ASTM_D_5064_-_16a_2021.pdf

Designation:D506416a(Reapproved 2021)Standard Practice forConducting a Patch Test to Assess Coating Compatibility1This standard is issued under the fixed designation D5064;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 practice covers the procedures for assessing coat-ing compatibility when maintenance of an in-place coatingsystem is being contemplated.It does not address proceduresfor assessing the integrity of the existing coating to determineif it can be repainted,nor does it establish the compatibility ofthe maintenance coating system with the substrate or corrosionproducts.The practice is intended for use in the field.SSPC-TU 3 discusses the risks associated with the mainte-nance painting practice known as overcoating.NOTE1Pass-Fail Criteria(for example,adhesion requirements)arenot established by this practice.These should be established by the user orspecifier with input from the coating manufacturer.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 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.1.4 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:2D16 Terminology for Paint,Related Coatings,Materials,andApplicationsD3359 Test Methods for Rating Adhesion by Tape TestD4138 Practices for Measurement of Dry Film Thickness ofProtective Coating Systems by Destructive,Cross-Sectioning MeansD4414 Practice for Measurement of Wet Film Thickness byNotch GagesD4541 Test Method for Pull-Off Strength of Coatings UsingPortable Adhesion TestersD6132 Test Method for Nondestructive Measurement of DryFilm Thickness of Applied Organic Coatings Using anUltrasonic Coating Thickness GageD6677 Test Method for Evaluating Adhesion by KnifeD7091 Practice for Nondestructive Measurement of DryFilm Thickness of Nonmagnetic Coatings Applied toFerrous Metals and Nonmagnetic,Nonconductive Coat-ings Applied to Non-Ferrous MetalsD7234 Test Method for Pull-Off Adhesion Strength of Coat-ings on Concrete Using Portable Pull-Off Adhesion Tes-ters2.2 SSPC Standards:3TU 3 Technology Update No.3 Overcoating3.Terminology3.1 DefinitionsFor definitions of terms used in thispractice,refer to Terminology D16.4.Summary of Test Method4.1 The materials under test are applied to the previouslypainted surface after surface preparation.After the appropriatetime has elapsed,the test patch is examined for visual defectsand adhesion is assessed.5.Significance and Use5.1 In performing maintenance of a coating system,the newcoating being applied must be compatible with the existingcoating.While general guides exist which indicate compatibil-ity of different generic types of coatings,differences inmanufacturers formulation and the condition of the in-placecoating system may affect compatibility.6.Procedure6.1 Select test locations for evaluation that adequatelycharacterize differences in configuration of the structure and1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.46 on Industrial Protective Coatings.Current edition approved June 1,2021.Published June 2021.Originallyapproved in 1990.Last previous edition approved in 2016 as D5064 16a.DOI:10.1520/D5064-16AR21.2For 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 Society for Protective Coatings(SSPC),800 Trumbull Drive,Pittsburgh,PA 15205,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.1the exposure environment;that is,vertical versus horizontalsurfaces;sheltered versus unsheltered exposure;atmosphericverses splash zone or immersion.