1、Designation:C17710C17713 Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus 1 This standard is issued under the xed designation C177; the number immediately following the designation indicates the year of origi
2、nal adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defe
3、nse. 1. Scope 1.1 This test method establishes the criteria for the laboratory measurement of the steady-state heat ux through at, homogeneous specimen(s) when their surfaces are in contact with solid, parallel boundaries held at constant temperatures using the guarded-hot-plate apparatus. 1.2 The t
4、est apparatus designed for this purpose is known as a guarded-hot-plate apparatus and is a primary (or absolute) method. This test method is comparable, but not identical, to ISO 8302. 1.3 This test method sets forth the general design requirements necessary to construct and operate a satisfactory g
5、uarded-hot- plate apparatus. It covers a wide variety of apparatus constructions, test conditions, and operating conditions. Detailed designs conforming to this test method are not given but must be developed within the constraints of the general requirements. Examples of analysis tools, concepts an
6、d procedures used in the design, construction, calibration and operation of a guarded-hot-plate apparatus are given in Refs (1-41). 2 1.4 This test method encompasses both the single-sided and the double-sided modes of measurement. Both distributed and line source guarded heating plate designs are p
7、ermitted. The user should consult the standard practices on the single-sided mode of operation, Practice C1044, and on the line source apparatus, Practice C1043, for further details on these heater designs. 1.5 Theguarded-hot-plateapparatuscanbeoperatedwitheitherverticalorhorizontalheatow.Theuserisc
8、autionedhowever, since the test results from the two orientations may be different if convective heat ow occurs within the specimens. 1.6 Although no denitive upper limit can be given for the magnitude of specimen conductance that is measurable on a guarded-hot-plate, for practical reasons the speci
9、men conductance should be less than 16 W/(m 2 K). 1.7 This test method is applicable to the measurement of a wide variety of specimens, ranging from opaque solids to porous or transparent materials, and a wide range of environmental conditions including measurements conducted at extremes of temperat
10、ure and with various gases and pressures. 1.8 Inhomogeneities normal to the heat ux direction, such as layered structures, can be successfully evaluated using this test method. However, testing specimens with inhomogeneities in the heat ux direction, such as an insulation system with thermal bridges
11、, can yield results that are location specic and shall not be attempted with this type of apparatus. SeeTest Method C1363 for guidance in testing these systems. 1.9 Calculations of thermal transmission properties based upon measurements using this method shall be performed in conformance with Practi
12、ce C1045. 1.10 In order to ensure the level of precision and accuracy expected, persons applying this standard must possess a knowledge of the requirements of thermal measurements and testing practice and of the practical application of heat transfer theory relating to thermal insulation materials a
13、nd systems. Detailed operating procedures, including design schematics and electrical drawings, should be available for each apparatus to ensure that tests are in accordance with this test method. In addition, automated data 1 This test method is under the jurisdiction of ASTM Committee C16 on Therm
14、al Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal Measurement. Current edition approved June 1, 2010Sept. 15, 2013. Published August 2010October 2013. Originally approved in 1942. Last previous edition approved in 20042010 as C17704C17710 . DOI: 10.1520/C0177-10.10.152
15、0/C0177-13. 2 The boldface numbers given in parentheses refer to the list of references at the end of this standard. This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because it may n
16、ot be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version of the standard as published by ASTM is to be considered the official document. Copyright ASTM International, 100 Barr Harbo
17、r Drive, PO Box C700, West Conshohocken, PA19428-2959. United States 1collecting and handling systems connected to the apparatus must be veried as to their accuracy. This can be done by calibration and inputting data sets, which have known results associated with them, into computer programs. 1.11 I
18、t is not practical for a test method of this type to establish details of design and construction and the procedures to cover all contingencies that might offer difficulties to a person without technical knowledge concerning theory of heat ow, temperature measurements and general testing practices.
19、The user may also nd it necessary, when repairing or modifying the apparatus, to become a designer or builder, or both, on whom the demands for fundamental understanding and careful experimental technique are even greater. Standardization of this test method is not intended to restrict in any way th
20、e future development of new or improved apparatus or procedures. 1.12 Thistestmethoddoesnotspecifyalldetailsnecessaryfortheoperationoftheapparatus.Decisionsonsampling,specimen selection, preconditioning, specimen mounting and positioning, the choice of test conditions, and the evaluation of test dat
21、a shall follow applicableASTM Test Methods, Guides, Practices or Product Specications or governmental regulations. If no applicable standard exists, sound engineering judgment that reects accepted heat transfer principles must be used and documented. 1.13 This test method allows a wide range of appa
22、ratus design and design accuracy to be used in order to satisfy the requirements of specic measurement problems. Compliance with this test method requires a statement of the uncertainty of each reported variable in the report. A discussion of the signicant error factors involved is included. 1.14 Th
23、e values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.15 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appr
24、opriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specic precautionary statements are given in Note 21. 1.16 Major sections within this test method are arranged as follows: Section Section Scope 1 Referenced Documents 2 Terminology 3 Summary
25、of Test Method 4 Signicance and Use 5 Apparatus 6 Specimen Preparation and Conditioning 7 Procedure 8 Calculation of Results 9 Report 10 Precision and Bias 11 Keywords 12 Figures GeneralArrangement of the Mechanical Components of the Guarded- Hot-PlateApparatus Fig. 1 Illustration of Heat Flow in th
26、e Guarded-Hot-PlateApparatus Fig.2 Example Report Form Fig. 3 Annexes Importance of Thickness A1.1 Measuring Thickness A1.2 Limitations Due toApparatus A1.3 Limitations Due to Temperature A1.4 Limitations Due to Specimen A1.5 Random and Systematic Error Components A1.6 Error Components for Variables
27、 A1.7 Thermal Conductance or Thermal Resistance ErrorAnalysis A1.8 Thermal Conductivity or Thermal Resistivity ErrorAnalysis A1.9 Uncertainty Verication A1.10 2. Referenced Documents 2.1 ASTM Standards: 3 C168Terminology Relating to Thermal Insulation C518Test Method for Steady-State Thermal Transmi
28、ssion Properties by Means of the Heat Flow Meter Apparatus C687Practice for Determination of Thermal Resistance of Loose-Fill Building Insulation C1043Practice for Guarded-Hot-Plate Design Using Circular Line-Heat Sources C1044Practice for Using a Guarded-Hot-Plate Apparatus or Thin-Heater Apparatus
29、 in the Single-Sided Mode C1045Practice for Calculating Thermal Transmission Properties Under Steady-State Conditions C1058Practice for Selecting Temperatures for Evaluating and Reporting Thermal Properties of Thermal Insulation C1363TestMethodforThermalPerformanceofBuildingMaterialsandEnvelopeAssem
30、bliesbyMeansofaHotBoxApparatus E230Specication and Temperature-Electromotive Force (EMF) Tables for Standardized Thermocouples 3 ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatserviceastm.org.ForAnnualBookofASTMStandards volume information, refer to the sta
31、ndards Document Summary page on the ASTM website. C17713 2E691Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method 2.2 ISO Standard: ISO 8302Thermal InsulationDetermination of Steady-State Areal Thermal Resistance and Related PropertiesGuarded- Hot-Plate Appar
32、atus 4 2.3 ASTM Adjuncts:ASTM Table of Theoretical Maximum Thickness of Specimens and Associated Errors 5 Descriptions of Three Guarded-Hot-Plate Designs 5 Line-Heat-Source Guarded Hot-Plate Apparatus 6 3. Terminology 3.1 Denitions: 3.1.1 For denitions of terms and symbols used in this test method,
33、refer to Terminology C168 and the following subsections. 3.2 Denitions of Terms Specic to This Standard: 3.2.1 auxiliary cold surface assembly, n the plate that provides an isothermal boundary at the outside surface of the auxiliary insulation. 3.2.2 auxiliaryinsulation,ninsulationplacedonthebacksid
34、eofthehot-surfaceassembly,inplaceofasecondtestspecimen, when the single sided mode of operation is used. (Synonymbackow specimen.) 3.2.3 cold surface assembly, nthe plates that provide an isothermal boundary at the cold surfaces of the test specimen. 3.2.4 controlled environment, nthe environment in
35、 which an apparatus operates. 3.2.5 guard, npromotes one-dimensional heat ow. Primary guards are planar, additional coplanar guards can be used and secondary or edge guards are axial. 3.2.6 guarded-hot-plate apparatus, nan assembly, consisting of a hot surface assembly and two isothermal cold surfac
36、e assemblies. 3.2.7 guarded-hot-plate, nthe inner (rectangular or circular) plate of the hot surface assembly, that provides the heat input to the metered section of the specimen(s). 3.2.8 hot surface/assembly, nthe complete center assembly providing heat to the specimen(s) and guarding for the mete
37、r section. 3.2.9 metered section, nthe portion of the test specimen (or auxiliary insulation) through which the heat input to the guarded-hot-plate ows under ideal guarding conditions. 3.2.10 mode, double-sided, noperation of the guarded-hot-plate apparatus for testing two specimens, each specimen p
38、laced on either side of the hot surface assembly. 3.2.11 mode, single-sided, noperation of the guarded-hot-plate apparatus for testing one specimen, placed on one side of the hot-surface assembly. 3.2.12 thermal transmission properties, n those properties of a material or system that dene the abilit
39、y of a material or system to transfer heat such as thermal resistance, thermal conductance, thermal conductivity and thermal resistivity, as dened by Terminology C168. 3.3 SymbolsThe symbols used in this test method have the following signicance: 3.3.1 r m specimen metered section density, kg/m 3 .
40、3.3.2 r s specimen density, kg/m 3 . 3.3.3 lthermal conductivity, W/(m K). 3.3.4 sStefan-Boltzmann constant, W/m 2 K 4 . 3.3.5 Ametered section area normal to heat ow, m 2 . 3.3.6 A g area of the gap between the metered section and the primary guard, m 2 . 3.3.7 A m area of the actual metered sectio
41、n, m 2 . 3.3.8 A s area of the total specimen, m 2 . 3.3.9 Cthermal conductance, W/(m 2 K). 3.3.10 C i the specic heat of the ith component of the metered section, J/(kg K). 3.3.11 dT/dtpotential or actual drift rate of the metered section, K/s. 3.3.12 l g thermal conductivity of the material in the
42、 primary guard region, W/(m K). 4 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org. 5 Available from ASTM Headquarters, Order Adjunct: ADJC0177. 6 Available from ASTM Headquarters, Order Adjunct: ADJC1043. C17713 33.3.13 L
43、in-situ specimen thickness, m. 3.3.14 mmass of the specimen in the metered section, kg. 3.3.15 m i the mass of the ith component, kg. 3.3.16 m s mass of the specimen, kg. 3.3.17 Qheat ow rate in the metered section, W. 3.3.18 qheat ux (heat ow rate per unit area), Q, through area, A, W/m 2 . 3.3.19
44、Q ge lateral edge heat ow rate between primary Guard and Controlled Environment, W. 3.3.20 Q gp lateral heat ow rate across the gap, W. 3.3.21 Q grd guard heat ow through Specimen, W. 3.3.22 Q se edge heat ow between Specimen and Controlled Environment, W. 3.3.23 Rthermal resistance, m 2 K/W. 3.3.24
45、 D Ttemperature difference across the specimen, T h T c . 3.3.25 T c cold surface temperature, K. 3.3.26 T h hot surface temperature, K. 3.3.27 T m mean temperature, K, (T h +T c )/2. 3.3.27.1 Discussion The Guarded-Hot-Plate Apparatus provides a means for measurement of steady state heat ux through
46、 insulation materials, that consists of a guarded heater unit, comprised of a center metering area and concentric separately heated guards, and an opposite, similarly sized cooling plate. Specimens are placed in the space between the heater plate and the cooling plate for testing. The guarded-hot-pl
47、ateisoperatedasasingleordoublesidedapparatus.Insulationthermalpropertiesarecalculatedfrommeasurements of metering area, energy input, temperatures, and thickness. The guarded-hot-plate, which provides an absolute measurement of heat ux, has been shown to be applicable for most insulating materials o
48、ver a wide range of temperature conditions. 4. Summary of Test Method 4.1 Fig. 1 illustrates the main components of the idealized system: two isothermal cold surface assemblies and a guarded-hot-plate. It is possible that some apparatuses will have more than one guard. The guarded-hot-plate is compo
49、sed of a meteredsectionthermallyisolatedfromaconcentricprimaryguardbyadeniteseparationorgap.Someapparatusmayhavemore than one guard. The test specimen is sandwiched between these three units as shown in Fig. 1. In the double-sided mode of FIG. 1 General Arrangement of the Mechanical Components of the Guarded-Hot-Plate Apparatus C17713 4measurement,thespecimenisactuallycomposedoftwopieces.Themeasurementinthiscaseproducesaresultthatistheaverage of the two pieces and therefore it is important that
