ASTM-E-337-02(R2007)

Designation:E337–02(Reapproved2007)StandardTestMethodforMeasuringHumiditywithaPsychrometer(theMeasurementofWet-andDry-BulbTemperatures)1ThisstandardisissuedunderthefixeddesignationE337;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1General:1.1.1Thistestmethodcoversthedeterminationofthehumidityofatmosphericairbymeansofwet-anddry-bulbtemperaturereadings.1.1.2Thistestmethodisapplicableformeteorologicalmeasurementsattheearth’ssurface,forthepurposeofthetestingofmaterials,andforthedeterminationoftherelativehumidityofmoststandardatmospheresandtestatmospheres.1.1.3Thistestmethodisalsoapplicablewhenthetempera-tureofthewetbulbonlyisrequired.Inthiscase,theinstrumentcomprisesawet-bulbthermometeronly.1.1.4Relativehumidity(RH)doesnotdenoteaunit.Un-certaintiesintherelativehumidityareexpressedintheformRH6rh%,whichmeansthattherelativehumidityisexpectedtolieintherange(RH−rh)%to(RH+rh)%,whereRHistheobservedrelativehumidity.Alluncertaintiesareatthe95%confidencelevel.1.2MethodA—PsychrometerVentilatedbyAspiration:1.2.1Thismethodincorporatesthepsychrometerventilatedbyaspiration.Theaspiratedpsychrometerismoreaccuratethanthesling(whirling)psychrometer(seeMethodB),anditoffersadvantagesinregardtothespacewhichitrequires,thepossibilityofusingalternativetypesofthermometers(forexample,electrical),easiershieldingofthermometerbulbsfromextraneousradiation,accidentalbreakage,andconve-nience.1.2.2Thismethodisapplicablewithintheambienttempera-turerange5to80°C,wet-bulbtemperaturesnotlowerthan1°C,andrestrictedtoambientpressuresnotdifferingfromstandardatmosphericpressurebymorethan30%.1.3MethodB—PsychrometerVentilatedbyWhirling(SlingPsychrometer):1.3.1Thismethodincorporatesthepsychrometerventilatedbywhirling(slingpsychrometer).1.3.2Thismethodisapplicablewithintheambienttempera-turerange5to50°C,wet-bulbtemperaturesnotlowerthan1°Candrestrictedtoambientpressuresnotdifferingfromstandardatmosphericpressurebymorethan30%.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.(Formorespecificsafetyprecautionarystatements,see8.1and15.1.)2.ReferencedDocuments2.1ASTMStandards:2D861PracticeforUseoftheTexSystemtoDesignateLinearDensityofFibers,YarnIntermediates,andYarnsD1193SpecificationforReagentWaterD1356TerminologyRelatingtoSamplingandAnalysisofAtmospheresD1357PracticeforPlanningtheSamplingoftheAmbientAtmosphereD3631TestMethodsforMeasuringSurfaceAtmosphericPressureD4023TerminologyRelatingtoHumidityMeasurements3D4230TestMethodofMeasuringHumiditywithCooled-SurfaceCondensation(Dew-Point)HygrometerE1SpecificationforASTMLiquid-in-GlassThermometersIEEE/ASTMSI-10PracticeforUseoftheInternationalSystemofUnits(SI)(theModernizedMetricSystem)3.Terminology3.1Definitions:3.1.1Fordefinitionsofhumiditytermsusedinthistestmethod,refertoTerminologyD4023.3.1.2Fordefinitionsofothertermsinthistestmethod,refertoTerminologyD1356.1ThistestmethodisunderthejurisdictionofASTMCommitteeD22onAirQualityandisthedirectresponsibilityofSubcommitteeD22.11onMeteorology.CurrenteditionapprovedOct.1,2007.PublishedDecember2007.Originallyapprovedin1931.Lastpreviouseditionapprovedin2002asE337-02.2ForreferencedASTMstandards,visittheASTMwebsite,@astm.org.ForAnnualBookofASTMStandardsvolumeinformation,refertothestandard’sDocumentSummarypageontheASTMwebsite.3Withdrawn.1Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.CopyrightASTMInternationalProvidedbyIHSunderlicensewithASTMLicensee=MHI-NAGOYArelatedto3944000/3944000013NotforResale,01/07/200822:43:28MSTNoreproductionornetworkingpermittedwithoutlicensefromIHS--`,,`,,,,`,```,,``,,,,,,````,-`-`,,`,,`,`,,`---3.2DefinitionsofTermsSpecifictoThisStandard:3.2.1MethodA—AspiratedPsychrometer:3.2.1.1aspiration—Thewetanddrybulbs(andthepsy-chrometer)aredescribedasaspiratedbecausethereisprovi-sionfortheforcedventilationbydrawingairoverthebulbsbysuction.Theflowmaybeeithertransverseorparalleltotheaxesofthebulbs.3.2.1.2thermometer—forpurposesofthisstandard,andexceptwhereaspecifictypeisindicated,thetermthermometermeansanytemperature-measuringdevice.3.2.1.3wet-bulbcoveringandwick—thewetbulbispro-videdwithawater-retainingcoveringofawoven-cottonmaterial.Acottonwickwhichconnectsthecoveringtoawaterreservoirmaybeprovidedsothatwaterisfedtothecoveringcontinuouslybycapillarity.3.2.2MethodB—SlingPsychrometer:3.2.2.1ventilation—thewetanddrybulbs(andthepsy-chrometer)aredescribedasventilatedbecausethereisprovi-sionforaflowoftheairoverthebulbs.Theflowistransversetotheaxesofthebulbs.3.2.2.2wet-bulbcovering—thewetbulbisprovidedwithawater-retainingcoveringofawoven-cottonmaterial.4.SummaryofMethods4.1Genera