ASTM_D_772_-_86_2011.pdf

Designation:D77286(Reapproved 2011)Standard Test Method forEvaluating Degree of Flaking(Scaling)of Exterior Paints1This standard is issued under the fixed designation D772;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 Department of Defense.1.Scope1.1 This test method covers the evaluation of the degree offlaking(scaling)of exterior paints by comparison with photo-graphic standards.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:2D1150 Single and Multi-Panel Forms for Recording Resultsof Exposure Tests of Paints2.2 Other Standards:Pictorial Standards of Coating Defects Handbook33.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 flaking(scaling),nthat phenomenon manifested inpaint films by the actual detachment of pieces of the film itselfeither from its substrate or from paint previously applied.3.1.1.1 DiscussionFlaking(scaling)is generally precededby cracking or checking or blistering,and is the result of lossof adhesion,usually due to stress-strain factors coming intoplay.4.Significance and Use4.1 Flaking(scaling)failure of paint films can occur in use.This test method provides a means of evaluating the degree offailure by comparing to pictorial standards.5.Type of Flaking(Scaling)5.1 Only one type of flaking(scaling)is recognized,asdefined in Section 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 ofcracking of exterior paint films.Fig.1 is for illustrationpurposes only 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 degree of failure will vary overany 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 In technical literature,a distinction is sometimes madebetween flaking and scaling.In most cases,however,flakingand scaling refer to the same phenomenon.In some instances,the term flaking is used to describe the detachment of pieces offilm less than 6.4 mm(14in.)in size,and scaling,thedetachment of pieces over14in.in size.In other instances,theterm flaking is used to describe the detachment of pieces offilm from the immediate undercoat(intercoat failure)andscaling the detachment of pieces from the base(completefailure).It should be kept in mind that the flakes may varywidely in size and shape from those illustrated by the referencestandards in Fig.1,varying from a fraction of an inch to severalinches in size.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 Nov.1,2011.Published November 2011.Originallyapproved in 1944.Last previous edition approved in 2005 as D772 86(2005).DOI:10.1520/D0772-86R11.2For 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 States1 FIG.1 Degrees of Flaking(Scaling)D772 86(2011)2 FIG.1 Degrees of Flaking(Scaling)(continued)D772 86(2011)3 6.2.4 Peeling is frequently due to a moisture condition andwhen this is evident it should be taken into consideration in anyevaluation.6.2.5 For convenience in recording the data obtained,therecords may be