【英文标准名称】:StandardPracticeforSelectionofWaterVaporRetardersforThermalInsulation
【原文标准名称】:热绝缘用水蒸气缓凝剂选择的标准实施规程
【标准号】:ASTMC755-2010
【标准状态】:现行
【国别】:
【发布日期】:2010
【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】:C16.33
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:设计;材料;选择;隔热
【英文主题词】:design;materials;selection;thermalinsulation
【摘要】:Experiencehasshownthatuncontrolledwaterentryintothermalinsulationisthemostseriousfactorcausingimpairedperformance.Waterentryintoaninsulationsystemmaybethroughdiffusionofwatervapor,airleakagecarryingwatervapor,andleakageofsurfacewater.Applicationspecificationsforinsulationsystemsthatoperatebelowambientdew-pointtemperaturesshouldincludeanadequatevaporretardersystem.Thismaybeseparateanddistinctfromtheinsulationsystemormaybeanintegralpartofit.Forselectionofadequateretardersystemstocontrolvapordiffusion,itisnecessarytoestablishacceptablepracticesandstandards.VaporRetarderFunction8212;Waterentryintoaninsulationsystemmaybethroughdiffusionofwatervapor,airleakagecarryingwatervapor,andleakageofsurfacewater.Theprimaryfunctionofavaporretarderistocontrolmovementofdiffusingwatervaporintoorthroughapermeableinsulationsystem.Thevaporretardersystemaloneisseldomintendedtopreventeitherentryofsurfacewaterorairleakage,butitmaybeconsideredasasecondlineofdefense.VaporRetarderPerformance8212;Designchoiceofretarderswillbeaffectedbythicknessofretardermaterials,substratetowhichapplied,thenumberofjoints,availablelengthandwidthofsheetmaterials,usefullifeofthesystem,andinspectionprocedures.Eachofthesefactorswillhaveaneffectontheretardersystemperformanceandeachmustbeconsideredandevaluatedbythedesigner.Althoughthispracticeproperlyplacesmajoremphasisonselectingthebestvaporretarders,itmustberecognizedthatfaultyinstallationtechniquescanimpairvaporretarderperformance.Theeffectivenessofinstallationorapplicationtechniquesinobtainingdesignwatervaportransmission(WVT)performancemustbeconsideredintheselectionofretardermaterials.Asanexampleoftheevaluationrequired,itmaybeimpracticaltospecifyalowerx201C;asinstalledx201D;value,becausedifficultiesoffieldapplicationoftenwillprecludex201C;asinstalledx201D;attainmentoftheinherentWVTvaluesofthevaporretardermaterialsused.Thedesignercouldapproachthisrequirementbyselectingamembraneretardermaterialthathasalowerpermeancemanufacturedin5-ft(1.5-m)widthorasheetmaterial20ft(6.1m)widehavingahigherpermeance.Thesealternativesmaybeapproximatelyequivalentonaninstalledbasissincethewidermaterialhasfewerseamsandjoints.Foranotherexample,whenselectingmasticorcoatingretardermaterials,thechoiceofaproducthavingapermeancevaluesomewhathigherthanthelowestobtainablemightbejustifiedonthebasisofitseasierapplicationtechniques,thusensuringx201C;asinstalledx201D;systemattainmentofthespecifiedpermeance.Thepermeanceofthesubstrateanditseffectsontheapplicationoftheretardermaterialmustalsobeconsideredinthiscase.1.1Thispracticeoutlinesfactorstobeconsidered,describesdesignprinciplesandproceduresforwatervaporretarderselection,anddefineswatervaportransmissionvaluesappropriateforestablishedcriteria.Itisintendedfortheguidanceofdesignengineersinpreparingvaporretarderapplicationspecificationsforcontrolofwatervaporflowthroughthermalinsulation.Itcoverscommercialandresidentialbuildingconstructionandindustrialapplicationsintheservicetemperaturerangefromx2212;40to+150x00B0;F(x2212;40to......
【中国标准分类号】:
【国际标准分类号】:91_120_10
【页数】:12P.;A4
【正文语种】:


【英文标准名称】:Photography(Sensitometry)-DensityMeasurements-SpectralConditions
【原文标准名称】:摄影(感光测定).密度测量.光谱条件
【标准号】:ANSIPH2.18-1985
【标准状态】:作废
【国别】:美国
【发布日期】:1985
【实施或试行日期】:
【发布单位】:美国国家标准学会(ANSI)
【起草单位】:ANSI
【标准类型】:()
【标准水平】:()
【中文主题词】:摄影;感光测定;光密度
【英文主题词】:opticaldensity;photography;sensitometry
【摘要】:
【中国标准分类号】:A15
【国际标准分类号】:37_040_00;37_040_20
【页数】:19P;A4
【正文语种】:英语