SSPC Guide 14

 

SSPC-Guide 14 May 1, 1999

SSPC: The Society for Protective Coatings

GUIDE 14 Guide for the Repair of Imperfections in Galvanized or Inorganic Zinc Coated Steel Using Organic Zinc-Rich Coating 1. Scope

3.4 SSPC AND JOINT STANDARDS:

1.1   This guide describes one method for repairing 1.1  galvanizing or inorganic zinc coating using an organic zincrich coating. ASTM A 780 briefly describes this and other alternative methods (metallizing and zinc-based solders) for repair of damaged and uncoated areas of hot-dip galvanized coatings.

PA 1

1.2   This method is intended to repair imperfections 1.2  resulting from application, welding, cutting, drilling, grinding, abrading, or rough handling during transport or erection. It may also be used to repair imperfections in galvanizing or inorganic zinc coating that have occurred from weathering during storage or after erection.

Paint 5

1.3   This method can also be used to repair topcoated 1.3  galvanizing or inorganic zinc coating.

2. Description 2.1 This method consists of selecting organic zinc-rich coatings and topcoats and preparing and applying the coatings to damaged galvanizing or inorganic zinc coating. 2.2   This method is intended for repairing localized 2.2  imperfections where the major portion of the existing zinc coating is intact. 2.3   Organic zinc-rich coatings are suitable for repair2.3  ing damaged zinc coatings because they combine several favorable properties. They can be readily applied by brush or spray under field conditions to small and irregular shapes and are compatible with both zinc and steel substrates.

PA Guide 3

Paint 20 Paint 29 PS Guide 8 PS Guide 12.00 SP 1 SP 2 SP 3 SP 5/NACE No. 1 SP 6/NACE No. 3 SP 7/NACE No. 4 SP 10/NACE No. 2 SP 11 SP 12/NACE No. 5

SP 14/NACE No. 8

3. References 3.1 The standards listed here are lis ted in Sections 3.4 through 3.7 and form a part of this guide. A standard marked with an asterisk (*) is referenced only in the Notes, which are not requirements of the guide. 3.2 The latest issue, revision, or amendment of the referenced standards in effect on the date of invitation to bid shall govern unless otherwise specified. 3.3  If there is a conflict between the requirements of 3.3 If any of the cited reference standards and the specification, the requirements of the specification shall prevail.

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PA 2

Shop, Field, and Maintenance Painting of Steel Measurement of Dry Coating Thickness wit h Magnet ic Gages A Guide to Safety in Paint Application Zinc Dust, Zinc Oxide, and Phenolic Varnish Paint Zinc-Rich Primers (Type I, Inorganic, and Type II, Organic) Zinc Dust Sacrificial Primer, Performance-Based Guide to Topcoating Zinc-Rich Paints Guide to Zinc-Rich Coating Systems Solvent Cleaning Hand Tool Cleaning Power Tool Cleaning White Metal Blast Cleaning Commercial Blast Cleaning Brush-Off Blast Cleaning Near-White Blast Cleaning Power Tool Cleaning to Bare Metal Surface Preparation and Cleaning of Steel and Other Hard Materials by High and Ultrahigh Pressure Water Jetting Prior to Recoating Industrial Blast Cleaning

3.5 AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) STANDARDS: A 123

Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products A 153 Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware A 780 Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings * D 3 96 0 Practice for Determining Volatile Organic Compound (VOC) Content of Paints and Related Coating* Coating*

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* D 44 57 Test Method for Analysis of Dichloromethane and 1,1,1 - Trichloromethane in Paints and Coatings by Direct Injection into a Gas Chromatograph D 6133 Test Method for Acetone Content of Solvent-Reducible and Water-Reducible Paints, Coatings, Resins and Raw Materials by Direct Injection into a Gas Chromatograph

•

The above levels may be used to specify zinc loading of repair products meeting requirements of SSPC-Paints 5, 20, and 29 and ASTM A 780. The user may specify any percentage of zinc loading (for example 95%) if desired. 4.4 VOLATILE ORGANIC COMPOUND (VOC) CONTENT: The VOC content of a merchantable coating meeti ng the compositional and performance requirements of this specification may vary widely. The specifier should consult applicable government regulations to determine the maximum allowable VOC content and the proper VOC test method for their application. As a part of the purchase

3.6 BAY AREA AIR QUALITY MANAGEMENT DISTRICT (BAAQMD) * M et h o d 4 1 Determination of Volatile Organic Compounds in Solvent-Based Coatings and Related Material Containing Parachlorobenzotrifluoride

4.5 TOPCOAT SELECTION: If SELECTION: If a topcoat is to be applied over the zinc-rich primer, select the topcoat in accordance with SSPC-PS Guide 8. (See Note 7.3.)

3.7 CALIFORNIA AIR RESOURCES BOARD (CARB): * Method 310 Test Method for Antiperspirants and Deodorants, Consumer Products, and Aerosol Coating Products

5. Procedures 5.1 SURFACE PREPARATION: 5.1.1 Visually identify damaged areas based on deterioration of the zinc, rusting of steel substrate, disbon dment, or other defects of the zinc coating.

4. Selecting Materials 4.1 GENERAL: Compositions and performances of organic zinc-rich primers vary with regard to the individual resin system, the level of metallic zinc, the volatile organic compound (VOC) content, along with other formulation variables. It is often desirable to require the zinc-rich coatings to meet performance criteria to verify that they can withstand the corrosion and weathering environments to which they will be subjected. Some performance tests are described in SSPC-Paint 20 and SSPC-Paint 29. Coating selection can best be made from actual field testing of candidate coatings in the environment in which the coatings are to be located.

5.1.2   Select surface preparation methods. Suitable 5.1.2  methods include SSPC- SP 2 or SP 3, SSPC-SP 11, SSPCSP 12/NACE No. 5, or abrasive blasting ( SSPC-SP 5/NACE No. 1, SSPC-SP 10/NACE No. 2, SSPC-SP 6/NACE No . 3, SSPC-SP 14/NACE No. 8, or SSPC-SP 7/NACE No. 4), depending upon the service environment. Table 1 can be used as a general guideline for appropriate surface preparation for a variety of exposures. In all cases, the surface clean liness should be at least as great as that recommended by the supplier of the primer.

4.2 TYPE OF BINDER: BINDER:   Organic zinc-rich coating formulations are available with a variety of binders. The choice of a particular generic type of binder is up to the user. A list of some of the currently available generic types is found in Note 7.1. 4.3 METALLIC ZINC LEVELS: LEVELS: Suppliers,  Suppliers, applicators, and owners do not agree on the metallic zinc level (or loading) necessary for long-term protection of steel by organic zinc-ri ch coatings. The user can select any metallic zinc level found to provide the best performance, or conversely, not specify a zinc level. Three levels of zinc loading that may be useful to the user are listed below: • Zinc Zin c Leve Levell 1: 1: Min Minim imum um zin zinc c load loading ing of 85 85% % by by weig weight ht •

5.1.3 Surface Contaminants: Remove all grease, oil, corrosion by-produ cts, dirt, and other surface contaminants from the areas with imperfections and from the existing intact coating within a minimum of five centimeters (two inches) of these areas by solvent cleaning or detergent washing (SSPC-SP 1), or other approved method. 5.1.4 Topcoated Areas: If any of the areas to be repaired consist of topcoated galvanized steel or topcoated inorganic zinc, all loose topcoat in the damaged area must be completely removed exposing an area of intact zinc coating surrounding the damaged area. 5.1.5 Weld Preparations: If the area to be repaired contains welds, all flux residue and weld spatter must be removed by blast cleaning or through mechanical means. (See Section 4.4.1 of SSPC Surface Preparation Commentary regarding removal of weld spatter.)

of the Zinc Zin c Level Ledry velfilm 2: Min Minimu imum m zinc zinc load loading ing of 77% 77% by by weigh weightt of the dry film

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Zinc Leve Zinc Levell 3: Mi Minim nimum um zin zinc c load loading ing of 65% 65% by by weig weight ht of the dry film

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SSPC-Guide 14 May 1, 1999

Table 1 Recommended Minimum Surface Preparation Service En Environment

Dry Ab Abrasive Bl Blast

Water Jetting (SP12/NACE No 5)

Hand or Power Tool Cleaning

Immersion

SP 10/NACE No. 2

WJ 2/SC 1*

None

Splash/Spillage

SP 6/NACE No. 3

WJ 3/SC 2

Chemical Fume, Neutral pH

SP 6/NACE No. 3

WJ 3/SC 2

SP 11

Atmospheric

SP 7/NACE No. 4

WJ 4/SC 3

SP 2 or 3

SP 11

* Note that SP 2 requires specific ation of visual cleanliness (WJ 1 through WJ 4) and non-visual cleanlines s (SC 1 through SC 3).

6. Disclaimer

5.2 REPAIRS WITH ZINC-RICH COATING: 5.2.1 Application: Apply the zinc-rich coating to the prepared surface by brush or spray according to the manufacturer’s recommendations and SSPC-PA 1. If a conflict exists between SSPC-PA 1 and the manufacturer’s printed recommendations, the latter should be followed. The patch of organic zinc-rich coating must extend a minimum of five centimeters (two inches) over the undamaged zinc coated surface. The contracting parties shall mutually agree upon the extent of repair overlap if more than five centimeters (two inches) is required.

6.1   This guide 6.1 guide is designed designed to describe, review, or analyze new or improved technolo gy and does not meet the definition of a specification as defined by SSPC. SSPC. A guide differs from a specification in that it is not suitable for referencing in a contract specification or procurement document. 6.2   While every precaution is taken to ensure that all 6.2  information furnished in SSPC guides is as accurate, complete, and useful as possible, SSPC cannot assume responsibility nor incur any obligation res ulting from the use of any materials, coatings, or methods described herein, or of the guide itself.

5.2.2 Application Temperature: In general, solventborne organic zinc-rich coatings should be applied only at temperatures temperatu res above 7 C (45 F) and relative humidities below 85%. Waterborne products may have other limitations. In all cases, consult the manufacturer’s literature for temperature, humidity, and ventilation requirements (see Note 7.4). °

5.2.3

°

7. Notes Notes are not considered requirements of this Guide.  7.1   Organic zinc-rich primers with the following bind 7.1 ers were marketed at the time of this writing: two-componen t

Pot Life: Life:   Multiple component zinc-rich coat-

ings must be applied within the pot life specified by the supplier, and the coating should be continuously agitated during application.

epoxy, epoxy ester, and moisture-curing polyurethane. Other organic binder types have been or may later be marketed. 7.2   ASTM D 3960 is a commonly used standard 7.2  practice to determine VOC, but this method may not be acceptable to all jurisdictions . Although ASTM D 3960 does not address analysis of VOC exempt solvents such as PCBTF (parachlorobenzotrifl ouride), it references two other ASTM Methods which do address exempt solvents , ASTM D 6133 and D 4457. Methods published by government agencies include Bay Area Air Quality Management District (BAAQMD) Method 41 and California Air Resources Board (CARB) Method 310.

5.2.4 Film Thickness: Thickness:   The dry film thickness of the organic zinc-rich coating should be that recommended by the manufacturer. Normally this is between 75 micrometers (3 mils) and 150 micrometers (6 mils). Dry film thicknesses should be measured in accordance with SSPC-PA 2. 5.2.5 Safety:  Safety:  Observe all safe safe handling procedures procedures described in the product material safety data sheet (MSDS) and SSPC-PA Guide 3. 5.3

TOPCOATING:

If a topcoat is specified, the

7.3 APPROPRIATE TOPCOATING: TOPCOATING:   Topcoating will usually provide additional service life to both zinc-rich primers and hot-dip galvanized coating. Topcoats must be formulated not only for environmental resistance, but also for

application of the topcoat should be in accordance with SSPC-PS Guide 8 or the manufacturer’s printed instructions.

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compatibility with the organic zinc-rich coating, hot-dip galvanizing, or inorganic zinc coating. Generally, topcoating will be required in more severe environments, as recommended by the manufacturer. 7.4 TEMPERATURE CONSTRAINTS: Consult the manufacturer of the organic zinc-rich coating to be used concerning service for temperature limitations, especially °

°

when the expected exposure is above 66 C (150 F). 7.5 MANUFACTURER’S LITERATURE:  LITERATURE:  This guide is intended for use to supplement the coating manufacturer’s printed instructions and literature.

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