1、Designation: C 1130 07Standard Practice forCalibrating Thin Heat Flux Transducers1This standard is issued under the fixed designation C 1130; 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 pa
2、rentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice, in conjunction with Test Method C 177,C 518, C 1114,orC 1363, establishes an experimental proce-dure for determining the sensitivit
3、y of heat flux transducers thatare relatively thin.1.1.1 For the purpose of this standard, the thickness of theheat flux transducer shall be less than 30 % of the narrowestplanar dimension of the heat flux transducer.1.2 This practice discusses a method for determining thesensitivity of a heat flux
4、transducer to one-dimensional heatflow normal to the surface and for determining the sensitivityof a heat flux transducer for an installed application.1.3 This practice should be used in conjunction with Prac-tice C 1046 when performing in-situ measurements of heat fluxon opaque building components.
5、1.4 This practice is not intended to determine the sensitivityof heat flux transducers that are components of heat flow meterapparatus, as in Test Method C 518.1.5 This practice is not intended to determine the sensitivityof heat flux transducers used for in-situ industrial applicationsthat are cove
6、red in Practice C 1041.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior
7、 to use.2. Referenced Documents2.1 ASTM Standards:2C 168 Terminology Relating to Thermal InsulationC 177 Test Method for Steady-State Heat Flux Measure-ments and Thermal Transmission Properties by Means ofthe Guarded-Hot-Plate ApparatusC 518 Test Method for Steady-State Thermal TransmissionPropertie
8、s by Means of the Heat Flow Meter ApparatusC 1041 Practice for In-Situ Measurements of Heat Flux inIndustrial Thermal Insulation Using Heat Flux TransducersC 1044 Practice for Using a Guarded-Hot-Plate Apparatusor Thin-Heater Apparatus in the Single-Sided ModeC 1046 Practice for In-Situ Measurement
9、of Heat Flux andTemperature on Building Envelope ComponentsC 1114 Test Method for Steady-State Thermal TransmissionProperties by Means of the Thin-Heater ApparatusC 1155 Practice for Determining Thermal Resistance ofBuilding Envelope Components from the In-Situ DataC 1363 Test Method for Thermal Per
10、formance of BuildingMaterials and Envelope Assemblies by Means of a HotBox Apparatus3. Terminology3.1 DefinitionsFor definitions of terms relating to thermalinsulating materials, see Terminology C 168.3.2 Definitions of Terms Specific to This Standard:3.2.1 maskmaterial (or materials) having the sam
11、e, ornearly the same, thermal properties and thickness surroundingthe heat flux transducer thereby promoting one-dimensionalheat flow through the heat flux transducer.3.2.2 sensitivitythe ratio of the electrical output of theheat flux transducer to the heat flux passing through the devicewhen measur
12、ed under steady-state heat flow.3.2.3 test stacka layer or a series of layers of material puttogether to comprise a test sample (for example, a roof systemcontaining a membrane, an insulation, and a roof deck).3.3 Symbols:R = thermal resistance, m2K/W (hft2F /Btu)q = heat flux, W/m2(Btu/hft2)Qexpect
13、ed= heat flux expected in application, W/m2(Btu/hft2)E = measured output voltage, VS = sensitivity, V/(W/m2) (V/(Btu/hrft2)DT = temperature difference, K (F)Rlayer= thermal resistance of a layer in the test stack,m2K/W (hft2F /Btu)T = temperature, K (F)uc= combined standard uncertaintyu1= standard u
14、ncertainty of the regression coefficients1This practice is under the jurisdiction of ASTM Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.30 on ThermalMeasurement.Current edition approved Sept. 1, 2007. Published September 2007. Originallyapproved in 1989. Las
15、t previous edition approved in 2001 as C 1130 90 (2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copy
16、right ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.u2= standard uncertainty for replicate measurementsu3= standard uncertainty for the measuremente = error term4. Significance and Use4.1 The use of heat flux transducers on building envelopec
17、omponents provides the user with a means for performingin-situ heat flux measurements.Accurate translation of the heatflux transducer output requires a complete understanding of thefactors affecting its output, and a standardized method fordetermining the heat flux transducer sensitivity for the app
18、li-cation of interest.4.2 The sensitivity of the heat flux transducer is determinedprimarily by the sensor construction and temperature of opera-tion and the details of the application, including geometry,material characteristics, and environmental factors.NOTE 1Practice C 1046 includes an excellent
19、 description of heat fluxtransducer construction.4.3 The presence of a heat flux transducer is likely to alterthe heat flux that is being measured. To determine the heat flowthat would occur in the absence of the transducer, it isnecessary to either:4.3.1 Ensure that the installation is adequately g
20、uarded (1).34.3.2 Adjust the results based on a detailed model ornumerical analysis. Such analysis is beyond the scope of thispractice, but details can be found in (2-6).4.3.3 Use the empirically measured heat flux transducersensitivity measured under conditions that adequately simulatethe condition
21、s of use in the final application.4.4 There are several methods for determining the sensitiv-ity of heat flux transducers, including Test Methods C 177,C 518, C 1114, and C 1363. The selection of the appropriateprocedure will depend on the required accuracy and thephysical limitations of available e
22、quipment.4.5 This practice describes techniques to establish uniformheat flow normal to the heat flux transducer for the determi-nation of the heat flux transducer sensitivity.4.6 The method of heat flux transducer application must beadequately simulated or duplicated when experimentally deter-minin
23、g the heat flux transducer sensitivity. The two mostwidely used application techniques are to surface-mount theheat flux transducer or to embed the heat flux transducer in theinsulation system.NOTE 2The difference between the sensitivity under uniform normalheat flow versus that for the surface-moun
24、ted or embedded configurationshas been demonstrated using multiple mathematical techniques (7-9).5. Specimen Preparation5.1 Specimen Preparation for All Cases:5.1.1 Check the electrical continuity of the heat flux trans-ducer. Connect the heat flux transducer voltage leads to theauxiliary measuremen
25、t equipment (for example, voltmeter)having a resolution of 6 2 V or better.5.1.2 When bringing the heat flux transducer voltage leadsout of the test instrument, take care to avoid air gaps in themask or between the sample stack and the test instrument. Fillair gaps with a conformable material, such
26、as toothpaste, caulk,or putty, or cover with tape.NOTE 3The heat flux transducers do not need to be physicallyadhered to the mask or embedding material but should fit well enough toassure good thermal contact. If needed, apply thermally conductive gel toone or both faces of the heat flux transducer
27、to improve the thermalcontact. Material compatibility must be considered in the selection of anysuch gel.5.1.3 Place a temperature sensor on or near the heat fluxtransducer. Connect temperature sensor(s) applied to the heatflux transducer to a readout device.5.1.4 When compressible insulation is inc
28、luded in the teststack, manually control the distance between the hot and coldapparatus surfaces.5.1.5 The heat flux transducer(s) must be located within themetered area of the apparatus. In a hot box apparatus, mountthe heat flux transducers in the central portion of the meteredarea of the test pan
29、el.5.2 Three separate test stack preparations are discussed todetermine appropriately: the one-dimensional sensitivity, thesensitivity for embedded configurations, and the sensitivity forsurface-mounted configurations.5.3 One-Dimensional SensitivityThe heat flux transducershall be embedded in a test
30、 stack and surrounded with a mask,as shown in Fig. 1.5.3.1 The test stack shall consist of a sandwich of the heatflux transducer/masking layer between two layers of a com-pressible homogeneous material, such as high-density fibrousglass insulation board, to assure good thermal contact betweenthe pla
31、tes of the tester and the heat flux transducer/maskinglayer.5.3.2 The mask must have the same thickness and thermalresistance as the heat flux transducer.5.3.3 The mask or embedding material should be signifi-cantly larger than the metering area of the test equipment andideally be the same size as t
32、he plates of the apparatus.5.3.4 To measure the sensitivity of multiple small heat fluxtransducers, the heat flux transducer/mask layer shown in Fig.1 is replaced with a layer containing an arrangement oftransducers located within the metered area of the apparatus asillustrated in Fig. 2.5.4 Sensiti
33、vity, Embedded ConfigurationPlace the heatflux transducer, in a fashion identical to its end use application,in a test stack duplicating the building construction to beevaluated. An example of a test stack, for the case where theheat flux transducer is to be embedded in gypsum wallboardfacing an ins
34、ulated wall cavity, is shown in Fig. 3.5.5 Sensitivity, Surface-Mounted ConfigurationApply theheat flux transducer in a manner identical to that of actual useas specified in Practice C 1046. Important considerations forsurface mounting include thermal contact between the heat fluxtransducer and the
35、surface and matching of the emittance of theheat flux transducer and test construction. An example of a testarrangement, for the case where the heat flux transducer is tobe surface-mounted, is shown in Fig. 4.NOTE 4In many cases, several surface-mounted heat flux transducers3The boldface numbers in
36、parentheses refer to the references at the end of thisstandard.C1130072will be used at one time and can be analyzed for sensitivity simulta-neously.6. Procedure6.1 Use a guarded-hot-plate, heat flow meter, hot box, orthin-heater apparatus. Follow Test Method C 177, C 518,C 1363,orC 1114, including t
37、est stack conditioning, to mea-sure the heat flux through the heat flux transducer. Apparatusesthat typically require two samples should be operated in thesingle-sided mode in conformance with Practice C 1044.6.2 Vary the hot- and cold-surface plates of the test instru-ment to produce the range of h
38、eat fluxes and mean tempera-tures according to the guidance found in Appendix X1 andAppendix X2.FIG. 1 Example of a Test Stack Used to Measure Heat Flux Transducer Sensitivity, Side ViewNOTESome apparatus metering areas are round.FIG. 2 Top View of the Heat Flux Transducer/Mask Layer Within the Test
39、 Stack for the Case Where Multiple Small Heat FluxTransducers are Evaluated SimultaneouslyC1130073FIG. 3 Example of Test Stack Emulating an Embedded Position Within an Insulated Wall Cavity, Side ViewNOTEDrawing not to scale, heat flux transducer size exaggerated relative to hot box dimensions.FIG.
40、4 Example of a Test Stack for a Surface-Mounted Heat Flux TransducerC11300746.2.1 For surface-mounted heat flux transducers tested usingTest Method C 1363, also control the convection and radiationconditions to match the expected application.6.3 Care shall be taken to perform these tests at heat flu
41、xesthat are large enough to limit errors due to the readoutelectronics and that are similar to the anticipated levels of heatflux in the end-use experiment.6.4 Ensure that the test stack has reached a steady statecondition before taking data, including the voltage output fromthe heat flux transducer
42、 leads. This may require a longersettling time than is typical for these test methods.NOTE 5Theoretically, the output of the heat flux transducer is zerowhen there is no heat flux through the transducer. Eq 1 and 2 are basedupon this assumption. For a more rigorous check of heat flux transducerrespo
43、nse, the user is referred to Appendix X1 which requires that the userflip the heat flux transducer over and repeat the test at the sametemperature conditions. A simpler approach that has been used to checkthis assumption is to enclose the heat flux transducer within heavyinsulation and place the hea
44、t flux transducer and insulation within atemperature-stable environment for 24 h before checking that the outputvoltage is indeed zero under conditions of no heat flux.7. Calculation7.1 For a single-point calibration, use the measured heatflux, q, and voltage, E to calculate the sensitivity, dependi
45、ngupon the test stack chosen, as shown in Eq 1.S 5Eq(1)7.2 When multiple data points are available, evaluate thedata using the selected model as discussed in Appendix X1.7.3 An example of a least square linear fit of sensitivity asa function of temperature is shown in Fig. 5. Alternativemodels and d
46、ata analysis are discussed in Appendix X1.NOTE 6Do not confuse calibration terminology in this practice withthat in other C16 application standards. For example, Practice C 1046 usesthe term “conversion factor” (which also is designated S and has units of(W/m2) per V) to relate the measured HFT outp
47、ut to the flux through thebuilding envelope. This practice advocates using the following form (Eq2) for applications of heat flux transducers:q 5ES(2)8. Report8.1 Report the following information:8.1.1 The heat flux transducer manufacturer, model identi-fication, size, thickness, geometry (that is,
48、square or round),and dimensions.8.1.2 The ASTM Test Method used and the size of theapparatus plates.8.1.3 The test stack composition, including the location ofthe heat flux transducer, the material used to mask or embed theheat flux transducer, and any additional layers of material usedin the assemb
49、ly.NOTE 7A diagram of the test stack is suggested.8.1.4 The temperatures of the heat flux transducer andsurface plates.8.1.5 The heat flux transducer sensitivity and/or calibrationfactor. When multiple data points are available, provide corre-lations and R2values.8.1.6 If known, provide the apparatus clamping pressure.9. Precision and Bias9.1 Precision data from one laboratory using Test MethodC 177 are given in Table 1 for two sizes of heat flux transducershaving coplanar copper-constantan thermoelectric junctions ina glass-fiber reinforced epoxy substr
