Designation:C1258−08(Reapproved2013)StandardTestMethodforElevatedTemperatureandHumidityResistanceofVaporRetardersforInsulation1ThisstandardisissuedunderthefixeddesignationC1258;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1ThistestmethodcoversthedeterminationoftheagingresistanceofflexiblelowpermeancevaporretardersforthermalinsulationasclassifiedinSpecificationC1136.Watervaporpermeancemeasurementandvisualinspectionafterexposureatelevatedtemperatureandhumidityareusedtoassessvaporretarderresponse.1.2Typicalvaporretardersapplicabletothistestmethodthatareintendedforindooruseincludefoil-scrim-kraftlaminates,metallizedpolyester-scrim-kraftlaminates,treatedfabrics,treatedpapers,films,foils,orcombinationsofthesematerialsthatmaycompriseavaporretardermaterial.Thistestmethodisnotintendedforassessmentoftheliquid-appliedcoatings,sealants,ormasticscommonlyusedwithinsulationproducts.1.3Thevaluesstatedininch-poundunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesaremathematicalconversionstoSIunitsthatareprovidedforinformationonlyandarenotconsideredstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2C168TerminologyRelatingtoThermalInsulationC1136SpecificationforFlexible,LowPermeanceVaporRetardersforThermalInsulationE96/E96MTestMethodsforWaterVaporTransmissionofMaterials3.Terminology3.1TerminologyC168shallbeconsideredasapplyingtothetermsusedinthisspecification.4.SummaryofTestMethod4.1Thevaporretardersaresubjectedtoacceleratedagingviaelevatedtemperatureandhumidityat120°F(49°C)and95%relativehumidityforaperiodof28days,thenv...
