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Designation:D3240–91(Reapproved2001)AnAmericanNationalStandardStandardTestMethodforUndissolvedWaterInAviationTurbineFuels1ThisstandardisissuedunderthefixeddesignationD3240;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheDepartmentofDefense.1.Scope1.1Thistestmethodcoversthemeasurementofundissolvedwaterinaviationturbinefuelsinflowingfuelstreamswithoutexposingthefuelsampletotheatmosphereortoasamplecontainer.Theusualrangeoftestreadingscoversfrom1to60ppmoffreewater.Thistestmethoddoesnotdetectwaterdissolvedinthefuel,andthustestresultsforcomparablefuelstreamscanvarywithfueltemperatureandthedegreeofwatersolubilityinthefuel.1.2Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.Terminology2.1DefinitionofaTermSpecifictoThisStandard:2.1.1freewater—waternotdissolvedinthefuel.3.SummaryofTestMethod3.1Ameasuredsampleoffuelispassedthroughasuraninedye-treatedfilterpad.Undissolved(free)waterinthefuelwillreactwiththeuraninedye.Whenthepadissubsequentlyilluminatedbyultraviolet(UV)light,thedyepreviouslycontactedbyfreewaterwillfluoresceabrightyellowwiththebrightnessincreasingforincreasingamountsoffreewaterinthefuel.TheUVlight-illuminatedpadiscomparedtoaknownstandardusingaphotocellcomparator,andthefreewaterinthefuelsampleisreadoutinpartspermillionbyvolume.Byvaryingthefuelsamplesize,therangeofthetestmethodcanbeincreased.4.SignificanceandUse4.1Undissolved(free)waterinaviationfuelcanencouragethegrowthofmicroorganismsandsubsequentcorrosioninthetanksofaircraftandcanalsoleadtoicingoffiltersinthefuelsystem.Controloffreewaterisexercisedingroundfuelingequipmentbyuseoffilter-coalescersandwaterseparators.5.Apparatus5.1TestPadRater—Adevice2forcomparingthefluores-cenceofthetestpadtoaknownstandard,whilebothareilluminatedbythesamesourceofUVlight,shallbeused.TheamountofUVlightstrikingthestandardshallbemodulateduntilthetotalfluorescenceofthetestpadandthestandardareequal;thisshallbedeterminedusingaphotocellbridgecircuitnullindicator.ThelightmodulatingdeviceforcontrollingtheUVlightstrikingthestandardshallprovideadirectreadinginpartspermillionbyvolumeoffreewater.5.2TestPads—Absorbentfilterdisksof25-mmdiametershallbecoatedononesidewithuranine(sodiumfluorescein)dyeataconcentrationof0.23to0.29mgper25mmpad.Thetestpads3shallbeindividuallypackagedinhermeticallysealedenvelopesorothersuitablecontainers.Fresh,unusedtestpadsshallhaveanorangecoloroverthedyedsurface.Anydiscoloration,unevennessindyecontent,orfaded(toayellowcolor)appearanceshallbecauseforrejection.5.3TestPadHolder4andSamplingLine—Atestpadholderandsamplinglineshallbeusedtodrawthefuelsamplethroughthetestpadatarateof600to800mL/min.Meansshallbeprovidedtoflushthetestpadsamplinglineandholderimmediatelypriortouse.Thetestpadholdershallincludeanorificeof1-mm(0.040-in.)diameterupstreamofthepadtodispersewaterdropletsinthefuel.5.4Tweezers—Suitableclean,drytweezersshallbeusedatalltimeswhenhandlingthetestpad.5.5BlottingPaper—Clean,dry,absorbentpapertowels,blotters,etc.,shallbeprovidedforblottingthetestpadpriortoratingtoremoveexcessfuel.Theblotterpapershallneitherimpartcolororstainnorleaveanyresidueonthetestpads.5.6SamplingValveConnection,designedtomeetthefol-lowingrequirements:(1)Itshallbemountedinthesampling1ThistestmethodisunderthejurisdictionofASTMCommitteeD02onPetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommitteeD02.J0onAviationFuels.CurrenteditionapprovedMay15,1991.PublishedJuly1991.OriginallypublishedasD3240–73T.LastpreviouseditionD3240–86a.2TheAqua-GloSeriesIIinstrumentmanufacturedbyGammonTechnicalProducts,Inc.,P.O.Box400,Manasquan,NJ08736-0400wasusedintheprecisiontestprogram.TheunitiscurrentlyavailableinaSeriesIIIconfigurationwhichischangedonlyinthepowersupply.AllwatercontentmeasuringcomponentsremainofthesameconfigurationastheSeriesIIinstrument.ManufacturerswhowishtooffersimilarproductsarereferredtoCommitteeD02EquipmentReplacementGuidelines.3Aqua-GlotestpadsusedinthePrecisionTestProgramareavailablefromGammonTechnicalProductsInc.,P.O.Box400,Manasquan,NJ08736-0400.4AtestpadholderusedinthePrecisionTestProgramisavailablefromGammonTechnicalProductsInc.,P.O.Box400,Manasquan,NJ08736-0400.1Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.pointandmustincorporateaself-sealingquickactioncouplingdesignedtomatewithasuitableconnectionleadingtotheselectorvalveofthesamplingassembly.(2)Itmustbecompletelyresistanttofuelandbeleakproofuptothemaximumworkingpressurestobeencountered.(3)Itmusthaveaminimumofinternalrecesseswhichcouldcausetheholdupofcontaminant.(4)Itmustbeprovidedwithadustcap.5.7CalibratingStandard,Calibrationoftheinstrumen