【astm標(biāo)準(zhǔn)】e 2079 - 07 (2013)

1、Designation:E2079?07(Reapproved2013)StardTestMethodsfLimitingOxygen(Oxidant)ConcentrationinGasesVaps1ThisstardisissuedunderthefixeddesignationE2079thenumberimmediatelyfollowingthedesignationindicatestheyearofiginaladopti

2、oninthecaseofrevisiontheyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperepsilon()indicatesaneditialchangesincethelastrevisionreapproval.1.Scope1.1Thesetestmethodscoverthedeterminationoftheli

3、mitingoxygen(oxidant)concentrationofmixturesofoxygen(oxidant)inertgaseswithflammablegasesvapsataspecifiedinitialpressureinitialtemperature.1.2Thesetestmethodsmayalsobeusedtodeterminethelimitingconcentrationofoxidizersoth

4、erthanoxygen.1.3Differentiationamongthedifferentcombustionregimes(suchasthehotflamescoolflamesexothermicreactions)isbeyondthescopeofthesetestmethods.1.4ThevaluesstatedinSIunitsaretoberegardedasstard.Nootherunitsofmeasure

5、mentareincludedinthisstard.1.5Thesetestmethodsshouldbeusedtomeasuredescribethepropertiesofmaterialsproductsassembliesinresponsetoheatflameundercontrolledlabatyconditionsshouldnotbeusedtodescribeappraisethefirehazardfirer

6、iskofmaterialsproductsassembliesunderactualfireconditions.Howeverresultsofthistestmaybeusedaselementsofafireriskassessmentwhichtakesintoaccountallofthefactswhicharepertinenttoanassessmentofthefirehazardofaparticularendus

7、e.1.6Thisstarddoesnotpurpttoaddressallofthesafetyconcernsifanyassociatedwithitsuse.Itistheresponsibilityoftheuserofthisstardtoestablishappropriatesafetyhealthpracticesdeterminetheapplicabilityofregulatylimitationspritous

8、e.2.ReferencedDocuments2.1ASTMStards:2E1445TerminologyRelatingtoHazardPotentialofChemicals2.2NFPAPublication:3NFPA69StardonExplosionPreventionSystems2.3NTISPublications:4Bulletin503CowardH.F.JonesG.W.BureauofMines“Limits

9、ofFlammabilityofGasesVaps”NTISAD7015751952Bulletin627ZabetakisM.G.BureauofMines“FlammabilityacteristicsofCombustibleGasesVaps”NTISAD7015761965Bulletin680KuchtaJ.M.BureauofMines“InvestigationofFireExplosionAccidentsintheC

10、hemicalMiningFuelRelatedIndustries—AManual”NTISPB8711394019853.Terminology3.1Definitions—SeealsoTerminologyE1445.3.1.1flammable—capableofpropagatingaflame.3.1.2ignition—theinitiationofcombustion.3.1.3limitofflammability—

11、theboundaryincompositionspacedividingflammablenonflammableregions.3.1.4limitingoxygen(oxidant)concentration(LOC)ofafueloxidantinertsystem—theoxygen(oxidant)concentrationatthelimitofflammabilityfthewstcase(mostflammable)f

12、uelconcentration.3.1.4.1Discussion—Limitingoxygen(oxidant)concentrationisalsoknownasminimumoxygen(oxidant)concentrationascriticaloxygen(oxidant)concentration.4.SummaryofTestMethod4.1Amixturecontainingonemeflammablecompon

13、ents(fuel)oxygen(oxidant)inertgas(es)(suchasnitrogencarbondioxideargonetc.)ispreparedinasuitabletestvesselatacontrolledinitialtemperaturemadetothespecifiedinitialpressure.Proptionsofthecomponentsaredeterminedbyasuitablem

14、eans.Ignitionofthemixtureisattemptedflammabilityisdeterminedfromthepressureriseproduced.Thecriterionfflammabilityisapressurerise1ThesetestmethodsareunderthejurisdictionofASTMCommitteeE27onHazardPotentialofChemicalsarethe

15、directresponsibilityofSubcommitteeE27.04onFlammabilityIgnitabilityofChemicals.CurrenteditionapprovedOct.12013.PublishedOctober2013.iginallyapprovedin2000.Lastpreviouseditionapprovedin2007asE2079–07.DOI:10.1520E207907R13.

16、2FreferencedASTMstardsvisittheASTMwebsitewww.astm.gcontactASTMCustomerServiceat.FAnnualBookofASTMStardsvolumeinfmationrefertothestard’sDocumentSummarypageontheASTMwebsite.3AvailablefromNationalFireProtectionAssociation(N

17、FPA)1BatterymarchParkQuincyMA021697471:www.nfpa.g.4AvailablefromNationalTechnicalInfmationService(NTIS)5285PtRoyalRd.SpringfieldVA22161:www.ntis.gov.Copyright?ASTMInternational100BarrHarbDrivePOBoxC700WestConshohockenPA1

18、94282959.UnitedStates17.9.1FuseWire—AfusewireignitercanbeconstructedfexamplefromapieceofNo.40(0.076mmdiameter)coppernichromeplatinumwirefastenedtopowersupplyterminalsinsuchmannerastoleaveafilamentofwirebetweentheterminal

19、sapproximately10mmlong.A500VA115Visolatingtransfmeraproperlysizeddiscretedisgecapacitcircuitwillserveasanadequateigniterenergysupply.7.9.2CarbonSpark—Four2mmdiametergraphiterodswrappedbytheleadscomingfromanelectricalpuls

20、egenerat.Thetwoelectricalleadsareseparatedbya6to10mmdistance.Theresultingdiscretesparkisinthefmofasurfacedisgeoverthegraphiterods.7.9.3ContinuousElectricArc—Anelectricarcignitermayconsistofapairofelectrodes(steelgraphite

21、)spacedapproximately6mmapartacrosswhicha30mAarcoftypicallylessthan1sdurationcanbesuppliedfroma11515000volttransfmer(socalledluminoustubetransfmer).7.9.4DiscreteElectricSpark—Anelectricsparkignitermayconsistofapairofelect

22、rodes(steelgraphite)spacedapproximately6mmapartacrosswhichashtdurationspark(lastingftypically1msless)iscausedtooccuruponasingledisgeofacapacit.Theelectricalenergystedondisgedfromthecapacitbothshouldbemeasuredrepted.Theen

23、ergydissipatedinthesparkgapmayalsobemeasuredbyappropriatemeans.Useofatleast10Joulesofnominal(sted)sparkenergyisrecommended.NOTE4—Electricarcssparkslistedin7.9.37.9.4mayfailtodisgewhentestingfuelswithhighdielectricstrengt

24、hduringtestsconductedatahighinitialpressure.7.9.5ChemicalIgniter—Somematerials(suchaschlofluocarbons)requireahigherignitionenergythanthatcanbeprovidedbytheelectricalmeansdescribedabove.Inthatcasetestswithchemicaligniters

25、(fexampleelectricmatcheselectricallyactivatedkitchenmatchheadsSobbeigniters)maybenecessarytodeterminethetruelimitingoxidantconcentration(theflammabilitylimit)asopposedtoan“ignitabilitylimit.”Iftestsareconductedinasuffici

26、entlylargevesselelectricmatchesSobbeignitersmaybeused.Howeveritshouldbekeptinmindthattheseignitersproducesignificantlylargersometimesmultipleignitionkernelsthantheelectricalignitionsources.Chemicalignitersarelikelytoover

27、drivecombustioneventsinsmalltestvesselsinthatcasemeasuredLOCvaluesareexpectedtobelowerthantheactualLOCvalues.Ifachemicaligniterisusedthepressurerisefromtheigniterbyitselfmustbedetermined.Duringatestthereisalsoanadditiona

28、lpressuregeneratedbythecombustionofthefuelgaswithintheigniterflameeventhoughthereisnopropagation.Onewaytopartiallycrectftheseignitereffectsistouseamestringentignitioncriterionthanthestard7%pressurerise.Appropriateignitio

29、ncriterionmaybedeterminedfromaseriesofbaselinetestsconductedonactualfueloxidantdiluentmixtureschosennearthenonflammablevicinityofthecompositionHdefinedinSection4.NOTE5—Ignitersdissipatinglargequantitiesofenergy(especiall

30、ychemicaligniters)arecapableofproducingafinitepressureriseinthesmallertestvesselsevenintheabsenceofflammabletestmixtures.ThepressureriseduetoignitermustbequantifiedbefetheLOCtestingmustbesubtractedfromthepeakpressurerise

31、measuredateachtest(see10.1.11).Ifthepressureriseduetoigniterisanonnegligiblefractionoftheabsolutepressureofthetestmixturetheaccompanyingcompressiveheatingofthetestmixturemustbeconsidered.NOTE6—Someignitersmaynotbecapable

32、ofdissipatingallanyoftheirratedenergyattheextremesofpressuretemperature.Ifthereisanydoubtthereliabilityoftheigniterfunctionmustbedemonstratedatthetestconditions.8.SafetyPrecautions8.1Adequateshieldingmustbeprovidedtoprev

33、entinjuryintheeventofequipmentrupture.Theapparatusshouldbesetupsothattheoperatisisolatedfromthetestvesselwhilethevesselcontainsageofreactantsincludingthetimewhilethevesselisbeingfilled.Thetestapparatusshouldbeequippedwit

34、hinterlockssothattheignitionsourcecannotbeactivatedunlesstheoperathastakennecessarystepstoprotectpersonnelequipment.Activationoftheignitionsourceshouldbepossibleonlyfromapositionshieldedfromthetestvessel.Thetestvesselmay

35、befittedwitharupturediskventedtoasafelocation.8.2Intheionofthesafelocationfthevesseldisgewhetheritisthroughdisgepipingthrougharupturediskfullconsiderationshouldbegiventothesafetyofthepersonnelenvironmentproperty.Theimpac

36、tofbothunburntburnttestmixtureventingmustbeconsiderednecessaryprotectionmitigationmeasuresmustbeimplemented.8.3Ifthefuelcaninadvertentlybeventedinsidetheheatedchamberinsidetheenclosedareatheheatedchambershouldbefittedwit

37、haninertgaspurgetheareashouldbeadequatelyventilatedtopreventbuildupofanflammablemixtureinthelargespace.8.4ItisrecommendedthatLOCevaluationsbeperfmedatatmosphericpressurepritoconductingevaluationsatelevatedinitialpressure

38、.Thismeasureshouldprovidebaselinedatawhichwillhelptoavoidunexpectedlyenergeticexplosionsathighinitialpressure.8.5WheretheLOCisexpectedtoexceed21%testingshouldbeginat21%oxygentheoxygenconcentrationshouldbeincreasedinsmall

39、increments.NOTE7—Themaximumdeflagrationpressurethatcanbedevelopedduringthetestshouldbeestimatedbyasuitablemeansbefetesting.8.6Testmatrixmustbeplannedcarefullytoavoidtestingofdetonablemixtures.8.7Compressedgascylinderssho

40、uldbesecuredbymeansappropriatetothesizeofcylinder.Gascylindervalvesshouldbeclosedwhennotinuse.Gascylindersshouldbefittedwithpressureregulatsofthecrectpressurerangetypesuitedfusewiththegascontainedtherein.Regulatdeliveryp

41、ressureshouldbesettothelowestvaluerequiredfefficientgastransfer.Theuseofcheckvalvesingassupplylinesisrecommended.Allconnectionsingastransferlinesshouldbecheckedftightness.8.8Whereoxidizersstrongerthanairareusedthepotenti