ASTM E681-2009 化学药品易燃浓缩限度的测试方法

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【英文标准名称】:StandardTestMethodforConcentrationLimitsofFlammabilityofChemicals(VaporsandGases)
【原文标准名称】:化学药品易燃浓缩限度的测试方法
【标准号】:ASTME681-2009
【标准状态】:现行
【国别】:美国
【发布日期】:2009
【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】:E27.04
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:Chemicalanalysis--chemicals;Chemicals(fire/flammabilitytesting);Flammability--chemicals;Hazardassessment/potential--liquidchemicals;HCFC(hydrochlorofluorocarbon);Ignition--chemicals;Limitsofflammability(ofchemicals);Vaporphaseanalysis/p
【摘要】:TheLFLandUFLofgasesandvaporsdefinetherangeofflammableconcentrationsinair.5.2ThismethodmeasurestheLFLandUFLforupward(andpartiallyoutward)flamepropagation.Thelimitsfordownwardflamepropagationarenarrower.Limitsofflammabilitymaybeusedtodetermineguidelinesforthesafehandlingofvolatilechemicals.Theyareusedparticularlyinassessingventilationrequirementsforthehandlingofgasesandvapors.NFPA69providesguidanceforthepracticaluseofflammabilitylimitdata,includingtheappropriatesafetymarginstouse.5.4AsdiscussedinBrandesandUral,thereisafundamentaldifferencebetweentheASTMandEuropeanmethodsforflammabilitydetermination.TheASTMmethodsaimtoproducethebestrepresentationofflammabilityparameters,andrelyuponthesafetymarginsimposedbytheapplicationstandards,suchasNFPA69.Ontheotherhand,Europeantestmethodsaimtoresultinaconservativerepresentationofflammabilityparameters.Forexample,inthisstandard,LFListhecalculatedaverageofthelowestgoandhighestno-goconcentrationswhiletheEuropeantestmethodsreporttheLFLastheminimumofthe5highestno-goconcentrations.Note28212;Forhydrocarbons,thebreakpointbetweennonflammabilityandflammabilityoccursoveranarrowconcentrationrangeatthelowerflammabilitylimit,butthebreakpointislessdistinctattheupperlimit.Formaterialsfoundtobenon-reproducibleper13.1.1thatarelikelytohavelargequenchingdistancesandmaybedifficulttoignite,suchasammoniaandcertainhalogenatedhydrocarbon,thelowerandupperlimitsofthesematerialsmaybothbelessdistinct.Thatis,awiderrangeexistsbetweenflammableandnonflammableconcentrations(seeAnnexA1).1.1Thistestmethodcoversthedeterminationofthelowerandupperconcentrationlimitsofflammabilityofchemicalshavingsufficientvaporpressuretoformflammablemixturesinairatatmosphericpressureatthetesttemperature.Thistestmethodmaybeusedtodeterminetheselimitsinthepresenceofinertdilutiongases.Nooxidantstrongerthanairshouldbeused.Note18212;Thelowerflammabilitylimit(LFL)andupperflammabilitylimit(UFL)aresometimesreferredtoasthelowerexplosivelimit(LEL)andtheupperexplosivelimit(UEL),respectively.However,sincethetermsLELandUELarealsousedtodenoteconcentrationsotherthanthelimitsdefinedinthistestmethod,onemustexaminethedefinitionscloselywhenLELandUELvaluesarereportedorused.1.2Thistestmethodisbasedonelectricalignitionandvisualobservationsofflamepropagation.Usersmayexperienceproblemsiftheflamesaredifficulttoobserve(forexample,irregularpropagationorinsufficientluminescenceinthevisiblespectrum),ifthetestmaterialrequireslargeignitionenergy,orifthematerialhaslargequenchingdistances.1.3AnnexA1providesamodifiedtestmethodformaterials(suchascertainamines,halogenatedmaterials,andthelike)withlargequenchingdistanceswhichmaybedifficulttoignite.1.4Inothersituationswherestrongignitionsources(suchasdirectflameignition)isconsideredcredible,theuseofatestmethodemployinghigherenergyignitionsourceinasufficientlylargepressurechamber(analogous,forexample,tothemethodsinTestMethodE2079formeasuringlimitingoxygenconcentration)maybemoreappropriate.Inthiscase,expertadvicemaybenecessary.1.5Theflammabilitylimitsdependonthetesttemperatureandpressure.Thistestmethodislimitedtoaninitialpressureofthelocalamb......
【中国标准分类号】:G04
【国际标准分类号】:71_080_01
【页数】:12P.;A4
【正文语种】:英语