()sspc the society for protective coatings Item No. 21065 Joint Surface Preparation Standard NACE No. 1/SSPC-SP 5 White Metal Blast Cleaning ‘This NACE International (NACE/SSPC: The Socity for Protective Coatings standard represents a ‘consensus of thoee individual members who have reviewed this document, ils scope, and Provisions It js intended to aid the manufacture, the consumer, and the general public. Its ‘acceptance does not in any respect preclude anyone, whether he has adopted the standard or not, ‘rom manufacturing, marketing, purchasing, of using products, processes, or procedures not addressed in this standard. Nothing contained in this NACE/SSPC standard is to be construed a. granting any right, by implication or otherwise, to manufacture, sell, or use in connection with any Tethod, apparatus, or product covered by Letters Patent, or as indemrifying or protecting anyone ‘against ably for irfringemient of Letters Patent. This standard represents current technology and should in no way be interpreted as a restriction on the use of better procedures or materiale [Neither is this standard Intended to apply in all cases relating to the subject. Unpredictable circumstances may negate the usefulness ofthis standard in specific instances. NACE and SPC. ‘assume ro responsibilty for the interpretation or use of this standard by other partes and accent Fesponsiblity or only those official interpretations issued by NACE or SSPC in accordance with their governing procedures and policies which preclude the issuance of interpretations by individu volunteers Users of this NACEISSPC standard are responsible for reviewing appropriate health, safety, ‘environmental, and regulatory documents and fer determining their applicability in relation to this Standard prior to its use. This NACE/SSPC standard may not necessarily address all potential hhealth and safely problems or environmental hazards associated with the use of material equipment, andlor operations detailed or referred to within this standerd. Users of this, NACE/SSPC standard are also responsible for establishing appropriate health, safely, 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to the Use ofthis standard CAUTIONARY NOTICE: NACEISSPC standards are subject to periodic review, and may be Fevised or withdrawn at any time without prior notice. The user is cautioned to obtain the latest edition, NACE and SSPC requir thal action be taken to reaffim, revise, or withdraw this standard To later than five years from the date of inital pubication, Roaffimmed 1999-09-07 Approved October 1994 ISBN 1-87590-107-2 (©2000, SSPC: The Society for Protective Coatings NACE International 'SSPC: The Society for Protective Coatings P.O. Box 218340 40 2ath Steet, Sixth Floor Houston, TX 77218-8340 Pittsburgh, PA 15222 olephone +1 281/228-6200) (telephone #1 412/281-2381) Printed by NACE InternationalNACE No. 4/SSPC-SP 5 Foreword ‘This joint standard covers the use of bast clearing abrasives to achieve a defined degree of clearing of stool surfaces prior to the application of a protective coating or lining system. This standard is intended for use by coating oF fining specifiers, applicators, inspectors, or others who may be responsible for defining a standard degree of surface cleanness “The focus of ths standard is white metal blast cleaning. Near-white metal blast cleaning, cornmercia blast cleaning, industrial blast clearing, and brushoff blast clearing are addressed in separate standards wie mata last demning rove a greater dre of searing fan near metal Best clear (NACE No. 2/SSPC-SP 10" “The diference between a white metal blast and a near-white metal bast is that a wite metal blast removes all ofthe coating mil scale, rust, oxides, corosion products, and other foreign matter from the surface. Near-white metal blasting allows light shadows, slight streaks, or minor discolorations ‘caused by stains of rust stains of mil sale, or stains of previously applied costing to remain on no Imore than § percent of each unit area of surface as defined in Paragraph 2.6 of NACE No. 2/SSPC- SP 10. ‘This join standard was orginally prepared in 1994 and reaffirmed in 2000 by the SSPCINACE Task Group Aon Surface Preparation by Abrasive Blast Clearing. Ths joint Task Group includes members of both the SSPC Surface Preparation Committee and the NACE Unit Committee T-66 on Surface Preparation, ‘NAGE No 25SP0-SP 10 (latest evslon), "‘NaarWhte Mota Blast Cleaning" Houston, TX: NACE, and Pitsburgh, PA: SSO) NACE International 1NACE No. 1/SSPC-SP 5 Joint Surface Preparation Standard NACE No. 1/SSPC-SP 5 White Metal Blast Cleaning Contents General Definition References Procedures Before Blast Cleaning Blast Cleaning Methods and Operation Blast Cleaning Abrasives svn Procedures Following Blast Cleaning and Immediately Prior to Coating Inspection Safety and Environmental Requirements 10. Comments «..rsnnnnsessnnnnninn ‘Appendix A: Explanatory Notes 1 1 cod 1 2 2 "2 3 3 3 3 Wi NACE InternationalSection 1: Gener 1.1. This joint standard covers the requirements for white metal blast cleaning of unpainted or painted steel surfaces. by the use of abrasives. These requirements inciude the nition ofthe surface and materials and procedures. necessary to achieve and very the end condition, NACE No, 1/SSPC-SP 5 1.2 The mandatory requirements are described in Sections 1'to 8. NOTE: Section 10, “Comments,* and Appendix A, “Brplanatory Notes,” are not mandatory requirements of tis stand. Section 2: Definition 241 A white metal biast cleaned surface, when viewed ‘without magnification, shall be free of all isible cil, grease, ‘dust, dt, mill scale, rust, coating, oxides, corrosion products, and other foreign matter. 2.2 Acceptable variations in appearance that do not affect surface cleanliness as defined in Paragraph 2.1 include ‘variations caused by type of steel, original surace condition, thickness of the ste), weld metal, mil or fabrication marke, heat treating, heataffected zones, blasting abrasives, and NAGE No. SSPC-S! 6 (last rovsion), “loin Suace Praparaton Standard Wrhta Metal Blest Cleaning (Housten, TA: NAGE, and Ptsburgh, PA: SPC) NACE InternationalNACE No. 1/SSPC-SP 5 the steel during preparation. While such embecment or residues are normally not detrimental, care should be taken to ensure that the abrasive i fee from detimental amounts Gf water-soluble, solventsoluble, acid-eoluble, or other Soluble contaminants (particular if the prepared steel is to be used in an immersion environmert). Criteria for ‘selecting and evaluating abrasives are given in SSPC-AB 1 SSPC-AB 2, and SSPC-AB 3. 3. SURFACE PROFILE: Surface profieis the roughness Of the surface that results from abrasive blast cleaning. The profile depth (or height) is dependent on the size, shepe, ype, and hardness of the abrasive, partcle velocity and ange of impact, hardness of the surface, amount of Tecyaling, and the proper maintagance of working mixtures of git andlor sho “The allowable minimum/maximum height of profieis usually dependent on the thiokness of the coating to be applied. Large partclesized abrasives (partcularly metalic) can prosuce a profile that may be too deep to be adequately Covered by a single thin fim coat. Accordingly. it is Tecommended that the use of larger abrasives be avoided in these cases, However, larger abrasives may be needed for thiekcfim coatings of to faciltate removal of thick coatings, heavy mil scale, or rust if contol of profile (minimurimaximum) is deemed to be significant to coating performance, i should be addressed in the procurement Gocuments (project specication). Typical maximum profile heights achieved with commercial sbrasive media are shown in Table & of SSPC-SP COM. Surface profile should be measured in accordance with NACE Standard RpO2e7!” “Field Measurement of Surface Profle of Abrasive Blast Cleaned Stoel, Surfaces Using Replica Tape,” or ASTM D 4417," “Test Method for Field Measurement of Surface Profie of Bast Cleaned Stool” Ad VISUAL STANDARDS: Note that the use of visual ‘standards or comparators in conjunction with this standard is required. only When specifed in. the procurement document (project specification) covering the work. Howaver, itis stongly recommended that the procurement document require the use of ‘visual standards or comparators. SSPC-Vie 1-89 pfovides color photographs for the various grades of surface preparation as a function ofthe inital condition of the steal. The series A-SP 5, B-SP 5, CSP 5, and D-SP 5 depicts surfaces cleaned to white metal grada. In adstion, the series A-SP 5 M and N depicts (NACE Standard RPO287 (latest “Tape (Houston, TX: NACE) FRSINe 100 Gar Harbor Dnve, Conshohocken, PA 18428-2950. ssufaces cleaned by various metalic. and nonmetalic Abrasives to SP 5 condition. The NACE “Visual Comparator for Surface Finishing of Welds Prior to Coating” is a plastic. weld replica that complements NACE Standard Rpot7e" “Fabrication Details, Surface Finish Requirements, and Proper Design Considerations for Tanks land Vessels to Be Lined for Immersion Service.” Other ‘vaiable visual standards are deserved in Secton 7 of 'SSPC-SP COM. AS SURFACE IMPERFECTIONS: Surface impertectons ‘can cause premature failure when the service is severe Coatings tend to pull away from sharp edges and projections, leaving litle of no coating to protect the Underlying steel. Other features that are dificult to properly Cover and protect include crevices, weld porosites, Tarninations, ete. The high oost of the mathods to remedy surface imperfections requires weighing the benefits of edge rounding, wald spatter removal, etc, against the costs ‘of a potential coating failure Poorly adhering contaminants, such as weld slag resicues, Joose weld spatter, and some minor surface laminations. may be removed dising the blast clearing operation. Other Surface defects (ste! laminations, weld porosities, or deep Corosion pits) may not be evident untl the surface preparation has been completed. Proper planning for such Etatace repair work is essential because the timing of the fepairs may occur before, during, oF after the blast cleaning operation. Section 4 of SSPC-SP COM and NACE Standard RPO178 contain additional information on surface imperfections. ‘AG CHEMICAL CONTAMINATION: Stee! contaminated with soluble salts (2g, chlordes and sulfates) develops rus back rap at intermediate and high levis of humiciy These soluble salts can be present on the steel surface prior to blast cleaning as a result of almospheric Contamination. In addition, contaminants can be deposited fon the steel eurface during blast cleaning if the abrasive is Contaminated. Therefore, rustback can be minimized by Femoving these salts from the steel surface and eliminating Souroes of recontamination during and afte biast clesning Wet methods of removal are desatibed in NACE_No. 5ISSPC-SP 12," "Surface Preparation of Steel and Other Hard Matale by High- and Utrahigh Pressure Water ating Prior to Recoating” Identification of the ion), "Feld Measuroment of Surface Prfe of Abasive Blast Cleaned Stoo! Suse Using a Replica 12 ASIN Baan? (atest rovsior), “Standard Test Methods for Feld Measurement of Suface Profle of Blast Cleaned Stoo” (West ‘Gonshohocken, PA: ASTM), Earn oor for Surface Finishing of Welds Prior to Coating” Visual Ad fr Use with NACE Standard RPOTTE (latest revision), (ieuston, TX: NACE) Pre Send RPO17®(lateat revision, "Ftsicatlon Detabs, Surface Finish Requirements, and Proper Design Considerations for Tanks and Veesaeto Bo Linod fr Immasion Servi R'NAGE No, S/SSPC-SP 12 (atest revsion), (Wouston, 7X: NACE). vataos Proparation of Steel and Other Hard Materials by High: and Utrahigh Pressure Waker “leting Povo Revealing” (Houston, TX: NACE, ana Pitsburgh, PA: SSPC), 4 NACE Internationalcontaminants along with their concentrations may be obtained from, laboratory and field tests as desoribed in ‘SSPC-TU 4," “Technology Update on Field Methods for Retrieval and Analysis of Soluble Salis on Substrates" AT RUST-BACK: Rust-back occurs when freshly cleaned sted is exposed to moisture, contamination, or a corosive aimosphere, The time interval botween blast clearing and Tust-back varies greatly from one environment to ancther. Under mild ambient conditions, i chemical contamination is not present (see Paragraph AB), itis best to blast clean and Coat a surface on the same day, Severe conditions may Fequire a_more expedient coating application to avoid contamination from fallout. Chemical contamination should be removed prior to coating (see Paragraph A6). AB. DEW POINT: Moisture condenses on any surface that is colder than the dew point of the surrounding air. tis, therefore, recommended that the temperature of the stee! surface be a least °C (5°F) above the dew point during dry Blast cleaning operations, It is advisable to visually inspect for moisture and periodically check the surface temperature ‘and dew point during bast clearing operations and to avoid the application of coating over a damp surface A. WET ABRASIVE BLAST CLEANING: Steel that is wet abrasive blast cleaned may rust rapidly. Clean water should be used for rinsing, It may bo necessary to add inhibitors. to the water or apply them to the suface immediately after blast clearing to temporarily prevent rust formation. The use of intibters or the application of coating NACE No, 1/SSPC-SP 5 cover slight discoloration should be in accordance with the Fequirements of the coating manufacturer. CAUTION: Some inhibive treatments may intefere with the performance of certain coating systems. AMOFILM THICKNESS: tis essential that ample coating be applied afer blast clearing to adequately cover the peaks of the surface profile. ‘The dry-fim thickness of the ‘coating above the peaks of the profile should equal thickness known to be neoded forthe desired protection. If the drefim thickness over the peaks is inadequate, rematire rustthrough or falure will occur. To assure thal Coating thicknesses are propery measured the procedures in SSPC-PA 2,” "Measurement of Dry Coating Thickness with Magnetic Gauges" should be used. AT MAINTENANCE ANO REPAIR PAINTING: When this standard is used in maintenance painting, spectic instructions should be provided on the extent of surface to be blast cleaned or spot blast cleaned to this degree of cleanliness. In these cases, the cleaning shall be performed aoross the entire specified area For example, i fll weld seame are to be cleaned in a maintenance operation, this degree of clearing shall be applied 100% to all weld seams. Ifthe entre structure isto be prepared, this degree of clearing chall be a 100% of the entre stusture — SSPC-PA 4") “Guide to Maintenance Repainting with Oi Base oe Alkyd Painting Systems,” provides a description of accepted practices for retaining old ‘sound coating, removing unsound coating, feathering, and ‘spot cleaning (5 SSPC-TU a (atest revision), “Field Methods for Retioval and Analysis of Scluble Sats on Substrates" (Pitsburgh, PA: SPO) {17 SSPC-PA2 (latent rovison), "Measurement f Dry Coating Thickness wih Magnetic Gages” (Pitsburgh, PA: SSO} (" SSPC-A 4 (latent ovslon), “Guide to Malntonarce Paring wih Ol B NACE International or Alkyd Painting Sytoms”(Pitsburgh, PA: SSPC)