Designation:D7938−21StandardPracticeforSamplingofC-14inGaseousEffluents1ThisstandardisissuedunderthefixeddesignationD7938;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Theintendeduseofthispracticeisforsamplingofgassescontaining14Cininorganic,organicorparticulateforms.Thissamplingpracticecapturesthe14Cinamediathatcanbesubmittedtoalaboratoryforanalysis,typicallybyliquidscintillationcounting(LSC)1.2Thispracticedoesnotincludetheneededstepsfortheliberationof14CfromthemediaonwhichitwasadsorbedorthoseforthepreparationforLSCsamplepreparationinthelaboratorypriortoliquidscintillationanalysis.ThispracticedoesnotincludethemethodologyusedtoanalyzethepreparedsamplesbyLSC.1.3Theoverall14Canalyticaldetectioncapabilityisim-pactedbyanumberoffactorsincludingthevolumesampled,themethodusedtodesorbthe14Cfromthemedia,andtheanalyticalmethodusedthemeasure14Cfromthemedia.Thispracticeonlydirectlyaddressesthevolumeofthegasstreamfromwhichanypresent14Cwouldbeadsorbed.1.4ThevaluesstatedinpCiunitsaretoberegardedasstandardgiventhereportingrequirementsoftheU.S.NRCRegulatoryGuide1.21.TheBqvaluesgiveninparenthesisaremathematicalconversionstoSIunitsthatareprovidedforinformationonlyandarenotconsideredstandard.OthervaluesstatedinSIunitsaretoberegardedasstandard.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.6Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)...
