ASTM_D_5064_-_07_2012.pdf

Designation:D506407(Reapproved 2012)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 testing coatingcompatibility when maintenance of an in-place coating systemis being contemplated.It does not cover procedures forassessing the integrity of the existing coating to determine if itcan be repainted,nor does it establish the compatibility of themaintenance coating system with the substrate or corrosionproducts.The practice is intended for use in the field.NOTE1Pass-Fail Criteria(for example,adhesion requirements)arenot established by this practice.These should be established by the user orspecifier with input from the supplier.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint,Related Coatings,Materials,andApplicationsD3359 Test Methods for Measuring 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 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-ters3.Terminology3.1 DefinitionsFor definitions of terms used in this prac-tice,refer to Terminology D16.4.Summary of Test Method4.1 The materials under test are applied to the previouslypainted surface after proper surface preparation.After theappropriate time has elapsed,the test patch is examined forvisual defects and adhesion is determined.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 may affect compatibility.6.Procedure6.1 Select test locations for evaluation that properly charac-terize differences in configuration of the structure and expo-sure;that is,vertical versus horizontal surfaces and shelteredversus unsheltered exposure.Aminimum of three test locationswith one test patch in each is recommended.6.2 The size of each test patch will be determined by thesize and configuration of the test locations.Each test patchshall be as large as possible,with a minimum size of 1.0 m2(10.8 ft2)recommended.6.3 Prepare the surface of the test areas using the methodsspecified for the maintenance painting procedure(Note 2).Alternative methods of preparation may also be evaluated inseparate,adjacent tests.1This 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 1,2012.Published August 2012.Originallyapproved in 1990.Last previous edition approved in 2007 as D5064 07.DOI:10.1520/D5064-07R12.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 NOTE2This test method assesses compatibility with the existingcoating only and does not apply to areas where the substrate is exposed bythe methods of preparation.6.4 Measure the existing coating thickness in accordancewith Test Methods D6132,D4138,or Practice D7091,asappropriate for the substrate.6.5 Measure the ambient conditions and surface temperatureand assure the conditions are within the limits specified by thecoatings manufacturer for the product being tested.6.6 Apply the test coating to the thickness recommended for