Designation:F1249−13StandardTestMethodforWaterVaporTransmissionRateThroughPlasticFilmandSheetingUsingaModulatedInfraredSensor1ThisstandardisissuedunderthefixeddesignationF1249;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversaprocedurefordeterminingtherateofwatervaportransmissionthroughflexiblebarriermaterials.Themethodisapplicabletosheetsandfilmsupto3mm(0.1in.)inthickness,consistingofsingleormultilayersyntheticornaturalpolymersandfoils,includingcoatedmaterials.Itprovidesforthedeterminationof(1)watervaportransmissionrate(WVTR),(2)thepermeanceofthefilmtowatervapor,and(3)forhomogeneousmaterials,watervaporpermeabilitycoefficient.NOTE1—Valuesforwatervaporpermeanceandwatervaporperme-abilitymustbeusedwithcaution.TheinverserelationshipofWVTRtothicknessandthedirectrelationshipofWVTRtothepartialpressuredifferentialofwatervapormaynotalwaysapply.1.2Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D374TestMethodsforThicknessofSolidElectricalInsu-lation(Withdrawn2013)3D1898PracticeforSamplingofPlastics(Withdrawn1998)3E96/E96MTestMethodsforWaterVaporTransmissionofMaterialsE104PracticeforMaintainingConstantRelativeHumiditybyMeansofAqueousSolutionsE177PracticeforUseoftheTermsPrecisionandBiasinASTMTestMethodsE178PracticeforDealingWithOutlyingObservationsE691PracticeforConductinganInterlaboratoryStudytoDeterminethePrecisionofaTestMethod3.Terminology3.1Definitions:3.1.1watervaporpermeabilitycoeffıcient—theproductofthepermeanceandthethicknessofthefilm.Thepermeabilityismeaningfulonlyforhomogeneousmaterials,inwhichcaseitis...
