ASTM_C_1114_-_06_2013.pdf

Designation:C111406(Reapproved 2013)Standard Test Method forSteady-State Thermal Transmission Properties by Means ofthe Thin-Heater Apparatus1This standard is issued under the fixed designation C1114;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the steady-state thermal transmission properties of flat-slab specimens ofthermal insulation using a thin heater of uniform power densityhaving low lateral heat flow.A thin heater with low lateralthermal conductance can reduce unwanted lateral heat flow andavoid the need for active-edge guarding.1.2 This primary test method of thermal-transmission mea-surement describes a principle,rather than a particular appa-ratus.The principle involves determination of the thermal fluxacross a specimen of known thickness and the temperatures ofthe hot and cold faces of the specimen.1.3 Considerable latitude is given to the designer of theapparatus in this test method;since a variety of designs ispossible,a procedure for qualifying an apparatus is given in5.3.1.4 The specimens must meet the following conditions ifthermal resistance or thermal conductance of the specimen is tobe determined by this test method2:1.4.1 The portion of the specimen over the isothermal areaof the heater must accurately represent the whole specimen.1.4.2 The remainder of the specimen should not distort theheat flow in that part of the specimen defined in 1.4.1.1.4.3 The specimen shall be thermally homogeneous suchthat the thermal conductivity is not a function of the positionwithin the sample,but rather may be a function of direction,time,and temperature.The specimen shall be free of holes,ofhigh-density volumes,and of thermal bridges between the testsurfaces or the specimen edges.1.4.4 Test Method C177 describes tests that can help ascer-tain whether conditions of 1.4 are satisfied.For the purposes ofthis test method,differences in the measurements of less than2%may be considered insignificant,and the requirementsfulfilled.1.5 The specimens shall meet one of the followingrequirements,in addition to those of 1.4.1.5.1 If homogeneous materials as defined in TerminologyC168 are tested,then the thermal resistivity and thermalconductivity can be determined by this test method.1.5.2 If materials which are layered or otherwise thermallyinhomogeneous are tested,thermal resistance and thermalconductance can be determined by this test method.1.6 Two versions of thin-heater apparatus using the sameprinciple of the standard are described in AnnexA1 and AnnexA2.They are similar in concept but differ in size andconstruction,and hence warrant separate descriptions for eachdesign.This test method in no way limits the size of thethin-heater element.One of the units described uses a thinmetal foil,while the other uses a metal screen as the heatsource.The smaller,foil apparatus is designed to make rapidmeasurements of heat transmission through specimens as thinas 0.5 cm and as thick as 2 cm;however,an apparatus using afoil heater could be designed to measure much thickermaterials,if desired.The larger,screen apparatus is designed tomeasure specimens with thicknesses between 3 and 15 cm,where the exact limits depend on the thermal resistance of thespecimens.Both apparatuses use thermocouples for measuringtemperature,but other temperature-sensing systems can beused.1.7 This test method covers the theory and principles of themeasurement technique.It does not provide details of construc-tion other than those required to illustrate two devices whichmeet the prescribed requirements.Detailed information isavailable in References(1-23)3and the Adjunct.1.8 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.9 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is the1This test method is under the jurisdiction ofASTM Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.30 on ThermalMeasurement.Current edition approved Sept.1,2013.Published January 2014.Originallyapproved 1989.Last previous edition approved 2006 as C1114 6.DOI:10.1520/C1114-06R13.2Further discussion on the definition of these limitations may be found in Tye,R.P.,“What Property Do We Measure?,”Heat Transmission Measurements inThermal Insulations,ASTM STP 544,ASTM,1974,pp 512.3The boldface numbers in parentheses refer to the list of references at the end ofthis test method.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulat