Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus

SCOPE
1.1 This test method covers the measurement of steady state thermal transmission through flat slab specimens using a heat flow meter apparatus.
1.2 The heat flow meter apparatus is used widely because it is relatively simple in concept, rapid, and applicable to a wide range of test specimens. The precision and bias of the heat flow meter apparatus can be excellent provided calibration is carried out within the range of heat flows expected. This means calibration shall be carried out with similar types of materials, of similar thermal conductances, at similar thicknesses, mean temperatures, and temperature gradients, as expected for the test specimens.
1.3 This a comparative, or secondary, method of measurement since specimens of known thermal transmission properties shall be used to calibrate the apparatus. Properties of the calibration specimens must be traceable to an absolute measurement method. The calibration specimens should be obtained from a recognized national standards laboratory.
1.4 The heat flow meter apparatus establishes steady state one-dimensional heat flux through a test specimen between two parallel plates at constant but different temperatures. By appropriate calibration of the heat flux transducer(s) with calibration standards and by measurement of the plate temperatures and plate separation. Fourier's law of heat conduction is used to calculate thermal conductivity, and thermal resistivity or thermal resistance and thermal conductance.
1.5 This test method shall be used in conjunction with Practice C 1045. Many advances have been made in thermal technology, both in measurement techniques and in improved understanding of the principles of heat flow through materials. These advances have prompted revisions in the conceptual approaches to the measurement of the thermal transmission properties (1-4). All users of this test method should be aware of these concepts.
1.6 This test method is applicable to the measurement of thermal transmission through a wide range of specimen properties and environmental conditions. The method has been used at ambient conditions of 10 to 40°C with thicknesses up to approximately 250 mm, and with plate temperatures from- 195°C to 540°C at 25-mm thickness (5, 6).
1.7 This test method may be used to characterize material properties, which may or may not be representative of actual conditions of use. Other test methods, such as Test Methods C 236 or C 976 should be used if needed.
1.8 To meet the requirements of this test method the thermal resistance of the test specimen shall be greater than 0.10 m 2K/W in the direction of the heat flow and edge heat losses shall be controlled, using edge insulation, or a guard heater, or both.
1.9 It is not practical in a test method of this type to try to establish details of construction and procedures to cover all contingencies that might offer difficulties to a person without pertinent technical knowledge. Thus users of this test method shall have sufficient knowledge to satisfactorily fulfill their needs. For example, knowledge of heat transfer principles, low level electrical measurements, and general test procedures is required.
1.10 Standardization of this test method is not intended to restrict in any way the future development of improved or new methods or procedures by research workers.
1.11 Since the design of a heat flow meter apparatus is not a simple matter, a procedure for proving the performance of an apparatus is given in Appendix X3.
1.12 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 consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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Historical
Publication Date
09-Sep-2002
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Drafting Committee
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ASTM C518-02e1 - Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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e1
Designation: C 518 – 02
Standard Test Method for
Steady-State Thermal Transmission Properties by Means of
1
the Heat Flow Meter Apparatus
This standard is issued under the fixed designation C 518; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1
e NOTE—Section 1.10 was editorially added and section 6.1 was editorially updated in September 2003.
1. Scope approaches to the measurement of the thermal transmission
2
properties (1-4). All users of this test method should be aware
1.1 This test method covers the measurement of steady state
of these concepts.
thermal transmission through flat slab specimens using a heat
1.6 This test method is applicable to the measurement of
flow meter apparatus.
thermal transmission through a wide range of specimen prop-
1.2 The heat flow meter apparatus is used widely because it
erties and environmental conditions. The method has been used
is relatively simple in concept, rapid, and applicable to a wide
at ambient conditions of 10 to 40°C with thicknesses up to
range of test specimens. The precision and bias of the heat flow
approximately 250 mm, and with plate temperatures from–
meter apparatus can be excellent provided calibration is carried
195°C to 540°C at 25-mm thickness (5, 6).
out within the range of heat flows expected. This means
1.7 This test method may be used to characterize material
calibration shall be carried out with similar types of materials,
properties, which may or may not be representative of actual
of similar thermal conductances, at similar thicknesses, mean
conditions of use. Other test methods, such as Test Methods
temperatures, and temperature gradients, as expected for the
C 236 or C 976 should be used if needed.
test specimens.
1.8 To meet the requirements of this test method the thermal
1.3 This a comparative, or secondary, method of measure-
resistance of the test specimen shall be greater than 0.10
ment since specimens of known thermal transmission proper-
2
m ·K/W in the direction of the heat flow and edge heat losses
ties shall be used to calibrate the apparatus. Properties of the
shall be controlled, using edge insulation, or a guard heater, or
calibration specimens must be traceable to an absolute mea-
both.
surement method. The calibration specimens should be ob-
1.9 It is not practical in a test method of this type to try to
tained from a recognized national standards laboratory.
establish details of construction and procedures to cover all
1.4 The heat flow meter apparatus establishes steady state
contingencies that might offer difficulties to a person without
one-dimensional heat flux through a test specimen between two
pertinent technical knowledge. Thus users of this test method
parallel plates at constant but different temperatures. By
shall have sufficient knowledge to satisfactorily fulfill their
appropriate calibration of the heat flux transducer(s) with
needs. For example, knowledge of heat transfer principles, low
calibration standards and by measurement of the plate tempera-
level electrical measurements, and general test procedures is
tures and plate separation. Fourier’s law of heat conduction is
required.
used to calculate thermal conductivity, and thermal resistivity
1.10 The user of this method must be familiar with and
or thermal resistance and thermal conductance.
understand the Annex. The Annex is critically important in
1.5 This test method shall be used in conjunction with
addressing equipment design and error analysis.
Practice C 1045. Many advances have been made in thermal
1.11 Standardization of this test method is not intended to
technology, both in measurement techniques and in improved
restrict in any way the future development of improved or new
understanding of the principles of heat flow through materials.
methods or procedures by research workers.
These advances have prompted revisions in the conceptual
1.12 Since the design of a heat flow meter apparatus is not
a simple matter, a procedure for proving the performance of an
1
apparatus is given in Appendix X3.
This test method is under the jurisdiction of ASTM Committee C16 on Thermal
Insulation and is the direct responsibility of Subcommittee C 16.30 on Thermal
Measurement.
2
Current edition approved Sept. 10, 2002. Published October 2002. Originally The boldface numbers in parentheses refer to the list of references at the end of
published as C 518 – 63T. Last previous edition C 518 – 98. this test method.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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