90092760023335812=Designation:D815-81($1)AMERICANSOCIETYFORTESTINGANDMATERIALS1916RaceSt.,Philadelphia,Pa.19103ReprintedfromtheAnnualBookofASTMStandards,CopyrightASTMifnotlistedinthecurrentcombinedindex,willappearinthenextedition.StandardMethodforTestingCOATEDFABRlCS-HYDROGENPERMEABILITY'ThisstandardisissuedunderthefixeddesignationDS15:thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(E)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.iThismethodcoversthemeasurementofthepermeabilityofhydrogenthroughfabricscoatedwithrubberorsyntheticelastomers.2.ApplicableDocument2.1ASTMStandardD3040-81PracticeforPreparingStatementsforStandardsRelatingtoRubberandRubberTesting'3.SignificanceandUse3.1Thismethodisintendedforqualitycon-trolofrubberizedfabricthatisusedtomanu-facturearticlesthatcontainhelium.Thereisadirectrelationbetweenthepermeabilityofhy-drogenandhelium,withthatofhydrogenbeingapproximatelytwicethatofhelium.3.2Itmayalsobeusedfordevelopmentandresearchpurposes.4.Apparatus4.1TheapparatusshallconsistoftheCam-bridgefabricpermeameteroritsequivalent.Theessentialcomponents,properlyassembledforthetestasshowninFig.1,shailcomprisethefollowing:4.1.1TestPlates-Testplates,essentiallyintwoparts,thelowerhalfbeingthehydrogenchamberandtheupperhalfcontainingtheanalysiscell.Thespecimentobetestedshzllbesandwichedbetweentheiipperandlowerplates.TheanalysisceliispartofaWheatstonebridgearrangement,whichiscontainedinthecontrolbox.Thehydrcpendiffusingintotheunalysisceliproducesacxrrentthermalchargeinthesensor.Thisthermalchargecauses3voltageimbalanceinthesystemthatisregis-teredonthegalvanometer.4.1.2WaxingPlateAssembly-AwaxingplateassemblyasshowninFig.2,consistingoftwometalplates127.0stl1mmindiameter(125cm'inarea)mountedinaholdersothatthefabricspecimenmaybeclampedbetweenthemwithaperipheralringapproximately8mminwidthexposedforwaxcoating...
