1、 Joint Surface Preparation Standard Waterjet Cleaning of MetalsVery Thorough Cleaning (WJ-2) This NACE International/SSPC: The Society for Protective Coatings joint surface preparation standard represents a consensus of those individual members who have reviewed this document, its scope, and provisi
2、ons. 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 NACE/SSPC standard is to be
3、 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 standard represents minimum r
4、equirements 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 standard in specific inst
5、ances. 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, which preclude the issuance
6、 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 may not necessarily address
7、 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, safety, and environmental pro
8、tection 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 to periodic review, and
9、may be revised or withdrawn at any time in accordance with NACE/SSPC technical committee procedures.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 the date of each reaffirm
10、ation 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 1-57590-249-4 2012, NACE and SSPC NACE Interna
11、tional The Society for Protective Coatings 1440 South Creek Drive 40 24thStreet, 6thFloor Houston, TX 77084-4906 Pittsburgh, PA 15222-4656 +1 281-228-6200 +1 412-281-2331 Approved: 2012-03-10 Printed by NACE International Item No. 21155 NACE WJ-2/SSPC-SP WJ 2 NACE International i _ Foreword This NAC
12、E/SSPC joint standard defines the Very Thorough Cleaning (WJ-2) degree of surface cleanliness of coated or uncoated metallic substrates achieved by the use of waterjet cleaning prior to the application of a protective coating or lining. Waterjet cleaning is the use of pressurized surface preparation
13、 water for removing coatings and other materials, including hazardous materials, from a substrate to achieve a defined degree of surface cleanliness. Waterjet cleaning includes various methods such as low-pressure water cleaning (LP WC), high-pressure water cleaning (HP WC), high-pressure waterjetti
14、ng (HP WJ), and ultrahigh-pressure waterjetting (UHP WJ). The four degrees of surface cleanliness achieved by waterjet cleaning, which are addressed in separate standards, are as follows: Degree of Surface Cleanliness Designation Cleaning to Bare Substrate WJ-1 Very Thorough Cleaning WJ-2 Thorough C
15、leaning WJ-3 Light Cleaning WJ-4 Very Thorough Cleaning (WJ-2) provides a greater degree of surface cleanliness than Thorough Cleaning (WJ-3), but a lesser degree of surface cleanliness than Cleaning to Bare Substrate (WJ-1). Waterjet cleaning to achieve the Very Thorough Cleaning (WJ-2) degree of s
16、urface cleanliness is used when the objective is to remove almost all rust and other corrosion products, coating, and mill scale, but when the extra effort required to remove all of these materials is determined to be unwarranted. Discoloration of the surface may be present. Waterjet cleaning does n
17、ot provide the primary anchor pattern on the metallic substrate known as “surface profile.” The coatings industry uses waterjet cleaning primarily for recoating or relining projects in which there is an adequate pre-existing surface profile. The degrees of surface cleanliness cited above to be achie
18、ved by waterjet cleaning methods are not intended to require that a surface profile be present or defined prior to coating application. Waterjet cleaning reduces and may completely remove water-soluble surface contaminants, notably those contaminants found at the bottom of pits on the surface of cor
19、roded metallic substrates. Waterjet cleaning also helps to remove oil, grease, rust and other corrosion products, and other foreign matter (for example, shotcrete spatter) from the surface, and is used when it is a more feasible method of surface preparation than, for example, abrasive blast cleanin
20、g, power or hand tool cleaning, or chemical stripping. Waterjet cleaning may be used when application of high-performance coatings requires extensive surface preparation, surface decontamination, or both. This standard is intended for use by coating or lining specifiers, applicators, inspectors, or
21、others who have responsibility to define a standard degree of surface cleanliness to be achieved by waterjet cleaning methods. NACE WJ-2/SSPC-SP WJ 2 ii NACE International This standard was prepared by NACE/SSPC Joint Task Group (TG) 276, “Surface Preparation of Metals to WJ-2 (Very Thorough or Subs
22、tantial Cleaning) by High-Pressure Waterjetting.” TG 276 is administered by Specific Technology Group (STG) 04, “Coatings and Linings, ProtectiveSurface Preparation,” and is sponsored by STG 02, “Coatings and Linings, ProtectiveAtmospheric,” and STG 03, “Coatings and Linings, ProtectiveImmersion and
23、 Buried Service.” This standard is issued by NACE under the auspices of STG 04, and by SSPC Group Committee C.2 on Surface Preparation. This standard is one of a set of four standards on degrees of surface cleanliness to be achieved by waterjet cleaning that are intended to replace NACE No. 5/SSPC-S
24、P 12,1which includes all four degrees of surface cleanliness. In NACE/SSPC standards, the terms shall, must, should, and may are used in accordance with Paragraph 2.2.1.8 of the Agreement between NACE International and SSPC: The Society for Protective Coatings. The terms shall and must are used to s
25、tate mandatory requirements. The term should is used to state something considered good and is recommended but is not mandatory. The term may is used to state something considered optional. _ NACE WJ-2/SSPC-SP WJ 2 NACE International iii _ NACE/SSPC Joint Surface Preparation Standard Waterjet Cleani
26、ng of MetalsVery Thorough Cleaning (WJ-2) Contents 1. General 1 2. Definitions 1 3. Additional Technical Considerations 2 4. Associated Documents 2 5. Procedures Before Waterjet Cleaning3 6. Waterjet Cleaning Methods 3 7. Procedures Following Waterjet Cleaning and Immediately Prior to Coating 4 Refe
27、rences 4 Appendix A: Explanatory Notes .5 Appendix B: Methods of Assessing the Degree of Flash Rust .8 Appendix C: Waterjet Cleaning Equipment and Operating Parameters .9 TABLE B1: Assessment of Degree of Flash RustTape Pull Test 9 _ NACE WJ-2/SSPC-SP WJ 2 NACE International 1 _ Section 1: General 1
28、.1 This standard defines the Very Thorough Cleaning (WJ-2) degree of surface cleanliness of uncoated or coated metallic substrates by use of waterjet cleaning. The defined degree of cleanliness shall be achieved prior to the application of a specified protective coating or lining system. These requi
29、rements include the end condition of the surface and materials and procedures necessary to achieve and verify the end condition, as determined by visual inspection. This standard also may be used in situations in which the degree of surface cleanliness is required, but protective coatings or linings
30、 are not immediately applied. (Paragraphs A1 and A2 of Appendix A provide additional information.) Waterjet cleaning does not establish but may reveal an existing surface profile on a metallic substrate. If the existing surface profile is not acceptable for subsequent coating application, alternativ
31、e surface preparation methods to create the required surface profile must be considered. (Paragraph A3 of Appendix A provides additional information.) 1.1.1 Very Thorough Cleaning (WJ-2) is essentially equivalent to the International Organization for Standardization (ISO)(1) 8501-42degree of cleanli
32、ness Wa 2.5, very thorough cleaning. ISO 8501-4 notes the use of various common terms for methods of waterjet cleaning: water jetting, water blast cleaning, hydrojetting, aquajetting, hydroblasting, aquablasting, and “cleaning by directing a jet of pressurized water onto the surface to be cleaned.”
33、1.1.2 Within the hierarchy of degrees of surface cleanliness achieved by waterjet cleaning, Very Thorough Cleaning (WJ-2) is intended to be similar to the degree of surface cleanliness of NACE No. 2/SSPC-SP 10,3 except that tightly adherent material, rather than only stains, is permitted to remain o
34、n the surface. 1.2 Although carbon steel is the metallic substrate most frequently cleaned in the field using waterjetting technology, waterjet cleaning may be used on metallic substrates other than carbon steel, including ferrous substrates such as alloy steels, stainless steels, ductile iron, and
35、cast irons, nonferrous substrates such as aluminum, and copper alloys such as bronze. For convenience, the written definitions of the degrees of surface cleanliness of the metallic substrate use the general term “rust and other corrosion products.” The term “rust” is intended to apply to carbon stee
36、l substrates and the term “other corrosion products” (such as surface oxides) is intended to apply to metallic substrates other than carbon steel that are being waterjet cleaned. “Flash rust” is an oxidation product that forms as a wetted carbon steel substrate dries. The visual guides and comparato
37、rs referenced for cleanliness and flash rust only illustrate carbon steel substrates. 1.3 This standard does not address waterjet cleaning of concrete. Information on surface preparation of concrete can be found in NACE No. 6/SSPC-SP 13.4 1.4 This standard is limited to requirements for visible surf
38、ace contaminants. Information on nonvisible contamination can be found in Paragraph A8 of Appendix A. _ Section 2: Definitions 2.1 Very Thorough Cleaning (WJ-2): A metal surface after Very Thorough Cleaning, when viewed without magnification, shall have a matte (dull, mottled) finish and shall be fr
39、ee of all visible oil, grease, dirt, rust, and other corrosion products except for randomly dispersed stains of rust and other corrosion products, tightly adherent thin coatings, and other tightly adherent foreign matter. The staining or tightly adherent matter shall be limited to no more than 5 per
40、cent of each unit area of surface and may consist of randomly dispersed stains of rust and other corrosion products or previously applied coating, tightly adherent thin coatings, and other tightly adherent foreign matter. 2.1.2 Coatings, mill scale, and foreign matter are considered tightly adherent
41、 if they cannot be removed by lifting with a dull putty knife. (Paragraphs A4 and A5 of Appendix A provide additional information.) 2.1.3 The gray to brown-black discoloration remaining on corroded and pitted carbon steel that cannot be removed by further waterjet cleaning is not considered part of
42、the percentage staining. 2.1.4 NACE VIS 7/SSPC-VIS 45or other visual guide or comparator may be specified to supplement the written definition. In any dispute, the written standard shall take precedence over the visual guide or comparator. (Paragraph A6 of Appendix A provides additional information.
43、) _ (1)International Organization for Standardization (ISO), 1 ch. de la Voie-Creuse, Case postale 56, CH-1211 Geneva 20, Switzerland. NACE WJ-2/SSPC-SP WJ 2 2 NACE International _ Section 3: Additional Technical Considerations 3.1 Flash Rust Flash rust is an additional consideration when a carbon s
44、teel substrate is subjected to waterjet cleaning. Gray or brown-black discoloration remaining in the pits of waterjet cleaned carbon steel is not the same as flash rust. Metals other than carbon steel can manifest discoloration as well. Degrees of flash rust may be qualitatively described as follows
45、: 3.1.1 No flash rust: A 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 substr
46、ate may be observed. The 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. 3.1.3 Moderate (M) flash rusted surface: A carbon steel surface that, when viewed without magnification, exhibits a layer
47、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 cloth that is lightly wiped over the surface. 3.1.4 Heavy (H) flash rusted surface: A carbon steel surface that, whe
48、n viewed without magnification, exhibits a layer 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. (Paragraphs A6, A9, and A10 of A
