Designation:C108−46(Reapproved2013)StandardSymbolsforHeatTransmission1ThisstandardisissuedunderthefixeddesignationC108;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.SPECIALPRACTICESRELATINGTOHEATFLOWTERMSTermsEndingin“ivity”—Termsendingin“ivity”designatecharacteristicsofmaterials,normallyindependentofsizeorshape,sometimescalled“specificproperties.”Examples:Conductivityandresistivity.TermsEndingin“ance”—Termsendingin“ance”designatepropertiesofaparticularobject,dependingnotonlyonthematerial,butalsouponsizeandshape,sometimescalled“totalquantities.”Examples:Conductanceandtransmittance.TermsEndingin“ion”—Termsendingin“ion”designatetimerateoftheprocessoftransfer;flux,flowrate.Examples:Conductionandtransmission.Transmission—“Transmission,”“transmissivity,”“transmit-tance”usuallyrefertotransferbyoneormoreoftheprocessesofconduction,convection,andradiation.Conduction—“Conduction,”“conductivity,”“conductance”usuallyrefertotransferwithinamedium,andwithoutbodilydisplacementasoccurswithconvection,andwithouttransferatadistanceasoccurswithradiation.HEATFLOWSYMBOLSA=areap=density;pounds,kilograms,etc.,perunitofvolumeL=lengthofpathofheatflowQ=totalquantityofheattransferred(withsubscriptsforparticularcasesandtodistinguishforQforvolumerate)Q=volumerate;dischargebyvolume;fluidrateofflowbyvolume.(Therealsoisusedqwithasubscripttodistinguishfromheatflowrate.)c=specificheatT=temperatureonabsolutescalet=temperature,degreesCelsiusorFahrenheitt,τ=timeW=weight;quantityofmattermeasuredinpounds,kilograms,etc.w=flowrate;pounds,kilograms,etc.,perunitoftimeq=heatflowrate;timerateofheattransferredforaparticularsetupwithanyvalueofareaAqisingeneralthetimederivativeoftotalquantityofheattransferred.Forsteady-stateheatflow,qistotalquantityofheatdividedbytime.k=...
