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《ASHRAE.4622-2003 Moisture Sensor Technology—A Summary of Techniques 》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。
1、4622MoistureSensorTechnology—ASummaryofTechniquesforMeasuringMoistureLevelsinBuildingEnvelopesWilliamM.Healy,Ph.D.MemberASHRAEABSTRACTsothatadjustmentscouldbemadetotheheatingandventila-tionsystemsorrepairscouldbemadetopreventanyfurtherAsmoisture-relatedproblemsincr
2、easeinhomes,theneedproblems.forsensorstoaccuratelymeasurethemoisturelevelintheTheterm“moisturecontent”referstotheamountofwaterbuildingenvelopegrows.Sensorsareneededtoassistinmodelpresentinasolidmaterial.Theamountofwaterpresentinair,verification,toindicatetheeffecti
3、venessofmoistureabate-ontheotherhand,isindicatedbysuchquantitiesastherelativementsteps,andtowarnofpotentialmoistureintrusion.Thehumidity,humidityratio,orpartialpressureofwatervapor.mostpopularsensorscurrentlyusedbybuildingscientistsareThestandardtestmethodformeasur
4、ingthemoisturecontentthosebasedonelectricalresistance,butagreatdealofdissat-ofwoodisdocumentedinASTMD4442(ASTM1992)andisfactionexistswiththistechnique.InstallationoftheseISO12570(ISO2000)andisrepresentativeofatypicalsensorsisdifficult,driftintheresponsecausestransi
5、entmethodforallbuildingmaterials.Inthismethod,theweightchangesinthemeasurements,andcalibrationhasproventobeofthespecimenatthemoisturecontentofinterestiscomparedachallenge.Numeroustechniquespromisebetteraccuracytotheweightofthespecimenafterithasbeendriedinanoven.and
6、easierusethantheelectricresistanceprobes,butworkisThemoisturecontentisgivenbytherelation,neededtoproduceasensorsmallenoughtofitunobtrusivelyinawallcavity.Thisworkhasidentifiedmanyexistingtech-W–W=------------------------------wetdry×100,niquesformeasuringmoisturean
7、dpresentsadvantagesandMC(1)Wdisadvantagesofeach.drywhereINTRODUCTIONMC=moisturecontentinpercent,BuildingpractitionershaveasignificantneedforinsituWwet=massofthespecimenbeforedrying,moisturecontentsensorstohelpalleviatetheproblemsasso-ciatedwithexcessmoistureaccumul
8、ationinbuildings.SuchWdry=massofthedryspecimen.problemscanleadtomoldandmildewgrowth,structuralThewoodspecimenisplacedinanovenmaintainedatdecay,lo
