NACE NO 4-2000 Brush-Off Blast Cleaning (Item No 21068 SSPC-SP 7).pdf

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1、 Item No. 21068 Joint Surface Preparation Standard NACE No. 4/SSPC-SP 7 Brush-Off Blast Cleaning This NACE International (NACE)/The Society for Protective Coatings (SSPC) standard represents a consensus of those individual members who have reviewed this document, its scope, and provisions. It is int

2、ended to aid the manufacturer, the consumer, and the general public. 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 addressed in this standard. Nothi

3、ng contained in this NACE/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 Le

4、tters Patent. This standard represents current technology and should in no way be interpreted as a restriction on the use of better procedures or materials. 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 interpretations issued by NACE or SSPC in accordance with their governing procedures and policies which preclude th

6、e issuance of interpretations by individual volunteers. Users of this NACE/SSPC standard are responsible for reviewing appropriate health, safety, environmental, 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 are also 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 standards are subject to periodic review, and m

9、ay be revised or withdrawn at any time in accordance with technical committee procedures. The user is cautioned to obtain the latest edition. 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. Reaff

10、irmed 2006-09-13 Revised 2000-06-16 Approved October 1994 ISBN 1-57590-102-1 2006, SSPC: The Society for Protective Coatings and NACE International NACE International 1440 South Creek Dr. Houston, TX 77084-4906 (telephone +1 281/228-6200) SSPC: The Society for Protective Coatings 40 24th Street, Six

11、th Floor Pittsburgh, PA 15222 (telephone +1 412/281-2331) Printed by NACE InternationalNACE No. 4/SSPC-SP 7 NACE International i _ Foreword This joint standard covers the use of blast cleaning abrasives to achieve a defined degree of cleaning of steel surfaces prior to the application of a protectiv

12、e coating or lining system. This standard is intended for use by coating or lining specifiers, applicators, inspectors, or others who may be responsible for defining a standard degree of surface cleanliness. The focus of this standard is brush-off blast cleaning. White metal blast cleaning, near-whi

13、te metal blast cleaning, commercial blast cleaning, and industrial blast cleaning are addressed in separate standards. Brush-off blast cleaning provides a lesser degree of cleaning than industrial blast cleaning (NACE No. 8/SSPC-SP 141). The difference between an industrial blast cleaning and a brus

14、h-off blast cleaning is that the objective of a brush-off blast cleaning is to allow as much of an existing adherent coating to remain as possible and to roughen the surface prior to coating application, whereas the purpose of the industrial blast cleaning is to remove most of the coating, mill scal

15、e, and rust, while the extra effort required to remove every trace of these is determined to be unwarranted. This joint standard was originally prepared in 1994 and revised in 2000 by the SSPC/NACE Task Group (TG) A on Surface Preparation by Abrasive Blast Cleaning. This joint TG includes members of

16、 both the SSPC Surface Preparation Committee and the NACE Unit Committee T-6G on Surface Preparation. It was reaffirmed in 2006 by NACE Specific Technology Group (STG) 04, Protective Coatings and Linings: Surface Preparation, and the SSPC Surface Preparation Committee. In NACE/SSPC standards, the te

17、rms 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 state mandatory requirements. The term should is used to state something considered good and

18、is recommended but is not mandatory. The term may is used to state something considered optional. _ NACE No. 4/SSPC-SP 7 ii NACE International _ Joint Surface Preparation Standard NACE No. 4/SSPC-SP 7 Brush-Off Blast Cleaning Contents 1. General 1 2. Definition 1 3. Associated Documents 1 4. Procedu

19、res Before Cleaning 1 5. Blast Cleaning Methods and Operation . 2 6. Blast Cleaning Abrasives . 2 7. Procedures Following Blast Cleaning and Immediately Prior to Coating 2 8. Inspection . 3 9. Safety and Environmental Requirements 3 10. Comments (Nonmandatory) 3 References 4 Appendix A: Explanatory

20、Notes (Nonmandatory). 4 _ NACE No. 4/SSPC-SP 7 NACE International 1 _ Section 1: General 1.1 This joint standard covers the requirements for brush-off blast cleaning of uncoated or coated steel surfaces by the use of abrasives. These requirements include the end condition of the surface and material

21、s and procedures necessary to achieve and verify the end condition. 1.2 The mandatory requirements are described in Sections 1 to 9. Section 10, “Comments,” and Appendix A,“Explanatory Notes,” are not mandatory requirements of this standard. 1.3 Information about the function of brush-off blast clea

22、ning is in Paragraph A1 of Appendix A. 1.4 Information about use of this standard in maintenance coating work is in Paragraph A2 of Appendix A. _ Section 2: Definitions 2.1 Brush-Off Blast Cleaned Surface: A brush-off blast cleaned surface, when viewed without magnification, shall be free of all vis

23、ible oil, grease, dirt, dust, loose mill scale, loose rust, 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 cle

24、aning has been performed. 2.1.1 The entire surface shall be subjected to the 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. 2.1.2 SSPC-VIS 12may be specified to

25、supplement the written definition. In any dispute, the written definition set forth in this standard shall take precedence over reference photographs and comparators. Additional information on reference photographs and comparators is in Paragraph A3 of Appendix A. _ Section 3: Associated Documents 3

26、.1 The latest issue, revision, or amendment of the documents listed in Paragraph 3.3 in effect on the date of invitation to bid shall govern unless otherwise specified. 3.2 If there is a conflict between the requirements of any of the documents listed in Paragraph 3.3 and this standard, the requirem

27、ents of this standard shall prevail. 3.3 Documents cited in the mandatory sections of this standard include: Document Title SSPC-AB 13Mineral and Slag Abrasives SSPC-AB 24Cleanliness of Recycled Ferrous Metallic Abrasives SSPC-AB 35Ferrous Metallic Abrasives SSPC-SP 16Solvent Cleaning SSPC-VIS 1 Gui

28、de and Reference Photographs for Steel Surfaces Prepared by Dry Abrasive Blast Cleaning _ Section 4: Procedures Before Cleaning 4.1 Before blast cleaning, visible deposits of oil, grease, or other contaminants shall be removed in accordance with SSPC-SP 1 or other agreed-upon methods. 4.2 Before bla

29、st cleaning, surface imperfections such as sharp fins, sharp edges, weld spatter, or burning slag should be removed from the surface to the extent required by the procurement documents (project specification). Additional information on surface imperfections is in Paragraph A4 of Appendix A. 4.3 If r

30、eference photographs or comparators are specified to supplement the written standard, the condition of the steel prior to blast cleaning should be determined before the blasting commences. Additional information on reference photographs and comparators is in Paragraph A3 of Appendix A. NACE No. 4/SS

31、PC-SP 7 2 NACE International _ Section 5: Blast Cleaning Methods and Operation 5.1 Clean, dry compressed air shall be used for nozzle blasting. Moisture separators, oil separators, traps, or other equipment may be necessary to achieve this requirement. 5.2 Any of the following methods of surface pre

32、paration may be used to achieve a brush-off blast cleaned surface: 5.2.1 Dry abrasive blasting using compressed air, blast nozzles, and abrasive. 5.2.2 Dry abrasive blasting using a closed-cycle, recirculating abrasive system with compressed air, blast nozzle, and abrasive, with or without vacuum fo

33、rdust and abrasive recovery. 5.2.3 Dry abrasive blasting using a closed-cycle, recirculating abrasive system with centrifugal wheels and abrasive. 5.3 Other methods of surface preparation (such as wet abrasive blast cleaning) may be used to achieve a brush-offl blast cleaned surface by mutual agreem

34、ent between those responsible for establishing the requirements and those responsible for performing the work. Information on the use of inhibitors to prevent the formation of rust immediately after wet abrasive blast cleaning is in Paragraph A5 of Appendix A. _ Section 6: Blast Cleaning Abrasives 6

35、.1 The selection of abrasive size and type shall be based on the type, grade, and surface condition of the steel to be cleaned, the type of blast cleaning system used, the finished surface to be produced (cleanliness and surface profile roughness), and whether the abrasive will be recycled. 6.2 The

36、cleanliness and size of recycled abrasives shall be maintained to ensure compliance with this standard. 6.3 The blast cleaning abrasive shall be dry and free of oil, grease, and other contaminants as determined by the test methods found in SSPC-AB 1, SSPC-AB 2, and SSPC-AB 3. 6.4 Any limitations on

37、the use of specific abrasives, the quantity of contaminants, or the degree of allowable embedment shall be included in the procurement documents (project specification) covering the work, because abrasive embedment and abrasives containing contaminants may not be acceptable for some service requirem

38、ents. Additional information on abrasive selection is in Paragraph A6 of Appendix A. 6.5 When a coating is specified, the cleaned surface shall be roughened to a degree suitable for the specified coating system. Additional information on surface profile and the film thickness of coating applied over

39、 the surface profile is in Paragraphs A7 and A8 of Appendix A. _ Section 7: Procedures Following Blast Cleaning and Immediately Prior to Coating 7.1 Visible deposits of oil, grease, or other contaminants shall be removed according to SSPC-SP 1 or another method agreed upon by those parties responsib

40、le for establishing the requirements and those responsible for performing the work. 7.2 Dust and loose residues shall be removed from prepared surfaces by brushing; blowing off with clean, dry air; vacuum cleaning; or other methods agreed upon by those responsible for establishing the requirements a

41、nd those responsible for performing the work. 7.2.1 The presence of toxic metals in the abrasives or coating being removed may place restrictions on the methods of cleaning permitted. The chosen method shall comply with all applicable regulations. 7.2.2 Moisture separators, oil separators, traps, or

42、 other equipment may be necessary to achieve clean, dry air. 7.3 After blast cleaning, any remaining surface imperfections (e.g., sharp fins, sharp edges, weld spatter, burning slag, scabs, slivers) shall be removed to the extent required by the procurement documents (project specification). Any dam

43、age to the surface profile resulting from the removal of surface imperfections shall be corrected to meet the requirements of Paragraph 6.5. Additional information on surface imperfections is in Paragraph A4 of Appendix A. 7.4 Immediately prior to coating application, the entire surface shall comply

44、 with the degree of cleaning specified in this standard. Information on chemical contamination, rust-back (rerusting), and the effect of dew point (surface condensation) is in Paragraphs A9, A10, and A11 of Appendix A. NACE No. 4/SSPC-SP 7 NACE International 3 _ Section 8: Inspection 8.1 Work perfor

45、med and materials supplied under this standard are subject to inspection by a representative of those responsible for establishing the requirements. Materials and work areas shall be accessible to the inspector. The procedures and times of inspection shall be as agreed upon by those responsible for

46、establishing the requirements and those responsible for performing the work. 8.2 Conditions not complying with this standard shall be corrected. In the case of a dispute, an arbitration or settlement procedure established in the procurement documents (project specification) shall be followed. If no

47、arbitration or settlement procedure is established, a procedure mutually agreeable to purchaser and supplier shall be used. 8.3 The procurement documents (project specification) should establish the responsibility for inspection and for any required affidavit certifying compliance with the specification. _