b'echnicalUdate HeatDefinition Loss and Calculations From time to time Ireceiveaturebetween thetwosur one side to air on the other questions onions fortfaces.side of theor structure. definit hea roof loss coe and how heat*"C" represents the conduc The "U" valuean uninsufficientsof loss is calculated to obtain spec tance of aand is usedlatedwall consisting of materialframe ifiedthermalvaluefortheto show the amount of h twoodsiding,plywood eaamount and type of insulation(Btu\'s) th will pass p hoursheathing, 2-by-4 studs gypater necessary to meet the \'U\' valuethrough onefoot of asum lath is 0.24 B . If insusquaretufor the overall roof assembly.homogeneous or non-homo lated with 2 inches of typical Therefore, the following willgeneous material or ai batt or blanket insulation, the combbe helpful incom nationofmaterialsforthe"U" value becomes 0.087 Btu determining pliance with energy conservationthickness or type under con and if insulated with 3 inches requirementsandthermalsideration for ainof baits or blankets, the "U" difference requirementssospecifiedintemperatureof1 degreeofvaluebe 0.065 Btu. would specificationsand job bids byFahrenheit between the twoThe fourmeasurements, "k", the many specifying agencies.surfaces. Forexample,the"C,""R"and"U,"asdefined Thesetermsandcalculationsaverage"C" value of an 8- above, shouldunderstood by be will assist you in recommendinginch hollow concrete block isanyonediscussinginsulation. the most effective insulation for0. Whenwetalkof anindividual 90. use in all types of roof assem *"R" represents resistivity ormaterial,refer to its "k" or "C" we blies:resistance that is the recipro value.reas, when Whe we *"B is the abbreviation ofcal ofity or conduc talkabout4l\\ " TU"conductiv"British Thermal Unit" and istance.comple the amount of heat needed toR-lorcceiing, - k1I raise the temperature of onef Io o r , poundofwater1 degreeroofor Fahrenheit. T Btu is usedwaI I he tomeasure the amountofassembly, heat just as the inch or footwerefer to isto measure length, ori ts used as the minute or hour is used totime. measure *"k" is the symbol for "Therm Conductivity," which is al the amount of heat (Btu\'s) transferredinonehourl through one square foot of a\\ homogeneousmaterial1-inch thick for ain difference temperatureof1degree F renh For ah eit.example, the average"k"for fiberboard*"U"designatesJie tO~I orT"U"value. In considering roof insulation is 0.38. This -inch meansthatfora 1 overall transmissioa of heatthese various factors, it should inhour pe;mind thickness,thereisa heat(Btu\'s)onesquarebe kept inthat the lower the transfer of 0.38 Btu per hour,foot ofa orac:,."5.-ireinvalue of "k","C,"and"U,"the reafpersquare foot, foreachtemperatureo;~e1;geemore resistan to heat tran e~~ cesfdegree difference in temper- Fahrenheitber,,-ee,:llta:,indicated. "R" beinge 0.1th meas~'