ASTMDb23b4075753000370525(&Designation:D621-64(Reapproved1988)"AnAmericanNationalStandardAMERICANSOCIETYFORTESTINGANDMATERIALS1916RaceSt.,Philadelphia,Pa.19103ReprintedfromtheAnnualBookofASTMStandards,CopyrightASTMIfnotlistedinthecurrentcombinedIndex,willappearinthenextedition.StandardTestMethodsforDeformationofPlasticsUnderLoad'ThisstandardisissuedunderthefixeddesignationD621;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.ThesetestmethodshavebeenapprovedjbrwebyagenciesoftheDepartmentofDefinsetoreplaceMethod1101ofFederalTesthfetliodStandard406.andforListingintheDoDIndexofSpecijicationsandStandards.Nor€-ThesafetyhazardscaveatandthePrecisionandBiassectionwereaddededitoriallyinMarch1988.TheReferencedDocumentssectionwasalsoadded,causingtherenumberingofsubsequentsections.1.Scope1.1Thesetestmethodscoverthedeterminationofthedeformationundercompressionofnonmetallicsheetandmoldedplasticmaterials,ofallclassesandailcommercialthicknesses,intendedforstructuralandinsulatingpurposes.Twotestmethodsareincluded,asfollows:TestMethodA-Forrigidplastics.TestMethodB-Fornonrigidplastics.1.2Theworddeformationisusedhereininthebroadsensetocover(I)dimensionalchangeduealmostentirelytoflow,and(2)dimensionalchangeduetoacombinationofflowandshrinkagecausedbylossofwaterorothervolatilematter.Thewordflowasusedinthesetestmethodsmaydescribeeitherplasticorelasticdeformationorcombinationsthereof.NOTE1-ThevaluesstatedinSIunitsaretoberegardedasthestandard.NOTE2-Methylmethacrylateandpolystyreneareexamplesofmateriaisthatdeformalmostentirelybyflow.Celluloseacetate,celluloseacetatebutyrate,phenoliclaminatedfiber,andvulcanizedfiberareexamplesofmaterialsthatdeformbyacombinationofflowandshrinkage.1.3Thisstandardmayinvolvehazardoicsmaterials,oper-alìons,andeqtiipntent.Thisstandarddoesnotpurporttoaddressal...
