ASTM_D_662_-_93_2019.pdf

Designation:D66293(Reapproved 2019)Standard Test Method forEvaluating Degree of Erosion of Exterior Paints1This standard is issued under the fixed designation D662;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers the evaluation of the degree oferosion of exterior paints by comparison with photographicstandards.1.2 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:2D4214 Test Methods for Evaluating the Degree of Chalkingof Exterior Paint Films2.2 Other Standards:Pictorial Standards of Coating Defects Handbook33.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 erosion,nthat phenomenon manifested in paint filmsby the wearing away of the finish to expose the substrate orundercoat.3.1.1.1 DiscussionThe degree of failure is dependent onthe amount of substrate or undercoat visible.Erosion occurs asthe result of chalking.(See Test Methods D4214 for evaluationof chalking.)4.Significance and Use4.1 Erosion failure of paint films can occur in use.This testmethod provides a mean of evaluating the degree of failure bycomparing to pictorial standards.5.Types of Erosion5.1 Only one type of erosion is recognized,as defined inSection 3.6.Use of Photographic Reference Standards6.1 The photographic reference standards that are part ofthis test method and are provided in the Pictorial Standards ofCoating Defects Handbook are representative of the degree oferosion of exterior paint films.Fig.1 is for illustration purposesonly and should not be used for evaluation.6.2 The use of the photographic reference standards3illus-trated in Fig.1 requires the following precautions:6.2.1 Care must be taken not to confuse various types offailure that may be present on the same surface.6.2.2 It must be realized that the degree of failure will varyover any given area.Therefore,an average portion of the filmshould be used for comparison.On larger surfaces it isrecommended that ratings be made at several locations and themean and range reported.6.2.3 The photographic standards used represent variousdegrees of erosion of a white brushing type paint over a darkprimer.This system was necessary to provide sufficient con-trast for photographic purposes.The erosion of a film to itsnormal substrate is,however,readily visible to the naked eyeso it may easily be compared to the standards and given anumerical rating.6.2.4 In doubtful cases,erosion is sometimes more visible ina damp film than in a dry film.Also,with severe erosion,it isoften easier to rate the degree of erosion in a damp film than ina dry film.6.2.5 While erosion of a sprayed film is more regular in itswearing away,a numerical rating can be given to it byinterpreting the amount of erosion in terms of these standards.6.3 For convenience in recording the data obtained,therecords should be kept on forms agreed upon between thepurchaser and the seller.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.25 on Evaluation of Weathering Effects.Current edition approved Oct.1,2019.Published October 2019.Originallyapproved in 1942.Last previous edition approved in 2011 as D662 93(2011).DOI:10.1520/D0662-93R19.2For 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.3Copies of the pictorial photographic reference standards are contained in thepublication Pictorial Standards of Coatings Defects and may be obtained from theFederation of Societies for Coatings Technology,492 Norristown Rd.,Blue Bell,PA19422.The silver halide-gelatin photographs are intended to be the only primaryreference standards for this method.The reproductions of them in this test methodare for the purpose of illustration only.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.1 7.Precision and Bi