Designation:D2221−01(Reapproved2021)StandardTestMethodforCreepPropertiesofPackageCushioningMaterials1ThisstandardisissuedunderthefixeddesignationD2221;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thistestmethodcoversthedeterminationofcreeppropertiesofpackagecushioningmaterials.Itisapplicabletomaterialsavailableinbulk,sheet,ormoldedformusedforthecushioningofarticlesduringstorage,handling,andshipment.1.2Thevaluesstatedininch-poundunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesaremathematicalconversionstoSIunitsthatareprovidedforinformationonlyandarenotconsideredstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.4Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandards:2D4332PracticeforConditioningContainers,Packages,orPackagingComponentsforTestingE105GuideforProbabilitySamplingofMaterialsE122PracticeforCalculatingSampleSizetoEstimate,WithSpecifiedPrecision,theAverageforaCharacteristicofaLotorProcess3.Terminology3.1DefinitionsofTermsSpecifictoThisStandard:3.1.1creep,n—thedeformationofamaterialoccurringwithtimeandduetoanexternallyappliedconstantstress.Forcushioningmaterialsspecifically,itmaybedefinedasthechangeinthicknessofacushionunderstaticcompressiveloadoveraperiodoftime.3.1.2permanentset,n—...
