ASTM C177-04
(Test Method)Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
SCOPE
1.1 This test method establishes the criteria for the laboratory measurement of the steady-state heat flux through flat, 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 test 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 guarded-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 and procedures used in the design, construction, calibration and operation of a guarded-hot-plate apparatus are given in Refs ().
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 permitted. The user should consult the standard practices on the single-sided mode of operation, Practice C 1044, and on the line source apparatus, Practice C 1043, for further details on these heater designs.
1.5 The guarded-hot-plate apparatus can be operated with either vertical or horizontal heat flow. The user is cautioned however, since the test results from the two orientations may be different if convective heat flow occurs within the specimens.
1.6 Although no definitive upper limit can be given for the magnitude of specimen conductance that is measurable on a guarded-hot-plate, for practical reasons the specimen conductance should be less than 16 W/(m 2K).
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 temperature and with various gases and pressures.
1.8 Inhomogeneities normal to the heat flux direction, such as layered structures, can be successfully evaluated using this test method. However, testing specimens with inhomogeneities in the heat flux direction, such as an insulation system with thermal bridges, can yield results that are location specific and shall not be attempted with this type of apparatus. See Test Methods C 976 or C 236 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 Practice C 1045.
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 and 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 collecting and handling systems connected to the apparatus must be verified 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 It 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 flow, temperature measurements and general testing practices. The user may also find 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 exper...
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Designation: C177 – 04
Standard Test Method for
Steady-State Heat Flux Measurements and Thermal
Transmission Properties by Means of the Guarded-Hot-Plate
1
Apparatus
This standard is issued under the fixed designation C177; the number immediately following the designation indicates the year of
original 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 Defense.
1. Scope 1.6 Although no definitive upper limit can be given for the
magnitude of specimen conductance that is measurable on a
1.1 This test method establishes the criteria for the labora-
guarded-hot-plate, for practical reasons the specimen conduc-
tory measurement of the steady-state heat flux through flat,
2
tance should be less than 16 W/(m K).
homogeneous specimen(s) when their surfaces are in contact
1.7 This test method is applicable to the measurement of a
with solid, parallel boundaries held at constant temperatures
wide variety of specimens, ranging from opaque solids to
using the guarded-hot-plate apparatus.
porous or transparent materials, and a wide range of environ-
1.2 Thetestapparatusdesignedforthispurposeisknownas
mental conditions including measurements conducted at ex-
a guarded-hot-plate apparatus and is a primary (or absolute)
tremes of temperature and with various gases and pressures.
method. This test method is comparable, but not identical, to
1.8 Inhomogeneities normal to the heat flux direction, such
ISO8302.
as layered structures, can be successfully evaluated using this
1.3 This test method sets forth the general design require-
testmethod.However,testingspecimenswithinhomogeneities
ments necessary to construct and operate a satisfactory
in the heat flux direction, such as an insulation system with
guarded-hot-plate apparatus. It covers a wide variety of appa-
thermal bridges, can yield results that are location specific and
ratus constructions, test conditions, and operating conditions.
shall not be attempted with this type of apparatus. See Test
Detailed designs conforming to this test method are not given
Methods C976 or C236 for guidance in testing these systems.
but must be developed within the constraints of the general
1.9 Calculations of thermal transmission properties based
requirements. Examples of analysis tools, concepts and proce-
upon measurements using this method shall be performed in
dures used in the design, construction, calibration and opera-
2 conformance with Practice C1045.
tionofaguarded-hot-plateapparatusaregiveninRefs (1-41).
1.10 In order to ensure the level of precision and accuracy
1.4 This test method encompasses both the single-sided and
expected, persons applying this standard must possess a
the double-sided modes of measurement. Both distributed and
knowledge of the requirements of thermal measurements and
line source guarded heating plate designs are permitted. The
testing practice and of the practical application of heat transfer
user should consult the standard practices on the single-sided
theory relating to thermal insulation materials and systems.
mode of operation, Practice C1044, and on the line source
Detailed operating procedures, including design schematics
apparatus, Practice C1043, for further details on these heater
and electrical drawings, should be available for each apparatus
designs.
to ensure that tests are in accordance with this test method. In
1.5 The guarded-hot-plate apparatus can be operated with
addition, automated data collecting and handling systems
either vertical or horizontal heat flow. The user is cautioned
connected to the apparatus must be verified as to their
however,sincethetestresultsfromthetwoorientationsmaybe
accuracy. This can be done by calibration and inputting data
different if convective heat flow occurs within the specimens.
sets, which have known results associated with them, into
computer programs.
1.11 It is not practical for a test method of this type to
1
ThistestmethodisunderthejurisdictionofASTMCommitteeC16onThermal
establish details of design and construction and the procedures
Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal
to cover all contingencies that might offer difficulties to a
Measurement.
Current edition approved Nov. 1, 2004. Published November 2004. Originally
person without technical knowledge concerning theory of heat
approved in 1942. Last previous edition approved in 1997 as C177–97 . DOI:
flow, temperature measurements and general testing practices.
10.1520/C0177-04.
2 The user may also find it necessary, when repairing or
The boldface numbers given in parentheses refer to the list of references at the
end
...
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