作者:标准资料网 时间:2024-05-15 09:48:10   浏览:8223   来源:标准资料网

【英文标准名称】:StandardPracticeforPerformingAcceleratedOutdoorWeatheringofNonmetallicMaterialsUsingConcentratedNaturalSunlight
【原文标准名称】:使用集中自然光对非金属材料进行加速室外候化的标准实施规程
【标准号】:ASTMG90-2010
【标准状态】:现行
【国别】:美国
【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】:G03.02
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:durability;exposure;fresnel-reflector;weathering;Acceleratedaging/testing--buildingmaterials;Acceleratedweathering;Durability--paints/relatedmaterials;Exposuretests--atmospheric;Fresnel-reflectorsystem;Mirrors;Nonmetallicmaterials;Outdoo
【摘要】:Resultsobtainedfromthispracticecanbeusedtocomparetherelativedurabilityofmaterialssubjectedtothespecifictestcycleused.Noacceleratedexposuretestcanbespecifiedasatotalsimulationofnaturalorfieldexposures.Resultsobtainedfromthispracticecanbeconsideredasrepresentativeofnaturalorfieldexposuresonlywhenthedegreeofcomparativeperformancehasbeenestablishedforthespecificmaterialsbeingtested.TherelativedurabilityofmaterialsinnaturalorfieldexposurecanbeverydifferentdependingonthelocationoftheexposurebecauseofdifferencesinUVradiation,timeofwetness,temperature,pollutants,andotherfactors.Therefore,evenifresultsfromaspecificacceleratedtestconditionarefoundtobeusefulforcomparingtherelativedurabilityofmaterialsexposedinaparticularexteriorlocation,itcannotbeassumedthattheywillbeusefulfordeterminingrelativedurabilityforadifferentlocation.Theuseofasingleaccelerationfactorrelatingtherateofdegradationinthisacceleratedexposuretotherateofdegradationinaconventionalexteriorexposureisnotrecommendedbecausetheaccelerationfactorvarieswiththetypeandformulationofthematerial.Eachmaterialandformulationmayresponddifferentlytotheincreasedlevelofirradianceanddifferencesintemperatureandhumidity.Thusanaccelerationfactordeterminedforonematerialmaynotbeapplicabletoothermaterials.Becauseofvariabilityintestresultsunderbothacceleratedandconventionalexteriorexposuresresultsfromasufficientnumberoftestsmustbeobtainedtodetermineanaccelerationfactorforamaterial.Further,theaccelerationfactorisapplicabletoonlyoneexteriorexposurelocationbecauseresultsfromconventionalexteriorexposurescanvaryduetoseasonalorannualdifferencesinimportantclimaticfactors.Variationsinresultsmaybeexpectedwhenoperatingconditionsvarywithinthelimitsofthispractice.Forexample,therecanbelargedifferencesintheamountofdegradationinasinglematerialbetweenseparate,althoughsupposedlyidentical,exposurescarriedoutforthesamedurationornumberofexposurecycles.Thispracticeisbestusedtocomparetherelativeperformanceofmaterialstestedatthesametimeinthesamefresnelreflectordevice.Becauseofpossiblevariabilitybetweenthesametypeofexposuredeviceandvariabilityinirradiance,temperatureandmoisturelevelsatdifferenttimes,comparingtheamountofdegradationinmaterialsexposedforthesamedurationorradiantenergyatseparatetimesisnotrecommended.Thispracticeshouldnotbeusedtoestablishax201C;pass/failx201D;approvalofmaterialsafteraspecificperiodofexposureunlessperformancecomparisonsaremaderelativetoacontrolmaterialexposedsimultaneously,orthevariabilityinthetestisdefinedsothatstatisticallysignificantpass/failjudgementscanbemade.Itisstronglyrecommendedthatatleastonecontroltestspecimenbeexposedwitheachtest.ThecontroltestspecimenshouldmeettherequirementsofTerminologyG113,andbechosensothatitsfailuremodeisthesameasthatofthetestspecimen.Itispreferabletousetwocontroltestspecimens,onewithrelativelygooddurabilityandonewithrelativelypoordurability.Theuseofatleasttworeplicatesofeachcontroltestspecimenandeachmaterialbeingevaluatedisrecommended.ConsultGuideG169forperformingstatisticalanalysis.1.1Fresnel-reflectingconcentratorsusingthesunassourceareutilizedintheacceleratedoutdoorexposuretestingofnonmetallicmaterials.......
【中国标准分类号】:H25
【国际标准分类号】:
【页数】:11P.;A4
【正文语种】:英语