ASTM C518-10
(Test Method)Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus
Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus
SIGNIFICANCE AND USE
This test method provides a rapid means of determining the steady-state thermal transmission properties of thermal insulations and other materials with a high level of accuracy when the apparatus has been calibrated appropriately.
Proper calibration of the heat flow meter apparatus requires that it be calibrated using specimen(s) having thermal transmission properties determined previously by Test Methods C177, or C1114.
Note 1—Calibration of the apparatus typically requires specimens that are similar to the types of materials, thermal conductances, thicknesses, mean temperatures, and temperature gradients as expected for the test specimens.
The thermal transmission properties of specimens of a given material or product may vary due to variability of the composition of the material; be affected by moisture or other conditions; change with time; change with mean temperature and temperature difference; and depend upon the prior thermal history. It must be recognized, therefore, that the selection of typical values of thermal transmission properties representative of a material in a particular application should be based on a consideration of these factors and will not apply necessarily without modification to all service conditions.
As an example, this test method provides that the thermal properties shall be obtained on specimens that do not contain any free moisture although in service such conditions may not be realized. Even more basic is the dependence of the thermal properties on variables, such as mean temperature and temperature difference. These dependencies should be measured or the test made at conditions typical of use.
Special care shall be taken in the measurement procedure for specimens exhibiting appreciable inhomogeneities, anisotropies, rigidity, or especially high or low resistance to heat flow (see Practice C1045). The use of a heat flow meter apparatus when there are thermal bridges present in the specimen may yield very unreliable resu...
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 C1045. 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 applic...
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Designation: C518 − 10
StandardTest Method for
Steady-State Thermal Transmission Properties by Means of
1
the Heat Flow Meter Apparatus
This standard is issued under the fixed designation C518; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
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
ertiesandenvironmentalconditions.Themethodhasbeenused
is relatively simple in concept, rapid, and applicable to a wide
at ambient conditions of 10 to 40°C with thicknesses up to
rangeoftestspecimens.Theprecisionandbiasoftheheatflow
approximately 250 mm, and with plate temperatures from
meterapparatuscanbeexcellentprovidedcalibrationiscarried
–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
C236 or C976 should be used if needed.
test specimens.
1.8 Tomeettherequirementsofthistestmethodthethermal
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-
tained from a recognized national standards laboratory. 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
1.4 The heat flow meter apparatus establishes steady state
contingencies that might offer difficulties to a person without
one-dimensionalheatfluxthroughatestspecimenbetweentwo
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
calibrationstandardsandbymeasurementoftheplatetempera-
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 C1045. 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
apparatus is given in Appendix X3.
1
ThistestmethodisunderthejurisdictionofASTMCommitteeC16onThermal
Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal
Measurement.
Current edition approved May 1, 2010. Published June 2010. Originally
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approved in 1963. Last previous edition approved in 2004 as C518 – 04. DOI: The boldface numbers in parentheses refer to the list of references at the end of
10.1520/C0518-10. this test method.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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C518 − 10
1.13 The values stated in SI
...
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 not 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.
Designation:C518–04 Designation:C518–10
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 C518; 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 (´) 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
1.1 This test method covers the measurement of steady state thermal transmission through flat slab specimens using a heat flow
meter apparatus.
1.2 Theheatflowmeterapparatusisusedwidelybecauseitisrelativelysimpleinconcept,rapid,andapplicabletoawiderange
oftestspecimens.Theprecisionandbiasoftheheatflowmeterapparatuscanbeexcellentprovidedcalibrationiscarriedoutwithin
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 C1045. 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
2
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 C236 or C976 should be used if needed.
2
1.8 To meet the requirements of this test method the thermal resistance of the test specimen shall be greater than 0.10 m ·K/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 The user of this method must be familiar with and understand theAnnex. TheAnnex is critically important in addressing
equipment design and error analysis.
1.11 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.
1.12 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.
1.13
1.13 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.14 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
1
This test method is under the jurisdiction of ASTM Committee C16 on Thermal Insulat
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