epoxy, or
solvent insoluble, apply one coat of epoxy primer and one coat of
aliphatic urethane finish to damaged areas. Again, if the match
is good, topcoating of undamaged areas will be unnecessary.
If an inorganic zinc-primed steel component has
suffered topcoat damage, it should be repaired with the original
topcoat system. If the inorganic zinc primer itself is damaged,
it should be repaired with a zinc-rich epoxy primer (e.g.,
MIL-P-24441, Formula 159) and then given an epoxy intermediate
coat and an aliphatic polyurethane finish coat. Sometimes,
corrosion of the galvanizing has been so severe that underlying
steel is exposed. Such areas should be treated as described
below for steel tower components.
5.7.2.3
Steel Tower Components (With No Zinc Coating) With
Damaged Organic Coating. Steel components of towers that have
never received a zinc coating and currently have damaged coatings
should be hand (SSPC SP 2) or power tool (SSPC SP 3 or 11)
cleaned to remove rust and loose paint. The preferred method of
surface preparation is SSPC SP 11. This method not only removes
all visible rust but also produces a roughened surface so that it
is considered comparable to SSPC SP 6. Powered needle guns and
grinders with flexible wheels and disks can produce the SSPC
SP 11 surface. The steel should be cleaned and primed the same
day, before flash rusting occurs.
If the old paint is oil, alkyd, latex, vinyl or solvent
soluble, apply two coats of alkyd primer to the exposed steel to
a total of 3 mils dry film thickness and overlay it 1 inch onto
the surrounding tight coating. A primer with raw linseed oil
(e.g., SSPC PAINT 25) will penetrate the surface better but dry
relatively slowly. A totally alkyd primer (e.g., TT-P-645) will
dry faster but may not penetrate the surface as well. After
priming, apply two alkyd or silicone alkyd (e.g., MIL-E-24635,
Enamel, Silicone Alkyd Copolymer (Metric)) finish coats at the
same thickness. Two additional coats of primer followed by one
or more latex finish coats can be used instead of the alkyd
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MIL-HDBK-1110
finish coats, if the alkyd finish coats are unavailable because
of environmental regulations. If the repaired area matches the
intact paint, it will not be necessary to topcoat the undamaged
areas.
If the existing finish coat
solvent insoluble, apply two coats of
of aliphatic urethane finish. Again,
topcoating of undamaged areas will be
is urethane, epoxy, or
epoxy primer and one coat
if the match is good,
unnecessary.
5.7.3
Galvanized Steel Guy Lines for Towers. Tall towers are
usually supported with galvanized steel stranded guy lines.
These are frequently coated with a commercial preservative
grease, as they are installed. These greases or pastes are most
frequently petroleum or drying oil products. Care should be
taken not to contaminate the guys before they are coated. Some
equipment is available for applying the grease after installation
of guys. Equipment for remote application is described in NCEL
Techdata Sheet 76-04. Galvanized steel anchor support systems
securing guys in place can also be protected by preservative
greases.
5.8
Waterfront Structures. The coating of steel waterfront
structures is described in NFGS-09967, Coating of Steel
Waterfront Structures. Coating systems are best applied in a
shop under controlled conditions. Systems which have provided
good protection have included abrasively blasting to a near-white
condition (SSPC SP 10) and application of one of the following
coating systems:
a) Epoxy polyamide system - e.g., three coats of
MIL-P-24441 starting with Formula 150 primer (each 3 mils dry
film thickness).
b) Coal tar epoxy-polyamide System - e.g., two coats
of SSPC PAINT 16 (each 8 mils dry film thickness).
Repainting or spot repairing coatings in or below tidal areas is
a real problem. Quick-drying lacquers that can dry between tidal
changes are not permitted at many locations because of VOC
restrictions. One approach to resolve the problem is to use a
cofferdam to apply suitable materials such as MIL-P-24441 or SSPC
PAINT 16 that can cure underwater. Another approach is to use
viscous splash-zone compounds that are applied manually or
thinner epoxy materials that can be applied underwater by brush,
roller, or pads.
5.9
Hydraulic Structures and Appurtenant Works. Coating of
hydraulic structures and associated pipe lines and equipment is
described in CWGS 09940, Painting: Hydraulic Structures and
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MIL-HDBK-1110
Appurtenant Works. Cathodic protection of gates is described in
CWGS 16643. Coatings for use on locks and dams must have good
abrasion resistance in addition to providing good corrosion
control. Vinyl systems have worked well for many years.
5.10
Factory Finished Metal Siding. Factory-finishing of
steel, galvanized steel, or aluminum siding is usually
accomplished by specialized procedures (e.g., coil coating) using
commercial products. It is best to consult the manufacturer of
the siding for recommended coating repair methods.
5.11
Chain Link Fences. Chain link fences are usually made
of galvanized steel (refer to NFGS-02821, Chain Link Fences and
Gates, or CEGS 02831, Fence, Chain Link). Occasionally, they are
made of vinyl-clad steel or aluminum-coated steel. As the
protective metals or vinyl corrode or erode away, they may need
coating to further protect them and/or to restore an attractive
finish. The fencing must be washed with a detergent solution to
remove loose contaminants before coating with a long-nap roller
or electrostatic spray equipment. The coating system should be
composed of two coats of acrylic latex (e.g., TT-E-2784) or one
coat each of epoxy-polyamide (e.g., MIL-P-24441, Formula 150) and
aliphatic polyurethane (MIL-C-85285).
5.12
Hot Steel Surfaces. Mufflers, stacks, and other hot
steel surfaces are not protected by conventional coatings,
because they are quickly burned away. Even thin fused aluminum
coatings such as TT-P-28 provide only limited protection,
provided that they are fused properly. (These coatings must be
exposed to at least 400 degrees F for a short time for fusion to
take place.) Such steel surfaces are better protected by
thermally sprayed zinc (withstand up to 700 degrees F) or
aluminum (withstand up to 1600 degrees F or higher when sealed)
after blasting to a white metal finish (SSPC SP 5). Thermal
spraying of aluminum is described in DOD-STD-2138(SH), Metal
Spray Coatings for Corrosion Protection Aboard Naval Surface
Ships (Metric).
5.13
Concrete Fuel Tanks. The DOD has many concrete fuel
tanks (mostly underground) that were built during World War II.
They have been lined with the cloth-reinforced latex coating
system described in NFGS-09980, Interior Linings for Concrete
Storage Tanks (for Petroleum Fuels), epoxy systems, and other
systems. Cloth-latex reinforced systems have been found to work
as well as any. However, they may not work well over concrete
that is contaminated with oil. Oil contamination is difficult to
remove and latex coatings do not bond well on this surface.
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MIL-HDBK-1110
5.14
Concrete Swimming Pools. Concrete swimming pools
require periodic painting to keep them watertight and attractive.
Even fiberglass-reinforced plastic pools may require refinishing
to restore them to an acceptable appearance should they fade or
chalk significantly. Chlorinated rubber coatings (e.g., TT-P-95,
Type I) have been used effectively for many years for lining
pools. Although these coatings are high in VOCs (solvent
content), they have received a temporary exemption for coating
concrete pools in most locations with VOC limitations. Epoxy
coatings perform well on interior concrete pools, but some of
them chalk to such an extent, even underwater, that the water is
clouded in exterior pools. Waterborne pool coatings have not
proven to be durable.
a) Exterior pools are usually coated in the spring
before the swimming season when the temperature is between 50 and
80 degrees F. New concrete pools should be allowed to cure at
least 2 months before painting. The first step in preparing
concrete pools for painting is to make necessary repairs:
(1)
Remove loose concrete
(2)
Repair small cracks and holes
(3)
Repair large cracks and spalls
b) Repair small cracks and holes with a non-shrinking
patching compound. Cracks greater than 1/2 inch and spalls
should be repaired with cementitious material (e.g., a mix
containing two parts of clean, hard, sharp sand to one part of
Portland cement). The repair area should be thoroughly wetted
and enough water added to the mix to make a heavy paste.
c) After repairs have been made, any efflorescence or
laitance on the surface of the concrete should be removed by
brushing with a dry bristle brush, treating with 5 to 10 percent
muriatic (hydrochloric) acid, and rinsing with clear water.
Mildew should be removed as described in par. 5.18, and body oils
should be removed with trisodium phosphate or other detergent.
Any deteriorated old paint should be removed by wire brushing or
careful light abrasive blasting.
d) Application of chlorinated rubber paint should
occur in two coats to completely dry surfaces. The first coat is
best applied by brush to fill the concrete pores, but the second
can be applied by roller or spray. A minimum of 24 hours should
occur between coats to ensure complete evaporation of solvent
from the first coat. Painting of individual walls should
continue until completion to avoid lap marks where the work was
interrupted. Because the coating dries very fast, it may be
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MIL-HDBK-1110
necessary to paint walls in the shade or at night during hot
weather. A minimum of 7 days should elapse between painting of
the pool and filling it with water.
5.15
Concrete Catchment Basins. Concrete catchments are
used by some activities with limited water supplies to collect
rainwater for both industrial and domestic use. The catchments
are usually sealed with a coating material and the joints caulked
with a flexible material to minimize water losses. Both of these
materials must be approved for potable water use, if the
collected water is to be for domestic use.
Thick cementitious coatings have been used
satisfactorily for many years to seal catchments. The Government
of Bermuda requires catchments to be free from unsightly mildew.
This is often a limiting factor there for cementitious coatings,
since their textured surfaces become mildew-defaced much sooner
than smooth coatings. Treatment with hypochlorite solution, as
described in par. 4.17, can restore mildew-defaced catchments to
a cosmetically pleasing appearance.
Acrylic latex elastomeric coatings have been found to
perform very well on concrete catchments. They provide excellent
resistance to water migration, weathering, and mildew. A primer
is usually required for good adhesion.
5.16
Chemically Resistant Finishes for Concrete Floors.
Chemically resistant urethane coatings (resistant to fuels and
hydraulic fluids) are sometimes used to impart improved lighting
to work areas such as under aircraft. Because of the smoothness
of these coatings, skid resistance is usually imparted by
sprinkling granules into the wet coating. Such a system is
described in A-A-50542, Coating System: Reflective, SlipResistant, Chemical-Resistant Urethane for Maintenance Facility
Floors. A commitment to maintenance is essential when deciding
to coat a concrete floor. Cleaning and repair will be needed on
a frequent and regular basis to maintain the reflectivity and
appearance of the floors.
Chemical resistance may also be required for floors
where chemicals or hazardous waste is stored to permit rapid
neutralization and removal without contaminating other stored
materials. The coating should be chosen to be resistant to the
stored materials, so that it is best to consult the activity
industrial hygienist. Chemical-curing polyurethane or epoxy
systems as described for fuel tank interiors in par. 4.2.1 are
good candidates.
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5.17
Slip-Resistant Floors. A slip-resistant coating is
often applied as a finish for other coating systems to prevent
accidental slipping. The resistance is imparted by sprinkling
granules in the wet coating. MIL-E-24635 is used for alkyd
systems and MIL-C-24667, Coating System, Non-Skid, for Roll or
Spray Application (Metric) for epoxy systems. The MIL-C-24667
may also be used on alkyd systems where MIL-E-24635 may exceed
local VOC limitations.
5.18
Fouling-Resistant Coatings. Antifouling coatings are
often used over a coating system that imparts corrosion
resistance to ships or other structures to be immersed in sea
water. A toxic material, usually copper ion, is slowly leached
into the sea water to deter attachment and growth of biological
fouling organisms. MIL-P-24647, Paint System, Anticorrosive and
Antifouling, Ship Hull is normally recommended for this purpose.
It has a large list of qualified products. Such a coppercontaining product should not be used on an aluminum boat,
because direct contact of a copper product with aluminum will
result in accelerated galvanic corrosion. Commercial organo-tin
antifouling paints are permitted on aluminum boats. There are
restrictions on their use on large Navy ships.
5.19
Mildew-Resistant Coatings. Mildew growth on painted or
unpainted surfaces of buildings can cause unsightly defacements,
especially at tropical and subtropical locations. This occurs on
interior and exterior surfaces of steel, concrete/masonry,
asbestos-cement, or wood. Mildew can also damage delicate
communications and utilities equipment. In addition serious
bronchial problems may be associated with living in quarters
contaminated with mildew-covered surfaces. The different species
of microorganisms usually present in mildew growths include
molds, yeast, algae, and bacteria. These same organisms are
found on mildew-defaced surfaces throughout the world. The
darkly pigmented organisms are most conspicuous and contribute to
most of the defacement.
5.19.1
Factors Affecting Mildew Growth.
likelihood of mildew growth include:
Factors that affect
a) Weather - Higher temperatures and dampness promote
growth, and light inhibits it.
b) Building Design - Rough surfaces assist pickup of
spores and dirt, roof overhang keeps wall surfaces damp longer,
poor drainage, and porous substrates such as wood retain
moisture; alkalinity on concrete surfaces inhibits growth; and
air exchange, temperature, and humidity may control growth.
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MIL-HDBK-1110
c) Paint - Textured, tacky, and peeling paint pick up
and retain spores and dirt; incompletely removed mildew may
rapidly reinfect new paint; drying oils in paints may be used as
nutrients. Mildewcides in paints can control the growth of
mildew organisms.
5.19.2
Use of Mildewcides in Paints. Mercury-containing
mildewcide additives were used very successfully in paints for
many years to control mildew growth. Only a small amount of the
mercury compound leaching from the paint was necessary to kill
microorganisms. Unfortunately, it also contaminated the
environment with toxic material. Thus, mercury-containing
mildewcides are no longer used in paints. EPA has approved
alternative nonmercurial compounds for use as paint mildewcides.
Some of these products, however, have not proven to be effective
in retarding mildew growth.
5.19.3
Removal of Mildew. Mildew must be killed before
repainting a mildewed surface to obtain control of the mildew.
If spores are just painted over, the mildew will quickly grow and
become unsightly. When a surface is to be cleaned for
repainting, scrub with a solution of 2/3 cup of trisodium
phosphate, 1 liquid ounce of household detergent, 1 quart of
5-1/4 percent sodium hypochlorite (available as household
bleach), and 3 quarts of warm water. Use rubber gloves with this
caustic solution and rinse it from the surface with water after
scrubbing. It will degrade alkyd and other oil-based coatings,
but this will be no problem, if the surface is to be repainted.
An alternate procedure is to remove all the visible mildew by
waterblasting at about 700 pounds per square inch (psi) and kill
the rest by rinsing with a solution of 1 quart of 5-1/4 percent
sodium hypochlorite and 3 quarts of warm water.
If a painted surface is to be merely cleaned without
repainting, apply the scrubbing solution without the trisodium
phosphate to avoid damage to the paint. Apply it first to a
small test area to see if the hypochlorite bleaches the paint.
If it does, merely clean with detergent and water.
Mildew on field structures can be distinguished from
dirt with bleach. Common household hypochlorite bleach will
cause mildew, but not dirt, to whiten.
5.20
Pavement Markings. Asphalt and concrete airfield and
road pavements on military bases are generally striped with paint
to show center and sidelines, as well as other information.
These markings are described in NFGS-02761, Pavement Markings,
and CEGS 02580, Joint Sealing in Concrete Pavements for Roads and
Airfields.
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5.20.1
Painted Markings. Military airfields and roadways have
been successfully marked with alkyd paints for many years.
Chlorinated rubber was added to the alkyd resin to obtain faster
drying times. More recently, environmental restrictions on total
paint solvent have in many geographical locations eliminated or
restricted the use of these marking paints. Thus, most pavements
at military activities are marked with latex paints today.
Yellow marking paints constitute a possible safety and
environmental problem. Historically, a lead chromate pigment has
been used to impart this color because it is relatively light,
stable, and inexpensive. Lead pigments were recently restricted
from use in consumer paints because of concerns that dust from
weathering paints might be ingested by children. More recently,
concern has been expressed about the hazards of chromate
pigments. New regulations impose restrictions on the removal of
old paints containing lead and chromium because of possible
adverse health effects the dust produced may have on workers or
residents in the area. Also, residues of lead and chromatecontaining paints may constitute hazardous waste which must be
specially handled, stored, and disposed of properly. This has
lead to the virtual elimination of lead and chromium constituents
in paint. The State of California Department of Transportation
and other state highway departments have had good success with
yellow striping paints with organic pigments that do not
constitute a health or environmental hazard.
5.20.1.1 Specifications for Marking Paints. Currently, there
are five federal specifications for marking paints.
Specification TT-P-85, Paint, Traffic and Airfield Marking,
Solvent Base is for a solvent-based traffic and airfield marking
paint, available in white and yellow. Alkyd formulations have
generally been used, even though no specific generic type is
required. Paints of this specification are high in VOCs and so
cannot be used in areas where such paints are prohibited (urban
areas with air pollution). Water-based marking paints conforming
to TT-P-1952 are used in such areas, as well as in areas without
such restrictions.
a) Specification TT-P-87, Paint: Traffic, Premixed,
Reflectorized is for a premixed, solvent-based, reflectorized
traffic paint, available in white and yellow. Low index of
refraction (road) beads are premixed with the paint before
packaging. The embedded beads are reported to be exposed as
vehicular traffic erodes away the marking. They are not suitable
for use on airfields because of the low index of refraction
beads.
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b) Specification TT-P-110, Paint, Traffic, Black
(Nonreflectorized) is for a solvent-based, black,
nonreflectorized traffic paint generally made with alkyd binders.
It is used mostly to outline white or yellow markings to make
them stand out or to obliterate old markings on asphalt
pavements. Such paints are not VOC-conforming, and there is no
specification for a black water-based marking paint.
c) Specification TT-P-115, Paint, Traffic (Highway,
White and Yellow) is for a solvent-based traffic paint, available
in white and yellow. Once, this specification called for alkyd
formulations for conventional-dry paints and chlorinated rubberalkyd formulations for fast dry types. This is no longer the
case. Because of VOC and safety concerns described below, this
specification is no longer recommended.
d) Specification TT-P-1952, Paint, Traffic and
Airfield Marking, Water Emulsion Base is for a water-based
traffic and marking paint, available in white or yellow.
Currently, there are no environmental restrictions on its use.
Acrylic and polyvinyl acetate resins are most frequently used in
paints conforming to this specification.
e) Specifications TT-P-85, TT-P-115, and TT-P-1952 are
formulated to permit glass beads to be dropped into the wet paint
immediately after spray application to provide night
retroreflectivity. Coarse beads are evenly dropped into wet
TT-P-87 paint to impart immediate retroreflectivity.
5.20.1.2 Specification for Reflective Glass Beads.
Specification TT-B-1325, Beads (Glass Spheres) Retro-Reflective
is for beads (glass spheres) to impart retroreflectivity to
painted markings. Lights from a plane or car are reflected back
to the eyes of the pilot or driver. Type I (low index of
refraction) is intended for use on roads. It is available in
Gradations A (coarse-drop on), B (fine-premix), and C (fine-drop
on). Type II (medium index of refraction), Gradation A (coarsedrop on) is not commercially available today. Type III (high
index of refraction) is intended for use on airfield pavements.
5.20.1.3 Application of Painted Markings. Although the five
above marking paint specifications are different from each other,
each is applied at about the same thickness. Some achieve this
by specifying a 15-mil wet film thickness, which results in a dry
film thickness of half that, since they contain 50 percent solids
by volume. Others specify a spreading rate of 100 to 110 square
feet per gallon. The water-based paint of specification
TT-P-1952 must be applied at temperatures at or above 45 degrees
F. The other products, which are solvent based, can be applied
at even lower temperatures. Surfaces to be marked must be well
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prepared for painting, free from dirt, oil and grease, other
surface contaminants, and from loose, peeling, or poorly bonded
paint. If removing lead-containing traffic marking paints (e.g.,
some yellows), environmental and worker safety regulations apply.
Refer to Section 3 for more information.
When airfield markings are to be reflectorized,
TT-B-1325, Type III beads are applied immediately after spray
application at the rate of 10 pounds per gallon of paint.
Roadways are reflectorized with TT-B-1325, Type I beads applied
at the rate of 6 pounds per gallon of paint. In both cases, any
more beads would have insufficient paint available to be
retained. Type I beads have a much lower specific gravity than
Type III beads.
For marking pavements, striping machines (specially
equipped trucks) are used. They have tanks that hold large
quantities of paints and beads. Striping machines for airfields
have arrays of multiple spray gun and bead dispensers and
necessary power and support equipment to apply long painted lines
3 feet wide. The spray guns and dispensers are adjusted to give
a uniform paint thickness and bead density across the entire
width of the marking.
5.20.1.4 Inspection of Marking Operation. Inspection procedures
for monitoring contracts for striping airfields are distinctly
different from other painting inspections. They are presented
below in the general order in which they might be used.
a) Procedure 1: General Appearance of Paint and
Beads. Visual examination of paint in the can and beads is done
to check for any apparent deficiencies. Products with apparent
discrepancies should receive a laboratory analysis or be
replaced. Product labels should also be checked to verify that
they are the ones specified. Paints must be homogeneous in color
and consistency. They should be stirred to assure that they are
free of settling, skinning, caking, strings, and foreign bodies
and have a viscosity suitable for spraying. Method 3011.2 of
FED-STD-141, Paint, Varnish, Lacquer, and Related Materials:
Methods of Inspection, Sampling, and Testing describes precisely
how to check for "Condition in Container."
Beads must be clean,
dry, free flowing, and free of air intrusions. They should be
only a few extremely large, small, or out-of-round beads. Type I
beads have a pure white color; Type III beads have a brownish
cast.
b) Procedure 2: Sampling of Paint and Beads. Paints
and beads may be sampled for immediate analysis or merely taken
for later use, if problems arise later. In any event, it is
necessary to procure samples that authentically represent the
material to be applied to the pavements. Incompletely cleaned
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paint tanks may contain significant amounts of water or another
batch of paint. Incompletely emptied bead tanks may contain
beads of another type. Paint and bead samples should be taken
from drums or sacks to determine whether the supplier's material
meets all requirements. Excessive mixing of latex marking paints
should be avoided prior to testing, because their wetting agents
cause them to froth when heavily mixed, and this may result in
testing errors. Excessive stirring of beads may cause smaller or
lighter density beads to migrate to the bottom of the container.
Full sampling and inspection procedures are presented in Method
1031 of FED-STD-141.
c) Procedure 3: Percent by Weight of Paint Total
Solids and Pigment. These tests are run to provide information
on the paint composition and a quick check for its conformance to
specification. These tests are done with the same sample using
ASTM D 2369, Volatile Content of Coatings and ASTM D 3723,
Pigment Content of Water-Emulsion Paints by Low-Temperature
Ashing. By using the relationships percent total solids equals
percent binder plus percent pigment and percent total solids
equals 100 minus percent volatile, results of the two referenced
test procedures can provide data on any of these components
(e.g., solvent, binder, pigment, and total solids). Testing
should be done in triplicate to indicate repeatability. The
percent by weight of total solids (or the percent volatile) of
latex paints is determined by measuring the loss of weight after
the solvent has been evaporated off by heating the sample at 110
degrees C for 2 hours. The percent by weight of pigment is
determined by measuring the weight after further heating of the
samples for 1 hour at 450 degrees C to burn up the organic
binder.
d) Procedure 4: Specific Gravity of Paints. In ASTM
D 1475, Density of Paint, Varnish, Lacquer, and Related Products,
a metal cup of precisely selected volume is weighed first empty
and then filled with paint until it is forced out a hole in the
cap. The additional weight is a direct measure of specific
gravity.
e) Procedure 5: Paint Binder Identification. ASTM D
2621, Infrared Identification of Vehicle Solids From SolventReducible Paints can readily identify the generic type of marking
paints as 100 percent acrylic. Only a small sample of the wet or
dry (e.g., 1 square inch) paint is necessary.
f) Procedure 6: Specific Gravity of Beads. The
specific gravity of beads can easily be determined by field
personnel with access to an inexpensive balance following the
procedure of par. 4.3.5 of TT-B-1325. A sample of dried and
weighed beads (about 60 g) is placed in a glass graduated
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cylinder containing 50 ml of xylene, and the resultant increase
in volume is noted. The specific gravity is then determined by
simple division:
Specific Gravity
=
Weight of Sample (about 60 g)
New Total Volume - 50 ml
g) Procedure 7: Index of Refraction of Beads. The
index of refraction of glass beads can be determined by immersing
them in standard liquids with different refractive indexes and
observing whether the beads blend into the liquid. Blending
occurs when the liquid has a higher refractive index than do the
beads. Indentations of a ceramic spot plate can be conveniently
used for holding the beads and liquid. Run this test when
substitution of TT-B-1325, Type I beads for Type III beads is
suspected. This is normally suspected from a low specific
gravity value in Procedure 6.
h) Procedure 8: Preparation of Drawdowns for
Determining Retroreflectivity. Drawdown specimens are prepared
using a metal drawdown bar as described in ASTM D 823, Producing
Films of Uniform Thickness of Paint, Varnish, and Related
Products on Test Panels. A paint film of 16 mil or other wet
film thickness is screeded onto a the white surface of a black
and white chart by drawing it across the paper in front of a bar
of proper clearance. Immediately after this action, beads are
manually sprinkled into the wet paint. After drying, the
drawdowns are measured with a retroreflectometer. The instrument
can be held in either direction, since the application procedure
does not have a directional effect.
i) Procedure 9: Surface Preparation. Inspection of
pavement surfaces prepared for marking with paint is basically
determining whether the surface is clean enough and sound enough
to permit tight bonding of the paint. Cleaning of concrete for
painting is described in ASTM D 4258, Surface Cleaning Concrete
for Coating. Of the several procedures described for cleaning,
high-pressure water blasting with truck-mounted equipment is
almost always the procedure selected for rubber and paint
removal. Washing with an aqueous detergent solution may be
necessary to remove oil, grease, and tightly bonded dirt. The
extent of paint removal should be verified visually. If only
loose paint is to be removed prior to restriping, the remaining
paint can be checked with a dull putty knife to determine whether
only sound paint remains. After a build-up of five coats (a dry
film thickness of 37 mils), the film becomes rather inflexible
and subject to cracking, and the skid resistance significantly
reduced. Thus, complete removal of the old marking is
recommended at this time. From a standpoint of eliminating the
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hazard of hydroplaning on wet pavements, it is not necessary to
remove 100 percent of the rubber build-up on runways. From a
standpoint of surface preparation for marking pavements, however,
virtually complete removal is more important. While one
contractor was observed to be able to achieve 100 percent removal
with his equipment without apparent difficulty, others could not
do so using their equipment without considerable expense and
damage to the pavement. It may be necessary to settle for less
than 100 percent (e.g., 90 percent) removal to permit competitive
bidding until the technology for 100 percent removal becomes
widely available.
j) Procedure 10: Check of Application Equipment.
Paint spray guns and bead dispensers should be checked to
determine that they are properly metered and functioning.
Metering can be checked individually, directing paint or beads
into a container for collection. To check for proper application
and overlap of paint patterns (fans) from spray guns and beads
from dispensers, apply a small area of paint and beads onto
roofing paper or other disposable material taped to the pavement.
k) Procedure 11: Monitoring of Marking Operation.
The prevailing conditions should be recorded before starting to
apply markings. This includes temperature; dew point, if
solvent-based paints are used; rain or prospects of rain; wind;
type of equipment used; and any unusual conditions. Wind can
cause overspray of the paint onto the beads to significantly
reduce their retroreflectivity. General weather forecasts are
normally available from operations offices. A variety of
thermometers are available for measuring temperature, and
inexpensive sling psychrometers are usually used for measuring
humidity and dew point. Photography can be an excellent method
of recording conditions. Solvent-based paints should not be
applied unless the temperature is at least 5 degrees above the
dew point and above 40 degrees F and rising or if rain is
expected within an hour. In addition, water-based paints should
not be applied when the temperature is below 45 degrees F. Paint
should be applied when the wind is over 5 mph, unless it can be
shown that the marking can be applied properly with the existing
equipment. None should ever be applied when the wind is over 10
mph. The marking should be continuous (no underlap at all or
overlap of adjacent spray patterns greater than 1/4 inch) with a
constant color that matches the standard or submittal, and free
from wind-blown dust and dirt. The edges of the marking should
be relatively sharp and straight. The marking should be touched
with a finger to determine if complete drying has occurred within
the time specified for the paint. Dried paints should be probed
with a dull putty knife to determine that they are well bonded.
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The beads should be relatively uniformly spread across and along
the marking. At least 25 beads should be found in every square
inch, to obtain desired level of retroreflectivity.
l) Procedure 12: Wet Film Thickness of Stripes. Wet
film thickness can easily be determined using the procedure of
ASTM D 1212, Measurement of Wet Film Thickness of Organic
Coatings. A metal or plastic gage with calibrated notches cut
into each of four faces is used for this purpose. The face
calibrated for the desired wet film thickness is pushed squarely
into a freshly painted surface and withdrawn. The wet film
thickness of the marking is equal to the depth of the deepest
notch with paint on it. A sample of wet paint without beads must
be applied to a rigid test panel by the striping machine in a
test run. It is best made on roofing paper or other disposable
material to avoid contamination of a pavement. Obviously, a
series of plates secured across the width of 3-foot-wide stripes
must be used for each test run to determine localized application
rates.
m) Procedure 13: Dry Film Thickness of Paint Film.
The dry film thickness of a paint film can be estimated from the
wet film thickness by the relationship:
Dry Film
Thickness = Wet Film Thickness x Percent Solids by Volume
100
Dry film thickness of paint applications can be determined quite
precisely using a magnetic gage as described in ASTM D 1186,
Nondestructive Measurement of Dry Film Thickness of Nonmagnetic
Coatings Applied to a Ferrous Base. A ferrous plate is coated
with marking paint by the striping machine but no beads are
applied. The paint is allowed to cure completely before its dry
film thickness is determined by magnetic gage. Again, a series
of test plates must be used on runway stripes to determine
thicknesses across the stripe. Tin-plated steel panels used in
paint elongation testing by ASTM D 522, Mandrel Bend Test of
Attached Organic Coatings are convenient to use for this purpose.
n) Procedure 14: Spreading Rate of Paint. After the
wet film thickness of a marking has been made, as described
above, the spreading rate of the paint can be estimated by the
relationship:
Spreading Rate of Wet Paint
in Square Feet/Gallon
=
70
1600
Wet Film Thickness in Mils
MIL-HDBK-1110
From a practical standpoint, it is easier to specify a
paint's wet film thickness than its spreading rate.
o) Procedure 15: Retroreflectivity of Pavement
Markings. Measure the retroreflectivity of airfield markings for
conformance to contract specification using a Mirolux 12 or
Erickson instrument. In addition to following the instrument
manufacturer's instructions, these precautions should be taken:
(1)
Keep an extra fully charged battery available.
(2)
Frequently check instrument calibration.
(3) Systematically make five measurements across
stripes at each test site rather than in the direction of or
opposite to application to avoid directional effects.
(4) Select numerous random test areas to obtain
representative measurements.
Use of a portable computer while making
retroreflectivity measurements can greatly accelerate the
procedure. This is especially important on busy runways with
limited access time. Typically, a two-person team has a driver
who stays in the vehicle keeping radio contact with the tower,
recording data into the computer and driving to the different
test locations. The other team member measures
retroreflectivities and calls out the data to the driver.
5.20.2
Alternative Markings. A variety of tapes, buttons, and
reflectorized squares have been successfully used to mark
roadways. Tapes have been used at military installations to
provide temporary markings. They may be damaged by turning
wheels of heavy trucks. None of these alternative marking
materials are recommended for use on runways because of concern
for foreign object damage.
5.21
Wooden Floors. The surface preparation (scraping and
sanding) and coating of wooden floors is described in NFGS-09900
and CEGS 09900. These finishes include stains and alkyd and
moisture-curing coating systems. For hardwood floors for
gymnasium-type use, a selection can be made from the MFMA Heavy
Duty and Gymnasium Finishes for Maple, Beech and Birch Finishes.
The products addressed include sealers, heavy-duty finishes,
gymnasium-type finishes, moisture-cured urethane finishes, and
water-based finishes. The individual suppliers should be
contacted for special applications such as handball and
racquetball.
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Section 6:
SURFACE PREPARATION
6.1
Introduction. Surface preparation is the single most
important factor in determining coating durability. Available
data and experience indicate that in most situations, money spent
for a clean, well-prepared surface reduces life-cycle costs. A
proper surface preparation:
a) Removes surface contaminants (e.g., salts and
chalk) and deteriorated substrate surface layers (e.g., rust and
sunlight-degraded wood) which hinder coating adhesion and;
b) Produces a surface profile (texture) that promotes
tight adhesion of the primer to the substrate.
6.1.1
Selection Factors. Factors which should be considered
in selecting the general type and degree of surface preparation
are:
a)
Type of the substrate
b)
Condition of the surface to be painted
c)
Type of exposure
d) Desired life of the structure, as some procedures
are much more expensive than others
e)
Coating to be applied
f)
Environmental, time, and economical constraints
6.1.2
Specification Procedure. A performance-based
requirement for surface preparation, rather than a prescriptive
requirement, is recommended for contract use. That is, it is
usually better to describe the characteristics of the cleaned
surface (e.g., profile and degree of chalk removal) than to
specify the specific materials and procedures to be used. Often
the general type of surface preparation (washing, blasting, etc.)
is specified, because of job or other constraints, along with
requirements for characteristics of the cleaned surface. In this
way, the specifier allows the contractor to select the specific
equipment, materials and procedures to get the job done and
avoids putting contradictory requirements into the job
specification.
6.1.3
Section Organization. This section is organized into:
discussions of repair procedures usually done in conjunction with
a painting contract and prior to painting; specific
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recommendations for surface preparation procedures and standards
for specific substrates; recommendations for coating removal; and
general background information on surface preparation methods.
Surface preparation methods are summarized in Table 6.
6.2
Repair of Surfaces. All surfaces should be in good
condition before recoating. If repairs are not made prior to
painting, premature failure of the new paint is likely. Rotten
wood, broken siding, and other deteriorated substrates must be
replaced or repaired prior to maintenance painting. Waterassociated problems, such as deteriorated roofs and
nonfunctioning drainage systems, must be repaired prior to
coating. Interior moist spaces, such as bathrooms and showers
must be properly vented. Cracks, holes, and other defects should
also be repaired.
Areas in need of repair can sometimes be identified by
their association with localized paint failures. For example,
localized peeling paint confined to a wall external to a bathroom
may be due to inadequate venting of the bathroom. Refer to
Section 11 for more examples.
6.2.1
Joints, Cracks, Holes, or Other Surface Defects.
Caulks and sealants are used to fill joints and cracks in wood,
metal and, in some cases, in concrete and masonry. Putty is used
to fill holes in wood. Glazing is used to cushion glass in
window sashes. Specially formulated Portland cement materials
are available for use in cracks and over spalled areas in
concrete. Some of these contain organic polymers to improve
adhesion and flexibility. Other materials are available to
repair large areas of interior plaster (patching plaster), to
repair cracks and small holes in wallboard (spackle), to fill
joints between wallboards (joint cement), and to repair mortar.
Before application of these repair materials, surfaces should be
clean, dry, free of loose material, and primed according to the
written instructions of the material manufacturer.
Caulking and sealant compounds are resin based viscous
materials. These compounds tend to dry on the surface but stay
soft and tacky underneath. Sealants have application properties
similar to caulking materials but tend to be more flexible and
have greater extendibility than caulks. Sealants are often
considered to be more durable than caulks and may also be more
expensive. Commonly available generic types of caulks and
sealants include oil-based, butyl rubber, acrylic latex,
silicone, polysulfide, and polyurethane. The oil-based and
butyl-rubber types are continually oxidized by exposure to
sunlight and become brittle on aging. Thus, their service life is
limited. Acrylic-latex and silicone caulks tend to be more
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stable and have longer service lives. Applications are usually
made with a caulking gun. However, some of these materials may
also be available as putties or in preformed extruded beads that
can be pressed in place.
Putty and glazing compounds are supplied in bulk and
applied with a putty knife. Putties are not flexible and thus
should not be used for joints and crevices. They dry to form a
harder surface than caulking compounds. Glazing compounds set
firmly, but not hard, and thus retain some flexibility. Rigid
paints, such as oil/alkyds, will crack when used over flexible
caulking, sealing, and glazing compounds and should not be used.
Acrylic-latex paints, such as TT-P-19, Paint, Latex (Acrylic
Emulsion, Exterior Wood and Masonry) are a better choice.
6.2.2
Cementitious Surfaces. Epoxy resin systems for
concrete repair are described in MIL-E-29245, Epoxy Resin Systems
for Concrete Repair. This document describes epoxy repair
materials for two types of application. They are: bonding
hardened concrete to hardened concrete, and using as a binder in
mortars and concrete. These types are further divided into
classes based on working temperature. Thus, an appropriate
material can be specified.
6.3
Recommendations by Substrate. Each different type of
construction material may have a preferred surface preparation
method. For substrates, grease and oil are usually removed by
solvent or steam cleaning and mildew is killed and removed with a
hypochlorite (bleach) solution, as described in par. 5.17.4.
6.3.1
Wood. Bare wood should not be exposed to direct
sunlight for more than 2 weeks before priming. Sunlight causes
photodegradation of surface wood-cell walls. This results in a
cohesively weak layer on the wood surface which, when painted,
may fail. If exposed, this layer should be removed prior to
painting by sanding. Failure of paint caused by a degraded-wood
surface is suspected when wood fibers are detected on the
backside of peeling paint chips.
When the existing paint is intact, the surface should
be cleaned with water, detergent, and bleach as needed to remove
surface contaminants, such as soil, chalk, and mildew. When the
existing paint is peeling and when leaded paint is not present,
loose paint can be removed by hand scraping. Paint edges should
be feathered by sanding. Power sanding may damage the wood if
improperly done. Water and abrasive blasting are not recommended
for wood, because these techniques can damage the wood. When
leaded paint is present, special precautions, such as wet
scraping, should be taken. Refer to Section 3.
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Table 6
Commonly Used Methods of Surface Preparation for Coatings
(IMPORTANT NOTE: Methods may require modification or special
control when leaded paint is present.)
Cleaning
Method
Equipment
Comments
Organic
solvent
Solvent such as
mineral spirits,
sprayers, rags, etc.
Removes oil and grease not readily removed by other
methods; precautions must be taken to avoid fires and
environmental contamination; local VOC regulations
may restrict use.
Detergent/
power
washing
Pumps, chemicals,
sprayers, brushes
At pressures not exceeding 2000 psi, removes soil,
chalk, mildew, grease, and oil, depending upon
composition; good for smoke, stain, chalk and dirt
removal.
Acid
Chemicals, sprayers,
and brushes
Removes residual efflorescence andlaitance from
concrete after dry brushing. Thoroughly rinse
afterwards.
Chemical
paint
strippers
Chemicals, sprayers,
scrapers, washing
equipment
Removes coatings from most substrates, but slow,
messy, and expensive; may degrade surface of wood
substrates.
Steam
Heating system pump,
lines, and nozzles
Removes heavy oil, grease, and chalk; usually used
prior to other methods.
Water
blasting
High pressure water
pumps, lines, and
nozzles
At pressures of 2000 psi and above, removes loose
paint from steel, concrete and wood; can damage wood
or masonry unless care is taken; inhibitor generally
added to water to prevent flash rusting of steel.
Hand tool
Wire brushes,
chipping hammers, and
scrapers
Removes only loosely adhering contaminants; used
mostly for spot repair; slow and not thorough.
Power tool
Wire brushes,
grinders, sanders,
needle guns, rotary
peeners, etc.
Faster and more thorough than hand tools because
tightly adhering contaminants can be removed; some
tools give a near-white condition on steel but not an
angular profile; slower than abrasive blasting; some
tools are fitted with vacuum collection devices.
Heat
Electric heat guns
Can be used to soften coatings on wood, masonry, or
steel; softened coatings are scraped away, torches
SHOULD NOT be used.
Abrasive
blasting
Sand, metal shot, and
metal or synthetic
grit propelled onto
metal by pressurized
air, with or without
water, or centrifugal
force
Typically used on metal and, with care on masonry;
can use recyclable abrasives; special precautions are
needed when removing lead containing paint. Water
may be added to control dust and its addition may
require use of inhibitors. Vacuum blasting reduces
dust but is slower than open. Centrifugal blasting
is a closed cycle system in which abrasive is thrown
by a spinning vaned wheel.
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Paint should be removed from wood when failure is by
cross-grain cracking (that is, cracking perpendicular to the wood
grain). This failure occurs when the total paint thickness is
too thick and/or the paint is too inflexible. Painting over this
condition almost always results in early failure of the
maintenance paint layer.
Paint removal from wood is difficult
and may not always be feasible. Chemical strippers can be used,
but the alkaline types may damage (chemically degrade) the
surface of the wood and cause a future peeling-paint failure.
Failure caused by a stripper-degraded wood surface is more likely
for exterior exposures than for interior exposures. This is
because the greater expansion and contraction of wood in exterior
exposures requires that the surface wood have a greater
mechanical strength.
6.3.2
Concrete/Masonry. Bare concrete and masonry surfaces,
as well as painted surfaces, are usually best cleaned with water
and detergent. Use low-pressure washing (less than 2000 psi) or
steam cleaning (ASTM D 4258) to remove loose surface contaminants
from surfaces. Use high-pressure water blasting (greater than
2000 psi and usually about 5000 psi) (ASTM D 4259, Abrading
Concrete) to remove loose old coatings or other more tightly held
contaminates or chalk. If existing paints are leaded, special
worker safety and environmental controls will be needed.
Abrasive blasting (ASTM D 4259 and D 4261, Surface
Cleaning Concrete Unit Masonry for Coating) or acid etching of
bare surfaces (ASTM D 4260, Acid Etching Concrete) may also be
used to obtain a surface profile as well as clean surfaces for
coating. Care must be taken to avoid damaging surfaces with
high-pressure water or abrasives. Grease and oil must be removed
with detergents or steam before abrasive blasting. Any
efflorescence present should first be removed by dry wire
brushing or acid washing. Special worker safety and
environmental controls may be needed.
Concrete surfaces must be completely dry prior to paint
application for all types of paints except waterborne. The
plastic sheet method (ASTM D 4263, Indicating Moisture in
Concrete by the Plastic Sheet Method) can be used to detect the
presence of water (i.e., tape a piece of plastic sheet to the
surface, wait 24 hours and look for condensed moisture under the
sheet - the inside of the sheet should be dry).
6.3.3
Steel. The first step in preparing steel for coating
is solvent cleaning as described in SSPC SP 1. Cleaning methods
described in SSPC SP 1 include organic solvents, vapor
degreasing, immersion in appropriate solvent, use of emulsion or
alkaline cleaners, and steam cleaning with or without detergents.
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MIL-HDBK-1110
SSPC SP 1 is specifically included as the first step in the SSPC
surface preparation procedures.
For large areas of uncoated steel and coated steel with
badly deteriorated coatings, the preferred method of removing
mill scale, rust and coatings is abrasive blasting (SSPC SP 7,
SSPC SP 6, SSPC SP 10, SSPC SP 5). These methods can both clean
the surface and produce a surface profile. The specific abrasive
method selected depends upon the conditions of the steel, the
desired coating life, the environment and the coating to be
applied. If leaded paint is present, special precautions must be
taken to protect workers and the environment. Refer to Section
3. High-pressure water blasting, with or without injected
abrasives, should be considered if dry abrasive blasting cannot
be done because of environmental or worker safety restrictions.
For small localized areas, other cleaning methods such
as hand tool cleaning (SSPC SP 2) or power tool cleaning (SSPC
SP 3 or SSPC SP 11) may be more practical.
6.3.3.1
Specific Surface Preparation Requirements for Coatings
for Steel. Different types of coatings may require different
levels of cleaning. Commonly agreed upon minimum requirements
are listed below. However, manufacturers of some specific
coatings may require or recommend a cleaner surface. Conflicts
between manufacturer's written instructions (tech data sheets)
and contract specifications should be avoided.
Coating
Minimum Surface Preparation
Drying Oil
Alkyd
SSPC
SSPC
SSPC
SSPC
SSPC
SSPC
SSPC
SSPC
SSPC
SSPC
SSPC
Asphaltic
Latex
Vinyl Lacquer
Chlorinated Rubber
Epoxy
Polyurethane
Organic Zinc
Inorganic Zinc
SP
SP
SP
SP
SP
SP
SP
SP
SP
SP
SP
2 or SSPC SP 3
6 or SSPC-SP 11
3 for limited localized areas
6 or SSPC SP 11
6 or SSPC SP 11
10
10
6 or SSPC SP 10
10
6 or SSPC SP 10
10 or SSPC SP 5
For immersion or other severe environments, the higher
level of the two options should be used. Higher levels may also
be used to ensure the maximum lives from coating systems.
6.3.4
Galvanized and Inorganic-Zinc Primed Steel. The
recommended method of cleaning uncoated galvanized steel varies
with the condition of its surface. Simple solvent (organic or
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MIL-HDBK-1110
detergent-based) cleaning (SSPC SP 1) is usually adequate for new
galvanizing. This will remove oil applied to the galvanizing to
protect it during exterior storage. If loose zinc corrosion
products or coating are present on either galvanized or
inorganic-zinc primed steel, they should be removed by bristle or
wire brushing (SSPC SP 2 or SSPC SP 3) or water blasting. The
method chosen must successfully remove the contaminants. Uniform
corrosion of unpainted galvanizing may expose the brownish ironzinc alloy. If this occurs, the surface should be painted as
soon as possible. If rusting is present on older galvanized or
on inorganic-zinc primed steel, remove the rust by sweep abrasive
blasting (SSPC SP 7) or using power tools, such as wire brushing
(SSPC SP 2, SSPC SP 3). Abrasive blasting is usually more
appropriate when large areas are corroded, while the use of hand
or power tools may be more appropriate when rusting is localized.
For either method, the procedure should be done to minimize
removal of intact galvanizing or of the inorganic zinc primer.
Deteriorated coatings should also be removed using abrasive
blasting or hand or power tools. When leaded-coatings are
present, special worker safety and environmental precautions must
be taken. Refer to Sections 3 and 13.
6.3.5
Aluminum and Other Soft Metals. New, clean aluminum
and other soft metals may be adequately cleaned for coating by
solvent cleaning (SSPC SP 1). The use of detergents may be
required for removal of dirt or loose corrosion products.
Abrasive blasting with plastic beads or other soft abrasives may
be necessary to remove old coatings. Leaded coatings will
require special worker safety and environmental precautions.
6.4
Standards for Condition of Substrates
6.4.1
Unpainted Steel. Verbal descriptions and photographic
standards have been developed for stating the condition of
existing steel substrates. SSPC VIS 1, Abrasive Blast Cleaned
Steel (Standard Reference Photographs) illustrates and describes
four conditions of uncoated structural steel. They are:
Title
Grade
Adherent mill scale
Rusting mill scale
Rusted
Pitted and rusted
A
B
C
D
Since the condition of the surface to be cleaned
affects the appearance of steel after cleaning, these conditions
are used in the SSPC VIS 1 cleanliness standards described below.
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MIL-HDBK-1110
6.4.2
Nonferrous Unpainted Substrates. There are no
standards describing the condition of other building material
substrates.
6.5
Standards for Cleanliness of Substrates
6.5.1
Standards for Cleaned Steel Surfaces
6.5.1.1
SSPC and NACE Definitions and Standards. The SSPC and
the NACE Standards are used most frequently for specifying degree
of cleanliness of steel surfaces. SSPC has standard definitions
and photographs for common methods of cleaning (SSPC VIS 1 and
SSPC VIS 3, Power- and Hand-Tool Cleaned Steel). NACE TM0170,
Surfaces of New Steel Air Blast Cleaned With Sand Abrasive;
definitions and metal coupons) covers only abrasive blasting.
Volume 2 of SSPC Steel Structures Painting Manual contains all
the SSPC standards, as well as other useful information. For
both types of standards, the definition, rather than the
photograph or coupon, is legally binding. The SSPC and NACE
surface preparation standards are summarized in Table 7.
To use the SSPC or NACE standards, first determine the
condition of steel that is to be blasted (e.g., Grade A, B, C, or
D), since different grades of steel blasted to the same level do
not look the same. After determining the condition of steel,
compare the cleaned steel with the pictorial standards for that
condition. The appearance of blasted steel may also depend upon
the type of abrasive that is used. NACE metal coupons represent
four degrees of cleanliness obtained using one of three types of
abrasives - grit, sand, or shot.
6.5.1.2
Job-Prepared Standard. A job-specific standard can be
prepared by blasting or otherwise cleaning a portion of the
structure to a level acceptable to both contractor and
contracting officer, and covering it with a clear lacquer
material to protect it for the duration of the blasting. A
12-inch steel test plate can also be cleaned to an acceptable
level and sealed in a water- and grease-proof bag or wrapper
conforming to MIL-B-131, Barrier Materials, Water Vaporproof,
Greaseproof, Flexible, Heat-Sealable.
6.5.1.3
Pictorial Standards for Previously Painted Steel.
Photographic standards for painted steel are available in the
Society for Naval Architects and Engineers Abrasive Blasting
Guide for Aged or Coated Steel Surfaces. Pictures representing
paint in an original condition and after each degree of blasting
are included.
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Table 7
SSPC and NACE Standards for Cleaned Steel Surfaces
Method
SSPC No.
NACE
No.
Intended Use
Solvent
Cleaning
SSPC SP 1
Removal of oil and grease prior to further
cleaning by another method
Hand Tool
SSPC SP 2
Removal of loose mill scale, rust, and paint
Power Tool
SSPC SP 3
Faster removal of loose mill scale, rust, and
coatings than hand tool cleaning
White Metal
Blast
SSPC SP 5 NACE 1 Removal of visible contaminants on steel
surfaces; highest level of cleaning for steel
Commercial
Blast
SSPC SP 6 NACE 3 Removal of all visible contaminants except
that one third of a steel surface may have
shadows, streaks, or stains
Brush-Off
Blast
SSPC SP 7 NACE 4 Removal of loose mill scale, rust, and paint
(loose paint can be removed with dull putty
knife)
Pickling
SSPC SP 8
Near-White
Blast
SSPC SP
10
Power Tool
Cleaning
SSPC SP
ll
Removal of mill scale and rust from steel
NACE 2 Removal of visible contaminants except that 5
percent of steel surfaces may have shadows,
streaks, or stains
Removal of visible contaminants (surface is
comparable to SSPC SP 6, also provides
profile)
6.5.2
Standards for Cleaned Nonferrous Metals. No industry
standards describe the degree of cleaning of nonferrous metals,
and previously painted non-steel substrates.
6.5.3
Previously Coated Surfaces. When the surface to be
painted is an old weathered coating film (that is, surface
preparation will not include removal of the old coating), ASTM
visual standards should be used for chalk, mildew, and dirt
removal. In general, a minimum chalk rating (ASTM D 4214,
Evaluating Degree of Chalking of Exterior Paint Films) of 8
should be required for chalk removal, a minimum mildew removal
rating (ASTM D 3274, Evaluating Degree of Surface Disfigurement
of Paint ) of 8 (preferably 10) should be required for mildew
removal, and an ASTM D 3274 rating of 10 should be required for
dirt removal. Consideration should be given to requiring
preparation of a job-specific standard (as described in
par. 6.5.1.2) when large jobs are contracted. This standard
should cover removal of loose material, chalk, and mildew, as
well as feathering of edges, and other requirements of the
contract specification.
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6.6
Recommendations for Paint Removal. It is often
necessary to remove old coatings that are peeling, checking,
cracking, or the like. General recommendations for removal of
paint from a variety of substrates are made in Table 8. More
specific information is provided in par. 6.7.
Table 8
Procedures for Coating Removal
(IMPORTANT NOTE - Presence of Leaded Paint Will Require
Environmental and Worker Safety Controls)
Substrate
Wood
Masonry
Steel
Miscellaneous
metals
Methods
Chemical removers; heat guns or hot plates
along with scraping; power sanding (must be
done with caution to avoid damaging wood).
Careful water blasting to avoid substrate
damage; brush-off blasting and power tools,
used with caution.
Abrasive blasting; water blasting.
Chemicals; brush-off blast; water blast
6.7
Methods of Surface Preparation. Information on surface
preparation methods and procedures are presented to help select
appropriate general procedures and to inspect surface preparation
jobs. It is not intended to be a complete source of information
for those doing the work.
6.7.1
Abrasive Blasting. Abrasive blast cleaning is most
often associated with cleaning painted and unpainted steel. It
may also be used with care to prepare concrete and masonry
surfaces and to clean and roughen existing coatings for painting.
Abrasive blasting is an impact cleaning method. High-velocity
abrasive particles driven by air, water, or centrifugal force
impact the surface to remove rust, mill scale, and old paint from
the surfaces. Abrasive cleaning does not remove oil or grease.
If the surface to be abrasive blasted is painted with leaded
paint, additional controls must be employed to minimize hazards
to workers and the surrounding environment. Leaded paint issues
are discussed in more detail in Section 3.
There are four degrees of cleanliness of blast cleaning
designated by the SSPC and the NACE for steel substrates. These
designations are white metal, near-white metal, commercial, and
brush-off. They are described in detail in par. 6.5.1.1. The
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MIL-HDBK-1110
degree of cleanliness obtained in abrasive blasting depends on
the type of abrasive, the force with which the abrasive particles
hits the surface, and the dwell time.
6.7.1.1
Types of Abrasive Blasting
a) Air (Conventional). In conventional abrasive
blasting (Figure 1), dry abrasive is propelled against the
surface to be cleaned so that rust, contaminates, and old paint
are removed by the impact of the abrasive particles. The surface
must be cleaned of blasting residue before painting. This is
usually done by blowing clean air across the surfaces. Special
care must be taken to ensure that horizontal or other obstructed
areas are thoroughly cleaned. Uncontrolled abrasive blasting is
restricted in most locations because of environmental
regulations. Consult the local industrial hygiene or
environmental office for regulations governing local actions.
Procedures for containment of blasting debris are being used for
paint removal from industrial and other structures. The SSPC has
developed a guide (SSPC Guide 6I) for selecting containment
procedures depending upon the degree of containment desired. The
amount of debris generated can be reduced by recycling the
abrasive. Recycling systems separate the paint waste from the
abrasive.
b) Wet. Wet-abrasive blasting is used to control the
amount of airborne dust. There are two general types of wet
abrasive blasting. In one, water is injected near the nozzle
exit into the stream of abrasive (Figure 2). In the other, water
is added to the abrasive at the control unit upstream of the
nozzle and the mixture of air, water, and sand is propelled
through the hose to the nozzle. For both types of wet-blasting,
the water may contain a corrosion inhibitor. Inhibitors are
generally sodium, potassium, or ammonium nitrites, phosphates or
dichromates. Inhibitors must be chosen to be compatible with the
primer that will be used. After wet blasting, the surface must
be rinsed free of spent abrasive. (The rinse water should also
contain a rust inhibitor when the blasting water does.) Rinsing
can be a problem if the structure contains a large number of
ledges formed by upturned angles or horizontal girders since
water, abrasives, and debris tend to collect in these areas. The
surface must be completely dry before coating. When leaded paint
is present, the water and other debris must be contained and
disposed of properly. This waste may be classified as a
hazardous waste under Federal and local regulations, and must be
handled properly.
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MIL-HDBK-1110
Figure 1
Schematic Drawing Illustrating Components of Conventional
Abrasive Blasting Equipment
c) Vacuum. Vacuum blasting systems collect the spent
abrasives and removed material, immediately adjacent to the point
of impact by means of a vacuum line and shroud surrounding the
blasting nozzle. Abrasives are usually recycled. Production is
slower than open blasting and may be difficult on irregularly
shaped surfaces, although shrouds are available for non-flat
surfaces. The amount of debris entering the air and the amount
of cleanup is kept to a minimum if the work is done properly
(e.g., the shroud is kept against the surface). This procedure
is often used in areas where debris from open air blasting or wet
blasting cannot be tolerated.
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MIL-HDBK-1110
Figure 2
Schematic Drawing of Cross Section of Typical Water-Injected
Wet Abrasive Blasting Nozzle
d) Centrifugal. Cleaning by centrifugal blasting is
achieved by using machines with motor-driven bladed wheels to
hurl abrasives at a high speed against the surface to be cleaned.
Advantages over conventional blasting include savings in time,
labor, energy, and abrasive; achieving a cleaner, more uniform
surface; and better environmental control. Disadvantages of
centrifugal blasting include the difficulty of using it in the
field, especially over uneven surfaces, although portable systems
have been developed for cleaning structures such as ship hulls
and storage tanks. Robots may be used to guide the equipment.
In many cases, the abrasive used is reclaimed and used again.
6.7.1.2
Conventional Abrasive Blasting Equipment. Components
of dry abrasive blasting equipment are air supply, air hose and
couplings, abrasive blast machines, abrasive blast hose and
couplings, nozzles, operator equipment, and oil and moisture
separators. A brief description of each component follows:
a) Air Supply. The continuous and constant supply of
an airstream of high pressure and volume is one of the most
critical parts of efficient blasting operations. Thus, the air
supply (compressor) must be of sufficient capacity. Insufficient
air supply results in excessive abrasive use and slower cleaning
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MIL-HDBK-1110
rates. The compressor works by taking in, filtering, and
compressing a large volume of air by rotary or piston action and
then releasing it via the air hose into the blasting machine.
The capacity of a compressor is expressed in volume of air moved
per unit time (e.g., cubic feet per minute (cfm)) and is directly
related to its horsepower. The capacity required depends upon
the size of the nozzle orifice and the air pressure at the
nozzle. For example, a flow of 170 to 250 cfm at a nozzle
pressure of 90 to 100 psi is necessary when using a nozzle with a
3/8 to 7/16 inch orifice. This typically can be achieved with a
45 to 60 horsepower engine.
b) Air-Supply Hose. The air-supply hose delivers air
from the compressor to the blasting machine. Usually the
internal diameter should be three to four times the size of the
nozzle orifice. The length of the hose should be as short as
practical because airflow through a hose creates friction and
causes a pressure drop. For this reason, lines over 100 feet
long generally have internal diameters four times that of the
nozzle orifice.
c) Blasting Machine. Blasting machines or "sand pots"
are the containers which hold the abrasives. The capacity of
blasting machines varies from 50 pounds to several tons of
abrasive material. The blasting machine should be sized to
maintain an adequate volume of abrasive for the nozzles.
d) Abrasive Blasting Hose. The abrasive blasting hose
carries the air and abrasive from the pot to the nozzle. It must
be sturdy, flexible, and constructed or treated to prevent
electrical shock. It should also be three to four times the size
of the nozzle orifice, except near the nozzle end where a smaller
diameter hose is attached.
e) Nozzles. Nozzles are available in a great variety
of shapes, sizes, and designs. The choice is made on the basis
of the surface to be cleaned and the size of the compressor. The
Venturi design (that is, large throat converging to the orifice
and then diverging to the outlet, Figure 3) provides increased
speed of abrasive particles through the nozzle as compared with a
straight bore nozzle. Thus, the rate of cleaning is also
increased. Nozzles are available with a variety of lengths,
orifice sizes, and lining materials. The life of a nozzle
depends on factors such as the lining material and the abrasives
and varies from 2 to 1500 hours. Nozzles should be inspected
regularly for orifice size and wear. Worn nozzles result in poor
cleaning patterns and efficiency.
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MIL-HDBK-1110
Figure 3
Cross-Sectional Drawing of Nozzles
f) Oil/Moisture Separators. Oils used in the
compressor could contaminate the air supply to the nozzles. To
combat this, oil/moisture separators are installed at the blast
machine. The separators require periodic draining and routine
replacement of filters. Contamination of the air supply can be
detected by a simple blotter test. In this test, a plain, white
blotter is held 24 inches in front of the nozzle with only the
air flowing (i.e., the abrasive flow is turned off) for 1 to 2
minutes. If stains appear on the blotter, the air supply is
contaminated and corrective action is required. ASTM D 4285,
Indicating Oil or Water in Compressed Air describes the testing
procedure in more detail.
g) Operators Equipment. The operators equipment
includes a protective helmet and suit. The helmet must be airfed when blasting is done in confined or congested areas. To be
effective it must furnish respirable air to the operator at a low
noise level, protect the operator from rebounding abrasive
particles, provide clear vision to the operator, and be
comfortable and not restrictive. Air-fed helmets must have
National Institute of Safety and Hygiene (NIOSH) approval. Refer
to Section 13 for additional information.
h) Wet Blasting. In addition to equipment needed for
dry abrasive blasting, metering, delivery, and monitoring devices
for water are needed.
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MIL-HDBK-1110
i) Vacuum Blasting. Although there are many designs
for vacuum blasting equipment, all systems have a head containing
a blast nozzle, surrounded by a shroud connected to a vacuum
system, and a collection chamber for debris.
j) Centrifugal Blasting. In centrifugal blasting,
abrasive is hurled by wheels instead of being air-driven. This
type of blasting is often used in shop work. Portable devices
have been developed for use on flat surfaces. Abrasive is
contained and usually recycled.
6.7.1.3
Abrasive Properties. The SSPC has a specification for
mineral and slag abrasive, SSPC AB 1, Mineral and Slag Abrasives.
Abrasives covered by the specification are intended primarily for
one-time use without recycling. The specification has
requirements for specific gravity, hardness, weight change on
ignition, water soluble contaminant, moisture content and oil
content. MIL-A-22262, Abrasive Blasting Media, Ship Hull Blast
Cleaning, a Navy Sea Systems specification for abrasives, also
limits the heavy metal content of abrasives. These and other
properties of abrasives are discussed below:
a) Size. Abrasive size is a dominant factor in
determining the rate of cleaning and the profile obtained. A
large abrasive particle will cut deeper than a small one of the
same shape and composition, however, a greater cleaning rate is
generally achieved with smaller-sized particles. Thus, a mix is
generally used.
b) Shape. The shape and size of abrasive particles
determine the surface profile obtained from blasting (Figure 4).
Round particles, such as shot, produce a shallow, wavy profile.
Grit, which is angular, produces a jagged finish. Usually a
jagged finish is preferred for coating adhesion. Round particles
are well suited for removal of brittle contaminants like mill
scale and are also used when little or no change in surface
configuration is permitted. Sand and slag, which are semiangular, produce a profile that is somewhere between that of shot
and grit. Currently, sand is used much less than other abrasives
because of health and breakdown factors.
c) Hardness. Hard abrasives usually cut deeper and
faster than soft abrasives. Hence, hard abrasives are best
suited for blast cleaning jobs where the objective is to remove
surface coatings. Soft abrasives, such as walnut hulls, can
remove light contaminants without disturbing a metal substrate
or, in some cases, the existing coating system.
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MIL-HDBK-1110
Figure 4
Drawing Illustrating Effect of Shape of Abrasive Particle on
Contour of Blast-Cleaned Metallic Substrate
d) Specific Gravity. Generally the more dense a
particle, the more effective it is as an abrasive. This is
because it takes a certain amount of kinetic energy to remove
contaminants from the surface and the kinetic energy of an
abrasive particle is directly related to its density (specific
gravity).
e) Breakdown Characteristics. Abrasive particles
striking the surface at high speeds are themselves damaged. The
way in which they fracture (breakdown) and/or in which they
change their shape and size is called their breakdown
characteristic. An excessive breakdown rate results in a
significant increase in dusting, requires extra surface cleaning
for removal of breakdown deposits, and limits the number of times
the abrasive can be reused.
f) Water-Soluble Contaminants. ASTM D 4940,
Conductimetric Analysis of Water Soluble Ionic Contamination of
Blasting Abrasives describes a conductivity test for determining
the level of contamination of metallic, oxide, slags, and
synthetic abrasives by water-soluble salts. SSPC AB 1 requires
that the conductivity of the test solution be below 100
microsiemens.
6.7.1.4
Abrasive Types. Abrasives fall into seven general
categories: metallic, natural oxides, synthetic, slags,
cellulose (such as walnut hulls), dry ice pellets (carbon
dioxide), sodium bicarbonate, and sponge. A summary of typical
properties of some of these abrasives is found in Table 9.
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MIL-HDBK-1110
Table 9
Typical Physical Characteristics of Abrasives (1)
Hardness
Shape
Specific
Bulk
Gravity Density
(pounds
per
cubic
foot)
Naturally Occurring Abrasives
(Mohs Scale)
Sands:
Silica
Mineral
Flint
5
5 to 7
6.7 to 7
Rounded
Rounded
Angular
Garnet
Zircon
Novaculite
7 to 8
7.5
4
Angular
4
Cubic
4.5
Angular
2.5
By-Product Abrasives
2 to 3
3 to 4
2 to 3
Color
Free
Degree
Silica
of
Wt
Dusting
Percent
100 White
123 Variable
80 Lt.
Grey
145 Pink
185 White
100 White
90 +
< 5
90 +
High
Medium
Medium
Nil
Nil
90 +
Medium
Low
Low
Angular
2.8
Angular
3.3
Angular
2.7
Cubic
1.3
Angular
1.3
Manufactured Abrasives
85
110
85
45
30
Black
Black
Green
Brown
Tan
Nil
Nil
Nil
Nil
Nil
High
Low
High
Low
Low
Angular
105 Black
Nil
Low
120 Brown
100 Clear
Nil
67
Low
Low
(Mohs Scale)
Slags:
Boiler
Copper
Nickel
Walnut Shells
Corn Cobs
7
8
8
3
4.5
(Mohs Scale)
Silicon
9
Carbide
Aluminum Oxide 8
Glass Beads
5.5
Cast Steel (2)
Shot & Grit
Malleable Iron
Shot or Grit
Chilled
Cast Iron
Shot or Grit
NOTES:
(1)
(2)
3.2
Blocky
4.0
Spherical 2.5
Metallic Abrasives
(Rockwell C)
as spec. or
range 35-65 RC
range:
28-40 RC
Spherical 3 to 10
or Angular
Spherical 3 to 10
or Angular
Grey
Nil
Grey
Nil
range:
57-65 RC
Spherical 3 to 10
or Angular
Grey
Nil
Taken from SSPC SP COM, Steel Structures Painting
Manual, Systems and Specifications, Vol. 2, p. 17,
and Vol. 1 of Good Painting Practice, p. 34.
Represents 85 percent of the metallic abrasives
used.
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MIL-HDBK-1110
a) Metallic. Steel shot and grit are the most
commonly used metallic abrasives. Metallic abrasives are used to
remove mill scale, rust, and old paint and provide a suitable
anchor pattern. The advantages of metallic abrasives include
longer useful life (can be recycled many times), greater impact
energy for given particle size, reduced dust formation during
blasting, and minimal embedment of abrasive particles. The
disadvantages include blast cleaning equipment must be capable of
recycling, abrasives must be kept dry to prevent corrosion, and
the impact of steel shot on metal surfaces may cause formation of
hackles on the surface. These hackles are relatively long
slivers of metal and must be removed mechanically by sanding or
grinding before coating to prevent pinpoint corrosion through the
paint film.
b) Natural Oxides. Silica is the most widely used
natural oxide because it is readily available, low in cost, and
effective. Sand particles range from sharply angular to almost
spherical, depending on the source. OSHA and EPA regulations
have restricted the use of sand in many areas. Nonsilica sands
(generally termed "heavy mineral" sands) are also being used for
blast cleaning. However, they are generally of finer particle
size than silica sand and are usually more effectively used for
cleaning new steel than for maintenance applications.
c) Synthetics. Aluminum oxide and silicon carbide are
nonmetallic abrasives with cleaning properties similar to the
metallics and without the problem of rusting. They are very
hard, fast-cutting and low-dusting, but they are costly and must
be recycled for economical use. They are often used to clean
hard, high tensile strength metals.
d) Slags. The most commonly used slags for abrasives
are by-products from metal smelting (metal slags) and electric
power generation (boiler slags). Slags are generally hard,
glassy, homogeneous mixtures of various oxides. They usually
have an angular shape, a high breakdown rate, and are not
suitable for recycling.
e) Cellulose Type. Cellulose type abrasives, such as
walnut shells and corncobs, are soft, low density materials used
for cleaning of complex shaped parts and removing dirt, loose
paint, or other deposits on paint films. Cellulose type
abrasives will not produce a profile on a metal surface.
f) Dry Ice. Special equipment is used to convert
liquid carbon dioxide into small pellets which are propelled
against the surface. Since the dry ice sublimes, the abrasive
leaves no residue. The method can be used to remove paint from
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MIL-HDBK-1110
some substrates, but not mill scale and will not produce a
profile. Paint removal is slow (and very difficult from wood)
and the equipment needed to carry out the blasting is expensive.
g) Sponge. Specially manufactured sponge particles,
with or without impregnated hard abrasive, are propelled against
the surface. Less dust is created when sponge abrasive is used
as compared to expendable or recyclable abrasives. The sponge is
typically recycled several times. If sponge particles with
impregnated hard abrasive are used, a profile on a metal can be
produced. Sponge blasting is typically slower than with
conventional mineral or steel abrasives.
h) Sodium Bicarbonate. Sodium bicarbonate particles
are propelled against the surface, often in conjunction with
high-pressure water. This method provides a way to reduce waste
if the paint chips can be separated from the water after cleaning
since sodium bicarbonate is soluble in water. These particles
can be used to remove paint, but not mill scale or heavy
corrosion.
6.7.1.5
Selection. Selection of the proper abrasive is a
critical part of achieving the desired surface preparation.
Factors that influence the selection include: desired degree of
cleanliness; desired profile; degree of rusting; deep pits; and
kind and amount of coating present. Since obtaining the desired
degree of cleanliness and profile are the main reasons for impact
cleaning, they must be given priority over all other factors
except environmental ones in abrasive selection.
6.7.1.6
Inspection. Abrasives must be dry and clean. It is
most important that they are free of inorganic salts, oils, and
other contaminants. There are only limited standard procedures
for inspecting abrasives. The following general procedure is
suggested:
a)
Visually inspect the abrasive to ensure that it is
dry,
b) Test for presence of water soluble salts by
following ASTM D 4940 in which equal volumes of water and
abrasive are mixed and allowed to stand for several minutes and
the conductivity of the supernatant is measured using a
conductivity cell and bridge,
c) Examine the supernatant of the ASTM D 4940 test for
presence of an oil film.
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6.7.1.7
Procedures/General Information. Good blasting
procedures result in efficient and proper surface preparation.
Adequate pressure at the nozzle is required for effective
blasting. Other factors, such as flow of abrasive, nozzle wear,
position of the nozzle with respect to the surface, and comfort
of operator are also important. A well trained operator is
essential to obtaining an acceptable job.
a) Handling the Nozzle. The angle between the nozzle
and the surface and the distance between the nozzle and surface
are important factors in determining the degree and rate of
cleaning (Figure 5). The working angle will vary from 45 to 90
degrees depending upon the job. To remove rust and mill scale,
the nozzle is usually held at an angle of between 80 and 90
degrees to the surface. This is also the preferred configuration
for cleaning pitted surfaces. A slight downward angle will
direct the dust away from the operator and ensure better
visibility. A larger angle between nozzle and surface allows the
operator to peel away heavy coats of old paint and layers of rust
by forcing the blast under them. Other surface contaminants may
be better removed with a cleaning angle of from 60 to 70 degrees.
By varying the distance between the nozzle and the surface, the
type and rate of cleaning can also be varied. The closer the
nozzle is to the surface, the smaller the blast pattern and the
more abrasive strikes it. Thus, a greater amount of energy
impacts the surface per unit area than if the nozzle were held
further away. A close distance may be required when removing
tight scale, for example. However, a greater distance may more
effectively remove old paint. Once an effective angle and
distance have been determined, each pass of the nozzle should
occur in a straight line to keep the angle and distance between
the nozzle and the surface the same (Figure 6). Arcing or
varying the distance from the surface will result in a nonuniform
surface.
b) Rates. The rate of cleaning depends on all of the
factors discussed above. Abrasive blasting of steel to a
commercial degree of cleanliness (SSPC SP 6 or better) is much
slower than painting. No more steel surface area should be blast
cleaned at one time than can be primed the same day, since
significant rusting can occur overnight. If rusting does occur,
the surface must be reblasted before painting.
6.7.2
Acid Cleaning. Acid cleaning is used for cleaning
efflorescence and laitance from concrete.
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Figure 5
Schematic Illustrating Typical Cleaning Angles
for Various Surface Conditions
Figure 6
Illustration of Proper Stroke Pattern for Blast Cleaning
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6.7.2.1
Concrete. Heavy efflorescence and laitance should be
removed from concrete surfaces by dry brushing or cleaning prior
to acid cleaning. This is to prevent dissolution of the
efflorescence and subsequent movement of the salts into the
concrete. Prior to application of an acid solution, heavy oil,
grease, and soil deposits must also be removed. Oily dirty
deposits can be removed by solvent or detergent washing. The
commonly used procedure to acid clean these surfaces is to
thoroughly wet the surface with clean water; uniformly apply acid
solution (often a 5 to 10 percent solution of hydrochloric
(muriatic) acid solution or a solution of phosphoric acid); scrub
the surface with a stiff bristle brush; and immediately rinse the
surface thoroughly with clean water. Measure the pH of the
surface and rinse water using pH paper (ASTM D 4262, pH of
Chemically Cleaned or Etched Concrete Surfaces). In general, the
pH should be within one pH unit of fresh rinse water. It is
essential for good paint performance that the acid be neutralized
before painting. Work should be done on small areas, not greater
than 4 square feet in size. This procedure or light abrasive
blasting can also be used to etch the surface of very smooth
concrete prior to coating. Coating adhesion on slightly rough
concrete surfaces is usually much better than on smooth and
(e.g., troweled) surfaces. An acid etched surface is usually
roughened to a degree similar in appearance to a medium grade
sandpaper. This cleaning method is described in detail in ASTM
D 4260.
6.7.3
Chemical Removal of Paint. Paint strippers can be used
when complete paint removal is necessary and other methods, such
as abrasive blasting, cannot be used due to environmental
restraints or potential damage to the substrate. Removers are
selected according to the type and condition of the old coating
as well as the nature of the substrate. They are available as
flammable or nonflammable types and in liquid or semi-paste
types. While most paint removers require scraping or other
mechanical means to physically remove the softened paint, types
are available that allow the loosened coating to be flushed away
with steam or hot water. If paint being removed contains lead,
additional environmental and worker safety precautions will be
needed. Many removers contain paraffin wax to retard evaporation
and this residue must be removed prior to recoating. Always
follow manufacturer's recommendations. In addition, surrounding
areas (including shrubs, grass, etc.) should be protected from
exposure to the remover, collection of the residue will probably
be required by environmental regulations. Removers are usually
toxic and may cause fire hazards. Management of the waste
associated with the procedure will also be necessary. Consult
the local environmental and safety offices for further
information.
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6.7.4
Detergent Washing. Detergent washing or scrubbing is
an effective way to remove soil, chalk and mildew. Detergent
cleaning solutions may be applied by brush, rags, or spray. An
effective solution for removal of soil and chalk is 4 ounces of
trisodium phosphate, 1 ounce household detergent, and 4 quarts of
water. For mildew removal, 1 part of 5 percent sodium
hypochlorite solution (household bleach) is added to 3 parts of
the cleaning solution used for chalk and soil removal. Of
course, if there is little or no existing chalk on the surface,
the cleaning solution should not contain the trisodium phosphate.
Note, that sodium hypochlorite solution (household bleach) must
not be added to cleaning solutions containing ammonia or other
similar chemicals. Toxic fumes will be produced. Thorough
rinsing with water is absolutely necessary to remove the soapy
alkaline residues before recoating. To test the effectiveness of
the rinse, place pH paper against the wet substrate and in the
rinse water and compare the pH of the two. (Refer to ASTM D 4262
for complete description of the procedure.) The pH of the
substrate should be no more than one pH unit greater than that of
the rinse water.
6.7.5
Hand Tool Cleaning. Hand cleaning is usually used only
for removing loosely adhering paint or rust. Any grease or oil
must be removed prior to hand cleaning by solvent washing. Hand
cleaning is not considered an appropriate procedure for removing
tight mill scale or all traces of rust and paint. It is slow
and, as such, is primarily recommended for spot cleaning in areas
where deterioration is not a serious factor or in areas
inaccessible to power tools. Hand tools include wire brushes,
scrapers, abrasive pads, chisels, knives, and chipping hammers.
SSPC SP 2 describes standard industrial hand-tool cleaning
practices for steel. Since hand cleaning removes only the
loosest contaminants, primers applied over hand-tool cleaned
surfaces must be chosen that are capable of thoroughly wetting
the surface. Paint performance applied to hand-cleaned steel
surfaces is not as good as that applied over blast cleaned
surfaces.
6.7.6
Heat. Electric heat guns and heat plates are used to
remove heavy deposits of coatings on wood and other substrates.
The gun or plate is positioned so that the coating is softened
and can be removed by scraping. Production rates depend upon the
thickness of the old coating and the smoothness of the substrate.
There is a possibility of creating toxic fumes, or conditions in
which burns are possible. The use of torches is not recommended,
although they have been used to remove greasy contaminates and
paints from surfaces prior to painting. This is an extremely
dangerous procedure. The SSPC no longer has a surface
preparation standard for flame cleaning because of the danger
involved.
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6.7.7
Organic Solvent Washing. Solvent cleaning is used for
removing oil, grease, waxes, and other solvent-soluble matter
from surfaces. VOC rules may prohibit or limit the use of
solvent cleaning. The local environmental and safety office
should be consulted before using or specifying solvent cleaning.
Inorganic compounds, such as chlorides, sulfates, rust, and mill
scale are not removed by solvent cleaning. Solvent cleaning or
detergent or steam washing must precede mechanical cleaning when
oil and grease are present on the surface because mechanical and
blast cleaning methods do not adequately remove organic
contaminants and may spread them over the surface. Before
solvent washing, any soil, cement splatter, or other dry
contaminants must first be removed. The procedure for solvent
washing is to: wet the surface with solvent by spraying or
wiping with rags wet with solvent; wipe the surface with rags;
and make a final rinse with fresh solvent. Fresh solvent must be
used continuously and the rags must be turned and replaced
continuously. Solvents rapidly become contaminated with oils and
grease since they clean by dissolving and diluting contaminants.
Mineral spirits is effective in most solvent cleaning operations.
SSPC SP 1 describes recommended industry practices for cleaning
steel using solvents.
Organic solvents pose health and safety threats and
should not come into contact with the eyes or skin or be used
near sparks or open flames. Table 3-5 lists the flash points
(the lowest temperature at which an ignitable mixture of vapor
and air can form near the surface of the solvent) and relative
toxicity of common solvents. Disposal of solvent must be done in
accordance with governing regulations. Rags must be placed in
fireproof containers after use. Additional safety information is
contained in Section 13.
6.7.8
Power Tool Cleaning. Power tool cleaning can be used
to remove more tightly adhering contaminants and existing paint
than hand tool cleaning. Either electrical or pneumatic power is
used as the energy source. Power tool cleaning is recommended
when deterioration is localized, deterioration is not a serious
problem, or when abrasive blasting is not possible. SSPC SP 3
and SSPC SP 11 describe the use of some of these tools for steel.
In general, power tool cleaning is less economical and more time
consuming than blasting for cleaning large areas. However, power
tools do not leave as much residue or produce as much dust as
abrasive blasting. Also, some power tools are equipped with
vacuum collection devices. Power tools include sanders,
grinders, wire brushes, chipping hammers, scalers, needle guns,
and rotary peeners. Power tools clean by impact or abrasion or
both. Near-white (i.e., rust and paint removed) steel surfaces
with anchor patterns (although different than those achieved in
blast cleaning) can be obtained with some power tools, as
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described in SSPC SP 11. Care must be taken when using wire
brushes to avoid burnishing the surface and thus causing a
reduced adhesion level of the primer coating. Grease and oil
must be removed prior to power tool cleaning. Danger from sparks
and flying particles must always be anticipated. The operator
and adjacent workers must wear goggles or helmets and wear
protective clothing. No flammable solvents should be used or
stored in the area. Refer to Section 13 for further safety
details.
6.7.9
Steam Cleaning. A high-pressure jet of steam (about
300 degrees F, 150 psi), usually with an added alkaline cleaning
compound, will remove grease, oil, and heavy dirt from surfaces
by a combination of detergent action, water, heat and impact
(refer to SSPC SP 1). The steam is directed through a cleaning
gun against the surface to be cleaned. The pressure is adjusted
to minimize spraying time. Any alkaline residue remaining on the
surface after the cleaning operation must be removed by thorough
rinsing with fresh water. Alkali cleaners used in steam cleaning
may attack aluminum and zinc alloys and should not be used on
these substrates. Steam cleaning may cause old paints to swell
and blister. Thus, when steam cleaning previously painted
surfaces, the cleaning procedure should first be tested in a
small area to assess the effect on the old paint.
Steam cleaning equipment is usually portable and is one
of two designs. With one type of equipment, concentrated
cleaning solution is mixed with water, fed through a heating unit
so that it is partially vaporized, pressurized, and forced
through a nozzle. With another type of equipment, sometimes
called a hydro-steam unit, steam from an external source is mixed
with the cleaning solution in the equipment or in the nozzle of
the cleaning gun. The shape of the nozzle is chosen according to
the contour of the surface being cleaned. Steam cleaning is
dangerous and extreme caution should be exercised with the
equipment. A dead man valve must be included in the equipment
and the operator must have sound, safe footing. Workers engaged
in steam cleaning operations must be protected from possible
burns and chemical injury to the eyes and skin by protective
clothing, face shields, and the like. Refer to Section 13 for
safety details.
6.7.10
Water Blast Cleaning. Water blast cleaning uses a
high-pressure water stream to remove lightly adhering surface
contaminants. Selection of water pressure and temperature and
addition of a detergent depend on the type of cleaning desired.
Low pressure - up to 2000 psi - (sometimes called "power
washing") is effective in removing dirt, mildew, loose paint, and
chalk from surfaces. It is commonly used on metal substrates and
generally does little or no damage to wood, masonry, or concrete
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substrates. For removing loose flaky rust and mill scale from
steel, water pressures as high as 10,000 psi or more and volumes
of water to 10 gallons per minute are used. However, water
blasting without an added abrasive does not provide a profile.
By introducing abrasives into the water stream, the cleaning
process becomes faster and an anchor pattern is produced.
Hydroblasting at high pressures can be dangerous and extreme
caution should be exercised with the equipment. A dead man valve
must be included in the equipment and the operator must have
sound, safe footing. He should wear a rain suit, face shield,
hearing protection, and gloves. Additional safety equipment may
be needed. Further safety procedures are described in Section
13.
6.7.10.1 Equipment. The basic water blasting unit (without
injection of an abrasive) consists of an engine-driven pump,
inlet water filter, pressure gauge, hydraulic hose, gun, and
nozzle combination. As with the equipment for abrasive blasting,
the gun must be equipped with a "fail-safe" valve so that the
pressure is relieved when the operator releases the trigger.
Nozzle orifices are either round or flat. The selection depends
on the shape of the surface to be cleaned. Flat orifices are
usually used on large flat surfaces. Nozzles should be held
about 3 inches from the surface for most effective cleaning.
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Section 7:
APPLICATION
7.1
Introduction. This section provides general
information on paint application and on activities associated
with application such as paint storage and mixing. Application
procedures discussed include brushing, rolling, and spraying
(conventional air, airless, air-assisted airless, high-volume
low-pressure, electrostatic, plural component, thermal, and
powder).
7.2
Paint Storage Prior to Application. The installation
industrial hygienist should be consulted about local regulations
for paint storage, since storage of paint may be subject to
hazardous product regulations. To prevent premature failure of
paint material and to minimize fire hazard, paints must be stored
in warm, dry, well ventilated areas. They should not be stored
outdoors, exposed to the weather. The storage room or building
should be isolated from other work areas. The best temperature
range for storage is 50 to 85 degrees F. High temperatures may
cause loss of organic solvent or premature spoilage of waterbased paints. Low temperature storage causes solvent-borne
coatings to increase in viscosity, and freezing can damage latex
paints and may cause containers to bulge or burst. (When paint
is cold, a 24-hour conditioning at higher temperatures is
recommended prior to use.) Poor ventilation of the storage area
may cause excessive accumulation of toxic and/or combustible
vapors. Excessive dampness in the storage area can cause labels
to deteriorate and cans to corrode. Can labels should be kept
intact before use and free of paint after opening so that the
contents can readily be identified.
The paint should never be allowed to exceed its shelf
life (normally 1 year from manufacture) before use. The stock
should be arranged, so that the first paint received is the first
paint used. Paint that has been stored for a long period of time
should be checked for quality and dry time before use. Quality
inspection procedures are described in par. 9.5.5.
7.3
Preparing Paint for Application
7.3.1
Mixing. During storage, heavy pigments tend to settle
to the bottom of a paint can. Prior to application, the paint
must be thoroughly mixed to obtain a uniform composition.
Pigment lumps or caked pigment must be broken up and completely
redispersed in the vehicle. Incomplete mixing results in a
change of the formulation that may cause incomplete curing and
inferior film properties. However, caution must be used not to
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overmix waterborne paints since excessive foam can be created.
Constant mixing may be required during application for paints
with heavy pigments, such as inorganic zincs.
Mixing can be done either manually or mechanically.
Two types of mechanical mixers are commonly used: ones which
vibrate and ones which stir with a propeller. Since manual
mixing is usually less efficient than mechanical mixing, paints
should only be manually mixed when little mixing is needed
because there is limited pigment settling or when mechanical
mixing is not possible. Vibrator-type mixers should not be used
with partly full cans of paint. This can cause air to become
entrained in the paint which, if applied, may lead to pinholes in
the dry film.
When pigments form a rather hard layer on the bottom of
the can, the upper portion of the settled paint can be poured
into a clean container (Figure 7), so that the settled pigment
can more easily be broken up and redispersed to form a smooth
uniform thin paste. When mixing manually, lumps may be broken up
by pressing them against the wall of the can. It is essential
that settled pigments be lifted from the bottom of the can and
redispersed into the liquid. Once the material is uniform, the
thin upper portion of the container is slowly poured into the
uniform paste while the paint is stirred. Stirring is continued
until the entire contents is uniform in appearance. No more
paint should be mixed than can be applied in the same day. Paint
should not be allowed to remain in open containers overnight.
7.3.1.1
Mixing Two-Component Coatings. Epoxies and
polyurethanes are commonly used two-component coatings. The base
component, A, contains the pigment, if any. The B component
contains the curing agent. The two components must be mixed in
the ratio specified by the coating manufacturer on the technical
data sheet, unless the coating is being applied using a plural
component gun (refer to par. 7.5.4.5). Usually the materials are
supplied so that the contents of one can of component A is mixed
with the contents of one can of component B. Failure to mix the
components in the proper ratio will likely result in poor film
formation. Binder molecules are cross-linked in a chemical
reaction upon mixing of the two components. Unless the two
components are mixed together, there will be no chemical reaction
and no curing of the paint.
a) Mixing. Two-component coatings are preferably
mixed with a mechanical stirrer as follows:
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Figure 7
Illustration of Mixing and "Boxing" One-Component Paint: A Pouring Off Pigment-Poor Vehicle, B and C - Mixing Pigment
to Form Smooth Paste, D - Pouring in Vehicle and Mixing,
E - Boxing Paint
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(1) The base component is mixed to disperse
settled pigment. If necessary, some of the thin, upper portion
may be poured off before stirring to make it easier to disperse
the pigment. When the upper portion is poured off, it must be
mixed back with the bottom portion before the two components are
mixed together.
(2) While continuing to stir, the two components
are slowly mixed together. No more than a few gallons should be
mixed at a time, or no more than that specified by the coating
manufacturer, since heat is usually generated upon mixing because
of the chemical cross-linking reaction. Excessive heat may lead
to premature curing of the coating, reducing the pot life.
(3) The two combined parts are agitated until they
are of smooth consistency and of uniform color. (Often the color
of the two components is different.)
b) Induction. Some two-component paints must stand
for approximately 30 minutes after mixing before application.
This time is called the induction time. During induction, the
chemical reaction proceeds to such an extent that the paint can
be successfully applied. However, some formulations of twocomponent paints do not require any induction time and can be
applied immediately after mixing the two components. Material
specifications and manufacturer's recommendations must be
followed carefully. Induction time will depend on temperature of
the paint.
c) Pot Life. Pot life is the time interval after
mixing in which a two-component paint can be satisfactorily
applied. Paints low in VOC content often have a reduced pot
life. The chemical reaction that occurs when two component
paints are mixed accelerates with increasing temperature. Thus,
a paint's pot life decreases as the temperature increases. Above
90 degrees F, the pot life can be very short. (Curing time of
the applied coating is also faster at higher temperatures.) Pot
life is also affected by the size of the batch mixed, because the
chemical reaction produces heat. The larger the batch, the more
the heat produced and the faster the curing reaction proceeds.
Thus, the shorter the pot life. Paint must be applied within the
pot life. The coating manufacturer's recommendations must be
followed carefully. Mixed two-component paint remaining at the
end of a shift cannot be reused and must be discarded. Lines,
spray pots, and spray guns must be cleaned during the pot life of
the paint.
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7.3.2
Thinning. Usually thinning to change the viscosity of
liquid paint should not be necessary. A manufacturer formulates
paint to have the proper viscosity for application. If thinning
is necessary, it must be done using a thinner recommended by the
coating manufacturer. Also, the amount used should not exceed
that recommended by the coating manufacturer. Prior to adding
the thinner, the temperature of the coating and the thinner
should be about the same. The thinner must be thoroughly mixed
into the paint to form a homogeneous material. Some "falsebodied" or "thixotropic" paints are formulated to reach the
proper application viscosity after stirring or during brush or
roller application. Undisturbed in the can, they appear gel
like, but upon stirring or under the high shear of brush or
roller application, these materials flow readily to form smooth
films. Upon standing, the coating in the can will again become
gel-like. Because of this property, thixotropic coatings may
require constant agitation during spray application.
7.3.3
Tinting. Tinting should be avoided as a general
practice. If materials are tinted, the appropriate tint base
(e.g., light and deep tones) must be used. Addition of excessive
tinting material may cause a mottled appearance or degrade the
film properties (e.g., adhesion). Also, tinting should only be
done with colorants (tints) known to be compatible with the base
paint. No more than 4 ounces of tint should be added per gallon
of paint.
7.3.4
Straining. Usually, paint in freshly opened containers
should not require straining. However, mixed paint having large
particles or lumps must be strained to prevent the film from
having an unacceptable appearance or clogging spray equipment.
Straining is especially important for inorganic zinc coatings.
Straining is done after mixing, thinning, and tinting is
completed by putting the paint through a fine sieve (80 mesh) or
a commercial paint strainer.
7.4
Weather Conditions Affecting Application of Paints.
Paint application is a critical part of a complete paint system.
Many of the newer paints are more sensitive to poor application
procedures and environmental conditions than oil paints. Four
main weather conditions must be taken into account before
applying coatings: temperature, humidity, wind, and rain or
moisture. The paint manufacturer's technical data sheets should
be consulted to determine the limits for these conditions as well
as other constraints on application of the paint. Applying
paints outside the limits is likely to lead to premature coating
failure.
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7.4.1
Temperature. Most paints should be applied when the
ambient and surface temperature is between 45 degrees F and 90
degrees F. Lacquer coatings such as vinyls and chlorinated
rubbers, can be applied at temperatures as low as 35 degrees F.
There are other special coatings that can be applied at
temperatures below 32 degrees F but only in strict compliance
with manufacturer's instructions. Application of paints in hot
weather may also cause unacceptable films. For example, vinyls
may have excessive dry spray and latex paints may dry before
proper coalescence, resulting in mud-cracking. In all cases
painting must be done within the manufacturer's acceptable range.
Also, the temperature of the paint material should be at least as
high as the surface being painted. Paint should not be applied
when the temperature is expected to drop below 40 degrees F
before the paint has dried (except when allowed in the
manufacturer's instructions).
7.4.2
Humidity. Ensuring the proper relative humidity during
application and cure can be essential for good film performance.
However, different types of coatings require different relative
humidities. The coating manufacturer's technical data sheet
should be consulted. Some coatings cure by reacting with
moisture from the air (e.g., moisture-curing polyurethanes,
silicones, and inorganic zincs). These coatings require a
minimum humidity to cure. However, too high a humidity may cause
moisture-curing coatings to cure too quickly resulting in a
poorer film. In addition, too high a humidity may cause blushing
(whitish cast on surface of dry film) of some solvent-borne
coatings. Blushing is caused when the surface of a coating film
is cooled by evaporation of a solvent to such an extent that
water condenses on the still wet film. Excessive humidity may
also cause poor coalescence of latex coatings since the
coalescing agent may evaporate before enough water evaporates to
cause coalescence of the film.
7.4.3
Wind. Wind can cause a number of problems during spray
application. These include uncontrollable and undesirable
overspray and dry spray caused by too fast evaporation of the
solvents. The wind velocity at which these undesirable effects
occur depends upon the material being applied and the application
parameters. Wind can also blow dust and dirt onto a wet surface
which could lead to future paint breakdown.
7.4.4
Moisture. Paint should not be applied in rain, wind,
snow, fog, or mist, or when the surface temperature is less than
5 degrees F above the dew point. Water on the surface being
painted will prevent good adhesion.
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7.5
Methods of Application. The most common methods of
application are brush, roller, and spray. They are discussed in
detail below. Paint mitts are recommended only for hard to reach
or odd-shaped objects such as pipes and railings when spraying is
not feasible. This is because it is not possible to obtain a
uniform film that is free of thin spots with mitt application.
Foam applicators are useful for touch-up or trim work. Dip and
flow coat methods are beyond the scope of this handbook. Of the
three primary methods, brushing is the slowest, rolling is
faster, and spraying is usually the fastest of all. A comparison
of approximate rates of application by one painter of the same
paint to flat areas is listed in Table 10.
Table 10
Approximate Rates of Paint Application
(From SSPC Good Painting Practice)
Method
Brush
Roller
Air Spray
Airless Spray
Square Feet Applied in 8 Hour
Day
800
2000
4000
8000
- 1400
- 4000
- 8000
- 12,000
7.5.1
Selection of Application Method. The choice of an
application method depends on the type of coating, the type of
surface, environmental factors, and cleanup. Alkyd coatings can
easily be applied by brush, but fast drying coatings, such as
vinyls, are difficult to apply by brush or roller. Brushing is
the preferred method for small areas and uneven or porous
surfaces, while rolling is practical on large flat areas. Also,
brushing of primers over rusted steel and dusty concrete is
preferred over spraying. (Note that applying paint over these
substrates should be avoided, if possible.) Spraying is usually
preferred on large areas and is not limited to flat surfaces.
Spraying may not be feasible is some locations and in some
environments because of the accumulation of toxic and flammable
fumes or overspray.
7.5.2
Brush Application. Brushing is an effective method of
paint application for small areas, edges, corners, and for
applying primers. Brush application of primers works the paint
into pores and surface irregularities, providing good penetration
and coverage. Because brushing is slow, usually it is used only
for small areas or where overspray may be a serious problem.
Brush application of paint may leave brush marks with paints that
do not level well, thus creating areas of low film thickness.
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Even a second coat of paint may leave the total coating system
with thin and uneven areas that may lead to premature failure.
Brushes are made with either natural or synthetic
bristles. A drawing of a typical paint brush is shown in Figure
8. Chinese hog bristles represent the finest of the natural
bristles because of their durability and resiliency. Hog
bristles are also naturally "flagged" or split at the ends. This
permits more paint to be carried on the brush and leaves finer
brush marks on the applied coating. Horsehair bristles are used
in cheaper brushes but are an unsatisfactory substitute for hog
hair. Nylon and polyester are used in synthetic bristles or
filaments. The ends are flagged by splitting the filament tips.
Synthetic bristles absorb less water than natural bristles and
are preferred for applying latex paints. However, synthetic
bristles may be softened by strong solvents in some paints.
Thus, natural bristles are preferred for application of paints
with strong solvents.
Brushes are available in many types, sizes, and
qualities to meet the needs for different substrates. These
types include wall, sash and trim (may be chisel or slashshaped), and enamel (bristles are shorter). It is important to
use high quality brushes and keep them clean. Brushes with
horsehair or with filaments that are not flagged should be
avoided. The brush should be tapered from side to center (see
Figure 8).
7.5.2.1
Procedure for Brush Application
a) Shake loose any unattached brush bristles by
spinning the brush between the palms of the hand and remove the
loose bristles.
b) Dip the brush to cover one-half of the bristle
length with paint. Remove excess paint on the brush by gently
tapping it against the side of the can.
c) Hold the brush at an angle of about 75 degrees to
the surface. Make several light strokes to transfer the paint to
the surface. Spread the paint evenly and uniformly. Do not
press down hard but use a light touch to minimize brush marks.
If there is time before the paint sets up, cross-brush lightly to
eliminate excessive brush marks.
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MIL-HDBK-1110
Figure 8
Illustration of Parts of Paint Brush
d) Confine painting to one area so that a "wet edge"
is always maintained. Apply paint to a surface adjacent to the
freshly painted surface sweeping the brush into the wet edge of
the painted surface. This helps to eliminate lap marks and
provides a more even coating film.
7.5.3
Roller Application. Roller application is an efficient
method for flat areas where the stippled appearance of the dry
film is acceptable. However, paint penetration and wetting of
difficult surfaces is better accomplished by brush than roller
application. Thus, brush application of primers is preferred
over roller application.
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A paint roller consists of a cylindrical sleeve or
cover which slips onto a rotatable cage to which a handle is
attached. The covers vary in length from 1 to 18 inches and the
diameter from 1.5 to 2.25 inches. A 9-inch length, 1.5-inch
diameter roller, is common. The covers are usually made of
lamb's wool, mohair, or synthetic fibers. The nap (length of
fiber) can vary from 0.25 to 1.25 inches. Longer fibers hold
more paint but do not give as smooth a finish. Thus, they are
used on rougher surfaces and chain link fence, while the shorter
fibers are used on smooth surfaces. Use of extension handles
makes the application of paint to higher surfaces easier.
However, use of a long extension handle usually results in a less
uniform film. Use a natural fiber roller (for example, woolmohair) for solvent base paints and a synthetic fiber roller for
latex paints.
7.5.3.1
Procedures for Roller Application. Rollers are used
with a tray which holds the coating or a grid placed in a 5gallon can (Figure 9). Application procedure is described below.
Figure 9
Equipment Used in Applying Paint by Roller
a) If a tray is being used, fill it half full with
premixed paint. If a grid or screen is being used, place it at
an angle in the can containing premixed paint.
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b) Immerse the roller completely in the paint and
remove the excess by moving the roller back on the tray or grid.
Skidding or tracking may occur if the roller is loaded with too
much paint.
c) Apply the paint to the surface by placing the
roller against the surface forming a "V" or "W" of a size that
will define the boundaries of the area that can be covered with
the paint on a loaded roller. Then roll out the paint to fill in
the square area. Roll with a light touch and medium speed.
Avoid letting the roller spin at the end of a stroke. Always
work from a dry adjacent surface to a wet surface. The wet edge
should be prevented from drying to minimize lap marks.
d) Use a brush or foam applicator to apply paint in
corners, edges, and moldings before rolling paint on the adjacent
areas.
7.5.4
Spray Application. Spray application is the fastest
technique for applying paint to large areas. Spray application
also results in a smoother, more uniform surface than brushing or
rolling. There are several types of equipment: conventional
air, airless, air-assisted airless, high-volume, low-pressure
(HVLP), electrostatic, multi-component, thermal, and powder.
Conventional air and airless were most commonly used. However,
with changing VOC requirements the other methods are being used
more. Air or air-assisted methods of spraying, including HVLP,
rely on air for paint atomization. Jets of compressed air are
introduced into the stream of paint at the nozzle. The air jets
break the paint stream into tiny particles that are carried to
the surface on a current of air. The delivery of the paint to
the nozzle may be assisted using hydraulic pressure. In airless
spray, paint is forced through a very small nozzle opening at
very high pressure to break the exiting paint into tiny droplets.
A general comparison of properties of conventional air and
airless spray are given in Table 11. Note that specific
application rates, the amount of overspray, and other properties
depend to a great extent upon the type of paint, and may vary
from those listed in the table. Air methods other than
conventional have been developed to overcome some of the
environmental and other concerns of air and airless spray. These
differences are discussed separately for each method below.
7.5.4.1
Conventional or Air Spray Equipment. The conventional
method of spray application is based on air atomization of the
paint. The basic equipment (air compressor, paint tank, hoses
for air and paint, spray gun) is shown in Figure 10. The coating
material is placed in a closed tank (sometimes called a pot)
connected to the nozzle by a hose and put under regulated
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pressure using air from the compressor. A hose from the air
compressor to the nozzle supplies the air required for
atomization of the paint. The tank may be equipped with an
agitator for continuously mixing paints with heavy pigments. The
air compressor must have sufficient capacity to maintain adequate
and constant air pressure and airflow for paint atomization at
the nozzle, for paint flow from the tank to the nozzle, for
powering the agitator and other job-site requirements. A
constant flow of air from the compressor is required for proper
painting. Loss of pressure at the nozzle can cause pulsating
delivery of the paint as opposed to the desired constant flow.
(Data sheets from paint manufacturers give recommended air
pressures for spraying.)
a) Air Hose. The air hose connecting the compressor
to the tank must be of sufficient diameter to maintain adequate
air pressure. Required diameter of the fluid hose connecting the
gun and tank depends on volume and pressure of paint required at
the gun. The hose should be kept as short as possible,
especially when spraying coatings with heavy pigments, to avoid
settling of pigments within the supply hose. Also, the fluid
hose must be resistant to paints and solvents that flow through
it. As with blasting equipment, the air supply must be free of
moisture, oil, and other impurities. Oil and water should be
removed by separator or extractor attachments to the compressor.
Table 11
Comparison of Conventional Air and Airless Spray
Property
Coverage, sq ft/day
Overspray
Transfer efficiency
"Bounce back"
Hoses
Penetration of corners,
crevices and cracks
Film build per coat
Versatility
Paint clogging problems
Operator control
Safety during painting
Safety during cleanup
Conventional Air
4-8000
Considerable
Poor (about 30
percent)
Significant
2 (air and fluid)
Fair
Fair
Good
Few
Good
Fair
Fair
110
Airless
6-10,000
Some
Fair (35-50)
Minor
1 (fluid)
Moderate
Good
Fair
More
Poor
Poor
Poor
MIL-HDBK-1110
Figure 10
Schematic Drawing Illustrating Basic Parts of Conventional
Air Spray Application Equipment
b) Gun or Nozzle. The gun or nozzle is a relatively
complex device (Figure 11). It consists basically of 10 parts:
(1) Air nozzle or cap that directs the compressed
air into the stream of paint to atomize it and carry it to the
surface.
(2) Fluid nozzle that regulates the amount of
and directs it into the stream of compressed air.
paint released
(3) Fluid needle that controls the flow of fluid
through the nozzle.
(4)
Trigger that operates the air valve and fluid
needle.
(5) Fluid adjustment screw that controls the fluid
needle and adjusts the volume of paint that reaches the fluid
tip.
(6)
through the gun.
Air valve that controls the rate of airflow
(7) Side port control that regulates the supply of
air to the air nozzle and determines the size and shape of the
spray pattern.
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(8)
Gun body and handle designed for easy
(9)
Air inlet from the air hose.
handling.
(10) Fluid inlet from fluid hose.
c) Air Nozzle. Two general types of air nozzles are
available: external atomization and internal atomization. In
both types, outer jets of air atomize the wet paint (see Figure
12). In the external type, paint is atomized outside the nozzle,
while in the internal type paint is atomized just inside the
nozzle opening. The type selected depends on the type of paint
to be sprayed and the volume of air available. The external type
is the more widely used. It can be used with paints and most
production work. The spray pattern can be adjusted. A fine mist
can be obtained which can result in a smooth even finish. Nozzle
wear and buildup of dry material are not major problems. The
internal-mix air nozzle requires a smaller volume of air and
produces less overspray and rebound than the external type. The
size and shape of the spray pattern of the internal-mix nozzle
cannot be adjusted. Catalyzed and fast drying paints tend to
clog the openings of internal-air nozzles. These coatings should
be sprayed with an external-mix nozzle.
d) Setting-Up, Adjusting Equipment, and Shutting-Down
Procedures. Both the pressure on the paint and the air pressure
at the gun must be properly regulated to obtain the optimum in
film performance. A properly adjusted nozzle will produce a fan
that is about 8 inches wide, 10 inches from the gun. The shape
of the spray pattern produced may vary from round to oval. The
pattern must have well defined edges with no dry spray at the
ends or heavy film buildup in the middle (Figure 13). Coating
manufacturers provide guidance on appropriate equipment and
pressures for application of their coatings. Additional job-site
adjustments may be necessary. The aim is to obtain a wet looking
film that is properly atomized with as little overspray as
possible. To minimize bounce back and dry spray, the atomizing
air pressure should be kept as low as possible. Common spray
pattern problems and their cause and remedy are listed in Table
12. The gun should be taken apart and cleaned at the end of each
day and the air cap and fluid tip should be cleaned with solvent.
Pivot points and packing should be lubricated with lightweight
oil. Leaving a gun in a bucket of solvent overnight will likely
cause the gun to become plugged and lead to premature failure of
the gun. The shutting-down procedure is detailed in the
instructions supplied by the manufacturer of the spray equipment
and these instructions should be followed. Other worker safety
issues are discussed in the section on safety.
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Figure 11
Drawing of Air-Spray Gun
Figure 12
Cross-Sectional Drawing of Nozzle of Air-Spray Gun
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Figure 13
Illustration of Proper Spray Patterns
(Note that the patterns are uniform throughout.)
Table 12
Common Conventional Air-Spray Problems and Their Causes
and Remedies
Description
Cause
Remedy
Thick center;
thin ends;
pinholes
Atomizing air
pressure too low;
too much fluid
to gun
Increase air pressure;
decrease fluid
pressure or use
smaller nozzle
Hourglass
shape; dry
spray on ends
Fluid pressure
low; air
pressure too
high; too wide
a spray pattern
Increase fluid
pressure; reduce
air pressure; adjust
pattern control;
reduce paint viscosity
Teardrop
shape;
thicker at
bottom
Problem with gun
- nick in needle
seat; partially
clogged orifice
or slightly bent
needle or loose
nozzle
Remove and clean air
nozzle; replace any
bent parts or tighten
air nozzle
"Boomerang"
Dried paint has
clogged one of
the side port
holes of the air
nozzle
114
Dissolve dried paint
with thinner; do not
probe into nozzle
with metal devices
MIL-HDBK-1110
7.5.4.2
Airless Spray
a) Equipment. Airless spray relies on hydraulic
pressure alone. Atomization of paint is accomplished by forcing
the material through a specially shaped orifice at pressures
between 1000 and 3000 psi. Because of the high pressures,
extreme care must be taken to prevent worker injury. The spray
manufacturer's instructions must be followed carefully. The
basic parts of airless spray equipment are a high-pressure paint
pump, a fluid hose, and an airless spray gun. The high-pressure
pump must deliver sufficient pressure and material flow to
produce a continuous spray of paint. The fluid hose must be able
to withstand the very high pressures required to deliver the
paint to the gun and atomize it. A filter screens out particles
that might clog the tip. Since atomization is controlled by the
size and shape of the orifice of the tip, a different tip is used
to obtain different patterns and atomization rates. The tip
angle controls the fan width. Tips having the same orifice size
but different angles deliver the same amount of paint, but the
area covered with one pass is different. Viscous materials
require a larger tip than less viscous materials. Coating
manufacturers recommend tip sizes on their data sheets. The
larger the orifice, the greater the production rate. But, if too
large an orifice is used for a thin coating, the rate of delivery
may be such that the operator cannot keep up with the flow. This
will result in sagging and running of wet paint. Airless spray
is available with heaters to reduce paint viscosity, permitting
spraying of coatings having higher ambient viscosities at a
faster production rate.
b) Setting-Up, Adjusting Equipment, and Shutting-Down
Procedures. The manufacturer's instructions should be followed
for setting up the spray equipment. To minimize tip clogging
problems, airless spray equipment must be scrupulously clean
before setting-up for a spray application and the coating must be
free of lumps. The manufacturer's recommendations should be
followed rigorously for the setting-up, using, and shutting-down
procedures. Since the pressures used are high, two safety
features are required for guns: a tip guard and a trigger lock.
The tip guard prevents the operator from placing a finger close
to the tip and injecting paint into the skin. The trigger lock
prevents the trigger from accidentally being depressed. Other
safety measures include never pointing the gun at any part of the
body; not making adjustments without first shutting off the pump
and releasing the pressure; making sure the fluid hose is in good
condition, free of kinks, and bent into a tight radius; and using
only high-pressure hose fittings. Also, never clean systems
containing aluminum with chlorinated solvents. Explosions may
occur. Causes of and remedies for faulty patterns are described
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in Table 13. Additional problems that may occur with airless
spraying may be associated with excessive pressure, undersized
equipment, and too long or too small paint hoses. Undersized
spray equipment, including hoses, may result in lower production
rates, a pebbly-appearing film caused by poor atomization (nozzle
tip too large), and thin films. Air supply hoses that are too
long or too small may cause instability of the pump, poor
atomization of the paint, or a pulsating spray pattern.
Table 13
Common Airless-Spray Problems and Their Causes and Remedies
Remedy
Description
Thick center,
pressure,
thin ends,
pinholes
Inadequate fluid
delivery or
improper
atomization
and
Cause
Increase fluid
decrease paint
viscosity, choose larger
tip orifice, or reduce
number of guns using one
pump
hour-glass
shape
Teardrop
replace
shape coating
thicker
Clogged or worn
Clean nozzle tip,
Rippling,
uneven pattern
Pulsating fluid
delivery or
suction leak
Increase supply to air
motor, reduce number of
guns using one pump,
choose smaller tip
orifice, clean tip
screen and filter, or
look for hose leak
Round pattern
Worn nozzle tip
or fluid too
viscous for tip
size
Replace worn tip,
decrease fluid viscosity
increase pressure, or
choose correct tip
orifice
Fluid spitting
Air entering
system, dirty
gun, or wrong
cartridge
adjustment
Check for hose leak,
clean gun, or adjust
cartridge and replace
if necessary
nozzle tip if necessary
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7.5.4.3
Air-Assisted Airless Spray. Air-assisted airless spray
uses air to help atomize paint as compared with only fluid
pressure in the airless system. Thus, a lower hydraulic pressure
(typically 500 to 1000 psi) can be used. Air pressure is
typically 10 to 15 psi. Air-assisted airless spray provides a
finer spray than airless spray, and the lower hydraulic pressure
provides improved operator control. Consequently, finishes tend
to be smoother with fewer runs and sags. Transfer efficiency is
about the same as airless spray, but air-assisted airless spray
is more expensive to maintain.
7.5.4.4
High-Volume, Low-Pressure Spray. HVLP spray is an air
spray technique that uses low pressure and large volumes of air
to atomize the paint. It has much better transfer efficiency
that conventional air spray and some systems have been found to
meet the 65 percent transfer efficiency requirement of
California's South Coast Air Quality District. Because of the
lower air pressures, there is also less bounce back than with
conventional systems. Turbine air-supply systems, along with
large (1-inch diameter) hoses are commonly supplied with the
systems. Since the air supply is not turned off when the trigger
is released, air flows continuously through a bleeder valve in
the gun. An HVLP gun can be equipped with different fluid and
air tips depending upon several variables: the desired spray
pattern (wide fan to narrow jet), viscosity of the finish, and
output of the turbine. Although some special training of
painters may be required because of differences between
conventional air systems and HVLP, such as less recoil, higher
delivery volumes and continuous flow of air, an experienced
operator has good control.
Conversion kits for air compressor systems are
available which allow the use of them with HVLP systems. Spray
techniques may be slightly different depending upon the source of
pressurized air.
7.5.4.5
Multi-Component Spray. Multi-component (or pluralcomponent) spray equipment combines components of multi-component
paints in the nozzle. The equipment is more complicated than
other spray equipment, and its use is usually confined to large
or specialized coating applications. The components are metered
to the gun in the proper relative volumes, mixed and then
atomized by one of the previously described techniques. Thus,
pot life is not a factor in application of multi-component
coatings. However, it is essential that the metering be done in
accordance with the coating manufacturer's instructions. Volume
mixing ratios are usually from 1:1 to 1:4. Heating of the
components before mixing is also provided with some equipment.
By heating the components, both the viscosity during application
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MIL-HDBK-1110
and the cure time can be altered. The equipment is cleaned by
purging with solvent. Because of the complicated nature of the
equipment, specialized operator training and skilled operators
are required. Initial and maintenance costs are also greater
than for other spray techniques.
7.5.4.6
Electrostatic Spray. In hand-held electrostatic spray
systems, a special protruding part of the gun is given a high,
negative voltage which places a negative charge on the spray
droplets as they come from the gun. The surface being painted is
grounded. This causes the paint droplets to be attracted to the
grounded surface to be painted. Because there is an electrical
attraction between the paint droplets and the object being
painted, a very high percentage of droplets lands on the surface.
That is, the transfer efficiency is high and there is minimal
overspray. Also, some droplets will be attracted to the edges
and the back of the surface, if they are accessible. This is
called the wraparound effect. Specially formulated paints are
required for electrostatic spraying. Also, painting is
restricted to use on conductive substrates, such as steel or
galvanized steel. Only one coat of paint may be applied to the
base metal by electrostatic spraying since a painted surface is
not conductive. Electrostatic spray is an ideal spraying method
for piping, fencing, channels, and cables because of the
wraparound effect and minimal overspray. However, because of
high voltage, special safety requirements must be met, including
grounding the power supply and the operator.
7.5.4.7
Powder Spraying. Powder coatings, usually epoxies, are
specially prepared polymeric coatings. They are applied to
preheated conductive surfaces, such as steel, by special
electrostatic spray equipment or in a fluidized bed. Once
applied, the coated component is heated to fuse the powder into a
continuous coating film. This technique is commonly used in shop
applications because heating can be done in an oven, there are no
volatile solvents to control and material that did not stick to
the surface can be collected and reused. Portable systems are
also available and can be used in special situations.
7.5.4.8
Thermal Spraying. Thermal spraying, sometimes called
metallizing, is a process in which finely divided metals are
deposited in a molten or nearly molten condition to form a
coating, usually on steel. Equipment and techniques are
available for flame or electric arc spraying of pure zinc, pure
aluminum, or an 85 percent zinc, 15 percent aluminum alloy. The
coating material is available in the form of a powder or wire,
with wire used more frequently. Once the metal becomes molten,
it is delivered to the surface with air or gas pressure. It
forms a porous coating that protects steel by cathodic protection
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MIL-HDBK-1110
in a variety of environments. For more severe service such as
very acid or alkaline conditions, or fresh or salt water spray,
splash, or immersion, the coating may be sealed with a thin
conventional organic coating or silicone. A white-metal blasted
surface is required. Metal spray coatings are normally very
abrasion resistant and provide excellent corrosion control.
Thermal spraying of metals is best accomplished in a
shop environment, but can also be done in the field.
DOD-STD-2138(SH) describes the wire flame spraying of aluminum
using oxygen-fuel gas. SSPC Guide 23, Coating Systems describes
thermal spray metallic coating systems.
7.5.4.9
Application Technique. Proper application technique is
essential for obtaining quality films. Poor technique can result
in variations in paint thickness, holidays (small holes), and
other film defects, and wasted time and materials. The same
basic techniques described below are used for both conventional
and airless spraying:
a) Stroking. With the spray gun at a right angle to
the work, the wrist, arm, and shoulder are moved at a constant
speed parallel to the surface. Holding the gun at an upward or
downward angle to the surface will result in a non-uniform
coating thickness and may increase the problem with dry spray or
overspray. Also, changing the distance between the gun and the
surface, arcing, as illustrated in Figure 14, will result in a
non-uniform coating thickness. For large flat surfaces, each
stroke should overlap the previous one by 50 percent as shown in
Figure 15. This produces a relatively uniform coating thickness.
The stroke length should be from 18 to 36 inches, depending upon
the sprayer's arm length and comfort. Surfaces of greater length
should be divided into smaller sections of appropriate length
(Figure 16). Each section should slightly overlap the previous
one along the lines where they are joined.
b) Triggering. The spray gun should be in motion
before triggering and continue briefly after releasing at the end
of a stroke. This is illustrated in Figure 17. Proper
triggering also keeps the fluid nozzle clean, reduces paint loss,
prevents heavy buildup of paint at corners and edges, and
prevents runs and sags at the start and end of each stroke.
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Figure 14
Illustration of Improper Movement of Spray Gun
When Applying Paint
120
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Figure 15
Illustration of Proper Procedure for Spray Painting
Large Flat Surfaces
121
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Figure 16
Schematic to Illustrate Proper Painting of Large Vertical
Surfaces
122
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Figure 17
Illustration of Proper "Triggering" of Spray Guns
c) Distance. Distance between the nozzle and the
surface being painted depends on atomization pressure and the
amount of material delivered. This distance usually varies from
6 to 12 inches for conventional spraying and from 12 to 15 inches
for airless spraying. If spray gun is held too close to the
surface, heavy paint application and sagging or running may
occur. If the gun is held too far away from the surface, a dry
spray with a sandy finish may result. Such paint films usually
contain holidays (small holes) and provide an unacceptable
surface.
d) Corners. Both inside and outside corners require
special techniques for uniform film thickness. Each side of an
inside corner should be sprayed separately as shown in Figure 18.
Too thick a layer of paint can easily be applied to an inside
corner. But when too thick a layer is applied, the coating may
shrink or pull away from the inside corner causing a void
underneath the coating. This will lead to premature failure. An
outside corner is first sprayed directly, as shown in Figure 19,
and then each side is coated separately. On an outside corner,
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MIL-HDBK-1110
the coating tends to pull away from the corner. Thus, the
coating on the corner tends to be too thin. Outside edges should
be ground so that the edge is rounded before painting.
Figure 18
Proper Spray Painting of Inside Corners
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MIL-HDBK-1110
Figure 19
Proper Spray Painting of Outside Corners
e) Welds. Welds are usually rougher than the adjacent
steel and a uniform coating is more difficult to achieve.
Failure often occurs first over welded areas. Thus, after
grinding the welds to smooth them, a coat of paint should be
brushed over the welds. Then the entire surface can be painted
by spray. With this extra coating over the welds, paint often
lasts as long over welds as on the adjacent flat areas.
f) Nuts, Bolts, and Rivets. It is a good coating
practice to brush-coat these areas before spraying the flat
areas. Paint can be worked into crevice and corner areas. Nuts,
rivets, and bolts should be sprayed from at least four different
angles to prevent thin coatings caused by shadowing effects
(Figure 20).
g) Common Errors. Some common errors and the results
that are produced in spray painting are summarized in Table 14.
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Figure 20
Schematic Illustrating Importance of Spraying Surfaces With
Protruding Parts From All Directions to Avoid "Shadowing Effect"
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Table 14
Spray Painting Errors
Error
Result
Improper spraying
technique (e.g.,
arcing, tilting
gun)
Spray pattern varied from narrow to wide
Variation of sheen from overspray
Uneven film thickness
Improper fan width
Inadequate or excessive film build on
complex substrate shapes, such as "I" or
"H" beams
Spray gun too
close to surface
Excessive film build
Runs, curtains, sags
Poor paint adhesion from improper curing
Wrinkling during and after surface curing
Excessive paint used
Orange peel pattern or blow holes
Spray gun too far
from surface
Film build too thin
Non-uniform film thickness
Dry spray
Uneven angular sheen from overspray
earlier work
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Section 8:
PREPARATION OF A PAINTING CONTRACT SPECIFICATION
8.1
General. A contract specification is a written
detailed, precise description of the work to be done; it
constitutes a part of the overall contract to describe the
quality of materials, mode of construction, and the amount of
work. The purposes of the specification are:
a)
To obtain a specific desired product
b)
To ensure quality materials and workmanship
c)
To ensure completion of work
d)
To avoid delays and disputes
e)
To obtain minimum or reasonable costs
f) To make the contract available to as many qualified
bidders as possible
g)
To avoid costly change orders and claims
h)
requirements
To meet safety, environmental, and legal
Construction specifications provide a description of
the desired work in such detail that a product other than that
desired may not result. Because painting frequently comprises
only a small part of construction work, it frequently receives
only limited attention so that it is inadequate to fill the
desired goals.
Construction specifications are further complicated by
the fact that they comprise legal documents and thus must meet
legal as well as technical requirements. Deficiencies in paint
or other construction specifications permit bidders to interpret
incompletely described requirements to their advantage, and to
provide lesser work or cheaper materials. These in turn, give
rise to disputes and litigation. Thus, it is extremely important
that specifications be prepared systematically, thoroughly, and
legally.
8.2
Background. At one time, it was a common practice to
use old painting specifications over and over again without
attempting to update them. Changes to meet new needs frequently
were made by "cutting and pasting." This did not permit the use
of new technology, address new requirements, or correct errors in
earlier documents.
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Another common practice was to have coating suppliers
prepare specifications for painting, particularly for small jobs.
As might be expected, the supplier's products were required by
the document. Today, specifications are usually prepared by
architect-engineers who specialize in this work. They have the
background, and the standards and other criteria documents at
their disposal, to prepare an engineering document for a specific
job in a professional manner that is technically correct
(complete and without error), clear (unambiguous), and concise
(no longer than absolutely necessary).
The specification writer must be able to describe the
important details while visualizing the desired final products of
the work. The different requirements and phases of the work must
be presented in logical, sequential steps to permit the work to
be accomplished efficiently. Poorly or incompletely written
specifications can result in the following bidding problems:
bids from unqualified contractors, fewer bids from qualified
contractors, or unrealistically high or low bids.
8.3
The CSI Format. A systematic format for construction
specifications is necessary to include important items. It also
makes it easier for those preparing bids or executing the
contract to accomplish their work, because the requirements can
be found in the same part of the document, as in previous
documents from the firm. The format of the Construction
Specification Institute (CSI) is used by the Federal and many
State governments, as well as private industry. It divides
construction work into 16 divisions by the building trade
involved with the work. Finishes are always in Division 9 and
paints and protective coatings in Section 09900 of Division 9.
Sections have five digit numbers. Each CSI section is divided
into three basic parts:
a)
Part 1.
General
b)
Part 2.
Products
c)
Part 3.
Execution
8.3.1
General Information Part. The general information part
of the CSI format includes the following sections:
a)
Summary or Introduction
b)
References
c)
Definitions
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d)
Submittals
e)
Quality Assurance
f)
Delivery, Storage, and Handling
g)
Site Conditions
8.3.1.1
Summary Section. A Summary or Introduction section at
the start may present the scope and purpose of the work. Care
must be taken here to avoid any repetition of work described
elsewhere in the document, because any variations in description
can result in problems of interpretation. Thus, many
specification writers prefer to use only the title of the
specification to introduce the document.
8.3.1.2
Reference Section. The reference section, sometimes
called "Applicable Documents," includes a listing of documents
used in the specification and no others. Others included only
for general information may be interpreted as requirements.
Listed references form a part of the specification to the extent
indicated.
a) Industry specifications and standards, such as
those of the SSPC, are preferred to Government standards for
equivalent products or processes. Their issuing organization,
number, and latest issue are normally listed. Unless otherwise
indicated, the issue in effect on the day of invitation for bids
applies. Where alternative standards occur, the normal order of
precedence is:
(1)
Industry documents
(2)
Commercial item descriptions (CIDs)
(3)
Federal documents
(4)
Military documents
b) This should not be confused with the order in which
they are normally sequenced in the specification reference
listing - alphabetically, by organization name, or by document
category name. For example:
(1)
American Society for Testing and Materials
(2)
Commercial item descriptions
(ASTM)
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(3)
Federal specifications
(4)
Steel Structures Painting Council (SSPC)
c) Within each of the above categories, individual
documents are listed numerically. As with other items,
references should be used as little as possible in the body of
the specification to minimize error. Where alternative standards
or practices are available, only one of them should be used.
8.3.1.3
Definition Section. An understanding of terms used in
painting operations may vary widely in different geographical
locations and even between different people in the same location.
Definitions for such words may prevent costly disputes over
different interpretations.
8.3.1.4
Submittals Section. Specification submittals are
documents or samples to be provided by the contractor to the
contracting officer. They are provided to ensure that specific
requirements will be met.
a)
Submittals on painting contracts may include:
(1)
Wet samples of coatings
(2)
Drawdown films of coatings
(3)
Blast-cleaned reference panels
(4)
Laboratory test results
(5)
Certificates of conformance
(6)
Product data sheets
(7)
Supplier's instructions
(8)
Supplier's field reports
(9)
Shop drawings
(10)
Warranties
b) Complete laboratory testing of paint for
conformance to specification can be very expensive and thus is
not often done except where very large areas are coated or where
the coating provides a critical function. More often, the
contracting officer accepts certificates of conformance. These
are basically statements that a previous representative batch of
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the same formulation have met specification requirements, and a
few quick laboratory tests (standard quality control (QC) tests)
by the supplier indicate that the present batch does also.
Sometimes, analytical results from an earlier batch are required
along with the certificate. When qualified products lists, for
Federal or military specifications, or suggested supplier lists,
for commercial item descriptions, are available, the listed
suppliers should be utilized.
c) For large or critical batches of paint, factorywitnessed manufacture or testing is sometimes done. These and
first article tests can be very expensive and so should be used
only where the expense is justified.
d) Sometimes, authenticated wet samples of coating are
retained for later testing, should early failure occur. They are
normally retained for only 1 year, the normal warranty period.
The specification should also permit field sampling of coatings
being applied. This may prevent unnecessary thinning or
substitution of products.
e) The data sheets and instructions of suppliers may
be used to define under what conditions and under what acceptable
procedures the product can be successfully applied to produce a
quality film. If SSPC PA 1, Shop, Field, and Maintenance
Painting, or a written description of the work requirements are
included in the specification, the order of priority of these
documents should be stated, should some differences occur.
f) At one time, many specifications stated that an
undercoat should be allowed to thoroughly cure before topcoating.
However, complete curing of thermosetting undercoats may present
problems of adhesion of finish coats.
g) Warranties should also be received as a submittal.
Some products such as textured coatings for masonry structures
are commonly warranted for 15 years. Such warranties are
normally limited to such conditions as flaking, blistering, or
peeling. They do not usually include fading or chalking in
sunlight.
h) Inspection, safety, or work sequence and scheduling
plans may be required in order to obtain information on how each
of these aspects will be handled. An inspection plan will show
how each of the inspection requirements will be met. SSPC has
examples of these plans and reporting forms. Information of the
sequencing and execution of the work will be important where they
affect other operations.
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8.3.1.5
Quality Assurance Section. The quality assurance
section includes those items not covered elsewhere in the general
information or execution parts that are necessary to ensure that
quality work will be obtained from the contractor.
a)
They may include the following:
(1)
Qualifications
(2)
Certifications
(3)
Field sampling
(4)
Regulatory requirements
(5)
Preconstruction conference
b) Qualification or certification statements may be
requested to establish the capabilities of the contractors and
his employees. This is particularly necessary, if capabilities
with high pressures from airless spray or other safety hazards
require special certification. The SSPC Painting Contractor
Certification Program will ensure the capability of completing
the work in a satisfactory manner and time. Additional
certification may be required if asbestos fibers or lead-based
paint complicate the work. It is desirable to include a clause
permitting the contracting officer to procure at any time a
sample of the paint being applied. Local air pollution personnel
usually have this authority.
c) The contractor must be familiar with prevailing
regulations. Material safety data sheets (MSDS) for paints,
solvents, and other materials to be used should also be submitted
and kept available on-site. In addition, coating manufacturer's
technical data sheets should also be on-site and available.
d) A preconstruction conference and site visit of
contracting officer and contractor personnel should be held
before the work begins. At this time, any differences of opinion
or uncertainties should be resolved. Any agreements reached that
affect the specification should be written down and signed by
both parties so that it becomes a part of the contract. Any
differences not resolved may result in costly change orders.
8.3.1.6
Delivery, Storage, Handling, and Disposal. Information
must be provided on acceptable methods of delivery, storage, and
handling. Packaging and shipping procedures must be in
accordance with prevailing regulations. There must also be
suitable arrangements for acceptance and storage of materials on
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the job site. Storage must provide for protection of materials
from deterioration, as well as conformance to prevailing safety
and environmental regulations. Spill kits must be present and
procedures established to clean up spills, and any hazardous
waste generated must be stored and disposed of in accordance with
local regulations.
8.3.1.7
Site Conditions. The site conditions must be
completely and correctly defined. Variations from the
description of the site conditions generally cause costly changes
in the specification. They may concern the size or scope of the
work, the extent of corrosion or coating deterioration, the
construction or coating materials, or other things that affect
the work to be done. Some specification writers do not examine
the job site but rely on drawings on file that may not be
current. Additions significantly increasing the level of effort
may have occurred since the drawing was made. The Federal
Government does not require inspection of the job site before
bidding, because it might be unduly costly to bidders located in
other geographical areas. Thus, bidding may not be as precise as
if the site were inspected. In fact, some bidders deliberately
do not inspect the work site in hope of finding variations that
would bring additional money to them.
Another common error is to underestimate the amount of
loose, deteriorated coating that must be removed in maintenance
painting. Loose paint is generally not well defined. The best
definition is probably paint that can be removed with a dull
putty knife.
Recently, a number of contracts have been awarded that
involve the removal of paint containing lead, chromium, asbestos,
or some other toxic material. Such paints must be identified as
containing hazardous material before the contract is advertised.
8.3.2
Products Part. The products part of a specification
includes requirements for materials to be used. This may include
abrasives and other cleaning materials and thinners, as well as
coating materials. Historically, materials with proven
performance and low life-cycle costs were usually chosen. Now,
most heavily populated areas require lead- and chromate-free
coatings that are low in VOCs. These are frequently more
difficult to apply than earlier formulations, have had very
little field testing, and thus may provide shorter term
protection.
Paint products are always best procured using a
specification or a specific brand name, if this is permitted and
if the product has data showing good field performance. Many
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Government agencies cannot purchase a sole source product, unless
it can be shown to be uniquely differentiated from other
products. Sometimes, a qualified products list can be used or
suggested suppliers of coatings for a particular specification,
for which good performance data are available. Specifying "Brand
X or equal" is dangerous, because there is no specific definition
of "equal" or procedure to determine such equality. Also
dangerous is to describe a product by its composition and/or
performance. These are sometimes done to procure a particular
product without calling out its name. Standard colors available
in the particular specification or commercial product should be
specified. FED-STD-595 provides a large number of color chips
for which many specification coatings are available. A fandeck
of these chips is also available from the General Services
Administration (GSA). It is better to use these standards than
to refer to a particular supplier's color code or name.
Whatever the method of specifying products, it is
always best to require that products for a multiple-coat system
be procured from the same supplier, who recommends their use
together. This will avoid compatibility problems and limit any
liability to one supplier.
8.3.3
Execution Part. The execution part of the
specification describes the use of the materials in the products
part. Because painting may be only a small part of a
construction project, it must be coordinated with the other
sections. This will permit surface preparation and coating
application under suitable conditions and without delays or other
interference.
Much information of the execution of a specification
may be found in drawings that form a part of the specification.
To prevent problems resulting from variations between
descriptions in the drawings and the body of the specification,
requirements in the body should be stated as preempting those in
drawings. They should not repeat requirements in the body of the
contract to avoid differences.
8.3.3.1
Work Conditions. This portion of the execution part
describes the weather conditions under which work is permitted.
If priming of steel is delayed by the weather or other reason, it
will be necessary to reblast the steel to remove any flash
rusting that has occurred during the delay.
The air temperature at the time of coating application
should be in the supplier's listed acceptable range. The
temperature should be at least 5 degrees above the dew point, and
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rising, to prevent moisture from condensing on the surface of the
wet paint film. The specification should state how frequently
temperature and dew point measurements should be taken.
Spray painting should also be restricted during times
of moderate to heavy winds. Painting at such times may not only
produce unsatisfactory films of coating but also result in
overspray onto automobiles or other structures in the area.
8.3.3.2
Surface Preparation. It is always best to describe the
desired prepared surface condition, using standards such as SSPC
SP 6, if available, rather than telling the contractor how to
prepare the surface. It is inappropriate to specify both the
desired condition and how to achieve it. These requirements may
cause legal problems if the surface cannot be obtained using the
directions specified. For example, it is much more effective to
require a "SSPC SP 10, Near-White Blast Cleaning" without
specifying how the blaster achieves it. However, if the
specification calls for abrasive blasting of steel at 90 to 100
psi using a venturi nozzle held 8 inches from the surface, then
there can be no requirement for a particular degree of
cleanliness other than that which is achieved when the specific
directions are followed.
Care must also be taken to use only standard terms such
as "brush-off blast cleaning" which is defined in SSPC SP 7
rather than "brush blast," "sweep blast," "shower blast," or some
other undefined term. Also avoid other vague terms such as
"heavy abrasive blasting" that are subject to interpretation.
8.3.3.3
Coating Application. Normally, painters are permitted
to apply their materials by brush, roller, or spray, unless the
material can only be applied satisfactorily by one or two of
these methods. Thus, zinc-rich coatings should be applied by
spray using an agitated pot and following the instructions of the
coating supplier. SSPC PA 1 may be referenced as an industrial
standard for shop and field painting. Local transfer efficiency
requirements may prevent the use of some types of spray
application (e.g., airless or conventional air spray).
Currently, requirements for transfer-efficient methods of
application are limited to shop work. Any thinning of paints
should be limited to thinner and the amount recommended by the
supplier. It should also be within the limits set by local air
pollution authorities.
8.3.3.4
Inspection. In the inspection section, inspection
requirements should be listed. By referring to standard test
procedures, details of both the procedures and their requirements
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can be found. Thus, SSPC PA 2, Measurement of Dry Paint
Thicknesses With Magnetic Gages, will indicate how many thickness
measurements must be made on each 100 square feet of coated steel
surface. If referencing SSPC PA 2, then do not reference
ASTM D 1186, Nondestructive Measurement of Dry Film Thickness of
Nonmagnetic Coatings Applied to a Ferrous Base. Slight
differences in these standards can cause problems.
Occasionally, the contractor and the representative of
the contracting officer informally agree on a surface preparation
standard for inspection. Often, this is a protected area of
steel, or a reference panel, that has been blast cleaned to an
acceptable level. Such agreements should be put down in writing
and signed by both parties. It then becomes an amendment to the
specification and can resolve any disputes that may arise
concerning the agreement.
8.4
Language to be Used in Specification. In order to meet
the goal of preparing a correct, clear, and concise
specification, the language of the document must be such as to
describe exactly what is desired. The contractor is required to
provide the product described in the specification, not
necessarily what is desired. In order to do this, the
specification writer must be very precise with his language.
This following recommendations will help:
a)
Use short, specific words (avoid vague terms)
b)
Use short sentences
c)
Put the action words up front
d)
Use strong verbs
e)
Use the imperative mood
f)
Do not repeat descriptions or requirements
8.4.1
Concise Words. Words in the specification should be
relatively short, specific, and readily understood. Avoid words
that are ambiguous, vague, or otherwise not readily understood.
Such expressions as "high-performance coatings" and "quality
workmanship" are too vague to be used.
a) Short sentences are more readily understood than
longer ones. Also, the action words (subject and verb) should go
up front. Thus, don't write, "After the steel has been properly
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cleaned and after the weather conditions have been verified to be
acceptable, apply one coat of the specified primer." Instead,
write, "Apply one coat of the specified primer after . . ."
b) Strong verbs such as "blast," "clean," and "prime"
are more precise than weaker verbs such as "make," "build," and
"establish." They are also more easily understood. Use of the
imperative mood is preferred, because it is more concise and more
easily understood. Thus, "Blast clean to an SSPC SP 10 surface"
is better than, "The surface shall be blast cleaned to an SSPC SP
10," or, "The contractor shall clean the surface to an SSPC SP
10."
c) No information in the specification should be
repeated in a second place because of the greater possibility of
errors or because slight differences in description may receive
different interpretations.
8.5
Construction Criteria Base. The Construction Criteria
Base (CCB) is a compact disc system containing the complete texts
of thousands of documents needed for the design and construction
of buildings and civil works, together with built-in software for
automatic accessing and processing the information. The CCB can
be obtained from the National Institute of Building Sciences,
1201 L Street, N.W., Washington, DC 20005.
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Section 9:
INSPECTION OF PAINTING OPERATIONS
9.1
Scope of Section. This section describes the duties of
an inspector, general inspection procedures, and specific
inspection methods used in inspecting painting operations.
Depending upon the job and the contract requirements, qualitycontrol inspectors may be contractor-supplied (that is,
contractor quality control - CQC) or Government personnel. In
either case, the contracting officer is responsible for ensuring
the quality of the job. The intent of this section is to
describe proper inspection procedures so that Government
personnel will know either how to inspect a painting operation or
to ensure that someone else has done it correctly.
9.2
Importance of Inspection. The success of a painting
job depends upon the specification requirements being met for
surface preparation, application and materials. Most coating
failures are the result of contract requirements not being met.
Inspection procedures are designed to detect situations when the
requirements of the contract are not being met. Thus, inspection
is a key factor in obtaining the performance and durability built
into the specification.
9.3
Contractor Quality Control Inspection. In Government
painting, quality control inspection is often provided by the
contractor. For large jobs, a contractor usually hires an
inspector. For smaller jobs (less than $200,000), a contractor's
superintendent may carry out the quality control inspection. If
deemed necessary because of the size or difficulty of a job, or
because of the crucial function of a structure, the contract
specification can require the contractor to hire a certified
inspector (e.g., NACE has a certification program). In this way,
the contractor's inspector may be more independent of the
contractor and may have better inspection skills. Although this
requirement may increase inspection costs, the increased cost of
proper inspection as opposed to none or poor inspection has been
found by the private sector to be cost effective. Quality
control inspectors should report deviances from the contract
specification in writing to the contracting officer. Appropriate
governmental action in response to these reports is essential in
obtaining the quality of the job built into the specification.
9.4
Duties of an Inspector. The duties of an inspector
include understanding the contract specification requirements,
making sure that the specification requirements are met by the
contractor, and keeping good records. Record keeping is a very
important part of inspection. It should occur during all phases
of the job. Records form an important part of the permanent
record on each building, and provide key information in the case
of contract disputes.
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9.4.1
Record Keeping. Inspectors should keep records in a
bound book (logbook). Each page should be initialed by the
inspector and dated. The record book should contain:
a) Written records of verbal agreements made between
the contracting officer or the inspector and the contractor.
b) Daily descriptions of the type of equipment and
number of workers on the job site.
c)
Descriptions of the coating materials that are on
d)
Records of the rate of work progression.
e)
Measurements of ambient conditions.
site.
f)
inspection.
Results and observations of the surface preparation
g) Measurements and observations of coating
application, including time between surface preparation and
coating application, and times between coats.
h)
inspections.
Results of the final and warranty acceptance
It is especially important that agreements between the
contracting officer (or designee) and the contractor that modify
the contract specification be in writing and be signed to
minimize future disputes.
9.5
Inspection Equipment. A description of equipment used
in typical inspections is summarized in Table 15. Instructions
on its use are provided in Section 10 and in the equipment
manufacturer's literature. Some of the equipment is readily
available from local hardware or variety stores but some is
specialized equipment for painting operations. Suppliers of
specialized equipment are listed in:
a)
ASTM, 1916 Race Street, Philadelphia, PA 19103.
b)
NACE, P.O. Box 218340, Houston, TX 77218.
c)
15213-3738.
SSPC, 516 Henry Street, Suit 301, Pittsburgh, PA
d) Paul N. Gardner Company, Inc., Gardner Building,
P.O. Box 10688, Pompano Beach, FL 33060-6688.
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e)
KTA-TATOR, Inc., 115 Technology Drive, Pittsburgh,
f)
ZORELCO, P.O. Box 25500, Cleveland, OH 44125.
PA 15275.
g) Pacific Scientific, 2431 Linden Lane, Silver
Spring, MD 20910.
h) S. G. Pinney & Associates, 2500 S.E. Midport Road,
P.O. Box 9220, Port St. Luice, FL 34952.
9.6
Inspection Steps. The inspector's tasks can be divided
into eight general steps, which are summarized in Table 16 and
discussed in more detail below. Special equipment required in
each of these steps is also listed in the table.
A form that
may be useful in reviewing the contract is provided in Figure 21,
and one for organizing inspection data is provided in Figure 22.
9.6.1
Review Specification and Correct Deficiencies, If Any.
The first part of any inspector's job is to read and understand
the contract specification. If deficiencies are found,
resolution of the deficiencies between the contracting officer
and the contractor is needed prior to start of work. Any changes
in the contract specification must be documented in writing and
signed by the two parties or their representatives. Copies of
these agreements should be kept in the inspector's records. In
addition to reviewing the specification, the inspector must also
review the contract submittal. The form shown in Figure 21 may
help an inspector to identify key specification requirements and
essential information from the submittals, and to prepare for the
preconstruction conference. Note that at this time, all the
information needed to complete the form may not be available.
However, the information should be available before the start of
the job.
9.6.2
Visit Job Site. It is important for the contractor to
visit the job site with an inspector prior to the preconstruction
conference so that the scope of the job and any constraints are
understood. Potential problems that are found, such as
difficulty with access to the job site, can then be resolved at
the preconstruction conference. Such visits have been shown to
be effective in reducing problems during the job.
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Table 15
Equipment for Inspecting Painting Operations
Tool
SSPC VIS 1
and VIS 3
visual
standards
Typical Use
Surface preparation of
steel
Description
Source
Colored prints illustrating the SSPC
degrees of blast, hand or powertool cleaning
NACE TM0170
and TM0175
standards
Surface Preparation of
steel
Abrasive blasted steel panels
illustrating 4 degrees of
cleaning
NACE
ASTM standards Surface preparation,
application, and
approval
Test methods for measuring
profile, film thickness and
comparing quality
ASTM
Comparator
gage
Determine surface
profile of blast
cleaned steel
Field instrument consisting of
comparator discs and lighted
magnifying glass
Supplier
Replica tape
Determine surface
profile of blast
cleaned steel
Plastic backed foam-like
material used to make a reverse
image of blasted surface
Supplier
Micrometer
Surface preparation,
dry film thickness
Instrument with adjustable
opening to measure small
thicknesses
Supplier
Inspection
mirror
Surface preparation,
application
Instrument with mirror on end of Supplier
handle
Moisture meter Application
Instrument to measure moisture
content of substrate
Supplier
Instrument consisting of wet and
dry-bulb thermometers used with
a table to determine relative
humidity and dew point
U.S.
Government
Printing
Office
Special thermometer to measure
temperature of substrate
Supplier
Clean cloth or Application
blotter
Use to detect oil in compressed
air lines
Supplier
Wet film
Application, approval
thickness gage
Flat metal panel with notches of Supplier
various depths corresponding to
expected thicknesses
Dry film
Application, approval
thickness gage
Magnetic or other gages to
measure dry film thickness
Supplier
Magnifying
lens
Application, approval
Illuminated microscope, 5x and
higher
Supplier
Holiday
detector
Application, approval
Portable, low voltage noise
detector for detecting coating
flaws or discontinuities on
metal substrates
Supplier
Adhesion
testers
Application, approval
Field instruments to measure
either tensile or peel adhesion
Supplier
Camera
Sling
psychrometer/
psychrometric
tables
Throughout job
Ambient conditions
Surface
thermometer
Application
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Table 16
Inspection Steps
Action
Brief Description
Tools (Not all may be needed for
any particular job)
Contract specification, material
technical data sheets, Figure 21
Review contract
specification
and submittals
Determine specified coating,
surface preparation, application
procedure and final appearance
Visit job site
Ensure that the contractor
understands the scope and
difficulties of the job
Conduct
preconstruction
conference
Discuss painting job with
contractor
Carry out
presurface
preparation
inspection
Ensure that repairs are complete,
oil, grease, weld splatter are
removed, surrounding area is
protected from potential damage
Inspect coating
material
Ensure adequate material is on the Paddle for stirring
job site; examine age and condition
of coatings and storage facilities
Assess ambient
conditions
Psychrometer and chart, surface
Throughout the painting job,
thermometer, and weather data
measure air and surface
temperature, relative humidity and
dew point, and wind velocity
Inspect surface
preparation
As required, inspect surfaces for
cleanliness, profile, removal of
loose paint, chalk, mildew, soil
and grease
Comparator, surface preparation
standards (SSPC VIS 1 and VIS 3,
NACE TM-01), felt for chalk
measurement, visual standards
for chalk and mildew assessment,
instrument for measuring profile
Inspect coating
application
Ensure specified materials are
used; check thinner and amount of
thinning; measure dry film
thickness and determine that one
layer has dried/cured properly
before another is applied
Material technical data sheets,
wet and dry film thickness gages
Final approval
of complete
system
Examine film for thickness,
Camera, dry film thickness gage,
appearance, uniformity, and defects holiday detector (if needed),
magnifying glass, adhesion
tester
143
Contract specification, visual
standards, material technical
data sheets
Project No. ____
Project Title _______________
Inspector __________________ Contractor ___________________
Buildings in Contract, Nos. ________________________________________________________________________________
Coating Materials:
Primer: Manufacturer ________________________ Product Designation ________________ Color _______________
Batch _______ Volume Solids ______% Number of Components ______ Storage Temp.
Requir. ______
Recommended Thinner ______________________________
Maximum Thinning Recommended ______________
For multi-component paints:
Induction Time ________
Mixing Ratio _________
Midcoat: Manufacturer ________________________
Batch _______
Volume Solids ______%
Product Designation _________________
Number of Components ______
Pot Life ________
Color _______________
Storage Temp.
Requir. ______
Recommended Thinner ______________________________
Maximum Thinning Recommended ______________
For multi-component paints:
Induction Time ________
Mixing Ratio _________
Pot Life ________
Topcoat: Manufacturer ________________________ Product Designation _________________ Color __________
Batch _______ Volume Solids ______% Number of Components ______ Storage Temp.
Requir. ______
Recommended Thinner ______________________________
Maximum Thinning Recommended ______________
For multi-component paints:
Induction Time ________
Mixing Ratio _________
Pot Life ________
Surface Preparation:
Method _____________________ Standard for Cleanliness __________________ Profile: min ______
max ______
Special Instructions ______________________________________________________________________________________
Application:
Ambient Conditions Limitations: Minimum Temperature __________ Maximum Temperature __________
Minimum % Relative Humidity __________ Maximum % Relative Humidity __________
Minimum Difference Between Dew Point and Surface Temperature __________
Equipment Requirements ____________________________________________________________________________________
Special Instructions ______________________________________________________________________________________
Date ______________
Time
Location
Project No. _________
Project Title ___________________________
Inspector ___________
Wet
Bulb
Dew
Point
Material Temp.
Dry
Bulb
Rel.
Hum.
Surface Weather
Temp
Condition
Wind Vel.
At Applic.
Storage
Painting Operation Report
Bldg
No.
Location
Operation
(# people
on site,
activity
type)
Surface
Preparation
Type
Cleanliness
Level
Moisture
Content
Profile
Color
Spec
No.
Application
Color Method
No.
Cure
Wet
Time
Film
Thick
Dry Film
Meas.
Spec
AcMethThick tual
Thick od
MIL-HDBK-1110
9.6.3
Conduct Pre-Construction Conference. At the beginning
of each new contract or work order before the start of any
surface preparation or coating application, a meeting should be
held with the contractor, contracting officer, inspector, and
other key people. Figure 21 may be helpful in this discussion.
During this conference, agreement should be reached on details of
the specification and the procedures and expectations of the
inspector. For example, the number and locations for inspecting
surface preparation and coating thickness should be determined.
Scheduling, job sequencing, job stops for inspection, and other
job-related issues should be discussed. Differences between
contractor and contracting officer should be resolved at this
time to avoid future misunderstandings and job delays.
Agreements that result in a change of the contract should be made
in writing, signed and included in the record book.
9.6.4
Inspect Job Site After Pre-Surface Preparation. Prior
to surface preparation or coating application, it is necessary to
be certain that requirements in the specification relating to
readying a surface or area for painting are carried out. These
may include protecting adjoining surfaces, removing weld
splatter, ensuring that surfaces are free of oil and grease,
grinding sharp metal edges, protecting plants and other
shrubbery, replacing rotted wood, caulking joints, and the like.
9.6.5
Inspect Coating Materials. Coating materials must be
inspected at the job site to identify deficiencies that could
result in failure of the paint film. The following checklist can
be used:
a) Read labels on the coatings to verify that the
coatings are the ones specified or approved.
b) Take one representative 1-quart sample in
accordance with the specification. Retain the sample for a
period of 1 year from the date of final approval of the contract
work in case of coating film failures or contract disputes.
c) Ensure that coating materials are in sealed,
unbroken containers that plainly show that the date of
manufacture is within 1 year. The label should display the
manufacturer's name, specification number/or designated name,
batch number, and FED-STD-595 color.
d) Inspect the paint after stirring for homogeneity,
weight, viscosity, color, and smell. If deficiencies are
suspected from these tests, the paint should be sent to a
laboratory for testing. A kit developed by the Army Construction
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Engineering Research Laboratory (Champaign, IL 61802,
1-800-USA-CERL) is available that will assist the inspector in
field inspection of latex and oil-based paints.
e) Count the cans of paint on the job site to
determine that a sufficient quantity is available to complete the
job as specified. For multi-component paints, confirm that the
proper ratio of materials for each specific coating is present.
To estimate the paint required for a job, use the nomograph
reproduced from a Naval Facilities Engineering Service Center
(Port Hueneme, CA 93043) Techdata Sheet shown in Figure 23.
f) Ensure that the paint is stored on site in an
approved building or area.
g)
Record number of cans and paint condition in record
book.
9.6.6
Measure Ambient Conditions. Most coating systems will
not dry or cure properly under extremes of temperature or
humidity, nor will they adhere well if applied over damp
surfaces. For example, specifications often require that the
substrate surface temperature be 5 degrees F above the dew point
and rising. For these reasons painting contracts have
requirements for air and surface temperature, dew point, and,
perhaps, additional environmental conditions. The paint
manufacturer's technical data sheet will also have limits for
acceptable environmental conditions. (If the limits are in
conflict, agreement on the limits should be reached during the
preconstruction conference.) Because temperature and dew point
may vary considerably within a small area, temperature and dew
point should be measured in the immediate vicinity of the work
being done. Surfaces being painted may be colder than the
atmospheric temperature and their temperatures should be measured
in addition to atmospheric temperatures. Dew point at the
surface being painted may also be different from that in the air
away from the surface. Thus, dew point should be measured near
the surface. Ambient condition measurements should be made about
every 4 hours. These times should include before start of job,
after breaks, and after sudden changes in environmental
conditions. Sudden changes in environmental conditions should
also be recorded in the logbook. In addition, do not paint in
rain, snow, fog, or mist, or when the surface is covered with
frost.
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Figure 23
Nomograph for Estimating Quantities of Paint Required for a Job
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9.6.6.1
Relative Humidity and Dew Point. These conditions are
measured using a psychrometer. Most psychrometers consist of a
wet bulb thermometer, a dry bulb thermometer, and a standard
psychometric table. Using the table, the relative humidity is
obtained from the two temperature readings. More detailed
information is provided in Section 10.
9.6.6.2
Surface Temperature.
Surface temperature is measured
using a special thermometer in which the temperature sensing
element is designed to come into intimate contact with the
surface and to be shielded from the surrounding air. The surface
temperature of the coldest and warmest surfaces should be within
the limits of the specification. The location, temperature and
time of the measurement should be recorded in the record book.
9.6.7
Inspect Surface Preparation. Surface preparation
inspection procedures include inspecting equipment, and
associated materials (e.g., blasting medium and chemicals), as
well as the cleaned surface itself. Proper surface preparation,
as described in the specification, must be completed to obtain a
durable coating film. Additional information on surface
preparation is presented in Section 6. Many of the surface
preparation requirements involve visual inspection of the
surface, and some are subjective. For example, the specification
may require removal of loose paint (for example, paint that can
be removed by a dull putty knife), removal of surface chalk to
some specified level and feathering of edges on the remaining
paint film. To help avoid conflicts between the contractor and
the inspector, it may be useful to have the contractor prepare a
test surface about 4 by 4 feet that can then be used as a
standard for surface preparation. Photographs of the test
surface could be part of the inspection record. For steel, the
test surface should be protected by a clear coating.
When blast cleaning is part of the surface preparation,
it should be performed in a manner so that no damage is done to
partially or entirely completed portions of the work, adjacent
surfaces, or equipment. Usually blast cleaning should progress
from the top towards the bottom of a structure, should be carried
on downwind from any recently painted structures, and should not
scatter abrasive on or into surrounding buildings or equipment.
All dust from blasting operations must be removed by brushing,
blowing, or vacuuming before painting.
9.6.7.1
Supplies
Abrasive-Blasting Surface Preparation Equipment and
a) Air Cleanliness. Routinely (at least two times a
day or every 4 hours) inspect air supply lines for both blast
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cleaning or paint spray application to ensure that the air supply
is clean and dry. A blotter test as described in ASTM D 4285 can
be used to determine whether the air supply is free of oil and
moisture. In this test, a clean white blotter is held downstream
about 19 inches from the nozzle for 2 minutes. It should remain
clean and dry.
b) Abrasive. Each batch or shipment of abrasive
should be checked for oil contamination and, if required, soluble
salts. Either can contaminate a cleaned surface and reduce the
service life of the coating. A commonly used test to check for
oil contamination is to take a small random sample of the
abrasive, place it together with clean water in a small bottle or
vial, shake the bottle for a minute and examine the surface of
the water. There should be no sheen of oil on the surface of the
water. Soluble ionic contaminants can be detected using the
electrical conductivity test described in ASTM D 4940. In
addition, the abrasive should feel dry to the touch when it is
placed in the abrasive blasting machine. Recycled abrasives
break down after several cycles, and the number of cycles depend
upon the type of the abrasive. The abrasive should be replaced
when it no longer meets the requirements of the specification.
c)
Blast Hoses and Nozzles. Blast hoses should be in
good condition and kept as short as possible. The nozzle
pressure and diameter of the nozzle orifice both affect the
cleaning rate. A nozzle orifice gage is used to determine the
orifice size. Air pressure at the nozzle is measured using a
hypodermic needle air pressure gage and should be from 90 to 100
psi for optimum efficiency. Usually these parameters are
measured at the start of a job and when production rates are
decreasing. An increase of nozzle size of more than 1/8-inch
causes loss of cleaning efficiency because of the increased
pressure drop. Increased nozzle size also causes increased use
of abrasive. Profile should be inspected when major changes in
cleaning efficiency are noted.
d) Safety. Special safety precautions are required
during abrasive blasting. Refer to Section 13 for more
information. These precautions include use of external couplings
on blast hoses and dead man controls, and electrical grounding of
equipment.
9.6.7.2
Water Blasting. Since contaminants, such as salts and
oils, in the blasting water will be left behind on the blastcleaned surface and may adversely affect the adhesion of the
coating to be applied, water should be essentially free of
contaminants. If cleaning agents are added to the water used for
blasting and cleaning, the surfaces must be thoroughly rinsed
with clear water. An exception is the use of flash-rusting
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control agents when cleaning steel. These agents should only be
used in accordance with the contract specification and the
coating manufacturer's recommendations. As for abrasive
blasting, hoses should be in good condition and kept as short as
possible. Special safety precautions, similar to those used in
abrasive-blast cleaning, also need to be taken. In addition,
consideration should be given to the slipperiness of wet
surfaces. More information on safety is provided in Section 13.
9.6.7.3
Frequency of Inspecting Cleaned Surfaces. The
objective of the inspection is to ensure that the entire surface
was prepared in accordance with the specification. The
inspection report should provide a representative description of
the cleaned surface. The specific number and location of places
at which surfaces should be inspected must be in accordance with
the contract specification. If not detailed in the
specification, SSPC PA 2 can be used as a guide. Additional
inspection sites that should be considered include those where
the existing paint was failing, in hard-to-reach areas where
surface preparation is difficult, and where major changes in
equipment were made.
9.6.7.4
Inspecting Prepared Steel Surfaces
a) Cleanliness. If a small representative sample of
surface was not prepared to use as the standard for surface
preparation, the degree of blast or tool cleaning should be
compared to the description given in the SSPC or NACE
specification referred to in the contract specification. The
appearance should correspond with the specified pictorial
standards of SSPC VIS 1, SSPC VIS 3, or a NACE panel. Complete
descriptions of the degrees of cleanliness are found in Section
6. After blasting, blast-cleaned surfaces must be cleaned (e.g.,
vacuum, air blast, or brushing) to remove traces of blast
products from the surface or pitted areas. One of two tests for
cleanliness can be used. In one, a white glove or other clean
cloth is rubbed over the surface and examined for soiling or
debris, and in the other, a piece of clear adhesive tape is
applied to the surface, removed and the adhesive side examined
for debris.
b) Profile. Profile is measured using one of three
pieces of equipment: comparator, depth micrometer, or replica
tape. It should be noted that the three techniques may give
slightly different results. Complete descriptions of standard
methods for each of these techniques are described in ASTM D
4417, Field Measurement of Surface Profile of Blast Cleaned Steel
and in Section 10.
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9.6.7.5
Inspecting Concrete, Masonry, Wood, Plaster, Wallboard,
Old Paint. On these surfaces, specifications may have
requirements for measurements of moisture content and residual
chalk, as well as visual condition. The specification should
state how moisture is to be measured, since the different methods
provide different types of data.
Moisture content can be
measured either using a plastic sheet test (ASTM D 4263) or an
electric moisture meter. In the plastic sheet test, a piece of
plastic film is taped (all edges) to the surface. After 24
hours, the film is removed and the underside is examined for the
presence of condensed water. Prior to application of most
coatings, the sheet should be free of condensed water. This is
because accumulation of water at the concrete/primer interface
will usually lead to delamination of the primer. To use a
moisture meter on hard surfaces, small holes must drilled for the
electrodes. These holes should be repaired after the
measurements are completed. The contract should state a moisture
requirement. Residual chalk is usually measured using a piece of
cloth of contrasting color, in accordance with ASTM D 4214.
Other procedures are also described in ASTM D 4214. In the cloth
method, a piece of cloth is wrapped around the index finger,
placed against the surface and then rotated 180 degrees. The
spot of chalk on the fabric is compared with a photographic
reference standard. Chalk readings of 8 or more indicate
adequate chalk removal providing reasonable assurance that the
new coating should not fail because of application to a chalky
surface.
9.6.8
Inspect Coating Application. Proper application is
another essential factor in determining paint performance, and
the requirements of the specification must be followed. General
guidance on paint application is presented in Section 7 and SSPC
PA-1. Inspectors should assess ambient conditions, application
equipment, ventilation, mixing, film thickness, and drying and
curing conditions to ensure that they are within the limits of
the specification and the technical data sheets for the paints.
It is especially important that the paints be applied and cure
within the temperature and relative humidity limits of the
specification, since these conditions affect film formation. A
properly dried and cured film is essential for satisfactory paint
performance, and deviations from these limits may prevent proper
film formation. For two-component systems, the inspector should
ensure that the materials were mixed together and in the proper
ratio. For all materials, thinning should only be allowed in
accordance with the manufacturer's data sheet.
9.6.8.1
Application Equipment. Equipment to apply the coating
must be in acceptable working condition. When spraying, the
spray pattern should be oval and uniform, the gun should be held
at the proper angle and distance from the surface, and each spray
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pass should overlap the previous one by 50 percent. Proper
techniques should also be used for brushing, rolling, or other
application procedures. Refer to Section 6. Special safety
requirements for paint application are described in Section 13.
9.6.8.2
Ventilation. The ventilation of tanks and other
enclosed areas where paint is to be applied and cured must meet
the requirements of OSHA's Confined Space Regulation, and the
contractor's safety plan required by contract specification.
Good ventilation is also necessary for proper coating cure.
9.6.8.3
Mixing/Thinning. Paints must be properly mixed as
described in Section 7. Paint solids often settle out during
storage and must be completely blended into the paint vehicle,
resulting in homogeneous mixture. For multi-component paints,
the inspector should ensure that all components have been mixed
in the proper proportion, that the mixing is thorough and that
the resulting paint is uniform in appearance. Required induction
times must also be met to obtain satisfactory application and
film properties. Although the paint manufacturer prepares paint
to produce a consistency for brushing, rolling, or spraying,
sometimes additional thinning is permitted in the specification.
Thinning of the paint must follow manufacturer's instructions for
both type and amount of solvent. A thinned paint will cover more
surface area but the dry film thickness will be less and may not
meet the requirements of the specification.
9.6.8.4
Film Thickness. Contract specifications may require a
minimum and/or a maximum dry film thickness for each coating
application. Wet film thickness measurements made at the time of
paint application are used to estimate dry film thickness so that
appropriate adjustments in the application procedure can be made
to meet the specification. Wet film thicknesses are not used in
meeting contract requirements because of the many factors
(solvent evaporation, wetting energies) that affect the
measurement. Procedures for making wet film thickness are
described in ASTM D 4414, Wet Film Thickness by Notch Gages and
in Section 10. The dry film thickness is estimated from the wet
film thickness according to:
Dry Film Thickness = Wet Film Thickness x Percent Volume Solids
100
The percent volume solids is available from the coating
manufacturer's data and should be part of the inspector's
records. Dry film measurements are made after the coating has
hardened. For steel surfaces, thickness measurements can be made
according to SSPC PA 2 or ASTM D 1186 or ASTM D 1400,
Nondestructive Measurement of Dry Film Thickness of Nonconductive
Coatings Applied to a Nonferrous Metal Base. (There are some
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differences in calibration procedures between SSPC PA 2 and the
ASTM standards. If the contract specification does not specify
the exact procedures to be used, the procedures should be agreed
upon, and the agreement documented, during the preconstruction
conference.) ASTM D 4128, Identification of Organic Compounds in
Water by Combined Gas Chromatography and Electron Impact Mass
Spectrometry describes a destructive procedure for measuring
coating thickness on non-metallic substrates using a Tooke gage
(refer to Section 10). If the contract specification requires
minimum film thicknesses for each layer, the measurements must be
made after each layer has cured, taking care not to depress soft
coatings during measurements.
9.6.8.5
Drying. The inspector should ensure that a previous
coat has dried or cured as required by the contract specification
before another coat is applied. For most thermosetting coatings,
manufacturers specify a maximum, as well as a minimum, curing
time before application of the next coat. In some situations, a
coating manufacturer may require use of a methyl ethyl ketone
(MEK) rub test to assess curing prior to application of another
layer. The inspector's record should provide information so that
the dry/cure time for each layer can be determined.
9.6.9
Final Approval Procedures. The final approval
inspection is very important since it determines whether the
contract requirements have been met, and whether identified
deficiencies have been corrected. Since most coatings function
as a barrier and since the protection of a surface is usually
directly related to coating thickness and continuity, inspection
of coating thickness and film continuity are essential. The
following checklist can be used to inspect the final job:
a) Examine, as required by the specification, the
cured coating system for visual defects, such as runs, sags,
blistering, orange peel, spray contaminants, mechanical damage,
color and gloss uniformity, and incomplete coverage. Note any
areas of rusting, or other evidence of premature failure of the
coating system.
b) If defects are observed, bring them to the
attention of the contractor for correction. If resolution of the
corrective action cannot be reached with the contractor, bring
the matter to the attention of the contracting officer. Dated
photographs of the defects could become part of the inspector's
records, if deemed appropriate.
c) Measure and record the total dry film thickness
using appropriate gages. When the Tooke gage is used, the
coating must later be repaired.
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d) Measure adhesion as required in the contract
specification. Adhesion measurements vary from those made with a
knife (ASTM D 3359, Measuring Adhesion by Tape) to those that
determine the amount of force needed to remove a dolly (Section
10 and ASTM D 4541, Pull-Off Strength of Coatings Using Portable
Adhesion Testers) that has been cemented to the surface.
e) Examine the coatings on steel structures for
pinholes using a holiday detector as described in NACE RP0188 and
Section 10, if required in the contract specification.
book.
f) Record the results of observations in the record
Document photographs taken and retain in the record book.
9.6.10
Year Warranty Inspection. The warranty inspection
includes a visual inspection of the film, and may involve a
chalk, film thickness, and adhesion measurements. Since the film
was found to be essentially free of defects upon completion of
the job, a goal of the inspection is to identify contractually
unacceptable defects that have formed during the course of the
year. Resolution of film deficiencies should follow the same
steps as for the final inspection. Deficiencies should be
recorded in the logbook. Documented photographs (date, location,
and photographer) should be included if deemed necessary to
resolve contract disputes.
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Section 10:
FIELD INSPECTION INSTRUMENTS
10.1
Introduction. This section describes field instruments
commonly used in inspection of field painting. The References
section of this handbook lists the full title and sources of
standard test methods referenced in this section. For equipment
descriptions having no referenced standards, no standards are
available. Typical suppliers include:
a) Paul N. Gardner Company, Inc., Gardner Building,
P.O. Box 10688, Pompano Beach, FL 33060-6688.
b)
KTA-TATOR, Inc., 115 Technology Drive, Pittsburgh,
c)
ZORELCO, P.O. Box 25500, Cleveland, OH 44125.
PA 15275.
d) Pacific Scientific, 2431 Linden Lane, Silver
Spring, MD 20910.
e) S. G. Pinney & Associates, 2500 S.E. Midport Road,
P.O. Box 9220, Port St. Luice, FL 34952.
10.2
Illuminated Microscope. A pocket-sized illuminated
microscope is frequently used to detect mill scale, other surface
contamination, pinholes, fine blisters, and other microscopic
conditions during painting operations. These microscopes are
available with magnifications of 5 and higher.
10.3
Instruments for Use With Abrasive Blasting. A few
instruments are available for testing the operational readiness
of equipment for abrasive blasting of metals for painting.
10.3.1
Gage for Determining Nozzle Pressure. A pocket-sized
pressure gage with a hypodermic needle is used to determine the
blasting pressure at the nozzle. The needle is inserted in the
blasting hose just before the nozzle in the direction of the
flow. Instant readings can be made up to 160 pounds per square
inch (gage) (psig).
10.3.2
Wedge for Determining Diameter of Nozzle Orifice. A
hand-held calibrated wedge is inserted in the direction of flow
into the nozzle orifice to determine its size (inches) and
airflow (cfm at 100 psig). The orifice measuring range is 1/4 to
5/8 inch, and the airflow range is 81 to 548 cfm.
10.3.3
Surface Contamination Detection Kit. The level of
cleanliness of abrasive blast cleaned steel can be determined by
comparing it with SSPC VIS 1 photographic standards. SSPC VIS 3
photographic standards are used for determining level of
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cleanliness of hand-cleaned steel and power-tool cleaned steel.
Standard coupons of steel blasted to different levels of
cleanliness are also available for comparison from NACE, and
procedures for their use are given in NACE TM0170. Test kits for
detection of chloride, sulfate, and ferrous ions, as well as pH,
are commercially available. They contain strips, swabs, papers,
and operating instructions for simple chemical testing.
10.3.4
Profile of Blasted Steel. There are three methods for
determining the profile (maximum peak-to-valley height) of
blasted steel surfaces described in ASTM D 4417.
10.3.4.1 Comparators. Several types of comparators are
available for determining surface profile. These include ISO,
Clemtex, and Keene-Tator comparators. Basically, they use a
5-power illuminated magnifier to permit visual comparison of the
blast-cleaned surface to standard profile depths. Standards are
available for sand, grit, and shot-blasted steel.
10.3.4.2 Surface Profile Gages. A surface profile gage is an
easy instrument to use to determine surface profile, but 10 to 20
measurements must be averaged to obtain reliable results. The
gage consists of an instrument with a flat base that rests on the
profile peaks and a tip that projects into the valleys. The tip
can be blunted by dragging it across steel surfaces. This
prevents the tip from reaching the bottom of the valleys in the
profile, resulting in a profile value that is less than the
correct value.
10.3.4.3 Testex Press-O-Film Replicate Tape. Testex
Press-O-Film replicate tape produces the most precise profile
measurements, according to the precision statement of ASTM D
4417. The tape consists of a layer of deformable plastic bonded
to a polyester backing. The tape is rubbed onto the blastcleaned surface with a plastic swizzle stick to produce a reverse
replicate of the profile. The tape profile is then measured with
a spring micrometer. The micrometer can be set to automatically
subtract the 2-mil non-deformable polyester backing. After
measurements, the tapes can be stored as records of profile
heights.
10.3.5
Thermometers. Several different types of thermometer
and temperature recorders are available for field use. They are
used to measure ambient temperatures, surface temperatures of
steel, and temperatures of wet paints.
10.3.6
Psychrometers. Several different manual or batterypowered psychrometers are available for measuring air
temperatures, relative humidity, and dew point. In most cases,
two glass thermometers are used with the instrument, as described
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in ASTM E 667, Clinical Thermometers (Maximum Self-Registering,
Mercury-in-Glass). One thermometer has a clean "sock" or "wick"
on it that is wetted with water. Air is circulated around the
thermometers by the motorized fan or by whirling the hand-held
sling psychrometer. Whirling should be with a steady, medium
speed. Both thermometers should be read periodically and the
airflow (whirling) continued until the reading becomes constant.
The "wet" bulb thermometer temperature will be lowered
by evaporation of the water on the sock. The evaporation rate is
related to the relative humidity and barometric pressure.
Psychrometric tables relate temperature depression (difference
between "dry" and "wet" bulb readings) to relative humidity and
dew point. These standard tables, available from suppliers of
psychrometers, cover the range from 23.0 to 30.0 inches
barometric pressure. The effect of barometric pressure is
relatively small; if it is unknown, use the 30.0-inch pressure
table near sea level and the 29.0-inch pressure table at high
elevations.
10.3.7
Wind Meter. A pocket-size wind meter is available for
determining wind speed in miles per hour and velocity of air
moving across a spray booth. Spraying on days with excessive
winds can cause overspray or dry spray problems.
10.3.8
Moisture Meter. Meters are available for determining
the moisture content of wood, plaster, concrete, or other
materials. Some are nondestructive, while others require contact
pins to be driven into the surface. An alternate non-destructive
procedure for determining if too much moisture is present in
cementitious surfaces is described in ASTM D 4263.
10.3.9
Wet Film Gage. Gages for determining paint wet film
thickness are available in different types, two of which are
described in ASTM D 1212 and one in ASTM D 4414. All are
destructive in that they disturb the paint and require touching
up the film.
10.3.9.1 Notched Metal Gage. The most widely used type of wet
film thickness gage, described in ASTM D 4414, consists of a thin
rigid metal notched gage, usually with four working faces. Each
of the notches in each working face is cut progressively deeper
in graduated steps. The gage with the scale that encompasses the
specified thickness is selected for use. To conduct the
measurement, the face is pressed firmly and squarely into the wet
paint immediately after its application. The face is then
carefully removed and examined visually. The wet film thickness
is the highest scale reading of the notches with paint adhering
to it. Measurements should be made in triplicate. Faces of
gages should be kept clean by removing the wet paint immediately
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after each measurement. An alternative circularly notched gage
("hot cake") is rolled perpendicularly through the wet film and
the clearance of the deepest face wetted is noted.
10.3.9.2 Cylindrical Gage. A cylindrical wet film thickness
gage is described in ASTM D 1212. These gages are also rolled
through the paint rather than being pressed into it. They have
an eccentric center wheel with constantly changing clearance
supported by two outer wheels. The position on the exterior
scale corresponding to the point that the wet paint first touches
the eccentric wheel indicates the wet film thickness.
10.3.10
Dry Film Thickness Gages for Coatings on Aluminum,
Copper, and Stainless Steel. Gages are available to determine
the dry film thickness of organic coatings on aluminum, copper,
and stainless steel. Alternating current from the instrument
probe coil induces eddy currents in the metal that in turn induce
magnetic fields that modify the electrical characteristics of the
coil. ASTM D 1400 fully describes the instrument and its
operating procedure.
10.3.11
Magnetic Dry Film Thickness Gages for Coatings on
Steel. There are many different types of gages available for
nondestructively determining the film thickness of cured organic
coatings on metal surfaces. Most rely on the ferromagnetic
properties of steel. Their use is described in detail in ASTM D
1186 and SSPC PA 2. They are available in different thickness
ranges to provide the best accuracy with different coating
thicknesses. Each has a probe or tip that is placed directly on
the coating during measurement.
a) Magnetic thickness gages should be calibrated
before use. It is also a good practice to check the calibration
during and after use. Gage suppliers provide a set of standard
thickness nonmagnetic (plastic or nonferrous metal) shims to
cover their working ranges. The shim for instrument calibration
should be selected to match the expected coating thickness. It
is placed on a bare steel surface and the gage probe placed on it
for calibration. If the instrument scale does not agree with the
shim, it should be properly adjusted. If adjustment is
difficult, the reading for bare steel can be added or subtracted
from field readings to determine actual thicknesses.
b) The steel surface used for calibration should be a
masked-off area of the steel being painted or an unpainted
reference panel of similar steel, if possible. Pull-off gages
are best calibrated using small chrome-plated steel panels of
precise thickness (Standard Reference Material No. 1358,
Certified Coating Thickness Calibration Standard) available from
the National Institute of Standards and Technology (formerly the
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National Bureau of Standards), Gaithersburg, MD 20899. These
panels should not be used on magnetic flux gages, because the
mass of steel is insufficient for their proper operation. Shims
from pull-off gages should not be interchanged with those from
magnetic flux gages.
c) About five field measurements should be made for
every 100 square feet of painted surface. Each of these five
measurements should be an average of three separate gage readings
taken within an inch or two of each other. Measurements should
be made at least 1 inch away from edges and corners.
10.3.11.1 Pull-Off Gages. Pull-off gages measure film thickness
by stretching a calibrated spring to determine the force required
to pull an attached permanent magnet from a coated steel surface.
The simplest type of pull-off instrument is the pencil gage with
a coil spring attached to the magnet. It is held in a vertical
position on the coated steel and lifted away slowly until the
magnet pops off the surface. The paint thickness is indicated by
the position of the indicator on the calibrated scale. The
attractive force of the magnet varies inversely with the paint
thickness.
Banana gages (long, narrow instruments) represent
another form of pull-off gage. They are more versatile and
precise than pencil gages. A helical spring is stretched by
manually turning a graduated dial, and a pin pops up when the
magnet is lifted. At least one company sells an automatic gage
with a dial that turns and stops automatically. Cheaper models
have a rubber foot contact for the painted surface. More
expensive models have a more durable tungsten carbide foot for
greater durability and precision. “V” grooves are cut in the
probe housing of these gages and the electrically operated flux
gages described below to permit more accurate measurement of
paint dry film thicknesses on cylindrical surfaces.
10.3.11.2 Flux Gages. Magnetic flux gages measure changes in the
magnetic flux within the probe or the instrument itself. Flux
changes vary inversely with distance between the probe and the
steel. Mechanically operated instruments of this type have a
horseshoe magnet that is placed directly on the coating, and
readings are made from the position of a needle on a calibrated
scale.
Electrically operated magnetic flux instruments have a
separate instrument probe that houses the magnet. Thickness
measurements are presented in a digital read-out. Some of these
gages have a probe attached to the instrument to permit greater
accessibility, especially in laboratory work. They may also have
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attachments for strip recorders for repetitive work or alarms to
produce sounds if minimum thicknesses are not met. For the paint
inspector, these more sophisticated attachments are normally
unnecessary.
10.3.12
Destructive (Nonmagnetic) Dry Film Thickness Gage.
There are several models of Tooke gage described in ASTM D 4138,
Measurement of Dry Film Thickness of Protective Coating Systems
by Destructive Means that measure paint dry film thickness on any
surface by microscopic observations of precision-cut angular
grooves in the film. The gage is not recommended with very soft
or brittle films which distort or crumble, respectively, when
cut.
A dark, thick line is first drawn on the painted
surface for later reference under the magnifier. A groove is
then firmly cut perpendicular across the line with a tungsten
carbide cutter tip as it forms a tripod with two support legs.
The width of the cut is determined visually using the illuminated
magnifier portion of the instrument. Tips with three different
cutting angles are available for use with films of thickness up
to 50 mils. Visual observations are multiplied by 1, 2, or 10,
depending upon the cutting angle of the tip, to determine the
actual film thickness. Thicknesses of individual coats of a
multi-coat system can be determined, if they are differently
colored.
10.3.13
Holiday Detector. Instruments for detecting pinholes
and other flaws in coatings on metal surfaces are used mostly on
waterfront and fuel storage and distribution facilities but
should be used on freshly coated critical metal structures.
Holiday detectors are available in two types: low and high
voltage, as described in NACE RP0188.
10.3.13.1 Low Voltage Holiday Detectors. Low voltage (30 to 90
volts) detectors are used on coatings up to 20 mils in thickness.
These portable devices have a power source (a battery), an
exploring electrode (a dampened cellulose sponge), an alarm, and
a lead wire with connections to join the instrument to bare metal
on the coated structure. A wetting agent that evaporates upon
drying should be used to wet the sponge for coatings greater than
10 mils in thickness. The wetted sponge is slowly moved across
the coated surface so that the response time is not exceeded.
When a holiday is touched, an electric circuit is completed
through the coated metal and connected wire back to the
instrument to sound the alarm. Holidays should be marked after
detection for repair and subsequent retesting.
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10.3.13.2 High Voltage Holiday Detectors. High voltage (up to
30,000 volts or more) holiday detectors are normally used on
coatings greater than 20 mils in thickness. The rule of thumb is
to use 100 volts per mil of coating. The exploring electrode may
consist of a conductive brush or coil spring. It should be moved
at a rate not to exceed the pulse rate of the detector. If a
holiday or thin spot in the coating is detected, a spark will
jump from the electrode through the air space or a thin area of
the coating to the metal. The resultant hole in the coating will
locate the holiday or thin spot that requires corrective action.
10.3.14
Adhesion Tester. There are two basic types of testing
for determining adhesion of coatings: the tape and the pull-off
test. The tape test is mostly used in the field, and the pulloff test, in the laboratory. The tape test is most useful when
adhesion is low. Thus, it is often used to determine whether an
old coating has adequate adhesion to support another layer of
paint, or whether there is compatibility between coating layers.
This test cannot distinguish among good adhesion levels. The
pull-off test is more time consuming to perform since a “dolly”
or fixture must be glued to the surface of the coating. The test
measures the tensile force needed to remove the fixture. Pulloff forces up to several thousand pounds per square inch can be
measured.
10.3.14.1 Tape Adhesion Test. In the tape test, ASTM D 3359, an
X or a lattice pattern is cut through the coating to the
substrate. Special pressure-sensitive tape is applied over the
cut and rapidly pulled off at an angle of 180 degrees. The cut
area is then examined for extent of deterioration. A kit is
available with a knife, chrome-plated steel template and tape for
performing the test.
10.3.14.2 Pull-Off Adhesion Test. In the pull-off test, ASTM D
4541, a metal dolly is bonded to a coated surface at a
perpendicular angle with an adhesive, usually a two-component
epoxy. After the adhesive has fully cured, a force is gradually
and uniformly applied to the dolly until it is detached from the
coating (or until the desired pull-off level is reached). One
type of pull-off tester has a hand wheel that is turned to apply
the force. The hand wheel/ratchet spanner is tightened until the
dolly is detached or a prescribed force is applied. Another type
applies the pull force pneumatically with compressed gas.
Machine application of pull produces more accurate results than
manual application. In both cases, care must be taken to make
sure the dolly and instrument are both aligned perpendicular to
the coated surface. A horizontal surface is preferred.
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10.3.15
Portable Glossmeter. Battery-powered, pocket-size
gloss meters can provide accurate measurements in the laboratory
or field. ASTM D 523, Specular Gloss, describes a method for
measuring gloss in the laboratory which could be adapted for use
with a portable device. Measurements can be made on any plane
surfaces.
10.3.16
Hardness Tester. A series of hardness pencils (drawing
leads) are available for determining rigidity or hardness of
organic coatings on rigid substrates. The film hardness is that
of the hardest lead that does not cause damage, as described in
ASTM D 3363, Film Hardness by Pencil Test. The procedure is used
to establish degree of cure, adverse effects of solvents from a
wet layer upon a dry film, and softening effects caused by
environmental exposure.
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Section 11:
ANALYSIS OF PAINT FAILURES
11.1
Definition. Organic coatings deteriorate and fail with
time. Failure analysis does not concern itself with this type of
deterioration. It is defined as an investigation to determine
the cause or causes of premature deterioration of coatings or
coating systems. It is obvious, however, that failure analyses
are often also directed at obtaining additional information than
that stated in the above definition. Thus, the failure analyst
may also wish to determine the extent of the damage, whether all
requirements of a specification of a contract or work order had
been met, who might be responsible for the failure and thus be
liable for repairs, or what is the best remedial action to
correct the existing condition.
11.2
Documentation of Findings. Measurements, photographs,
specimens, and other observations made at the job-site or later
in the laboratory should be firmly documented with dates,
locations, etc., because they may at a later time become legal
evidence. Personnel conducting failure analyses should routinely
follow the procedures necessary for such documentation to prepare
for any eventuality.
11.3
Scope of Failure Analysis. Paint failure analysis can
be conducted by anyone with a basic understanding of coatings.
However, they are best conducted by someone specially trained for
the work. This is particularly true if the investigation becomes
part of a dispute, since credibility of the analyst may be a
determining factor in a dispute. In some instances, an analysis
need not be extensive, but care must be taken not to make
important conclusions based on superficial observations. A
complete paint failure analysis includes most or all of the
following actions:
a)
Review of specification including modifications
b)
Review of supplier’s data
c)
Review of inspector’s daily reports
d)
Thoroughly documented on-site inspection
e)
Laboratory analysis of retained and/or field
f)
Analysis of data
samples
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g)
conclusions
Preparation of a report containing findings and
11.3.1
Review of Specification for Coating Work. The
specification and the submittals required in the specification
for the coating work should be thoroughly reviewed and
understood. The specification states precisely the work that was
to have been done and the methods and materials that were to be
used, so that any deviations from them should become apparent.
The review may also point out discrepancies or lack of clarity in
the document that may have contributed to the failure.
11.3.2
Review of Supplier’s Data. Supplier data sheets should
be reviewed, because they describe the intended purpose of the
coatings used, along with recommended surface preparation and
application practices. They may also include compositional
information that can be checked later by laboratory analysis to
determine if the batch actually used was properly prepared.
11.3.3
Review of Inspector’s Daily Reports. The inspector’s
daily reports should be reviewed, because they provide
information about the conditions under which the work was
accomplished and the quality of the surface preparation and
coating application. Any compromises in the conditions required
by the specification or recommended by the supplier may lead to
early failure. These reports may also reveal field changes that
were made to the original specification.
11.3.4
On-Site Inspection. Just as the inspector on the job,
the person analyzing paint failures must have access to areas
where failures have occurred. This may require ladders or lift
equipment, lighting, or mirrors. The analyst should also have
photographic equipment to document conditions and be skilled in
its use. Scales should be used to show relative size, and
permanent markings should be made on each photographic exposure
for positive identification. Dates should also be placed on the
photographs.
The analyst should have a standard kit of field test
equipment including one or more thickness gages and calibration
standards, a knife, a hand lens, and containers for samples.
Obviously, he should be well trained in their use and use them
systematically, as described elsewhere in this text. A container
of methyl ethyl ketone (MEK) or other strong solvent may be
useful in either determining paint solubility (e.g., verifying
the general paint type or its complete cure) or to strip off a
coating to examine the condition of the underlying surface or the
thickness of the underlying galvanizing or other insoluble
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coating. Standard forms for manually recording data or equipment
for voice recording are also very useful. A failure analysis
checklist can ensure that no important item is overlooked.
Obviously, all items on the list may not be important at all
times, but to inadvertently skip an important one may be a
serious oversight.
11.3.5
On-Site Inspection Techniques. An overall visual
analysis should first be made to determine the areas where the
deterioration is most extensive and where any apparent deviation
from specification may have occurred. This should then be
followed by a closer examination as to the specific types of
deterioration that may be present.
a) Use of a hand lens may provide information not
otherwise visually apparent. All types of failure, including
color changes and chalking, should be described fully. For
example, does peeling occur between coats or from the substrate?
Are blisters broken or filled with water? This detailed
information may be necessary for finalizing conclusions as to the
type of failure. The terms defined later in this section should
be used to describe failures rather than locally used terms that
may not be clear to other people. Care must be taken not to come
to final conclusions until all the data are analyzed. It is a
good practice to state at the inspection site that the final
conclusions on causes of failure cannot be made until completion
of laboratory testing.
b) Dry film thicknesses should be routinely measured
and recorded, as any significant deviations from recommended
thicknesses can be a factor contributing to coating failure. The
procedure for measurement of these thicknesses required in the
specification should be followed.
c) Other measurements that may be important are
coating adhesion and hardness, since they may provide important
information on application or curing of the coating. Adhesion
can be easily determined with a simple tape test described in
Section 9 or by using more sophisticated instrumentation (refer
to Sections 8 and 9). Hardness can be tested in the field with a
knife or special hardness pencils.
d) It is generally important to verify the identity of
the finish coatings and occasionally the identity of the entire
coating system. If wet samples of the paints used have been
retained, they can be submitted for laboratory analysis for
conformance to specification or manufacturer’s data sheet. If
these are not available, a simple solvent rub test may be useful
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in determining whether the exterior coatings are thermoplastic,
thermosetting, or bituminous. A cotton-tipped swab stick is
dipped in MEK or acetone and rubbed against the paint surface. A
thermosetting coating such as a vinyl which has been deposited on
the surface by simple solvent evaporation will redissolve in the
solvent and be wiped onto the cotton. A bituminous (coal tar or
asphalt) coating will also behave in this manner, but it will
impart a characteristic brown stain to the cotton. Properly
cured multiple-component thermosetting coatings such as epoxies
that cure by chemical reaction will not be affected by the
solvent. These solvents can also be used at the job site to
remove thermoplastic coatings to examine the condition of the
underlying substrate. The presence of mill scale may establish
the extent of surface cleaning. If rust is found, care must be
taken to determine if it was present before painting or resulted
from underfilm corrosion. Samples of the finish coat can also be
removed by sanding and taken to the laboratory for identification
as described in par. 11.3.6.
e) Once the various types of failure that may be
present have been identified, the extent of each type of
deterioration should be estimated. Standard block methods that
help to quantify the extent of coating deterioration are
described in ASTM F 1130, Inspecting the Coating System of a
Ship. Two sets of drawings are used to illustrate failures. One
set is used to identify the portion of the surface on which the
paint is deteriorated. The other set is used to identify the
level of deterioration within the deteriorated areas. For
example, a fourth of the surface could exhibit blistering and
within the areas 10 percent of the surface could be blistered.
11.3.6
Laboratory Testing. A more definitive laboratory
analysis of deteriorated paint is generally desired and may
become critical if the problem goes into litigation. Such
analyses require several representative paint samples to be
collected at the job site. Peeled and blistered paint is easily
sampled, but it may be necessary to obtain samples from sound
paint by scraping or sanding. Each sample should be placed in a
sealed container and properly identified and dated. Chain of
custody procedures (ASTM D 4840, Sampling Chain of Custody
Procedures) should be used if litigation is involved.
If samples of wet paint used on the job are available,
they can be tested by standard laboratory tests for conformance
to any SSPC, Federal, military, or State specification referenced
in the contract specification. If none of these standards was
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referenced in the specification, the paints can be tested for
conformance to manufacturer’s listed composition or properties.
11.3.6.1 Microscopic Examination. Samples of paint collected at
the job site should be examined under a light microscope. An
edge examination may reveal the number of coats and the thickness
of each coat. An examination of the surface may reveal fine
cracking or other irregularities. Examination under a scanning
electron microscope (SEM) can reveal much more detailed
information about the paint film. Also, the SEX often has an
attachment for energy dispersive x-ray analysis which can
identify the metals and other elements in the pigment portion of
small areas of the coating.
11.3.6.2 Spot Tests. There are several simple laboratory spot
tests that can be run on samples of deteriorated paint collected
at the job site. They generally provide specific information
about the paint binder (ASTM D 5043, Field Identification of
Coatings) or pigment. Special chemicals and training are usually
required by the analyst.
11.3.6.3 Infrared Spectrophotometric Analysis. The most widely
used technique in laboratory analysis of paint failures is the
infrared spectrophotometry. The use of new Fourier transform
infrared (FTIR) spectrophotometers permits much more versatility
and precision than earlier instruments. The technique can
identify the resin components of paints from the shapes and
locations of their characteristic spectral peaks. It is highly
desirable to separate the resin from the paint pigment before
analysis, because the pigment may cause spectral interference.
This is easy to do with thermoplastic but not thermosetting
paints. Thermoplastic resins can be dissolved in solvents that
are transparent in part or all of the infrared region, filtered
to remove the pigment, and the solution placed in standard liquid
cells or cast as films onto sodium chloride or other plates that
are transparent in the infrared region. Thermosetting coatings
can be pressed into potassium bromide pellets or their spectra
measured using diffuse reflectance equipment. Although the
pigment is not separated in these procedures, the spectrum of the
pigment can often be separated from that of the total coating by
the FTIR spectrometer. Spectra of field samples are compared
against published standards or authentic samples. It should be
remembered that exterior weathering may cause oxidation that may
appear in spectral analyses.
11.3.6.4 Other Specialized Instrumentation. There are other
specialized instruments that can be very helpful in failure
analysis. These include emission spectroscopy, atomic absorption
spectroscopy, and x-ray fluorescence instruments that can
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identify and quantity the metals present in a coating. Their
methods of operation are beyond the scope of this document.
11.3.7
Forming Conclusions and Preparing Reports. Field and
laboratory data should be analyzed logically and systematically
to form conclusions as to the causes of paint failure. No data
should be overlooked, and the conclusions should be consistent
with the data. The report should include conclusions and
recommendations requested by the activity for which the analysis
was made.
The report is perhaps the most important part of the
failure analysis, because it presents the findings and
conclusions of the investigation. No amount of good field or
laboratory work will be useful unless it is presented well in the
report. There must be a clear, systematic, and logical
presentation of the findings, so that the conclusions are well
supported. The report should not contain errors or otherwise be
subject to challenge. Where conclusions are not firm, the extent
of uncertainty should be stated.
11.4
Expert System for Failure Analysis. An expert system
for failure analysis provides a systematic approach first to make
a preliminary identification based on visual observations and
then to verify it with supplementary information. The initial
identification is based upon the answers to a series of questions
designed to distinguish one type of failure from another.
Decision trees 1 and 2 are used for this, one for surface defects
and one for film failures. This same approach can be used in an
expert system for a computer. The importance of a systematic
approach cannot be overemphasized. One should be careful not to
make permanent decisions on types and causes of failure until all
the evidence is considered.
The first step in the identification of a coating
failure is to determine which decision tree to use. Tree l for
cosmetic defects should be used if only surface damage is
present, i.e., if the surface coat has not been completely
penetrated to the underlying coat or structural substrate. Tree
2 for film failures should be used if coating damage has
completely extended through the surface coat.
After a preliminary decision of the type of failure has
been made, look at the additional comments in the verification
section below to obtain further support for this selection. If
this information does not support the initial decision, reexamine
the evidence or reconsider answers to the decision tree, until
you are satisfied that you received the best overall answer.
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Remember, answers are not always easily obtained in failure
analysis, and there may be multiple types and causes of failure.
Thus, one may in some cases have to be content with the most
probable cause or causes of coating failure.
11.4.1
Cosmetic Defects. The following paragraphs further
describe the cosmetic defects chosen in the initial decision.
11.4.1.1 Chalking. Chalking occurs only on exterior surfaces,
since it is caused by the sun’s ultraviolet rays. The loose
chalk will be the same color as the coating, and, if it is
severe, an undercoat may be visible. Chalking should not be
confused with loose dirt which will not be the same color as the
finish coat.
11.4.1.2 Mildew. Mildew may resemble dirt but generally grows
in discrete colonies rather than being uniformly distributed. In
addition, it can be bleached with household bleach, but dirt
cannot. Also, it can also be identified microscopically by its
thread-like (hyphae) structures and its groups of spherical
spores. Mildew is usually black in color but some microorganisms
on coatings may have a green or red coloration.
11.4.1.3 Dirt. Dirt may be tightly or loosely held. It can
normally be removed by washing with detergent solution. However,
it may resist washing, if the dirt became embedded in the wet or
soft paint.
11.4.1.4 Uneven Gloss. Localized glossy spots may often be
detected only if observed from a particular angle. They occur
most frequently from spray application of heavy areas that do not
penetrate into wood or concrete/masonry surface.
11.4.1.5 Blushing. Blushing is a
evaporating coatings, particularly
chlorinated rubbers, on hot, humid
moisture on the wet film dulls the
opalescence.
defect from spraying fastlacquers such as vinyls and
days. Condensation of
finish to cause an
11.4.1.6 Bleeding. Bleeding occurs when solvent-containing
coatings are applied to a bituminous coating or pavement. The
stronger the solvent and the slower its evaporation, the greater
will be the tendency to dissolve the bituminous material and
cause it to bleed to the surface of the finish. New asphalt
pavements or toppings should be allowed to remain 4 weeks before
marking with paint to allow evaporation of volatile materials in
the asphalt.
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11.4.1.7 Fading. Fading of paint pigments occurs greatest in
the sunlight. Thus, there will be less fading of coatings under
eaves and other shaded areas. It also occurs more with synthetic
organic pigments than with naturally-occurring mineral pigments
(earth tones).
11.4.1.8 Discoloration. Discoloration is caused by exposure of
unstable pigments or resins to sunlight. Unstable resins like
polymerized linseed oil may yellow. The only prevention is to
use light-stable materials.
11.4.1.9 Pigment Overload. Pigment overload frequently results
in a mottled appearance or a poor quality film. It can occur
when attempting to tint a white paint to a deep tone. Latex
paints are particularly susceptible to this problem. By
specifying colors produced by the supplier, this problem can be
avoided.
11.4.1.10 Checking. Early checking may be caused by improper
formulation or application that causes the coating to shrink upon
curing. Excessive thickness or rapid curing may be responsible.
Aging will eventually cause checking of most coatings. It will
often occur when existing paints are topcoated with more rigid
finish coats that do not expand or contract as easily.
11.4.1.11 Dry Spray. Dry spray produces an uneven, pebbly finish
with holidays. The holidays can be verified on a metal substrate
with a holiday detector. It occurs most frequently when applying
coatings with fast evaporating solvents on warm days or when the
spray gun is held too far from the surface being painted.
11.4.1.12 Sagging. Sags may not permit complete curing of the
body of oil-based coatings and so may be soft below the surface.
Reduced film thickness in the areas where the sagging initiated
may be detected using a magnetic thickness gage on steel surfaces
and by using a Tooke gage on other surfaces.
11.4.1.13 Orange Peel. Orange peel is a defect of spray
application. It usually is widespread, when it occurs, and is
easily identified by its resemblance to the skin of an orange.
11.4.1.14 Wrinkling. Wrinkling occurs mostly with oil-based
paints that are applied so thickly on hot days that the surface
of the film cures rapidly to form a skin that does not permit
oxygen to reach the interior of the film to cure it. The coating
under the ridges is usually soft. Ridges generally occur in
parallel rows.
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11.4.2
Film Failures. The following paragraphs further
describe the film defects chosen in the initial decision.
11.4.2.1 Crawling. Crawling, sometimes called bug eyeing or
fish eyeing, occurs during coating application, frequently on
contaminated surfaces. It can usually be detected at the time of
application. The smooth, oval shapes resembling eyes are
characteristic of crawling.
11.4.2.2 Alligatoring. The characteristic checkered pattern of
cracked coating will identify alligatoring. The coating is quite
inflexible and cannot expand and contract with the substrate. It
is a special form of cracking or checking.
11.4.2.3 Intercoat Delamination. Intercoat delamination is
simply the peeling of a stressed coat from an undercoat to which
it is poorly bonded. It may occur in a variety of situations,
but occurs frequently when a chemically curing coating such as an
epoxy or a urethane has cured too hard to permit good bonding of
a topcoat. It may also occur when coating a contaminated
surface.
11.4.2.4 Intercoat Blistering. Intercoat blistering in a
storage tank or other enclosed area is likely due to solvent
entrapment. In water tanks or other areas exposed to water, the
trapped solvent will cause water to be pulled into the blister.
If the blisters are large, unbroken, and filled with water, it is
sometimes possible to smell the retained solvent after breaking
them. Intercoat blistering may lead to intercoat delamination.
11.4.2.5 Pinpoint Rusting. Pinpoint rusting is frequently
caused by applying a thin coating over a high profile steel
surface. A thin coating can be verified using a magnetic
thickness gage. It may also occur when steel is coated with a
porous latex coating system. Pinpoint rusting may initiate
corrosion undercutting of the coating.
11.4.2.6 Cracking. Cracking is the splitting of a stressed film
in either a relatively straight or curved line to an undercoat or
the structural substrate. Cracking may occur from rapidly curing
coatings such as amine-cured epoxies. Mudcracking is a more
severe condition caused by rapid drying, particularly by heavily
pigmented coatings such as inorganic zincs. It also occurs with
latex coatings applied too thickly on hot days. On wood, too
thick or too inflexible a film (usually a buildup of many layers)
can cause cracking perpendicular to the grain of the wood.
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11.4.2.7 Blistering to Substrate. The blisters that arise from
the substrate may be broken or unbroken. If broken, they may
lead to peeling and be hard to identify. Blistering to wood or
concrete/masonry substrates may be caused by moisture in the
substrate.
11.4.2.8 Peeling. Peeling is the disbanding of stressed
coatings from the substrate in sheets. It is generally preceded
by cracking or blistering.
11.4.2.9 Flaking (Scaling). Flaking or scaling is similar to
peeling, except the coating is lost in smaller pieces. Flaking
of aged alkyd coatings occurs commonly on wood.
11.4.3
Examples of Using Decision Trees. The decision trees 1
and 2 (Figures 24 and 25) can best be understood by using
examples.
11.4.3.1 Example of Surface Defect. This example is a surface
defect that does not penetrate the finish coat so that use of
decision tree 1 is required. We start with Question 1, “Does
detergent washing remove the defect?” In our example, the answer
is “Yes,” so we proceed to Question 2, “Does wiping with a dry
felt cloth remove defect?” This time the answer is “No,” so we
proceed to Question 3, “Does defect disappear when treated with
household bleach?” In our example, the answer is “Yes,” so we
have tentatively identified the defect as “Answer 2” mildew.
11.4.3.2 Example of a Film Defect. This example is a defect
that penetrates the finish coat so that use of decision tree 2 is
required. We start with Question 10, “Do oval voids that
originate at time of coating application expose an undercoat or
the structural substrate?” In our example, the answer is “No,”
so we proceed to Question 11, “Does the failure expose only an
undercoat?” This time the answer is “Yes,” so we proceed to
Question 12, “Which best describes the failure?” In our example,
the answer is “Peeling topcoat to expose undercoat,” so we have
tentatively identified the defect as “Answer 17” intercoat
delamination.
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Figure 24
Decision Tree 1: Support for Analysis of Coating Failures
That Do Not Penetrate the Finish Coat
174
Figure 25
Decision Tree 2: Support for Analysis of Coating Defects
That Penetrate the Finish Coat
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Section 12:
PROGRAMMING MAINTENANCE PAINTING
12.1
Definitions of Programmed Painting and Maintenance
Painting. Paint programming is a systematic planning process for
establishing when painting is required, what painting should be
done, by whom, at what times, and in what manner. Maintenance
painting is a vital adjunct to programmed painting. It is
defined as a field procedure for maintaining existing coatings in
an acceptable condition.
12.2
Components of Programmed Painting. There are three
basic components of successful paint-programming plans: plans
for initial design of the facility, plans for monitoring
conditions of structures and coating systems, and plans for
maintenance painting. Each plan must be prepared properly and
completely for the total program to be successful.
Programmed painting can best be implemented as a
computer program. This program will contain the initial design
data, data on the conditions of the structures and their coating
systems obtained from an annual inspection report, and
recommended maintenance painting schedules and procedures. The
latter should include cost estimates for each item of work so
that funding can be requested well in advance of the time it will
be spent. Cost estimating programs for construction work are
available in the Construction Criteria Base (CCB) (National
Institute of Building Sciences, Washington, DC) and proprietary
sources.
12.2.1
Initial Design. The design of both new structures and
their coating systems is critical to achieving maximum life of
each.
12.2.1.1 Structural Design. Structures should be designed so
that they are easy to coat initially and to maintain in an
acceptable condition. Common structural design defects include:
a) Contact of Dissimilar Metals. The more active
metal will rapidly be consumed by galvanic corrosion to protect
the less active metal. This includes contact of steel and
stainless steel.
b) Water Traps. Structural components that collect
rainwater corrode more rapidly. These components should either
be turned upside down or have weep holes of sufficient size and
correct placement drilled in them. Weep holes should be as large
as possible and placed at the bottom of the structure.
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c) Configurations That Permit Vapors or Liquids to
Impinge on Structural Components. Structures such as steam
lines.
d) Configurations Restricting Access. Structures that
restrict access for painting receive poor quality maintenance.
e) Designs Creating Crevices. Crevices are difficult
to coat, and the oxygen deficiencies in them produce a type of
galvanic corrosion.
f) Other Difficult to Paint Surfaces. Sharp edges and
welds should be ground, pits should be filled, and corners should
be avoided.
12.2.1.2 Design of Coating System. The original coating system
must be designed to be compatible with both the environment in
which it is to be located and the substrate to which it is to be
applied. Sections 4 and 5 of this handbook list systems that
meet this requirement and are cost effective. As far as
possible, it is desirable to specify coating systems that are
easy to apply and maintain. It is always preferable to do the
surface preparation and the paint application in the controlled
environment of a shop as compared to the field. If this is not
possible, this work should be accomplished at the work site
before rather than after erection.
12.2.2
Plan for Monitoring Conditions of Structures and Their
Protective Coatings. Annually, each coated structure at each
military activity should be inspected for deterioration of both
the substrates and their coatings. Both the types and the extent
of deterioration should be noted, and the generic type of the
finish coat should be determined if it not already known. An
estimate should also be made as to when structural and coating
repairs should be made to prevent more serious damage. Other
structures at the activity that require the same type of
maintenance should also be noted, since it would be more
economical to include as many structures as appropriate in a
single contract. An example of an inspection form which has been
successfully used for routine inspections and could be modified
to meet an installation’s needs is shown in Figure 26.
12.2.2.1 Determining the Type of Coating Failure. The type of
coating failure can be determined by following the procedure
given in Section 11.
12.2.2.2 Determining the Extent of Coating Failure. In
maintenance painting, it is necessary to determine the extent of
coating failure to permit realistic bidding for the repair work.
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To do this, both the severity of the deterioration and its
distribution must be defined. The level of severity will
indicate whether only the finish coat or other coats are involved
in the deterioration and how it can best be repaired. If the
distribution is limited, spot repairing is likely to be
practical; if it is extensive, it is probably best to remove all
the coating and repaint.
Standard block diagrams for estimating coating
deterioration on ships for “Overall Extent” and “Extent Within
Affected Areas” are generally also appropriate for shore
structures. They are described in ASTM F 1130. First, draw an
imaginary line enclosing all deterioration and select the
standard “Overall Extent” diagram that best matches the imaginary
area. Then, select the standard “Extent Within Affected Area”
diagram that best matches the areas within the imaginary line.
The number and letter of the selected diagrams establish the
extent of deterioration. Whatever system is used to determine
the extent of deterioration, it should utilize a standard format
so that evaluations of different structures can be compared and
priorities can be established.
It is also important in maintenance painting to
determine precisely the amount of loose and peeling paint to
establish the amount of work to be done. This will eliminate any
controversy over a “site variation,” i.e., the contractor
claiming that there was much more work necessary than described
in the specification. It is a standard practice to define “loose
and peeling paint” as that paint that is easily removed with a
dull putty knife.
12.2.2.3 Determining the Generic Type of the Finish Coat. Once a
painting program is set up, the identifications of paints being
applied will automatically be entered into the database. If the
generic type of the finish coat is not known, it can be
determined by infrared spectrophotometric analysis as described
in Section 11. The general compatibility of a coating can be
determined by the solvent rub test, also described in Section 11.
12.2.3
Types of Maintenance Painting. In planning maintenance
painting, it is first necessary to determine the general scope of
the work. There are four different approaches to maintaining an
existing coating in an acceptable condition:
a) Cleaning only to restore to an acceptable
condition. This may be accomplished by pressure washing or
steam cleaning.
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Structure Number ___________
Date ____________
Reason for Inspection ____________________
Inspector's Name _________________________
_________________________________________________________________
Substrate:
Component:
Wood
Siding
Aluminum
Window Frame
Concrete
Door
Transite
Door Pocket
Steel
Door Frame
Galvanized Steel
Eaves
Other ____________
Other ____________
_________________________________________________________________
Appearance:
Deterioration:
Chalking
Cracking
Fading
Blistering
Mildew
Peeling
Other ____________
Other ____________
_________________________________________________________________
MEK Rub Test:
Evaluation (1=good, 4=bad):
- (no effect)
1
+
2
++
3
+++ (large effect)
4
_________________________________________________________________
Suspected Binder Type:
Samples Collected:
Alkyd
Chip Sample
Latex
Photograph
Epoxy
Factory Finish
Other ____________
Figure 26
Coating Condition and Identification Form
b) Spot repair (priming and topcoating) of areas with
localized damage but otherwise sound paint. This should be done
before the damage becomes more extensive.
c) Localized spot repair plus complete refinishing
with topcoat only. This should be done when localized repair
only would produce an unacceptable patchy finish.
d) Complete removal of existing paint and total
repainting. This should be done when the damage is so extensive
that types “b” or “c” are impractical or uneconomical.
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Repair of exterior coatings may not be warranted with
the first appearance of weathering, but deterioration should not
proceed to the point that damage occurs to the substrate, or more
costly surface preparation or application techniques become
necessary. If lead-containing paint is present, the costs for
paint repair or removal will be much more expensive. If the
paint can be maintained in place, a great deal of savings will
result. New restrictions on abrasive blasting and other surface
preparation techniques may also significantly increase total
costs. Thus, scheduling of repairs should be made to avoid such
costly operations.
12.2.4
Plan for Maintenance Painting. The plan for
maintenance painting includes selection of the surface
preparation, application, and inspection methods and the
materials to be used.
12.2.4.1 Selecting Materials for Maintenance Painting. For
localized repairs to an otherwise sound coating system (12.2.3
types “b” and “c”), it is wise to repair a damaged coating system
with the same coating previously used or one of the same generic
type or curing mechanism to avoid incompatibility. If in doubt
as to the compatibility of a paint to be applied to an existing
finish, apply a small patch to it and inspect it after 2 to 3
days for any bleeding, disbanding, or other sign of
incompatibility.
For total recoating (12.2.3 type “d”), select the
coating as described for new work in Section 4 or 5.
12.2.4.2 Surface Preparation for Maintenance Painting. For
making localized repairs, it is best to use the surface
preparation methods for different substrates described in Section
6. It may be more practical or necessary, however, to use hand
or power tools rather than abrasive blasting where the amount of
work to be done is small, or where abrasive blasting would
contaminate an area.
Loose and peeling coating should be removed, and the
adjacent intact coating should be sanded to produce a feathered
edge and roughened paint surface extending 2 inches beyond the
repair area. The feathered edge will produce a smoother
transition between the old and new paint and roughening the
adjacent intact paint will permit good adhesion of the new
primer.
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Feather edging of steel may be accomplished by blasting
with a fine abrasive (e.g., 60 mesh grit or finer) with the
nozzle held at a low angle about 3 or 4 feet from the surface.
However, even fine abrasive may damage adjacent coating. Thus,
it is best to determine if there are any adverse effects with a
surface preparation procedure before proceeding will it.
12.2.4.3 Application for Maintenance Painting. Spot application
of paint in maintenance painting is usually done by brush or
spray, as the painter determines to be most efficient. Brushing
of the primer is usually preferred where the surface is rough or
otherwise difficult to paint. Patches should be extended 2
inches beyond the areas of damaged coatings where the adjacent
intact paint has been previously roughened.
12.2.4.4 Inspection of Maintenance Painting. Inspection of
maintenance painting usually consists of visual inspection for
workmanship, dry film thickness, and adhesion. Fuel tanks and
lines, waterfront structures, and other critical structures
should also be tested for holidays Imperfections in the coating).
These inspection procedures are described in Section 9.
12.2.5
Scheduling the Work. By planning work well in advance,
it is possible to schedule it at a time when minimum inclement
weather is expected. It may also be possible to schedule it when
there will be less interference with other trades doing
construction work or personnel utilizing the structures.
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Section 13:
GENERAL SAFETY PRACTICES DURING PAINTING OPERATIONS
13.1
Introduction. This section discusses general safety
concerns during painting operations and appropriate actions to be
taken to protect those conducting these operations and others in
the immediate area. Installation safety and industrial hazards
offices should be consulted to determine detailed requirements
for worker safety, including protection from toxic materials.
General concerns will be discussed, much as they are discussed
for safety paint application in SSPC PA 3, Safety in Paint
Application. OSHA provides requirements for safety in the
workplace. These requirements include:
29 CFR 1910.106/29 CFR 1926.152, Flammable and
Combustible Liquids
29 CFR 1910.1200/29 CFR 1926.59, Hazard Communication
29 CFR 1910.146, Permit-Required Confined Spaces
29 CFR 1910.151, Medical Services and First Aid
29 CFR 1910.25, Portable Wood Ladders
29 CFR 1910.26, Portable Metal Ladders
29 CFR 1910.28, Safety Requirements for Scaffolding
Written policies are available at installation safety
offices. These offices are responsible for providing necessary
safety support, and it is important that personnel interact
freely and positively with them in a total safety program.
Attitude is of great importance in ensuring a safe working
environment.
13.2
Standard Operation and Safety Plans. Every operation
that involves any type of hazard should have a standard operating
plan incorporating safety and health considerations. Contracted
operations should have safety and health requirements clearly
addressed in the contract specifications. Personnel have the
right to learn of any unsafe or unhealthful conditions or
operations that they will be involved with and to receive
training or equipment necessary to conduct their work safely.
Personnel must also be able to report hazardous conditions and
conditions suspected of being hazardous without fear of
retaliation. Workers, on the other hand, also have the
responsibility of conducting their work in a safe and healthful
manner, correcting or reporting unsafe or unhealthful conditions,
and wearing appropriate personal protection equipment. This
includes reducing exposures as much as possible. Only necessary
personnel should be present in the hazardous areas.
13.3
Hazard Communication. The best way to protect yourself
from chemical products used in painting operations is to know
their identification, the hazards associated with them, and their
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proper and safe use. Every employer must provide this
information to his employees. Each container of hazardous
material must be labeled to identify its contents. Unlabeled
products should never be used. Other important information on
chemicals, including health and safety data, precautions for
handling, and emergency and first aid procedures, can be obtained
from the material safety data sheet (MSDS) for the product.
These sheets are required to be present when hazardous materials
are being shipped, stored, or used in any operation. Finally,
the activity must have a written program providing personnel with
information about the hazardous chemicals used in each operation
and an inventory of hazardous chemicals on site. The activity
must also provide employees with necessary safety training.
13.3.1
Labels. Labels should be replaced, if they are torn,
hat, or illegible. When materials are transferred to other
containers for easier use, these containers must also be properly
labeled. Labels usually contain the following information:
a) Complete identification - may include several
alternative names
b)
precautions
Basic warnings - list hazardous chemicals and
c) First aid requirements - what to do when splashed
on eyes or skin
d)
Fire actions - how to properly extinguish fires
e) Treatment of spills - equipment and materials for
cleaning up spills
f) Handling and storage procedures - safety equipment
and practices for proper handling
g) Disposal procedures - describe methods for safe and
legal disposal
13.3.2
Material Safety Data Sheets.
following information:
a)
MSDSs provide the
Chemical identification - identify chemicals
present
b) Hazardous ingredient data - list hazardous
chemicals and safety limits
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c)
Physical data - describe odor, appearance, etc., of
chemicals
d) Fire and explosion data - list flash point and
extinguishing media
e) Health hazards - symptoms of overexposure and
emergency action
f) Reactivity data - stability and reactivity with
other chemicals
g) Spill or leak procedures - clean-up and disposal
procedures; always notify safety office
h) Special protection - necessary respirators,
clothing, eye protection, etc.
i) Special precautions - special handling precautions,
including safety signs and standby clean-up kits
Note: Specific requirements for personal protective
equipment and use of the chemical should be based on a local
evaluation by an industrial hygienist or health professional.
13.4
Toxicity Hazards. Many toxic materials may be
encountered during cleaning and painting operation, such as
organic solvents and lead- and chromate-containing pigments.
Personnel working with toxic materials should be knowledgeable
about how to protect themselves from them.
13.4.1
Entrance of Toxic Materials Into Body. Although toxic
materials can enter the body during any part of a coating
operation, surface preparation and coating application activities
may present the greatest hazard. Toxic materials can enter the
body by three different routes:
a)
Inhaling in the lungs
b)
Ingestion through the mouth
c)
Absorption through the skin
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13.4.1.1 Inhalation. Toxic vapors or suspended particles
inhaled into the lungs may be rapidly taken into the rest of the
body. Individual solvents in blends in paints vary widely in
human toxicity. Exposures can be reduced with ventilation and
respirator protection.
13.4.1.2 Ingestion. Ingestion through the mouth usually occurs
from contaminated hands not washed before eating, drinking, or
smoking. Good personal hygiene (hand washing, avoidance of
clothing contamination and keeping tools/surfaces clean) should
be practiced even when gloves are used.
13.4.1.3 Skin Absorption. Skin absorption must occur through
contact. This can be minimized by use of protective clothing.
Contaminated clothing should be removed and disposed of at the
job site and be completely cleaned, and the contaminated person
should thoroughly shower before leaving the job site. The
appropriate protective clothing is paramount to preclude
significant skin contact as some chemicals easily permeate (pass
through) the protective material.
13.4.2
Types of Toxic Materials.
major categories:
a)
Toxic substances are of four
Irritants - inflame eyes, nose, throat, and lungs
b) Asphixiants (e.g., carbon monoxide, nitrogen) Interfere with oxygen assimilation or displaces available oxygen
to breathe
c) Nerve poisons (organic solvents, lead compounds,
etc.) - attack nervous system
d) Systemic poisons - affect heart, liver, kidney, or
blood forming organs
13.5
Respiratory Hazards. There are four types of
respiratory hazards:
a)
Dusts - dry particles from grinding and blasting
operations
b)
Mists - liquid particles from cleaning and spraying
operations
c) Gases and vapors of liquids - evaporated cleaning
or paint solvent
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d)
Oxygen deficiencies - especially in confined areas
Dusts include smoke particles from combustion. Gases
and some particles may not be seen by the naked eye. Any of
these products resulting from painting operations may require a
cartridge-type respirator. Specific recommendations for
respiratory protection should come from a workplace evaluation of
potential exposures.
13.6
Hazards in Different Painting Operations. Painting
procedures may include one or more of the following hazardous
operations: surface preparation, paint application, and working
in high, confined, or remote places.
13.6.1
Surface Preparation. Surface preparation hazards occur
in abrasive and water blasting operations, mechanical cleaning,
chemical cleaning, and high temperature operations. Protection
of workers and the environment from dust containing toxic metals
(such as lead, cadmium, or chromate compounds) produced during
removal of old paint is discussed in Section 3.
13.6.1.1 Abrasive and Water Blasting. Abrasive and water
blasting are by far the most dangerous operations concerned with
surface preparation for painting. High-pressure nozzles (over
100 psi for abrasive and over 30,000 psi for water blasting) pose
major threats. Hoses and couplings must be checked for
soundness, and the pot pressures must be checked to ensure that
the maximum allowable pressures are not exceeded. The blast
nozzle must have a deadman valve, so that it will automatically
shut off, if it is lost by the blaster. No attempt should be made
to override this or other safety devices. No safety omissions
should be permitted, even for very small blasting jobs. The
blasting area should be posted for no admittance, and the pot
tender located in a protected area behind the blaster, so that no
one is in the vicinity of the blaster. Each person in the
operation should wear the proper safety equipment, including an
air-supplied respirator (type CE) specifically designed for the
blaster.
Isolation from the blaster and use of deadman valves
are also important during water blasting. Electrical operations
should be shut down at that time to prevent electrical shock.
Care should also be taken to avoid slipping on wetted surfaces.
13.6.1.2 Mechanical Cleaning. Grinders, sanders, and other
powered cleaning tools require special attention to meet the
safety provisions of Subpart P of OSHA Standard 29 CFR 1910.
They should have safety shields or devices to protect eyes and
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fingers. OSHA regulations do not permit the use of faulty hand
and power tools such as cracked grinders and wheels or damaged
rotary brushes. Power tools should only be operated as
recommended by the manufacturer.
13.6.1.3 Chemical Cleaning. Chemical cleaning is inherently
dangerous and requires special precautions. Chemicals must be
properly labeled (refer to par. 13.3.1), stored, and used.
Chemicals should be
and ventilated room separated
they may react. Any shelving
to the wall and have a lip on
accidentally knocked onto the
stored off the floor in a secured
from other chemicals with which
used for storage should be secured
each shelf to prevent being
floor.
Chemicals should be used in accordance with written
standard operating procedures or the manufacturer’s instructions.
Proper eye, face, hand, and skin protection should be taken by
using appropriate chemical protective clothing, eye/face
equipment and following recommended operating procedures when
working with caustic chemicals or solvents. Where the eyes or
body of any person may be exposed to corrosive materials,
suitable facilities for quick drenching or flushing of the eyes
(eye washes) and body (deluge showers) shall be provided in the
work area for immediate emergency use. Contaminated personnel or
the work areas should be appropriately cleaned and treated as
soon as possible. Spill kits and instructions for their use
should be available for each type of chemical.
13.6.1.4 High Temperature Operations. High temperature cleaning
can be achieved with steam, flame, or heat guns. They should be
thermostatically controlled and used only where appropriate and
according to standard operating procedures. Insulated gloves
should be used where necessary to protect hands from heat.
13.6.2
Painting Operations. Hazards occur during storage,
mixing, and application of paints.
13.6.2.1 Storage of Paints. Coating materials should be stored
off the floor under cover in secured and well ventilated areas
away from sparks, flames, and direct sunshine. The temperature
should be well below the flash point of stored products. Flash
point is the minimum temperature at which a liquid gives off
enough vapor to become ignited in the presence of a spark or
flame. Flammable liquids such as turpentine and toluene have
flash points below 100 degrees F; combustible liquids have flash
points of 100 degrees F or greater. The flash points of
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individual solvents vary greatly. So do the explosive limits the concentration range in air at which combustion may occur.
Any shelving used for storage should be secured to the
wall and have a lip on each shelf to prevent being accidentally
knocked onto the floor. Equipment for removal of spills should
be present.
13.6.2.2 Mixing and Applying Paints. Mixing and application
operations have associated spill, fire, and toxicity hazards.
Eye protection, gloves, and other appropriate equipment and
clothing should be used during paint mixing operations.
Individual solvents in blends in paints vary widely both in
solvency and in human toxicity. They can remove moisture and
natural oils from the skin to make it more sensitive to other
irritants.
a) When mixing and applying paints, the following
precautions should be observed:
(1)
Protect eyes, face, hands, and skin
(2)
Keep paint well below flash point
(3) Use in well ventilated areas. Consult the
facility’s safety office, if in doubt, for evaluation of the work
space
(4)
Use slow-speed stirrers to prevent buildup of
(5)
Permit no matches, sparks, or flames in area
(6)
Ground equipment and work
static charge
b)
When spraying paint:
(1)
Ground equipment and metal work
(2)
Use only non-sparking tools
(3)
Permit no matches, open flames, or smoking in
(4)
Perform in a well ventilated area or in an
the area
approved spray
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Airless guns should only be used by trained personnel
and with protective guards because, at the high pressures (over
2000 psi), paint droplets can penetrate flesh. They should never
be pointed at any part of the body, and their nozzle guards
should never be removed.
13.6.3
Work in High, Confined, and Remote Places. Work in
high, confined, and remote places presents special hazards.
13.6.3.1 Work in High Places. Working safely in high places
requires the proper use of equipment designed to provide access
to the work site. Safety requirements for ladders, scaffolding,
and stages can be found in OSHA Safety and Health Standards (29
CFR 1910), Paragraphs 1910.25 (Portable Wood Ladders), 1910.26
(Portable Metal Ladders), 1910.28 (Safety Requirements for
Scaffolding), and 1910.29 (Manually Propelled Ladder Stands and
Scaffolds (Towers)).
a) General requirements for ladders used in painting
operations include
(1)
Do not use if rungs/steps are loose, bent, or
(2)
Keep ladders away from power lines
(3)
Never use as horizontal scaffold members
(4)
Use only as intentionally designed
split
b)
General requirements for scaffolds include:
(1) The footing/anchorage shall be sound and rigid
(do not use bricks, boxes, etc., to support)
(2) Have rigid guard rails (never ropes) and
toeboards or rails
(3) Keep them clean and free of abrasive, mud,
grease, and other debris
(4)
Remove unnecessary equipment
(5)
Keep platforms level at all times
(6)
Regular inspection and repair, as necessary
(7)
Never use ladders on their platforms to add
height
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MIL-HDBK-1110
(8)
Do not move when occupied
c) Additional requirements for swing (suspended)
scaffolds suspended by block and tackle are:
d)
(1)
Secure life lines to personnel on them
(2)
Never allow then to swing freely
(3)
Limit to two the number of personnel on them
(4)
Follow OSHA requirements for suspension
Additional requirements for rolling scaffolds are:
(1)
Always set caster brakes when in a fixed
(2)
Never ride while moving
(3)
Remove materials from platform before moving
position
Permanent scaffolding should be built for routine
maintenance operations on aircraft or other standard
configurations. Powered lift platforms or boom machines are
often used to reach high places. Some extend as high as 100
feet. Scissor lifts, the most common type, only go straight up.
Booms can provide greater access where there are obstructions in
the way. Continuous forced-air ventilation may be used to
control any hazardous atmosphere. Gas monitoring during the
operation may be necessary where unsafe conditions could develop.
When painting bridges, towers, or other tall structures, safety
nets or harnesses should be utilized. They not only provide
safety but also result in better workmanship. Safety harnesses
are much preferred to safety belts because they distribute the
shock from the safety line. Some harnesses have breakaway
sections to further distribute the shock. Suppliers of harnesses
provide detailed instructions for proper use.
13.6.3.2 Confined Areas. Confined areas such as fuel storage
tanks, boilers, and utility tunnels present the following
hazards:
a)
Buildup of flammable or explosive atmospheres or
b)
Buildup of toxic atmospheres or materials
c)
Insufficient oxygen to support life
materials
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d)
Excess oxygen posing fire or explosion hazard
Confined areas being cleaned or painted should be well
ventilated to prevent the accumulation of toxic or combustible
airborne contaminants. Mechanical equipment should be grounded,
along with conductive substrates being cleaned or coated, to
prevent sparking. Otherwise, an explosion may occur.
Confined spaces with limited ventilation and access may
have hazards that are not easily detected. They should be
checked for safety requirements before entering. Specific safety
requirements for confined spaces can be found in OSHA Safety and
Health Standards (29 CFR 1910) Paragraph 146 (Permit Required
Confined Spaces). Paints with “safety solvents” (relatively high
flash points) should be used in these areas. Hand and power
tools and other electrical equipment including lighting should be
non-sparking and explosion-proof. Because paint solvent vapors
are heavier than air, ventilation of confined spaces requires
exit of contaminated air from the lowest point. Other special
considerations may apply. Installation safety offices generally
provide guidance and support for confined space operations.
13.6.4
Remote Areas. When doing field work at remote
locations, personnel should have a response plan for emergencies.
Access to a telephone and medical treatment should be
established. Knowledge of first aid, especially CPR, for
immediate action is also beneficial.
13.7
Personal Protective Equipment. Hazards in painting
operations can be greatly reduced by use of protective clothing,
respirators, and other personal protective equipment.
13.7.1
Clothing. Protective garments must resist chemical
attack from three different routes of entry:
a)
Permeation - chemical works its way through the
b)
Penetration - entry through physical imperfection
c)
Degradation - properties of material chemically
suit
(damage)
degraded
Selection of the chemical protective clothing must be
based on the chemical, the operation (i.e., need for abrasion
resistance), and the effectiveness of the clothing material as a
barrier against the chemical. Contaminated clothing should be
discarded at the job site or thoroughly cleaned before reuse.
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Personnel exposed to contamination should thoroughly shower and
put on clean clothes before leaving work area. Torn clothing
should not be worn, because it can get caught in machinery or on
structural projections. Trouser cuffs and ties present a similar
problem.
13.7.1.1 Gloves. Gloves come in different lengths and chemical
compositions. The length should provide full protection, and the
material should be resistant to the chemicals and materials with
which it will come into contact. Selection of the right work
glove can protect you from unnecessary injury or contamination.
Commonly used protective gloves include:
a) Disposable gloves - usually lightweight plastic;
protect from mild irritants
b) Fabric gloves - cotton or other fabric; improve
grip; minimal protection from contaminants
c) Rubber gloves - may also be of different plastics;
protection from chemical contamination
d)
Leather gloves - protect from abrasion
e) Metal mesh gloves - protect from cuts/scratches;
used with cutting tools
f)
Aluminized gloves - insulates hands from intense
heat
13.7.2
Protective Headgear. Head injuries can be very
devastating and can result in brain damage or death. Selection
of the proper head protection for different hazards is especially
important. Protective headgear includes:
a)
Hard hats
b)
Bump hats
c)
Hair covers
13.7.2.1 Hard Hats. Hard hats are made of rigid, impactresistant, nonflammable materials such as fiberglass or
thermoplastics. A network of straps and harnesses holds the
shell on the head and serves as a cushion. A full-brimmed hard
hat provides general protection to the head, neck, and shoulders,
192
MIL-HDBK-1110
while the visored brim which does not, is often used in confined
spaces. Hard hats must be worn in areas designated to require
them.
13.7.2.2 Bump Hats. Bump hats are made of lightweight plastic
that only protect the head from minor bumps. They should be worn
only where there are minor head hazards and never as a substitute
for a hard hat.
13.7.2.3 Hair Covers. Hair covers are made of breathable fabric
or lightweight materials and are adjustable to fit properly.
They are intended to prevent hair from becoming caught in moving
machine parts.
13.7.3
Eye Protection. Installation safety offices have eye
protection equipment available in many forms to protect eyes from
flying particles, dust, sparks, splashes, and harmful rays. The
appropriate type of eye protection should be used for each job.
13.7.3.1 Safety Glasses. Safety glasses have impact-resistant
frames and lenses that meet OSHA and American National Standards
Institute (ANSI) standards. Safety glasses may also have side
shields, cups, or tinted lens to provide additional protection.
Assistance in procuring safety glasses with prescription lenses
may be available at the safety office. Safety glasses should be
cleaned as described by the supplier and stored in a clean, dry
place available for use when needed.
13.7.3.2 Safety Goggles. Safety goggles may be impact
resistant, or provide chemical splash protection or optical
radiation protection. The appropriate goggle should be procured
and used for that purpose only. Goggles form a secure seal
around each eye to provide protection from all sides. They may
have direct or indirect ventilation to eliminate fogging.
13.7.3.3 Safety Shields. Safety shields or helmets have sheets
of clear, resistant plastic to protect the face from splash or
flying particles during grinding and welding operations or when
working with molten materials. Safety shields are ordinarily
worn with goggles or safety glasses to provide additional
protection.
13.7.4
Hearing Protection. Hearing loss occurs over time from
repeated exposure to excessively loud noises. Muffs, plugs, and
canal caps offer a variety of devices to protect our hearing.
Check the noise reduction rating (NRR) provided with each device
to determine its noise protection capabilities.
193
MIL-HDBK-1110
13.7.4.1 Ear Muffs. Ear muffs come in a variety of styles.
Most have spring-loaded head bands to secure them in place
covering the entire ear. Ear muffs can reduce noise levels by 15
to 30 decibels.
13.7.4.2 Ear Plugs. Ear plugs of deformable rubber or plastic
materials are positioned in the outer part of the ear. Ear plugs
may be disposable or reusable. The latter should be cleaned and
properly stored after use.
13.7.4.3 Canal Caps. Canal caps (headband plugs) close off the
ear canal at its opening. A flexible headband ensures a close
fit. Canal caps must also be cleaned and properly stored after
use.
13.7.5
Safety Shoes. About 12,000 accidental foot injuries
occur each year. Steel-reinforced shoes are designed to protect
feet from common machine accidents - falling or rolling objects,
cuts, and punctures. The entire toe box and insole are
ordinarily reinforced.
Safety boots offer more protection from splash.
Neoprene or nitrile boots are often required when handling
caustics, solvents, or oils. Quick-release fasteners may permit
speedy removal in case a hazardous substance gets in the boot.
Slip-resistant soles are required for both shoes and boots, if a
slip hazard is present.
13.7.6
Respirators/Ventilation. Respiratory hazards can be
minimized by a good ventilation system. Note that respiratory
protection is considered a secondary line of defense to protect
the worker when ventilation cannot control exposures.
a) Further protection can be provided by one of the
following types of respirator:
(1) Disposable dust masks/filters (fiber masks
over nose and mouth filter particulates)
(2) Half masks - fits over nose and mouth;
cartridges absorb or trap the contaminate; select the appropriate
cartridge for the particulate (dust) or vapor
(3) Full face mask (they also protect eyes and
face; vapors absorbed by canisters or cartridges; may also have
dust filter)
194
MIL-HDBK-1110
(4) Air-supplied respirators (air from line or
self-contained; positive air pressure in helmet or mask; provides
greatest protection)
b) Personnel using respirators must do the following
for full protection from respiratory hazards:
(1)
Receive medical examination before wearing
(2)
Receive knowledge of respiratory hazard
(3)
Receive proper respirator training
(4)
Get proper respirator fitting and testing
(5)
Keep the respirator clean and properly stored
(6)
Use the right respirator/cartridge for the job
(7)
Receive periodic medical monitoring
respirator
13.8
Safety Program. A safety program should be a vital part
of every shop conducting cleaning or painting operations. Each
routine operation should have a standard operating procedure that
includes a safety plan. Each non-routine operation should have a
special operating plan that includes safety. Each worker should
receive periodic training to keep him aware of pertinent
Government regulations, potential health hazards, and measures
that may be taken to minimize the hazards.
195
MIL-HDBK-1110
REFERENCES
NOTE: THE FOLLOWING REFERENCED DOCUMENTS FORM A PART OF THIS
HANDBOOK TO THE EXTENT SPECIFIED HEREIN. USERS OF THIS HANDBOOK
SHOULD REFER TO THE LATEST REVISIONS OF THE CITED DOCUMENTS
UNLESS OTHERWISE DIRECTED.
FEDERAL/MILITARY SPECIFICATIONS, STANDARDS, HANDBOOKS, AND GUIDE
SPECIFICATIONS:
Unless otherwise indicated, copies are available from the Naval
Printing Service Detachment Office, Building 4D (Customer
Service), 700 Robbins Avenue, Philadelphia, PA 19111-5094.
P-PUBLICATION
P-309
Colors for Navy Shore Facilities.
MILITARY HANDBOOK
MIL-HDBK-1004/10
Electrical Engineering Cathodic
Protection.
MILITARY SPECIFICATIONS
MIL-B-131
Barrier Materials, Water Vaporproof,
Greaseproof, Flexible, Heat-Sealable.
MIL-A-22262
Abrasive Blasting Media, Ship Hull Blast
Cleaning.
MIL-P-24441
Paint, Epoxy-polyamide.
MIL-E-24635
Enamel, Silicone Alkyd Copolymer
(Metric).
MIL-P-24647
Paint System, Anticorrosive and
Antifouling, Ship Hull.
MIL-P-24648
Primer Coating, Zinc Dust Pigmented for
Exterior Steel Surfaces (Metric).
MIL-E-24763
Enamel, Emulsion Type, for Shipboard
Use.
MIL-P-28577
Primer, Waterborne, Acrylic or Modified
Acrylic, for Metal Surfaces.
196
MIL-HDBK-1110
MIL-P-28578
Paint, Waterborne, Acrylic or Modified
Acrylic, Semigloss, for Metal Surfaces.
MIL-P-28582
Primer Coating, Exterior, Lead PigmentFree (Undercoat for Wood, Ready-Mixed,
White and Tints)
MIL-E-29245
Epoxy Resin Systems for Concrete Repair.
MIL-P-53022
Primer, Epoxy Coating, Corrosion
Inhibiting, Lead and Chromate Free.
MIL-C-85285
Coating:
MIL-P-85582
Waterborne Epoxy Primer With 340 Grams
per Liter Maximum VOC Content.
Polyurethane, High-Solids.
MILITARY STANDARD
DOD-STD-2138(SH)
Metal Spray Coatings for Corrosion
Protection Aboard Naval Surface Ships
(Metric).
Lead-Based Paint (LBP) - Risk Assessment, Associated Health
Risk in Children and Control of Hazards in DOD Housing and
Related Structures.
FEDERAL SPECIFICATIONS
TT-B-1325
Beads (Glass Spheres) Retro-Reflective.
TT-C-555
Coating, Textured (for Interior and
Exterior Masonry Surfaces).
TT-E-489
Enamel, Alkyd, Gloss, Low VOC Content.
TT-E-2784
Enamel (Acrylic-Emulsion, Exterior Gloss
and Semigloss).
TT-P-19
Paint, Latex (Acrylic Emulsion, Exterior
Wood and Masonry).
TT-P-25
Primer Coating, Exterior (Low VOC
Undercoat for Wood, White and Tints).
TT-P-28
Paint, Aluminum, Heat Resisting (1200
Degrees F).
TT-P-29
Paint, Latex.
197
MIL-HDBK-1110
TT-P-31
Paint, Oil: Iron-Oxide, Ready-Mixed,
Red and Brown.
TT-P-85
Paint, Traffic and Airfield Marking,
Solvent Base.
TT-P-87
Paint: Traffic, Premixed,
Reflectorized.
TT-P-95
Paint, Rubber: For Swimming Pools and
Other Concrete and Masonry Surfaces.
TT-P-102
Paint, Oil (Alkyd Modified, Exterior,
Low VOC).
TT-P-110
Paint, Traffic, Black
(Nonreflectorized).
TT-P-115
Paint, Traffic (Highway, White and
Yellow).
TT-P-645
Primer, Paint, Zinc-Molybdate, Alkyd
Type.
TT-P-650
Primer Coating, Latex Base, Interior,
White (for Gypsum Wallboard, or
Plaster).
TT-P-664
Primer Coating, Alkyd, CorrosionInhibiting, Lead and Chromate Free,
VOC-Compliant.
TT-P-1510
Paint, Latex, Exterior, for Wood
Surfaces, White and Tints.
TT-P-1511
Paint, Latex (Gloss and Semigloss, Tints
and White) (for Interior Use).
TT-P-1728
Paint, Latex Base, Interior, Flat, DeepTone.
TT-P-1952
Paint, Traffic and Airfield Marking,
Water Emulsion Base.
TT-P-001984
Primer Coating, Latex Base, Exterior
(Undercoat for Wood), White and Tints.
198
MIL-HDBK-1110
TT-P-002119
Paint, Latex-Base, High-Traffic Area,
Flat and Eggshell Finish (Low Lustre)
(for Interior Use).
TT-S-001992
Stain, Latex, Exterior for Wood
Surfaces.
FEDERAL STANDARDS
FED-STD-141
Paint, Varnish, Lacquer, and Related
Materials: Methods of Inspection,
Sampling, and Testing.
Method 3011.2, Condition in Container
Method 6271.2, Mildew Resistance.
FED-STD-595
Colors Used in Government Procurement.
COMMERCIAL ITEM DESCRIPTIONS
A-A-50542
Coating System: Reflective, SlipResistant, Chemical-Resistant Urethane
for Maintenance Facility Floors.
NAVFAC GUIDE SPECIFICATIONS
NFGS-02761
Pavement Markings.
NFGS-02821
Chain Link Fences and Gates.
NFGS-09900
Paints and Coatings.
NFGS-09967
Coating of Steel Waterfront Structures.
NFGS-09970
Interior Coatings for Welded Steel Tanks
(for Petroleum Fuels).
NFGS-09971
Exterior Coating System for Welded Steel
Petroleum Storage Tanks.
NFGS-09973
Interior Coating System for Welded Steel
Petroleum Storage Tanks.
NFGS-09980
Interior Linings for Concrete Storage
Tanks (for Petroleum Fuels).
NFGS-13112
Cathodic Protection System (Steel Water
Tanks).
199
MIL-HDBK-1110
NFGS-13217
Fiberglass-Plastic Lining for Steel Tank
Bottoms (for Petroleum).
NFGS-13219
Cleaning Petroleum Storage Tanks.
NFGS-13283
Removal and Disposal of Lead-Containing
Paint.
OTHER GOVERNMENT PUBLICATIONS:
ARMY CORPS OF ENGINEERS GUIDE SPECIFICATIONS
CEGS 02090
Removal of Lead-Based Paint.
CEGS 02580
Joint Sealing in Concrete Pavements for
Roads and Airfields.
CEGS 02831
Fence, Chain Link.
CEGS 09900
Painting, General.
CWGS 09940
Painting: Hydraulic Structures and
Appurtenant Works.
CEGS 16641
Cathodic Protection System (Steel Water
Tanks).
CWGS 16643
Cathodic Protection Systems (Impressed
Current) for Lock Miter Gates.
ARMY TECHNICAL MANUAL
TM 5-807-7
Color for Buildings.
(Unless otherwise indicated, copies are available from the Naval
Printing Service Detachment Office, Building 4D (Customer
Service), 700 Robbins Avenue, Philadelphia, PA 19111-5094.
CENTER FOR DISEASE CONTRL (CDC)
Strategic Plan for Elimination of Childhood Lead Poisoning
1991 Strategic Plan.
(Unless otherwise indicated, copies are available from the Center
for Disease Control (CDC), 4770 Buford Highway N.E., Mail Stop
F-42, Room 1160, Atlanta, GA 30341-3724.)
200
MIL-HDBK-1110
DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT (HUD)
Lead-Based Paint: Interim Guidelines for Hazard
Identification and Abatement in Public and Indian
Housing.
(Unless otherwise indicated, copies are available from
ENVIRONMENTAL PROTECTION AGENCY (EPA)
40 CFR 50-99
EPA National Ambient Air Quality
Standards.
40 CFR 60
Method 24, Test Measuring VOC Content in
Coatings—Appendix A.
40 CFR 240-280
40 CFR 261
EPA Toxic Characteristic Leaching
Procedure (TCLP)—Appendix II.
(Unless otherwise indicated, copies are available from the
Environmental Protection Agency (EPA), Public Affairs Office,
Rockville, MD 20852; or the Superintendent of Documents, U.S.
Government Printing Office, Washington, DC 20402.)
FEDERAL AVIATION ADMINISTRATION (FAA)
AC 70/7460-1G
(Unless otherwise indicated, copies are available from the
Department of Transportation, FAA Aeronautical Center, AAC-492,
P.O. Box 25082, Oklahoma City, OK 73125-5082.)
NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY (NIST)
Standard Reference Material No. 1358, Certified Coating
Thickness Calibration Standard.
(Unless otherwise indicated, copies are available from National
Institute of Standards and Technology (NIST), Chief, Office of
Standards Code and Information, Admin. Building 101, Room A629,
Gaithersburg, MD 20879.)
OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA)
29 CFR 1910.25
Portable Wood Ladders.
29 CFR 1910.26
Portable Metal Ladders.
201
MIL-HDBK-1110
29 CFR 1910.28
Safety Requirements for Scaffolding.
29 CFR 1910.29
Manually Propelled Ladder Stands and
Scaffolds (Towers).
29 CFR 1910.106/
29 CFR 1926.152
Flammable and Combustible Liquids.
29 CFR 1910. 146
Permit-Required Confined Spaces.
29 CFR 1910.151
Medical Services and First Aid.
29 CFR 1910. 1200/
29 CFR 1926.59
Hazard Communication.
29 CFR 1926.62
(Unless otherwise indicated, copies are available from the
Superintendent of Documents, U.S. Government Printing Office,
Washington, DC 20402.)
NON-GOVERNMENT PUBLICATIONS:
AMERICAN CONFERENCE OF GOVERNMENTAL INDUSTRIAL HYGIENISTS (ACGIH)
Threshold Limit Values for Chemical Substances and Physical
Agents in the Workroom Environment.
(Unless otherwise indicated, copies are available from the
American Conference of Governmental Industrial Hygienists
(ACGIH),
AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)
ASTM D 522
Mandrel Bend Test of Attached Organic
Coatings.
ASTM D 523
Specular Gloss.
ASTM D 823
Producing Films of Uniform Thickness of
Paint, Varnish, and Related Products on
Test Panels.
ASTM D 1186
Nondestructive Measurement of Dry Film
Thickness of Nonmagnetic Coatings
Applied to a Ferrous Base.
ASTM D 1212
Measurement of Wet Film Thickness of
Organic Coatings.
202
MIL-HDBK-1110
ASTM D 1400
Nondestructive Measurement of Dry Film
Thickness of Nonconductive Coatings
Applied to a Nonferrous Metal Base.
ASTM D 1475
Density of Paint, Varnish, Lacquer, and
Related Products.
ASTM D 2369
Volatile Content of Coatings.
ASTM D 2621
Infrared Identification of Vehicle
Solids From Solvent-Reducible Paints.
ASTM D 3273
Resistance to Growth of Mold on the
Surface of Interior Coatings in an
Environmental Chamber.
ASTM D 3274
Evaluating Degree of Surface
Disfigurement of Paint Films by
Microbial (Fungal or Algal) Growth or
Soil and Dirt Accumulation.
ASTM D 3359
Measuring Adhesion by Tape Test.
ASTM D 3363
Film Hardness by Pencil Test.
ASTM D 4128
Identification of Organic Compounds in
Water by Combined Gas Chromatography and
Electron Impact Mass Spectrometry.
ASTM D 4214
Evaluating Degree of Chalking of
Exterior Paint Films.
ASTM D 4258
Surface Cleaning Concrete for Coating.
ASTM D 4259
Abrading Concrete.
ASTM D 4260
Acid Etching Concrete.
ASTM D 4261
Surface Cleaning Concrete Unit Masonry
for Coating.
ASTM D 4262
pH of Chemically Cleaned or Etched
Concrete Surfaces.
ASTM D 4263
Indicating Moisture in Concrete by the
Plastic Sheet Method.
ASTM D 4285
Indicating Oil or Water in Compressed
Air.
203
MIL-HDBK-1110
ASTM D 4414
Wet Film Thickness by Notch Gages.
ASTM D 4541
Pull-Off Strength of Coatings Using
Portable Adhesion Testers.
ASTM D 4840
Sampling Chain of Custody Procedures.
ASTM D 4940
Conductimetric Analysis of Water
Soluble Ionic Contamination of Blasting
Abrasives.
ASTM D 5043
Field Identification of Coatings.
ASTM E 667
Clinical Thermometers (Maximum SelfRegistering, Mercury-in-Glass).
ASTM F 1130
Inspecting the Coating System of a
Ship.
(Unless otherwise indicated, copies are available from the
American Society for Testing and Materials (ASTM), 1916 Race
Street, Philadelphia, PA 19103.)
MAPLE FLOORING MANUFACTURERS ASSOCIATION (MFMA)
Heavy Duty and Gymnasium Finishes for Maple, Beech, and
Birch Floors.
(Unless otherwise indicated, copies are available from the Maple
Flooring Manufacturers Association (MFMA), 60 Revere Drive, Suite
500, Northbrook, IL 60062.)
NATIONAL ASSOCIATION OF CORROSION ENGINEERS (NACE)
NACE No. 1
White Metal Blast.
NACE No. 2
Near-White Blast.
NACE No. 3
Commercial Blast.
NACE No. 4
Brush-Off Blast.
NACE RP0188
Standard Recommended Practice,
Discontinuity (Holiday) Testing of
Protective Coatings.
NACE TM0170
Visual Standard for Surfaces of New
Steel Air Blast Cleaned With Sand
Abrasive.
204
MIL-HDBK-1110
NACE TM0175
Visual Standard for Surfaces of New
Steel Centrifugally Blast Cleaned
With Steel Grit and Shot.
(Unless otherwise indicated, copies are available from the
National Association of Corrosion Engineers, P.O. Box 218340,
Houston, TX 77218.)
NATIONAL SANITATION FOUNDATION (NSF) INTERNATIONAL
NSF 60
Drinking Water Treatment Chemicals Health Effects.
NSF 61
Drinking Water System Components Health Effects.
(Unless otherwise indicated, copies are available from National
Sanitation Foundation (NSF) International, 3475 Plymouth Road,
P.O. Box 1468, Ann Arbor, MI 48106.)
SOCIETY FOR NAVAL ARCHITECTS AND ENGINEERS
Abrasive Blasting Guide for Aged or Coated Steel Structures.
STEEL STRUCTURES PAINTING COUNCIL (SSPC)
Steel Structures Painting Manual, Volume 2, Systems and
Specifications.
SSPC Guide 6I (CON)
Containment of Lead-Based Paints.
SSPC Guide 7I (DIS)
Disposal of Lead-Contaminated Surface
Preparation Debris.
SSPC Guide 23
Coating Systems.
SSPC AB 1
Mineral and Slag Abrasives.
SSPC PA 1
Shop, Field, and Maintenance Painting.
SSPC PA 2
Measurement of Dry Paint Thickness With
Magnetic Gages.
SSPC PA 3
Safety in Paint Application.
SSPC PAINT 16
Coal Tar Epoxy-Polyamide Black (or Dark
Red).
SSPC PAINT 24
Latex Semi-gloss Exterior Topcoat.
205
MIL-HDBK-1110
SSPC PAINT 25
Red Iron Oxide, Zinc Oxide, Raw Linseed
Oil and Alkyd Primer.
SSPC QP 2
Evaluating the Qualifications of
Painting Contractors to Remove Hazardous
Paint.
SSPC SP 1
Solvent Cleaning.
SSPC SP 2
Hand Tool Cleaning.
SSPC SP 3
Power Tool Cleaning.
SSPC SP 5
White Metal Blast Cleaning.
SSPC SP 6
Commercial Blast Cleaning.
SSPC SP 7
Brush-off Blast Cleaning.
SSPC SP 8
Pickling.
SSPC SP 10
Near-White Blast Cleaning.
SSPC SP 11
Power Tool Cleaning to Bare Metal.
SSPC SP COM
Surface Preparation Commentary.
SSPC VIS 1
Abrasive Blast Cleaned Steel (Standard
Reference Photographs).
SSPC VIS 3
Power- and Hand-Tool Cleaned Steel.
(Unless otherwise indicated, copies are available from the Steel
Structures Painting Council (SSPC), 4516 Henry Street, Suite 301,
Pittsburgh, PA 15213-3728.)
206
MIL-HDBK-1110
GLOSSARY
Painting operations often use terms that are peculiar to this
field and, as such, may require some explanation or definition.
This glossary is designed to provide the reader with some basic
understanding of terms commonly used in painting and thus,
eliminate possible misunderstandings resulting from conflicting
interpretations of terms and improve communication between
persons involved in the painting operation.
Abrasion.
Act of being worn away.
Abrasive. Material used for abrasive blast cleaning; for
example, sand, grit, steel shot, etc.
Absorption. Process of soaking up, or assimilation of one
substance by another.
Accelerator. Catalyst; a chemical material which accelerates the
hardening of certain coatings.
Acetone.
A fast evaporating, highly flammable organic solvent.
ACGIH. American Conference of Governmental Industrial
Hygienists.
Acoustic Paint.
Paint which absorbs or deadens sound.
Acrylic Resin. A clear resin derived from polymerized esters of
acrylic acids and methacrylic acid, often used in water-based
paints, e.g., TT-P-l9.
Activator.
Catalyst or curing agent; accelerator.
Adhesion. Bonding strength; adherence of coating to the surface
to which it is applied.
Agglomeration.
not dispersed.
Air Bubble.
Air Cap.
Formation of masses or aggregates of pigments;
Bubble in paint film caused by entrapped air.
Housing for atomizing air at head of spray gun.
Airless Spraying.
paint.
Spraying using hydraulic pressure to atomize
Air Manifold. Device that allows common air supply chamber to
supply several lines.
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MIL-HDBK-1110
Air Quality Control Regions. Geographical units of the country,
as required by U.S. law reflecting common air pollution problems,
for purpose of reaching national air quality standards, for
example California’s South Coast Air Quality District.
Alcohols. Flammable solvents; alcohols commonly used in painting
are ethyl alcohol (ethanol) and methyl alcohol (methanol, wood
alcohol).
Aliphatic Polyurethane.
ultraviolet light.
Aliphatic Solvent.
spirits.
Type of polyurethane resin resistant to
Weak organic solvent, such as mineral
Alkali. Caustic, strong base, high pH, such as sodium hydroxide,
lye, etc.
Alkyd Resins. Resins prepared from polyhydric alcohols and
polybasic acids.
Alligatoring. Surface imperfections of paint having the
appearance of alligator hide.
Ambient Temperature.
American Gallon.
Temperature or temperature of surroundings.
231 cubic inches, 3.8 liters.
Amides.
Possible curing agent for epoxy resins.
Amines.
Possible curing agent for epoxy resins.
Anchor Pattern.
by blasting.
Anhydrous.
ANSI.
Profile or texture of surface, usually attained
Dry, free of water in any form.
American National Standards Institute.
Antifouling Coating. Coating with toxic material to prevent
attachment and growth of marine fouling organisms.
Arcing. Swinging spray gun or blasting nozzle in arc at
different distances from substrate.
Aromatic. Type of polyurethane with good chemical resistance but
poor urethane ultraviolet resistance.
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MIL-HDBK-1110
Aromatic Solvents. Strong organic solvents, such as benzene,
toluene, and xylene.
Asphalt. Residue from petroleum refining; also a natural complex
hydrocarbon.
ASTM.
American Society for Testing and Materials.
Atomize.
Break steam of liquid into small droplets.
Baking Finish. Paint product requiring heat cure, e.g., as used
on factory coated metal siding.
Barrier Coating. Coating that protects by shielding substrate
from the environment.
Batch. Industrial unit or quantity of production used in one
complete operation.
Binder. Resin; non-volatile vehicle; film forming portion of
paint, such as oil, alkyd, latex emulsion, epoxy, etc.
Bituminous Coating.
Coal tar or asphalt based coating.
Blast Angle. Angle of blast nozzle to surface; also angle of
particle propelled from rotating blast cleaning wheel with
reference to surface.
Blast Cleaning.
Bleaching.
Cleaning with propelled abrasives.
Removing color.
Bleeding. Penetration of color from the underlying surface to
surface of existing paint film, e.g., brown color from asphalt
coatings.
Blisters. Bubbles in film, areas in which film has lost adhesion
to substrate.
Blocking. Undesirable sticking together of two painted surfaces
when pressed together under normal conditions.
Blooming.
blushing.
Whitening of surface of paint film; moisture blush;
Blow-back (Spray Term).
sprayed droplets.
Term relating to rebounding of atomized
209
MIL-HDBK-1110
Blushing. Whitening and loss of gloss of paint film due to
moisture or improper solvent balance.
Body.
Consistency; to thicken.
Bonding.
Adhesion.
Bounce-back.
back.
Rebound of paint spray particles, similar to blow-
Boxing. Mixing of paint by pouring back and forth from one
container to another.
Bridging. Forming a skin over a depression, crack, inside
corner, etc.
Broadcast.
To sprinkle solid particles on a surface.
Brush-off Blast. Degree of blast cleaning in which surface is
free of visible oil, grease, dirt, dust, loose mill scale, loose
rust, and loose paint; SSPC SP 7, NACE No. 4, Brush-off Blast.
Bubbling. A term used to describe the formation of blisters on
the surface while a coating is being applied.
Burnish.
Caking.
To polish or rub to a smoother or glossier surface.
Hard settling of pigment from paint.
Catalyst.
Accelerator; curing agent; promoter.
CCB.
Construction Criteria Base.
CDC.
Center for Disease Control.
Cellosolve. Proprietary name for the monoethyl ether of ethylene
glycol, used as a solvent in paints.
CEGS.
Corps of Engineers Guide Specification.
CERL.
Construction Engineering Research Laboratory.
CFR.
Code of Federal Regulations.
Chalking.
Powdering of surface of paint film.
Checking. Formation of slight breaks in the topcoat that do not
penetrate to the underlying paint films.
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Chlorinated. Type of resin used as a paint binder that cures by
solvent rubber evaporation.
CID.
Commercial item description.
Coal Tar-Epoxy Paint. Paint in which binder or vehicle is a
combination of coal tar with epoxy resin.
Coatings.
Surface coverings; paints; barriers.
Cobwebbing. A spider web effect on surface of film caused by
premature drying of sprayed paint.
Cohesion.
Property of holding self together.
Cold-checking.
Color-fast.
Checking of film caused by low temperatures.
Non-fading.
Color Retention.
Ability to retain original color.
Commercial Blast. Degree of blast cleaning in which surface is
free of visible oil, grease, dirt, dust, loose mill scale, loose
rust, and loose paint; SSPC SP 6, NACE No. 2, Commercial Blast.
Compatibility. Ability to mix with or adhere properly to other
component or substances.
Continuity.
Degree of being intact or pore-free.
Conversion Coating. System used to convert rusted surface to one
that is paintable without abrasive or mechanical cleaning.
Conversion Treatment. Treatment of metal surface to convert it
to another coating chemical form, e.g., a phosphate on steel.
Copolymer. Large molecule resulting from simultaneous
polymerization of different monomers.
Corrosion. Oxidation of material; deterioration due to
interaction with environment.
CPVC.
CQC.
Critical pigment volume concentration.
Contractor quality control.
Cracking. Splitting, disintegration of paint by breaks through
film to substrate.
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MIL-HDBK-1110
Cratering. Formation of holes or deep depressions in paint film
as paint film dries.
Crawling. Shrinking of paint to form uneven surface shortly
after application.
Crazing or Cracking. Development of non-uniform surface
appearance of myriad tiny scales as a result of weathering.
Cross-linking.
form films.
Cross-spray.
angles.
CSI.
A particular method by which molecules unite to
Spraying first in one direction and then at right
Construction Specification Institute.
Curing.
Setting-up or hardening of paint film.
Curing Agent.
Curtaining.
Hardener; promoter.
A kind of sagging or running of paint when applied.
Deadman Valve. Valve at blast nozzle for starting and automatic
shutoff of abrasive flow.
Degreaser. Chemical (i.e., solvent or detergent solution) for
grease and oil removal.
Delamination. Separation and peeling of one or more layers of
paint from underlying substrate.
Density.
Weight per unit volume.
Descaler.
Tool used to remove heavy scale.
Detergent.
Cleaning agent.
Dew Point.
Temperature at which moisture condenses.
DFT.
Dry film thickness.
Diluents.
Dispersion.
Thinners; reducer.
Suspension of one substance in another.
Distillation. Purification or separation by liquid
volatilization and condensation.
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MIL-HDBK-1110
Doctor Blade.
thickness.
Knife applicator for applying paint of fixed film
Drawdown. Preparation of a paint film of a fixed uniform
thickness using a doctor blade.
Drier. Chemical which promotes oxidation or drying of paint,
particularly those made with oils.
Dry Film. Thickness of applied coating when dry, thickness
usually expressed in mils (1/1000 inch).
Dry Spray. Overspray or bounce-back; sandy or pebbly finish due
to spray particle being partially dried before reaching the
surface.
Drying Oil.
An oil which hardens in air.
Drying Time. Time interval between application and a specified
condition of dryness.
Dry to Recoat. Time interval between application and ability to
receive next coat satisfactorily.
Dry to Touch. Time interval between application and ability to
be touched lightly without damage (tack-free time).
DTM.
Direct to metal coating (self-priming).
Dulling.
Loss of gloss or sheen.
Efflorescence. Powdery white to gray soluble salts deposited on
surface of brick and other masonry.
Eggshell. Paint having gloss between semi-gloss and flat; paint
having high sheen.
Elasticity.
Degree of recovery from stretching.
Electrostatic Spray. Spraying with electrically charged paint
and substrate to attract paint to surface.
Emulsion Paint. Water-thinned paint with resin or latex vehicle
dispersed in water.
Enamel. A paint which is characterized by an ability to form an
especially smooth and usually glossy film.
EPA.
Environmental Protection Agency.
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Epoxy Resins. A type of resin; film formers usually made from
bisphenol A and epichlorohydrin.
Erosion. Wearing away of paint films to expose the substrate or
undercoat.
Etch.
Surface preparation of metal by chemical means.
Evaporation Rate.
Rate at which a solvent evaporates.
Explosive Limits. A range of the ratio of solvent vapor to air
in which the mixture will explode if ignited. Below the lower or
above the higher explosive limit, the mixture is too lean or too
rich to explode. The critical ratio runs from about 1 to 12
percent of solvent vapor by volume at atmospheric pressure.
Extender Pigment. Pigment which can contribute specific
properties to paint, generally low in cost.
External Mix Nozzle. Spray nozzle in which the paint and air are
mixed outside the gun.
FAA.
Federal Aviation Administration.
Fading. Reduction in brightness of color or change in color of
paint film as a result of weathering.
Fan Pattern.
Geometry or shape of spray pattern.
Feathered Edge.
Tapered edge.
Feathering. (1) triggering a gun at the end of each stroke; (2)
tapering edge of paint film adjacent to peeled area.
Ferrous.
Iron.
Field Painting.
Filler.
Painting at the job site.
Extender; building agent for paint; inert pigment.
Film Build.
Thickness of one coat of paint.
Film-former. Paint component that cures to form a dry film;
binder; resin.
Film Integrity.
Degree of continuity of film.
Film Thickness Gage. Device used for measuring film thickness;
both wet and dry gages are available.
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MIL-HDBK-1110
Filter.
Strainer; purifier.
Fineness of Grind (Dispersion). Measure of pigment size or
roughness of liquid paint; degree of dispersion of pigment in the
binder.
Fire-Retardant Paint.
heating of substrate.
Paint which will delay flaming or over-
Fish Eye. Pulling apart of paint film similar to cratering to
form holes.
Flaking. Disintegration of dry film into small pieces or flakes;
see scaling.
Flammability.
Measure of ease of catching fire; ability to burn.
Flash Point. The lowest temperature at which a given flammable
material will flash if a flame or spark is present.
Flash Rusting. Rusting of steel after cleaning, particularly in
humid environments or after wet blasting.
Flatting.
Loss of gloss in coating film.
Flexibility.
Elongation; ability to bend without damage.
Floating.
Separation of pigment colors on surface of paint film.
Flooding.
paint.
Floating; separation of pigment colors on surface of
Flow.
A property of self-leveling.
Fog Coat.
FTIR.
Thin or mist coat (about 1/2 mil dry film thickness).
Fourier transform infrared.
Fungicide.
Mildewcide; toxic chemical to control fungal growth.
Galvanized Steel. Zinc-coated steel, usually by dipping in a
bath of molten zinc.
Generic. Basic class or type; generic type of paint is denoted
by the type of resin present.
Gloss.
Luster; sheen; brightness.
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MIL-HDBK-1110
Graffiti-Resistant Coating.
removed by scrubbing.
Coating from which graffiti can be
Grit. Abrasive from slag and other sources used in blast
cleaning.
Grounding.
GSA.
Dissipation of electric charge.
General Services Administration.
Hardener.
Hazing.
Catalyst; curing agent.
Clouded appearance.
Hegman Number. Measure of fineness of grind or dispersion of
pigment into the vehicle.
Hiding Power.
surface.
Ability of paint film to obscure underlying
High Build Coating. Coating that can be applied so as to obtain
a thick film in one coating application.
Hold out. Ability to prevent nonuniform soaking into the
substrate resulting in a nonuniform appearing film.
Holiday.
HUD.
HVLP.
Pinhole, skip, or other discontinuity in paint film.
Department of Housing and Urban Development.
High-volume, low-pressure.
Humidity. Measure of moisture content; relative humidity is the
ratio of the quantity of water vapor in the air compared to the
greatest amount possible at a given temperature. Saturated air
has a humidity of 100 percent.
Hydroblasting. Water blasting; cleaning a surface with water at
extremely high pressures.
Hydrolysis. Chemical reaction in which a compound, such as an
oil resin, is split into two parts by reaction with water; see
saponify.
Impermeable.
substance.
Restricting the passage of moisture, air or other
216
MIL-HDBK-1110
Incompatibility. Inability of a coating to perform well over
another coating because of bleeding, poor bonding, or lifting of
old coating; inability of coating to perform well on a substrate.
Induction Time. Time interval required between mixing of
components and application of two or more component paints to
obtain proper application properties.
Indicator Paper (pH). Vegetable dyed paper indicating relative
acidity or paper basicity (alkalinity).
Inert Pigment.
A non-reactive pigment.
Inhibitive Primer.
process.
Primer pigment that retards the corrosion
Inorganic Silicate or Coating. Those employing inorganic binders
or vehicles such as phosphate rather than organic, that is those
of petroleum, animal, or plant origin.
IPM.
In-place management.
Internal Mix Nozzle. Spray nozzle in which the fluid and air are
combined before leaving gun.
Intumescent Ignition. Fire-retardant coating that forms a
voluminous char on coating.
Ketones. Flammable organic solvents; commonly used ketones are
acetone; methyl ethyl ketone (MEK); and methyl isobutyl ketone
(MIBK).
Krebs Unit (KU).
Arbitrary unit for measuring viscosity.
Lacquers.
Coatings which dry by solvent evaporation.
Laitance.
White to gray deposit on surface of new concrete.
Latex.
LBP.
Natural or synthetic binder for emulsion (water) paints.
Lead-based paint.
Leafing. Orientation of pigment flakes in wet paints in
horizontal planes to increase impermeability of dry film.
Leveling. Flowing of paint to form films of uniform thickness;
tendency of brush marks to disappear.
217
MIL-HDBK-1110
Lifting. Softening and raising of an undercoat by application of
a top coat.
Livering.
Condition of paint in can having curds or gelling.
Low Pressure Spraying.
Mastic.
MEK.
Conventional air spraying.
Heavy-bodied, high build coating.
Methyl ethyl ketone, strong flammable organic solvent.
MFMA.
Maple Flooring Manufacturers Association.
MIBK.
Methyl isobutyl ketone.
Mil.
0.001 inch.
Micron.
Micrometer, 0.001 of a millimeter.
Mildewcide.
Toxic chemical added to paint to control mildew.
Mill Scale. Bluish layer of iron oxide formed on surface of
steel by hot rolling.
Mistcoat. A thin (about 1/2 mil dry film thickness) coat applied
to existing paint for bonding of a subsequently applied coat.
MSDS.
Material safety data sheet, described in Section 13.
Mud Cracking. Irregular cracking of dried paint resembling
cracked mud, usually caused by paint being too thick.
NACE.
National Association of Corrosion Engineers.
Naphtha.
F1ammable aliphatic hydrocarbon (weak) solvent.
Near White Blast. Grade of blast cleaning in which surface is
free of visible oil, grease, dirt, dust, mill scale, rust paint
oxides, corrosion products, and other foreign matter, except for
staining; SSPC SP 10, NACE No. 2, Near-White Blast.
NFGS.
NIOSH.
NIST.
Naval Facilities Engineering Command Guide Specification.
National Institute of Safety and Hygiene.
National Institute of Standards and Technology.
Nonvolatile Vehicle.
paints.
Resin; binder; film-forming component of
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MIL-HDBK-1110
NRR.
Noise reduction rating.
NSF.
National Sanitation Foundation.
Oleoresinous.
oxidation.
Opacity.
Vegetable or fish oil resin that cures by air
Hiding power; ability to obscure underlying surface.
Orange Peel.
an orange.
Hills and valleys in paint resembling the skin of
Organic Coating. Coating with organic binder, generally of
petroleum or vegetable origin.
OSHA.
Occupational Safety and Health Administration.
Overcoat.
Overlap.
Top coat.
Portion (width) of fresh paint covered by next layer.
Overspray.
target.
Paint.
Dry spray, particularly such paint that failed to hit
Coating materials used in painting.
Paint Heater.
Paint Program.
Device for lowering viscosity of paint by heating.
Comprehensive painting plan.
Paint System. Surface preparation, and the complete number and
type of coats comprising a paint job.
Pass (Spray).
Motion of spray gun in one direction.
Peeling. Failure in which paint curls or otherwise strips from
substrate.
Perm. Unit of permeance; grains of water vapor per hour per
square foot per inch of mercury-water vapor pressure difference.
Phosphatize. To form a thin inert phosphate coating on surface
usually by treatment with phosphoric acid or other phosphate
compound.
pH Value. Measure of acidity or alkalinity; pH 7 is neutral; the
pH values of acids are less than 7, and of alkalies (bases),
greater than 7.
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MIL-HDBK-1110
Pickling. A dipping process of cleaning steel and other metals;
the pickling agent is usually an acid; SSPC SP 8.
Pigment.
Solid, opaque, frequently colored component of paint.
Pigment Grind.
Dispersing of pigment in vehicle.
Pigment Overload.
Mottle surface from too much pigmentation.
Pigment Volume Concentration (PVC).
by pigment in wet paint.
Percent by volume occupied
Pitting. Formation of small, deep or shallow cavities formed in
steel by rusting.
Pinholing. Formation of small holes through coating from
improper application.
Plasticizer.
Paint component added to increase flexibility.
Polyvinyl Acetate (PVA).
emulsion (water) paints.
Synthetic resin used extensively in
Polymer. Large molecule formed by reaction of smaller molecules;
used to make synthetic resins.
Pot Life. Time interval after mixing of components during which
the coating can be satisfactorily applied.
Primer or Prime Coat. First coat on a substrate usually
containing inhibitive pigments when formulated for use on metals.
Profile.
steel.
Surface texture, particularly of abrasive blast cleaned
Proprietary.
Psychrometer.
Commercially available under a brand name.
Instrument for measuring humidity.
PVC. Pigment volume concentration; pigment concentration by
volume in the whole paint.
QC.
RCRA.
Quality control.
Resource Conservation and Recovery Act.
Rebound.
Paint spray bounce-back.
220
MIL-HDBK-1110
Reducer. Thinner; solvent added to reduce paint viscosity for
easier application.
Resin. Binder; nonvolatile vehicle; film-forming component of
paints.
Run.
Rust.
Sag; curtain; associated with too heavy a paint film.
Corroded iron; red iron oxide deposited on metal.
Rust Bloom.
Discoloration indicating the beginning of rusting.
Safety Valve. Pressure release valve preset to be released when
pressure exceeds a safe operating limit.
Sag.
Run in coating film; curtain.
Sand Blast. General term used to mean blast cleaning; blast
cleaning using sand as an abrasive.
Sandy Finish. A surface condition having the appearance of
sandpaper; may result from overspray or dry spray.
Saponify. Chemical reaction between some resins (e.g., oil and
alkyds) and alkaline solutions converting resin to soaps.
Saponified paint may become sticky and lose adhesion to
substrate. See also hydrolysis.
Scale. Heavy layer of iron oxide on surface of steel, could be
rust or mill scale; see also mill scale.
Scaling.
Process of removing scale.
Seal Coating. Coating used to prevent excessive absorption of
the first coat of paint by the substrate; a primer.
Sealer. A low viscosity (thin) liquid sometimes applied to wood,
plaster, gypsum board, concrete, or masonry to reduce
permeability.
SEM.
Scanning electron microscope.
Settling.
Caking of paint pigments in wet paint; sediment.
Sheen. Appearance characteristic of dry film in which film
appears flat when viewed at an angle near to perpendicular and
glossy when viewed at an angle near to grazing, such as 85
degrees.
221
MIL-HDBK-1110
Shelf-Life. Maximum interval in which a material may be stored
and still be in usable condition.
Shop Coat.
Coating applied in fabricating shop.
Shot Blasting.
Blast cleaning using steel shot as the abrasive.
Silicate Paints. Those employing silicates as binders; used
primarily in inorganic zinc-rich coatings.
Silicone Resins. A particular group of film formers; used in
water-repellent and high-temperature paints.
Silking. A surface defect characterized by parallel hair-like
striations in dry coating films.
Skinning.
Skips.
Formation of a solid membrane on top of liquid paint.
Holidays; misses; uncoated area; voids.
Sling Psychrometer. Instrument to measure relative humidity
consisting of dry/wet bulb thermometers suitably mounted for
swinging through the air.
Solids By Volume. Percentage of total volume of wet paint
occupied by non-volatile compounds.
Solubility.
Degree to which a substance may be dissolved.
Solution. A liquid in which a substance (solute) is dissolved in
a solvent.
Solvent. A liquid in which another substance may be dissolved;
thin liquid used to add to paint to reduce viscosity.
Solvent Balance. Ratio of amounts of different solvents in a
mixture of solvents.
Solvent Pop.
solvent.
Solvent Wash.
Blistering of paint film caused by entrapped
Cleaning surface to be painted with solvent.
Stalling. The cracking, breaking, or splintering of the surfaces
of substrates, such as cinder block, from the bulk material.
Spreading Rate. Area covered by a unit volume of paint at a
specific thickness.
222
MIL-HDBK-1110
SSPC.
Steel Structures Painting Council.
STEL.
Short-term exposure limit.
TCLP.
Toxic characteristic leaching procedure.
Thermoplastic. Paint softened by heat or solvent (type of onecomponent coating made up of high molecular resins which dry/cure
by solvent evaporation, e.g., vinyls).
Thermosetting. Paint that cures by undergoing a chemical
reaction leading to a relatively insoluble material (e.g.,
epoxies, polyurethanes).
Thinner. Reducer; solvent added to reduce paint viscosity for
easier application.
Thixotropic. Paint of gel consistency in the can that becomes a
liquid paint when stirred or brushed but becomes a gel again upon
standing.
Through Drying. Curing of paint film through the entire
thickness as opposed to curing only on the surface.
Tiecoat. Thin coat applied to a cured paint to enhance the
bonding of a topcoat.
TLV.
Tooth.
Threshold limit value.
Profile; mechanical anchorage; surface roughness.
Top Coat.
Finish coat.
Triggering.
trigger.
TWA.
Intermittent squeezing and releasing of spray gun
Time weighted average.
Ultraviolet Radiation. Portion of sunlight having a shorter
wavelength than visible light.
Undercutting. Blistering and/or peeling of paint from underfilm
corrosion in areas of a paint defect.
Urethane Resins.
Useful Life.
in service.
A particular group of film formers.
The length of time a coating is expected to remain
223
MIL-HDBK-1110
UV.
Ultraviolet.
VM&P Naphtha. Varnish and paint manufacturers naphtha; a low
power flammable hydrocarbon solvent.
Vapor Degreasing. A cleaning process utilizing condensing
solvent as the cleaning agent, usually done in a shop.
Vaporization.
state.
Conversion of material from liquid to a gaseous
Varnish. Liquid composition which converts to a transparent or
translucent solid film after application as a coating.
Vehicle. Liquid portion of paint; binder or resin and solvent
components of paint.
Venturi Nozzle. Blast nozzle with tapered lining for increased
blasting speed and a large, more uniform blast pattern.
Vinyl Coating. One in which the major portion of the binder is
of a vinyl resin.
Viscosity.
VOC.
Consistency; a measure of fluidity.
Volatile organic compound.
Volatiles.
Fluids which evaporate rapidly.
Volatile Content. Amount of materials which evaporate when paint
cures; usually expressed as a percentage.
Volatile Organic Compound (VOC). As defined by California Air
Quality Districts, excluding carbon monoxide, carbon dioxide,
carbonic acid, metallic carbides or carbonates, ammonium
carbonate, methane, l,l,l-trichloroethane, methylene chloride,
and trichlorotrifluoroethane, are compounds which may be emitted
to the atmosphere during the application of and/or subsequent
drying or curing of coatings.
Wash Primer. A thin rust-inhibiting primer with phosphoric acid
and rust inhibitor which provides improved adhesion to subsequent
coats.
Water Blasting.
Weld Spatter.
Wet Edge.
Blast cleaning using high velocity water.
Beads of metal left adjoining a weld.
Fluid boundary.
224
MIL-HDBK-1110
Wet Film Gage.
Device for measuring wet film thickness.
White Metal Blast. Highest degree of cleaning, when surface is
viewed without magnification it is free of visible oil, grease,
dirt, dust, mill scale, rust, paint, oxides, corrosion products,
and other foreign matter; SSPC SP 5, NACE No. 1, White Metal
Blast.
Wrinkling. Rough, crinkled surface, usually related to surface
skinning over uncured paint.
CUSTODIAN
NAVY - YD2
PREPARING ACTIVITY
NAVY - YD2
PROJECT NO.
FACR-1131
225
STANDARDIZATION DOCUMENT IMPROVEMENT PROPOSAL
INSTRUCTIONS
1. The preparing activity must complete blocks 1, 2, 3, and 8. In block 1, both the document number and revision
letter should be given.
2. The submitter of this form must complete blocks 4, 5, 6, and 7.
3. The preparing activity must provide a reply within 30 days from receipt of the form.
NOTE: This form may not be used to request copies of documents, nor to request waivers, or clarification of
requirements on current contracts. Comments submitted on this form do not constitute or imply authorization to waive
any portion of the referenced document(s) or to amend contractual requirements.
I RECOMMEND A CHANGE:
1.
DOCUMENT NUMBER
MIL-HDBK-1110
2.
DOCUMENT DATE (YYMMDD)
3.
DOCUMENT TITLE
4.
NATURE OF CHANGE (identify paragraph number and include proposed rewrite, if possible.
950117
HANDBOOK FOR PAINTS AND PROTECTIVE COATINGS FOR FACILITIES
Attach extra sheets as
needed.)
5.
6.
REASON FOR RECOMMENDATION
SUBMITTER
a.
NAME (Last, First, Middle Initial)
b.
ORGANIZATION
c.
ADDRESS (Include Zip Code)
d.
TELEPHONE (Include Area
Code)
7.
DATE SUBMITTED:
(YYMMDD)
(1)
Commercial
(2)
DSN
(If applicable)
8.
a.
PREPARING ACTIVITY
NAME
Commanding Officer
b.
Northern Division, Naval Facilities Engineering
(1)
TELEPHONE (Include Area Code)
Commercial
(2)
DSN
Command
c.
ADDRESS (Include Zip Code)
ATTN Code 164
10 Industrial Highway, Mail Stop 82
Lester, PA 19113-2090
DD Form 1426, OCT 89
(610) 595-0661
443-0661
IF YOU DO NOT RECEIVE A REPLY WITHIN 45 DAYS,
CONTACT:
Defense Quality and Standardization Office
5203 Leesburg Pike, Suite 1403, Falls
Church, VA
22041-3466
Telephone (703) 756-2340
DSN 289-2340
Previous editions are
198/290
obsolete.
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