1、 Standard Practice SSPC Surface Preparation Standard NACE WAB-4/SSPC-SP 7 (WAB) Brush-Off Wet Abrasive Blast Cleaning This NACE International/SSPC: The Society for Protective Coatings joint surface preparation standard represents a consensus of those individual members who have reviewed this documen
2、t, its scope, and provisions. Its acceptance does not in any respect preclude anyone, whether he or she has adopted the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not in conformance with this standard practice. Nothing contained in this NA
3、CE/SSPC standard is to be construed as granting any right, by implication or otherwise, to manufacture, sell, or use in connection with any method, apparatus, or product covered by letters patent, or as indemnifying or protecting anyone against liability for infringement of letters patent. This stan
4、dard represents minimum requirements and should in no way be interpreted as a restriction on the use of better procedures or materials not discussed herein. Neither is this standard intended to apply in all cases relating to the subject. Unpredictable circumstances may negate the usefulness of this
5、standard in specific instances. NACE and SSPC assume no responsibility for the interpretation or use of this standard by other parties, and accept responsibility for only those official NACE or SSPC interpretations issued by NACE or SSPC in accordance with their governing procedures and policies, wh
6、ich preclude the issuance of interpretations by individual volunteers. Users of this NACE/SSPC standard are responsible for reviewing appropriate health, safety, and regulatory documents and for determining their applicability in relation to this standard prior to its use. This NACE/SSPC standard ma
7、y not necessarily address all potential health and safety problems or environmental hazards associated with the use of materials, equipment, and/or operations detailed or referred to within this standard. Users of this NACE/SSPC standard also are responsible for establishing appropriate health, safe
8、ty, and environmental protection practices, in consultation with appropriate regulatory authorities if necessary, to achieve compliance with any existing applicable regulatory requirements prior to the use of this standard. CAUTIONARY NOTICE: NACE/SSPC joint surface preparation standards are subject
9、 to periodic review, and may be revised or withdrawn at any time in accordance with NACE/SSPC technical committee procedures. NACE and SSPC require that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of initial publication and subsequently from
10、the date of each reaffirmation or revision. The user is cautioned to obtain the latest edition. Purchasers of NACE/SSPC standards may receive current information on all standards and other NACE/SSPC joint publications by contacting the organizations at the addresses below: ISBN 1-57590-326-1 Approve
11、d Date: 2015-03-14 NACE International 15835 Park Ten Place Houston, TX 77084-5145 +1 281-228-6200 2015, NACE International SSPC: The Society for Protective Coatings 800 Trumbull Drive Pittsburgh, PA 15205 +1-412-281-2331 2015, SSPC: The Society for Protective Coatings NACE SP1015 WAB ITEM No. 21401
12、NACE WAB-4/SSPC-SP 7 (WAB) NACE International i _ Foreword This NACE/SSPC joint standard defines the process for preparing a carbon steel surface to the Brush-Off degree of surface cleanliness using a wet abrasive blast (WAB) method of cleaning. This standard is intended for use by coating or lining
13、 specifiers, applicators, inspectors, or others whose responsibility is to define a standard degree of surface cleanliness for carbon steel surfaces to be achieved by wet abrasive blast cleaning. WAB cleaning is a process using a mixture of water and abrasive that can produce various levels of surfa
14、ce cleanliness and surface profile (roughness) similar to those obtained with dry abrasive blast (DAB) cleaning. WAB cleaning may be specified when dust suppression is desired, and may also be a means for reducing soluble salt contamination. The WAB cleanliness level specified should be the same as
15、the corresponding degree of cleaning specified if DAB cleaning were the process being used. The focus of this standard is Brush-Off WAB Cleaning. The five degrees of WAB cleaning are as follows: Degree of Surface Cleanliness Designation White Metal WAB NACE WAB-1/SSPC-SP 5 (WAB)1 Near-White Metal WA
16、B NACE WAB-2/SSPC-SP 10 (WAB)2 Commercial WAB NACE WAB-3/SSPC-SP 6 (WAB) 3 Industrial WAB NACE WAB-8/SSPC-SP 14 (WAB)4 Brush-Off WAB NACE WAB-4/SSPC-SP 7 (WAB) Brush-off WAB cleaning provides a lesser degree of cleaning than Industrial WAB cleaning NACE WAB-8/ SSPC-SP 14 (WAB).4 The difference betwe
17、en an Industrial WAB cleaning and a Brush-Off WAB cleaning is that the objective of a Brush-Off WAB cleaning is to allow as much of an existing adherent coating to remain as possible and to roughen the surface before coating application. Industrial WAB Cleaning allows tightly adherent paint, mill sc
18、ale and rust to remain on no more than 10% of each unit area of surface. This standard references the three levels of flash rust as defined in the NACE/SSPC joint standards for waterjetting (see Paragraph 3.1).5-8 Additional information regarding flash rust is provided in Nonmandatory Appendixes A,
19、B, and C. Steel surfaces prepared by WAB cleaning can develop flash rust within minutes after the cleaning is completed. The project specification often contains requirements for the permissible level of flash rust before coating application. Additional information is provided in Paragraph A1 of App
20、endix A and in Appendix C. NACE WAB-4/SSPC-SP 7 (WAB) ii NACE International This standard was prepared in 2015 by NACE/SSPC Joint Task Group (TG) 350E, “Brush-Off Blast Cleaning Surface Preparation by Wet Abrasive Blast Cleaning.” TG 350E is administered by NACE Specific Technology Group (STG) 04, “
21、Coatings and Linings, Protective: Surface Preparation”; and SSPC C.2 Surface Preparation Group Committee. This joint standard is issued by NACE/SSPC under the auspices of NACE STG 04 and SSPC C.2. This standard is one of a set of five standards on the degrees of surface cleanliness to be achieved by
22、 WAB cleaning. In NACE/SSPC standards, the terms shall, must, should, and may are used in accordance with the definitions of these terms in the NACE/SSPC Joint Publications Style Manual, Paragraph 2.2.1.8. Shall and must are used to state mandatory requirements. The term should is used to state some
23、thing considered good and is recommended but is not mandatory. The term may is used to state something considered optional. _ NACE International iii _ STANDARD PRACTICE SSPC SURFACE PREPARATION STANDARD NACE WAB-4/SSPC-SP 7 (WAB) Brush-Off Wet Abrasive Blast Cleaning Contents 1. General 1 2. Definit
24、ions .1 3. Additional Technical Considerations .1 4. Associated Documents .2 5. Procedures before Wet Abrasive Blast Cleaning .2 6. Wet Abrasive Blast Cleaning Methods .3 7. Wet Abrasive Blast Cleaning Materials 3 8. Procedures Following Wet Abrasive Blast Cleaning and Immediate before Coating .3 Re
25、ferences 4 Appendix A: Explanatory Notes (Nonmandatory) 5 Appendix B: Procedures and Process Controls (Nonmandatory) 9 Appendix C: Methods of Assessing the Degree of Flash Rust (Nonmandatory) 9 TABLE C1: Assessment of Degree of Flash RushTape Pull Test 9 _ NACE WAB-4/SSPC-SP 7 (WAB) NACE Internation
26、al 1 _ Section 1: General 1.1 A WAB-cleaned surface is one prepared by combining water and abrasive in a blast cleaning operation by one of several methods, including 1) injection of water into the abrasive stream either internally or externally as the abrasive stream exits the blast nozzle; 2) inje
27、ction of abrasive into pressurized water; or 3) use of an abrasive slurry under pressure to achieve the specified WAB degree of cleanliness. 1.2 This standard defines the Brush-Off Wet Abrasive Blast Cleaning (NACE WAB-4/SSPC-SP 7 WAB) degree of visible surface cleanliness of uncoated or coated stee
28、l surfaces achieved by the use of wet abrasive blast cleaning. The requirements include the end condition of the surface as determined by visual inspection, and materials and procedures used to achieve and verify the end condition. 1.3 This standard is limited to requirements for visible surface con
29、taminants. Additional information on nonvisible contamination is provided in Paragraph A2 of Appendix A. Additional information on soluble salt testing is provided in SSPC-Guide 15.9 1.4 Information about the function of WAB cleaning is provided in Paragraph A3 of Appendix A. 1.5 Information about u
30、se of this standard in maintenance coating work is provided in Paragraph A4 of Appendix A. _ Section 2: Definition 2.1 Brush-Off WAB Cleaned Surface: A brush-off WAB cleaned surface, when viewed without magnification, shall be free of all visible oil, grease, dirt, dust, loose mill scale, loose rust
31、, and loose coating. Tightly adherent mill scale, rust, and coating may remain on the surface. Mill scale, rust, and coating are considered tightly adherent if they cannot be removed by lifting with a dull putty knife after abrasive blast cleaning has been performed. 2.1.1 The entire surface shall b
32、e subjected to the wet abrasive blast. The remaining mill scale, rust, or coating shall be tight. Flecks of the underlying steel need not be exposed whenever the original substrate consists of intact coating. _ Section 3: Additional Technical Considerations 3.1 Flash Rust: Flash rust is an oxidation
33、 product that forms as a wetted carbon steel substrate dries. Flash rust is an additional consideration when a carbon steel substrate is subjected to WAB cleaning. Additional information is provided in Section 8. Degrees of flash rust may be qualitatively described as follows: 3.1.1 No flash rust: A
34、 carbon steel surface that, when viewed without magnification, exhibits no visible flash rust. 3.1.2 Light (L) flash rusted surface: A carbon steel surface that, when viewed without magnification, exhibits small quantities of a rust layer through which the carbon steel substrate may be observed. The
35、 rust or discoloration may be evenly distributed or present in patches, but it is tightly adherent and not easily removed by lightly wiping with a cloth. (Table C1 in Appendix C provides flash rust evaluation criteria if the tape pull test is specified for assessing the degree of flash rust.) 3.1.3
36、Moderate (M) flash rusted surface: A carbon steel surface that, when viewed without magnification, exhibits a layer of rust that obscures the original carbon steel surface. The rust layer may be evenly distributed or present in patches, but it is reasonably well adherent and leaves light marks on a
37、cloth that is lightly wiped over the surface. (Table C1 in Appendix C provides flash rust evaluation criteria if the tape pull test is specified for assessing the degree of flash rust.) 3.1.4 Heavy (H) flash rusted surface: A carbon steel surface that, when viewed without magnification, exhibits a l
38、ayer of heavy rust that hides the original carbon steel surface completely. The rust may be evenly distributed or present in patches, but it is loosely adherent, easily comes off, and leaves significant marks on a cloth that is lightly wiped over the surface. (Table C1 in Appendix C provides flash r
39、ust evaluation criteria if the tape pull test is specified for assessing the degree of flash rust.) 3.1.5 Additional information is provided in Paragraphs A3, A5, A6, and A7 of Appendix A. Additional information on methods of assessing the degree of flash rust is provided in Appendix C. NACE WAB-4/S
40、SPC-SP 7 (WAB) 2 NACE International 3.1.6 NOTE: When performing the wipe test mentioned in Paragraphs 3.1.2, 3.1.3, and 3.1.4 and described in Paragraph C2 of Appendix C, the angular profile that results from surface preparation using WAB cleaning can pull lint from a cloth. The pressure sensitive t
41、ape pull test, which is an alternate technique for determining the level of flash rust that does not involve cloth and will not deposit lint on a WAB-cleaned surface, is described in Appendix C. 3.2 Appearance Variations 3.2.1 Acceptable variations in appearance that do not affect the degree of surf
42、ace cleanliness defined in Paragraph 2.1 include variations caused by composition of the metallic substrate, original surface condition, thickness of the metal, weld metal, mill or fabrication marks, heat treating, heat-affected zones, and differences resulting from the abrasive blast pattern. 3.2.2
43、 The visual appearance of WAB-cleaned surfaces is not necessarily the same as the visual appearance of DAB cleaned surfaces. Visual guides or reference photographs, such as SSPC-VIS 1,10 prepared as a guide to the amount of material or staining allowed to remain on the cleaned surface for the variou
44、s degrees of DAB cleaning, do not depict the appearance of the flash rust that often occurs with WAB cleaning. Visual guides or reference photographs prepared for DAB cleaned surfaces must not be used as inspection or judgment criteria for WAB-cleaned surfaces. Direct correlation to existing dry abr
45、asive blasting standards and visual comparators may be inaccurate, inappropriate, or both. 3.3 NACE VIS-9/SSPC-VIS 5 or other visual guide or comparator may be specified to supplement the written definition.11 In any dispute, the written standard shall take precedence over the visual guide or compar
46、ator. Additional information is provided in Paragraph A6 of Appendix A and in Appendix B. _ Section 4: Associated Documents 4.1 Documents cited in the mandatory sections of this standard include: Document Title SSPC-AB 112 Mineral and Slag Abrasives SSPC-SP 113 Solvent Cleaning ASTM D 428515 ASTM(1)
47、 D428514 Method for Indicating the Presence of Oil or Water in Compressed Air 4.2 The latest issue, revision, or amendment of the documents listed in Paragraph 4.1 in effect on the date of invitation to bid shall govern unless otherwise specified. 4.3 If there is a conflict between the requirements of any of the documents listed in Paragraph 4.1 and this standard, the requirements of this standard shall prevail. _ Section 5: Procedures Before Wet Abrasive Blast Cleaning 5.1 Precleaning: Visible d
