ASTM_D_4940_-_15_2020.pdf

Designation:D494015(Reapproved 2020)Standard Test Method forConductimetric Analysis of Water Soluble IonicContamination of Blast Cleaning Abrasives1This standard is issued under the fixed designation D4940;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes a procedure for assessingblast cleaning abrasives for the presence of conductive-potential,ionic contaminants by determining the total concen-tration of water soluble conductive species using a conductivitytest.1.2 This test method does not identify the ionic speciespresent nor provide quantitative results on each species.1.3 This test method is based on a volume comparisonamong abrasives of similar sizes.A volume comparison ismore closely related to surface area of the abrasives than is aweight comparison.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE832 Specification for Laboratory Filter Papers2.2 Other Standard:ISO 11127-6 Preparation of Steel Substrates before Applica-tion of Paints and Related Products-Test Methods forNon-Metallic Blast Cleaning Abrasives-Part 6:Determi-nation of Water-Soluble Contaminants by ConductivityMeasurement32.3 SSPC:The Society for Protective Coatings:4SSPC-AB 1 Mineral and Slag AbrasivesSSPC-AB 2 Cleanliness of Recycled Ferrous Metallic Abra-siveSSPC-AB 3 Ferrous Metallic AbrasiveSSPC-AB 4 Recyclable Encapsulated Abrasive Media3.Summary of Test Method3.1 Abrasive and pure water are combined into a slurry thatis stirred to leach the soluble salts from the abrasive.Thisslurry is filtered and conductance of the filtrate is measured.The conductivity,which is related to the concentration ofsoluble ionic materials contaminating the abrasive,is calcu-lated from the conductance and the cell constant.4.Significance and Use4.1 Abrasive media may contain ionic contamination natu-rally(for example,beach sand),from manufacturing(quench-ing with contaminated water),transportation,storage or use(inthe case of abrasive that is reused).Ionic contamination on theabrasive may transfer to the surface during abrasive blastcleaning,resulting in potential osmotic blistering,acceleratedunderfilm corrosion and premature coating failure.4.2 This test method describes a shop/field procedure forassessing the level of conductive species on an abrasive.4.3 Abrasive standards published by SSPC(AB)and ISO11126 provide tolerance levels for water soluble contaminantsof the abrasive.5.Apparatus5.1 Conductivity Bridge and CellAny commercial con-ductivity bridge and conductivity cell typically having a range1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.46 on Industrial Protective Coatings.Current edition approved Feb.1,2020.Published February 2020.Originallyapproved in 1989.Last previous edition approved in 2015 as D4940 151.DOI:10.1520/D4940-15R20.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.4Available from Society for Protective Coatings(SSPC),40 24th St.,6th Floor,Pittsburgh,PA 15222-4656,http:/www.sspc.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.of at least 5 mho/cm to 10 000 mho cm with built-intemperature compensation is satisfactory.A dip-type,pipet-type,or cup-type cell may be used.5.2 Filter Paper,conforming to Sp