【英文标准名称】:StandardTestMethodforPredictingLong-TermThermalResistanceofClosed-CellFoamInsulation
【原文标准名称】:预测闭孔绝缘泡沫的长期热电阻的标准试验方法
【标准号】:ASTMC1303/C1303M-2011
【标准状态】:现行
【国别】:
【发布日期】:2011
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:C16.30
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:老化;长期热变电阻;LTTR;刚性密闭气泡泡沫塑料;比例因子;绝热;热变电阻;抗老化性;受控测试条件/环境;苯酚塑料;聚异三聚氰脲酯绝缘;聚苯乙烯(PS);聚氨酯绝缘;精确热绝缘;换算;热绝缘材料;热阻/电阻率;无晶面热绝缘
【英文主题词】:aging;long-termthermalresistance;LTTR;rigidclosed-cellplasticfoams;scalingfactors;thermalinsulation;thermalresistance;Agingresistance;Controlledtestingconditions/environments;Phenolicplastics;Polyisocyanurateinsulation;Polystyrene(PS);Polyur
【摘要】:Rigidgas-filledclosed-cellfoaminsulationsincludeallcellularplasticinsulationswhichrelyonablowingagent(orgas),otherthanair,forthermalresistancevalues.Atthetimeofmanufacture,thecellsofthefoamusuallycontaintheirhighestpercentageofblowingagentandthelowestpercentageofatmosphericgases.Astimepasses,therelativeconcentrationsofthesegaseschangedueprimarilytodiffusion.Thisresultsinageneralreductionofthethermalresistanceofthefoamduetoanincreaseinthethermalconductivityoftheresultantcellgasmixture.Thesephenomenaaretypicallyreferredtoasfoamaging.Forsomerigidgas-filledclosed-cellfoaminsulationproductsproducedusingblowingagentgasesthatdiffuseveryrapidlyoutofthefull-thicknessfoamproduct,suchasexpandedpolystyrene,thereisnoneedtoacceleratetheagingprocess.5.1.2Physicalgasdiffusionphenomenaoccurinthreedimensions.Theone-dimensionalformofthediffusionequationsusedinthedevelopmentofthispracticearevalidonlyforplanargeometries,thatis,forspecimensthathaveparallelfacesandwherethethicknessismuchsmallerthanthewidthandmuchsmallerthanthelength.Note38212;PleaseseeAppendixX3foradiscussionofthetheoryofacceleratedagingviathinslicing.Note48212;Theoreticalandexperimentalevaluationsoftheagingofinsulationinradialforms,suchaspipeinsulation,havebeenmade.(6)However,thesepracticeshavenotevolvedtothepointofinclusionintheteststandard.Thechangeinthermalresistanceduetothephenomenadescribedin5.1usuallyoccursoveranextendedperiodoftime.Informationregardingchangesinthethermalresistanceofthesematerialsasafunctionoftimeisrequiredinashorterperiodoftimesothatdecisionsregardingformulations,production,andcomparisonswithothermaterialscanbemade.SpecificationsC578,C591,C1029,C1126andC1289onrigidclosed-cellfoamsmeasurethermalresistanceafterconditioningat23x00B1;1x00B0;C[73x00B1;2x00B0;F]for180x00B1;5daysfromthetimeofmanufactureorat60x00B1;1x00B0;C[140x00B1;2x00B0;F]for90days.Thisconditioningcanbeusedforcomparativepurposes,butisnotsufficienttodescribelong-termthermalresistance.Thisrequirementdemonstratestheimportanceoftheagingphenomenawithinthisclassofproducts.ThePrescriptiveMethodinPartAprovideslong-termthermalresistancevaluesonaconsistentbasisforavarietyofpurposes,includingproductevaluation,specifications,orproductcomparisons.Theconsistentbasisforthesepurposesisprovidedbyaseriesofspecificproceduralconstraints,whicharenotrequiredintheResearchMethoddescribedinPartB.ThevaluesproducedbythePrescriptiveMethodcorrespondtothethermalresistanceatanageoffiveyears,whichcorrespondscloselytotheaveragethermalresistanceovera15-yearservicelife(7,8).Itisrecommendedthatanymaterialstan......