1、6-1SSPC-Paint COMNovember 1, 2004SSPC: The Society for Protective CoatingsCOMMENTARY ON PAINT SPECIFICATIONS 1. DescriptionSince 1955, the SSPC has issued specifi cations for coat-ings that have performed well in actual use on steel structures. When these paint specifi cations are used in conjunctio
2、n with the SSPC standards for surface preparation, paint application, and thickness measurement, they provide complete paint systems for most steel structures and environments. Tables 1 and 2 summarize the SSPC paint specifi cations. Each paint specifi cation contains a scope and a description of th
3、e paint. The composition specifi cations also contain directions for use. Performance specifi cations provide wide latitude on composi-tion but require minimum performance levels that the coating must meet.2. Approaches to Procuring PaintProcurement of paint by specifi cation represents an attempt b
4、y the purchaser to exercise a degree of control over the quality of the product. That degree of control may range from tight, as when one of the SSPC paints with composition specifi cation is cited, to virtually nil, as when a minimally de-scriptive, generic designation is used, e.g., a zinc-rich pr
5、imer, a shop coat, a urethane. In addition to purchaser control, specifi cations make competitive procurement practical.Another approach to the purchase of paint is represented by the naming of a specifi c proprietary product, the composi-tion of which may be described in a label analysis. Usually,
6、the citation of a proprietary product denotes a high degree of confi dence in that products performance record. It also implies confi dence in the manufacturers reputation for quality and integrity - in other words, in the likelihood that the manufacturer will continue to maintain the quality for wh
7、ich the product has become known.Unfortunately, in a vain attempt to promote competition, faith in the performance expected of a known proprietary product is often undermined by addition of the bland phrase “or equal.” Adding an “or equal” provision to a procurement specifi cation without specifying
8、 the criteria that characterize equality of performance is a meaningless exercise.Composition specifi cations offer the assurance of a desired measure of quality, but they also have the disadvantage of “locking in” a product to the level of quality or value prevailing during a specifi c period in th
9、e history of an evolving technol-ogy. One of the important objectives of SSPC is to focus on the expertise of its highly qualifi ed, voluntary collaborators on critical evaluations of the products of new technology, so that those products may be assimilated into the spectrum of reliable materials wi
10、th deliberate speed.While no organization deliberating by consensus can operate at a rapid pace, the background of information gen-erated by a mature organization such as SSPC presents the user with enough choices of time-tested paints, both old and new, to justify deferral of judgment on commercial
11、 products that are not as yet backed by documented history of proven performance in the fi eld.If a paint is procured through a pure composition specifi -cation, SSPC-Paint 16 for example, the purchaser knows the physical, chemical, and performance properties of the product. The manufacturer follows
12、 the formula to produce the paint.If paints are not being supplied to a composition specifi ca-tion, the purchaser is entitled, without transgressing into the area of proprietary information, to request a statement of the products principal composition and performance parameters, such as the followi
13、ng: Case histories of fi eld performance Performance in standard salt fog, combination cyclic salt fog/UV condensation tests, and condensing cabinet tests Non-volatile content by weight and volume Volatile organic compound (VOC) content Viscosity range at a specifi ed temperature Viscosity reduction
14、 resulting from specifi cation dilution ratios with thinners Spreading rate for complete hiding Specifi c resistance properties where resistance to unusual chemical exposures is required Special or unusual drying time requirements Suitability for one or another type of application, such as brushing,
15、 airless spray, etc. Lightfastness rating of the color pigments Chalk resistance and gloss retention rating (for top-coats) under specifi ed conditions of test at named exposure locations for indicated periods of timeWhile not all of these criteria may be important in specifi c circumstances, they a
16、re indicative of the kind of questions that any discriminating purchaser is entitled to ask any manufacturer who is supplying paint for exterior exposure. If purchasers believe that there are no specifi cation paints available that exactly fi t requirements, or if they feels that they would like to
17、have a better paint than can be obtained from among the available specifi cation paints, they may engage qualifi ed professional consultanta to secure informed and objective guidance.3. Current SSPC Specifi cation Trends3.1 COMPOSITION AND PERFORMANCE: In many of the current SSPC specifi cations, an
18、 attempt is made to 6-2SSPC-Paint COMNovember 1, 2004PRIMER DESCRIPTION PIGMENTAPPROX.Wt. %PIGMENTVEHICLE SOLIDSAPPROX.SET TOTOUCH (h)DRY THROUGH (h)MINIMUM SURFACE PREP. RECOMMENDED%VOLUMESOLIDSSSPC- Paint 8 A vinyl-aluminum primer; may be used over bare steel, or wash primer, or over other vinyls.
19、 Suitable for very severe neutral exposures and immersion.Aluminum 100% 6.7 Vinyl 0.25 1 Near-white blast or pickling14SSPC-Paint 9 Vinyl primer similar to above. Recommended for alkaline or acidic exposure.Titanium dioxide 95% min., tint 5% max.12 Vinyl 0.25 0.5 Near-white blast or pickling17SSPC-P
20、aint 15 Fast-drying shop paints for temporary protection of steel joists; performance based.Not specifi ed Not Specifi ed Hand cleaning SSPC-Paint 16 Two-component coal tar epoxy self-priming paint for water immersion, chemical, and underground.Magnesium silicate or iron oxide31 Coal tar pitchand po
21、lyamideand epoxy resins Commercial blast 75SSPC- Paint 17 Chlorinated rubber inhibitive primer for non-submerged surfaces and most sub-merged surfaces.Rust inhibitor 65%, extender 35%29-49 Chlorinatedrubber 66%,chlorinated plasticizer 34%0.25 1 Commercial blast 32SSPC- Paint 18 Chlorinated rubber in
22、termediate paint (or topcoat) in white or tints.Titanium dioxide 75%*, magnesium silicate 15%, mica 10%16-30 Chlorinatedrubber 75%,chlorinated plasticizer 25%0.25 1 Commercial blast 35SSPC- Paint 19 Chlorinated rubber topcoat in white or tints.Various 18-28 Chlorinatedrubber 72%chlorinated plasticiz
23、er 28%0.25 1 Commercial blast 35SSPC-Paint 20Type IType IIInorganic zinc-rich primerOrganic zinc-rich primerZn Level 185%Zn Level 277 to 85%Zn Level 365 to 77%Varies Not Specifi ed Commercial blast SSPC-Paint 21Type Ihigh glossType IImed. glossHighly weather resistant white or colored silicone-alkyd
24、 paint suitable for fi nish coat.Various Type I, 11-37Type II,29-48Silicone alkyd 2 8 Commercial blast 60-67SSPC-Paint 22* PrimerTwo-component polyamide epoxy primer for industrial exposure marine environment and some chemical exposure.Red iron oxide, magnesium oxide, mica46 Epoxy/poly-amide 65/352
25、8 Commercial blast 65IntermediateTwo-com-ponent polyamide epoxy intermediate coat.Red iron oxide, magnesium oxide, mica40 Epoxy/poly-amide 65/352 8 Commercial blast 65TopcoatTwo-component polyamide epoxy topcoat.Titanium dioxide, chromium oxide, magnesium silicate, mica, lampblack36 Epoxy/poly-amide
26、 65/352 8 Commercial blast 60SSPC- Paint 23 Air drying latex primer and intermediate coat for blast cleaned steel.Not Specifi ed Not Specifi edLatex 4 24 Commercial blast 36SSPC Paint 24 Air drying semi-gloss latex topcoat.Not Specifi ed Not Specifi edLatex 4 24 Commercial blast 27TABLE 1SSPC PAINTS
27、6-3SSPC-Paint COMNovember 1, 2004PRIMER DESCRIPTION PIGMENTAPPROX.Wt. %PIGMENTVEHICLE SOLIDSAPPROX.SET TOTOUCH (h)DRY THROUGH (h)MINIMUM SURFACE PREP. RECOMMENDED%VOLUMESOLIDSSSPC-Paint 25Type IType IIZinc oxide oil and alkyd primer for hand cleaned steel.Type II has lower VOC content than Type I.Zi
28、nc oxide(French process),red iron oxide,magnesiumsilicate, micaType I, 52Type II, 5450/50 raw linseed oil/long oil alkyd20 36 Hand cleaning Type I, 65Type II, 70SSPC-Paint 25 BCSType IType IIZinc oxide oil and alkyd primer for blast cleaned steel.Type II has lower VOC content than Type I.Zinc oxide(
29、French process),red iron oxide,magnesiumsilicate, micaType I, 52Type II, 54Type I, 34/66raw linseed oil/alkyd; Type II, 33/67 raw linseed oil/alkyd6 18 Commercial blast Type I, 82Type II, 86SSPC-Paint 26 Very slow drying black one-coat maintenance primer.Zinc oxide (French process) 16%, basic lanola
30、te 4%, magnesium silicate 75%, lampblack 5%54 80/20 raw linseed oil/long oil alkyd24 168 Hand cleaning 87SSPC Paint 27*Wash primer for clean steel free of rust and scale or for clean galva-nized metal.Basic zinc chro-mate Vinyl butyral 0.5 4 Commercial blast 10SSPC-Paint 28 Water-borne epoxy primer
31、for steel surfaces.Not specifi ed SSPC Paint 29 Zinc dust sacrifi cial primer, performance-based.Min. 65% zinc in dry fi lm SSPC-Paint 30 Weld-through inorganic zinc primer Zinc dust min. 65% by wt of total solids Water or solvent-reducible, self-curing SSPC- Paint 31 Single-package, water-borne alk
32、yd primer, performance-based. Ambient dry-ing, single-package824 SSPC-Paint 32 Coal-tar emulsion coating. 40SSPC-Paint 33 Coal-tar mastic, cold applied. 70SSPC-Paint 34 Water-borne epoxy topcoat. Not specifi ed SSPC-Paint 35Type IType IIZinc oxide and medium oil alkyd primer for blast cleaned steel
33、(air dry or low bake).Type II has lower VOC content than Type I.Zinc oxide (French process), red iron oxide, magnesium silicate, micaType I, 41Type II, 55Medium oil alkyd7 (air dry) 18 (air dry)0.75 (bake)Commercial blast Type I, 37Type II, 66SPPC- Paint 36 Two-component weatherable aliphatic polyur
34、ethane topcoat, performance-based Min. 17% polyisocya-nate by wt. SSPC-Paint 37 Water-borne epoxy coating for cementitious substrates, performance based Epoxy resin with curing agent min. 40% by weight of total solids concrete SSPC-Paint 38 Single-component moisture-cure weatherable aliphatic polyur
35、ethane topcoat, performance-based Polyisocya-nate product that cures through a reaction with atmospheric moisture SSPC-Paint 39 Two-component aliphatic polyurea topcoat, fast or moderate drying, performance-based Hindered, non-hindered, or hybrid aliphatic polyurea30 min to 2 h TABLE 1 (continued)SS
36、PC PAINTS*These pigment compositions are from a control formula.*These pigments listed are for use in reference (or control) paint. A lead- and chromate-free pigment may be used provided it meets performance requirements.*These paints include chromate-containing pigments. Users are urged to follow a
37、ll health, safety, and environmental requirements in applying, handling, or disposing of these materials.Note: Alkyd and vinyl topcoats are summarized in Table 2.6-4SSPC-Paint COMNovember 1, 2004FINISH PAINT PIGMENT APPROX.Wt. %PIGMENTVEHICLESOLIDSDENSITY(lb/gal)DENSITY(kg/L)APPROX.SET TOTOUCH(h)APP
38、ROX DRY TO TOUCH(h)REMARKSSSPC-Paint 101Type I, Leafi ngType II, Non-Leafi ngAluminum 100% 13.3 Alkydvarnish(long oil)8.4 1.0 4 10 For atmospheric use. Used as aluminum top coat over oil paints or alkyds. Used as barrier coat on bitu-mens. Type I is usually supplied ready to mix. Type II is supplied
39、 ready-mixed.SSPC-Paint 102 Carbon black 100% 5.5 Alkydvarnish(long oil)7.7 0.9 6 18 Very durable black fi nish coat for oil or alkyd paints. For atmospheric exposure, particularly severe industrial or railroad.SSPC-Paint 104Type I, WhiteTitanium dioxide 67%,extender 33%47.5 Alkydvarnish(long oil)11
40、.6 1.4 6 18 White, inert pigmented, alkyd fi nish paint for useover oil or alkyd paints.Type II, Mediumto Light Gray or TanTitanium dioxide 26%,extender, tint 74%42.4 Alkydvarnish(long oil)10.7 1.3 6 18 Color to be specifi ed. For use over oil or alkydpaint. Colorfast.Type III, Light or Gray GreenTi
41、tanium dioxide 25%,extender, tint 75%44.8 Alkydvarnish(long oil)11.6 1.4 6 18 Color to be specifi ed. For use over oil or alkydpaint. Colorfastness good, but depends upontinting pigments used.Type IV, Dark orForest GreenChrome green 90%,extender, tint 10%21.5 Alkydvarnish(long oil)9.0 1.1 6 18 Very
42、dark chrome greenalkyd paint. Colorfast-ness good in mild atmospheres, but poor in chemical exposure.SSPC-Paint 106 Carbon black 100% 1 7.4 0.9 0.25 0.5 Black vinyl fi nish paint. Use over vinyls only or over wash primers. Verygood resistance to most exposures.SSPC-Paint 108 Aluminum paste 17 Thixo-
43、tropic alkyd 4 16 High-build thixotropic aluminum leafi ng paint, 49% volume solids.TABLE 2SSPC ALKYD AND VINYL INTERMEDIATE AND FINISH PAINTS6-5SSPC-Paint COMNovember 1, 2004combine the advantage of composition requirements, perfor-mance criteria, and availability from proprietary sources.For two r
44、easons there is still a need for some compositional requirements in most paint or coating specifi cations. First, the correlation between long-term durability and short-term accel-erated performance tests is still an incomplete one, in spite of considerable recent progress. Secondly, in the present
45、state of the art, it is still essential for the buyer to know, for example, that a zinc-rich paint contains at least some zinc, and that an epoxy contains some epoxy.3.2 PERFORMANCE LEVELS: Several specifi cations, (e.g., SSPC-Paint 34, a waterborne epoxy; SSPC-Paint 29, a zinc dust primer; and SSPC
46、-Paint 39, a polyurea topcoat) have incorporated the concept of performance levels of paints. The higher the level, the higher the degree of confi dence in the performance of the paint. Under this approach, a lower level is generally based on accelerated tests, which can be performed relatively rapi
47、dly, but which offer a lower degree of confi dence. The second or third levels of performance may be based on actual exterior exposure of 12 to 48 months at defi ned exterior sites or may be based on longer term acceler-ated tests. In some instances, a low level may be used as an interim qualifi cat
48、ion. In this case, the specifi er would accept the products for limited use while waiting to accumulate the longer time fi eld data required for the higher level of performance.3.3 VOC LEVELS: In response to the continuing aware-ness of protecting the environment, governmental districts now restrict
49、 the emission of volatile organic compounds (VOC) from painting operations. SSPC does not defi ne VOC levels because of the wide variation in VOC limits among different localities and among different applications. The contracting parties are referred to the federal, state, and local regulatory authorities for guidance on the allowable levels of VOC emissions.4. Government Specifi cations and Standards There are fewer federal and military specifi cations f
