SSPC SP COM-2004 Surface Preparation Commentary for Steel and Concrete Substrates《钢基板和混凝土基板的表面处理说明》.pdf

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1、SSPC-SP COMNovember 1, 20042-1SSPC: The Society for Protective CoatingsSURFACE PREPARATION SPECIFICATIONSSurface Preparation Commentary for Steel and Concrete Substrates1. IntroductionThis Surface Preparation Commentary (SP COM) is in-tended to be an aid in selecting the proper surface preparation m

2、ethod, materials, and specifi cation for steel, other metals, and concrete. A compilation of standards, guides, and speci-fi cations related to concrete is available as SSPC publication #04-03 “Surface Preparation and Coating of Concrete.” The SP COM is not part of the actual standards, but is inclu

3、ded to provide a better understanding of the SSPC surface prepara-tion standards. In addition, surface preparation standards other than those published by SSPC are referenced.The SSPC standards, summarized in Table 1, represent a broad consensus of users, suppliers, and public interest groups. Detai

4、ls of the methods used to measure many of the properties discussed in this SP COM are described in SSPC publication 03-14, “The Inspection of Coatings and Linings, A Handbook of Basic Practice for Inspectors, Owners, and Specifi ers, 2nd Ed.”2. Contents1. Introduction2. Contents3. Importance of Surf

5、ace Preparation4. Surface Conditions4.1 New Construction4.2 Maintenance4.3 Surface Contaminants4.3.1 Rust, Stratifi ed Rust, Pack Rust, and Rust Scale4.3.2 Mill Scale4.3.3 Grease and Oil4.3.4 Dirt and Dust4.3.5 Moisture4.3.6 Soluble Salts4.3.7 Paint Chalk4.3.8 Deteriorated Paint4.4 Surface Defects4.

6、4.1 Welds and Weld Spatter4.4.2 Weld Porosity4.4.3 Sharp Edges 4.4.4 Pits4.4.5 Laminations, Slivers4.4.6 Crevices4.4.7 Concrete Defects4.5 Rust Back5. Summary of SSPC Surface Preparation Standards5.1 SSPC-SP 1, “Solvent Cleaning”5.1.1 Petroleum Solvents and Turpentine5.1.2 Alkaline Cleaners5.1.3 Emu

7、lsion Cleaners5.1.4 Steam Cleaning5.1.5 Threshold Limit Values5.1.6 Paint Removal5.2 SSPC-SP 2, “Hand Tool Cleaning”5.2.1 Loose Rust, Mill Scale, and Paint5.2.2 Consensus Reference Photographs5.3 SSPC-SP 3, “Power Tool Cleaning”5.3.1 Loose Rust, Mill Scale, and Paint5.3.2 Consensus Reference Photogr

8、aphs5.4 SSPC-SP 4, “Flame Cleaning of New Steel”5.5 SSPC-SP 5/NACE No. 1, “White Metal Blast Cleaning”5.5.1 Consensus Reference Photographs5.6 SSPC-SP 6/NACE No. 3, “Commercial Blast Cleaning”5.6.1 Reference Photographs5.7 SSPC-SP 7/NACE No. 4, “Brush-Off Blast Cleaning”5.7.1 Consensus Reference Pho

9、tographs5.8 SSPC-SP 8, “Pickling”5.9 SSPC-SP 9, “Weathering Followed by Blast Cleaning”5.10 SSPC-SP 10/NACE No. 2, “Near-White Blast Cleaning”5.10.1 Consensus Reference Photographs5.11 SSPC-SP 11, “Power Tool Cleaning to Bare Metal”5.11.1 Power Tools and Cleaning Media5.11.2 Power Tools with Vacuum

10、Shrouds5.11.3 Consensus Reference Photographs5.12 SSPC-SP 12/NACE No. 5, “Surface Preparation and Cleaning of Metals by Waterjetting Prior to Coating”5.12.1 Surface Cleanliness5.12.2 Flash Rusting5.12.3 Consensus Reference Photographs5.13 SSPC-SP 13/NACE No. 6, “Surface Preparation of Concrete”5.14

11、SSPC-SP 14/NACE No. 8, “Industrial Blast Cleaning”5.14.1 Consensus Reference Photographs5.15 SSPC-SP 15, “Commercial Grade Power Tool Cleaning”5.15.1 Consesnsus Reference Photographs6. Selection of Abrasives, Blast Cleaning Parameters, and Equipment6.1 Abrasive Characteristics6.1.1 Hardness6.1.2 Siz

12、e6.1.3 Shape6.1.4 Bulk Density6.1.5 Friability/Waste Generation6.1.6 RecyclabilitySSPC-SP COMNovember 1, 20042-26.2 Factors Affecting Surface Profi le6.2.1 Profi le Height6.2.2 Profi le Texture (Roughness)6.3 Parameters That Affect Productivity6.3.1 Particle Size6.3.2 Hardness6.3.3 Shape6.3.4 Specif

13、i c Gravity6.3.5 Nozzle Pressure6.3.6 Nozzle Type6.3.7 Nozzle to Surface Distance6.3.8 Impact Angle6.3.9 Abrasive Metering6.3.10 Abrasive Cleanliness6.3.11 Embedment6.4 Abrasive Types6.4.1 Metallic Abrasives6.4.2 Non-Metallic Abrasives6.5 Blast Equipment6.5.1 Conventional Blasting6.5.2 Vacuum Blasti

14、ng6.5.3 Abrasive Blast Cleaning Above 760 kPa (110 psi)7. Summary of SSPC Abrasive Standards7.1 SSPC-AB 1, “Mineral And Slag Abrasives7.2 SSPC-AB 2, “Cleanliness of Recycled Ferrous Metallic Abrasives”7.3 SSPC-AB 3, “Ferrous Metallic Abrasive”8. Wet Abrasive Blast and Waterjetting Methods8.1 Water C

15、leaning and Waterjetting (Without Abrasive)8.1.1 Degrees of Cleaning8.1.2 Profi le8.1.3 Water Consumption8.1.4 Equipment8.1.5 Flash Rust8.2 Wet Abrasive Blast Cleaning8.2.1 Air/Water/Abrasive Blasting8.2.2 Water/Abrasive Blast Cleaning8.3 Flash Rust and Rust Bloom8.4 Inhibitors and Salt Removers9. O

16、ther Cleaning Methods9.1 Chemical Stripping9.2 Sodium Bicarbonate (Baking Soda) Blast Cleaning9.3 Pliant Media Blasting (Sponge Jetting)9.4 Carbon Dioxide (Dry Ice) Blasting9.5 Electrochemical Stripping10. Film Thickness11. Consensus Reference Photographs11.1 SSPC-VIS 1,” Guide and Reference Photogr

17、aphs for Steel Surfaces Prepared by Dry Abrasive Blast Cleaning “11.2 SSPC-VIS 2, “Standard Method of Evaluating Degree of Rusting on Painted Steel Surfaces”11.3 SSPC-VIS 3, “ Guide and Reference Photographs for Steel Surfaces Prepared by Hand and Power Tool Cleaning “11.4 SSPC-VIS 4/NACE VIS 7, “Gu

18、ide and Reference Photographs for Steel Surfaces Prepared by Waterjetting”11.5 SSPC-VIS 5/NACE VIS 9, “Guide and Reference Photographs for Steel Surfaces Prepared by Wet Abrasive Blast Cleaning”11.6 ISO Pictorial Standards11.7 Other Photographic Standards11.8 Project Prepared Standards12. Other SSPC

19、 Surface Preparation Documents in This Volume12.1 SSPC-TR 1/NACE 6G194, “Joint Technology Report on Thermal Precleaning”12.2 SSPC-TR 2/NACE 6G198, “Joint Technical Report on Wet Abrasive Blast Cleaning”12.3 SSPC-TU 2/NACE 6G197, “Informational Report and Technology Update on Design, Installation, an

20、d Maintenance of Coating Systems for Concrete Used in Secondary Containment”12.4 SSPC-TU 4, “Field Methods for Retrieval and Analysis of Soluble Salts on Substrates”12.5 SSPC-TU 6, “Chemical Stripping of Organic Coatings from Steel Structures”13. Non-SSPC Cleaning Standards14. Surface Preparation of

21、 Concrete for Coating14.1 Industry Standards14.2 Methods of Cleaning Concrete15. Surface Preparation of Other Metallic Surfaces15.1 Aluminum15.2 Stainless Steel15.3 Copper Alloys3. Importance of Surface PreparationOften, the surface preparation of steel for painting requires a three step process: 1)

22、 initial pre-cleaning to remove grease, oil, dirt, and other surface contaminants; 2) cleaning with hand/power tools, pressurized water, chemicals, or abrasive blast-ing; 3) creation or verifi cation of the specifi ed anchor pattern profi le. The life of a coating depends as much on the degree and q

23、uality of surface preparation as on the selected coating system, because most coating failures can be attributed to inadequate surface preparation or lack of coating adhesion. Surface preparation, therefore, should receive thorough con-sideration. The primary functions of surface preparation are: To

24、 remove surface contaminants that can induce premature coating failure To provide a clean surface with adequate profi le for good coating adhesion.Where conventional abrasive blast cleaning is not allowed or is impractical, alternative abrasives or methods of cleaning the surface must be employed. C

25、hemical stripping will remove paint and is relatively easy to contain. Hence, chemical strip-ping may be used around sensitive machinery or in densely populated areas. (Refer to SSPC-TU 6, “Chemical Stripping of Organic Coatings from Steel Structures.”) Alternative abrasives SSPC-SP COMNovember 1, 2

26、0042-3TABLE 1SUMMARY OF CURRENT SSPC ABRASIVE ANDSURFACE PREPARATION STANDARDS AND SPECIFICATIONSSSPC SPECIFICATION DESCRIPTIONAB 1Mineral and Slag AbrasivesDefinition of requirements for selecting and evaluating mineral and slagabrasives used for blast cleaning.AB 2Cleanliness of Recycled FerrousMe

27、tallic AbrasiveCleanliness requirements for a recycled work mix and a description of thetest procedures.AB 3Ferrous Metallic AbrasiveRequirements of chemical and physical properties of iron and steelabrasives.SP 1Solvent CleaningRemoval of oil, grease, dirt, soil, salts, and contaminants by cleaning

28、 withsolvent, vapor, alkali, emulsion, or steam.SP 2Hand Tool CleaningRemoval of loose rust, loose mill scale, and loose paint to degree specified,by hand chipping, scraping, sanding, and wire brushing.SP 3Power Tool CleaningRemoval of loose rust, loose mill scale, and loose paint to degree specifie

29、d,by power tool chipping, descaling, sanding, wire brushing, and grinding.SP 5/NACE No. 1White Metal Blast CleaningRemoval of all visible rust, mill scale, paint, and foreign matter by blastcleaning by wheel or nozzle (dry or wet) using sand, grit or shot. For verycorrosive atmospheres where high co

30、st of cleaning is warranted.SP 6/NACE No. 3Commercial Blast CleaningBlast cleaning until at least two-thirds of the surface is free of all visibleresidues with only staining permitted on the remainder. For conditionswhere a thoroughly cleaned surface is required.SP 7/NACE No. 4Brush-Off Blast Cleani

31、ngBlast cleaning of all except tightly adhering residues of mill scale, rust, andcoatings, while uniformly roughening the surface.SP 8PicklingComplete removal of rust and mill scale by acid pickling, duplex pickling, orelectrolytic pickling.SP 10/NACE No. 2Near-White Blast CleaningBlast cleaning nea

32、rly to White Metal cleanliness, until at least 95% of thesurface is free of all visible residues with only staining permitted on theremainder. For high humidity, chemical atmosphere, marine, or othercorrosive environments.SP 11Power Tool Cleaning to Bare MetalComplete removal of all rust, scale, and

33、 paint by power tools, with resultantsurface profile.continued.SSPC-SP COMNovember 1, 20042-4such as sodium bicarbonate (baking soda) or dry ice (CO2) can sometimes be used in places where conventional abrasives cannot be used. A class of abrasives has been developed where each abrasive particle is

34、contained in a urethane sponge. The sponge contains the abrasive and facilitates cleanup and recycling. Alternative methods of surface preparation are discussed in more detail in Chapter 2.9 of the SSPC Painting Manual, Vol. 1.An advantage of all wet blast methods is the control of dust emissions. W

35、et blast methods may involve water alone, abrasive injected into the water stream, water injected into an abrasive air stream, or a water curtain surrounding an air/abrasive stream. Power tools with vacuum shrouds have also been proven effective in controlling dust emissions, particularly in removin

36、g lead-containing paint. It is important to note that surface preparation methods used to control dust may not necessarily eliminate any hazards associated with disturbance of hazardous materials such as lead. In applications where the presence of soluble salts on the steel surface creates a serious

37、 problem, such as tank linings, it may be benefi cial to incorporate water into the cleaning process.To gain maximum benefi t from a high performance industrial coating, it is not prudent to cut back on the surface preparation. Surface preparation is important even when a “surface tolerant” coating

38、is used. When the manufacturer claims a particular coating will “tolerate” a given amount of rust, old paint, or other contamination on the steel surface, it is likely that the coating will perform even better if the surface is prepared to a higher level of cleanliness.SP 12/NACE No. 5Surface Prepar

39、ation and Cleaning ofMetals by Waterjetting Prior toCoatingDefines four degrees of cleaning for visible contaminants (similar toSP 5, 6, 7, and 10) and three levels of flash rust and describes threelevels of non-visible surface cleanliness for non-visible soluble saltcontamination.SP 13/NACE No. 6Su

40、rface Preparation of ConcreteDescription of inspection procedures prior to surface preparation,methods of surface preparation, inspection, and classification ofprepared concrete surfaces.SP 14/NACE No. 8Industrial Blast CleaningBetween SP 7 (brush-off) and SP 6 (commercial). The intent is toremove a

41、s much coating as possible, but contaminants difficult toremove can remain on 10 percent of the surface.SP 15Industrial Grade Power Tool CleaningBetween SP 3 and SP 11. Removes all rust and paint but allows forstaining; requires a minimum 1 mil (25 m) profile.VIS 1Guide and Reference Photographs for

42、Steel Surfaces Prepared by DryAbrasive Blast CleaningStandard reference photographs; recommended supplement toSSPC surface preparation standards SSPC-SP 5, 6, 7, 10, and 14.VIS 2Standard Method of EvaluatingDegree of Rusting on Painted SteelSurfacesA geometric numerical scale for evaluating degree o

43、f rusting ofpainted steel. Color photographs show staining while matchingblack and white images depict only rust. Three rust distributions,general, spot, and pinpoint, are depicted.VIS 3Guide and Reference Photographs forSteel Surfaces Prepared by Power-and Hand-Tool CleaningStandard reference photo

44、graphs; recommended supplement toSSPC-SP 2, 3, 11, and 15.VIS 4/NACE VIS 7Guide and Reference Photographs forSteel Surfaces Prepared byWaterjettingStandard reference photographs depict previously rusted steel(painted and unpainted) cleaned by water jetting. Photographsdepict three levels of flash ru

45、sting. Recommended as a supplementto SSPC-SP 12.VIS 5/NACE VIS 9Guide and Reference Photographs forSteel Surfaces Prepared by WetAbrasive Blast CleaningStandard reference photographs depict previously rusted unpaintedsteel cleaned by wet abrasive blast cleaning to SSPC SP 6 and SP10. Photographs dep

46、ict three levels of flash rusting. Recommendedas a supplement to SSPC-SP 6 and SP 10 when wet blast cleaningmethods are used.SSPC-SP COMNovember 1, 20042-54. Surface ConditionsThe initial condition of the surface to be cleaned will determine the amount of work, time, and money required to achieve an

47、y particular degree of surface cleanliness. It is more diffi cult to remove contaminants from rusty steel than from intact mill scale. Therefore, it is necessary to consider the surface condition prior to selecting the method of cleaning. The initial condition of the steel may determine the choice o

48、f abrasive to be used. Steel shot is an economical and ef-fective choice for removing intact mill scale. However, if the steel is rusted and/or pitted, a more angular abrasive such as steel grit or a nonmetallic mineral abrasive will more effectively “scour out” the rust.Although there are almost an

49、 infi nite number of initial conditions, they can be broadly divided into three categories as follows: New constructionsteel not previously painted Maintenancepreviously painted steel Contaminated surfacescommon to both new con-struction and maintenance.4.1 NEW CONSTRUCTION: For new construction there are four surface conditions based upon the rust condition classifi cations. These initial conditions, defi ned in SSPC visual consensus references, namely, SSPC-VIS 1, SSPC-VIS 3, and SSPC-VIS 4, are as follows:Rust Condition A Steel surface covered completely with adherent mill scale; l