ASTM E1225-09
(Test Method)Standard Test Method for Thermal Conductivity of Solids by Means of the Guarded-Comparative-Longitudinal Heat Flow Technique
Standard Test Method for Thermal Conductivity of Solids by Means of the Guarded-Comparative-Longitudinal Heat Flow Technique
SIGNIFICANCE AND USE
The comparative method of measurement of thermal conductivity is especially useful for engineering materials including ceramics, polymers, metals and alloys, refractories, carbons, and graphites including combinations and other composite forms of each.
Proper design of a guarded-longitudinal system is difficult and it is not practical in a 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 technical knowledge concerning theory of heat flow, temperature measurements, and general testing practices. Standardization of this test method is not intended to restrict in any way the future development by research workers of new or methods or improved procedures. However, new or improved techniques must be thoroughly tested. Requirements for qualifying an apparatus are outlined in Section 10.
SCOPE
1.1 This test method describes a steady state technique for the determination of the thermal conductivity, λ, of homogeneous-opaque solids (see Notes 1 and 2). This test method is for materials with effective thermal conductivities in the approximate range 0.2 λ 200 W/(m·K) over the approximate temperature range between 90 and 1300 K. It can be used outside these ranges with decreased accuracy.
Note 1—For purposes of this technique, a system is homogeneous if the apparent thermal conductivity of the specimen, λA, does not vary with changes of thickness or cross-sectional area by more than ±5 %. For composites or heterogeneous systems consisting of slabs or plates bonded together, the specimen should be more than 20 units wide and 20 units thick, respectively, where a unit is the thickness of the thickest slab or plate, so that diameter or length changes of one-half unit will affect the apparent λA by less than ±5 %. For systems that are non-opaque or partially transparent in the infrared, the combined error due to inhomogeneity and photon transmission should be less than ±5 %. Measurements on highly transparent solids must be accompanied with infrared absorption coefficient information, or the results must be reported as apparent thermal conductivity, λA.
Note 2—This test method may also be used to evaluate the contact thermal conductance/resistance of materials.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E1225 − 09
StandardTest Method for
Thermal Conductivity of Solids by Means of the Guarded-
1
Comparative-Longitudinal Heat Flow Technique
This standard is issued under the fixed designation E1225; 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 2. Referenced Documents
2
1.1 This test method describes a steady state technique for 2.1 ASTM Standards:
the determination of the thermal conductivity, λ,of C177Test Method for Steady-State Heat Flux Measure-
homogeneous-opaque solids (see Notes 1 and 2). This test ments and Thermal Transmission Properties by Means of
methodisformaterialswitheffectivethermalconductivitiesin the Guarded-Hot-Plate Apparatus
the approximate range 0.2 < λ < 200 W/(m·K) over the C408Test Method for Thermal Conductivity of Whiteware
approximate temperature range between 90 and 1300 K. It can Ceramics
be used outside these ranges with decreased accuracy. C1045Practice for Calculating Thermal Transmission Prop-
erties Under Steady-State Conditions
NOTE 1—For purposes of this technique, a system is homogeneous if
D4351Test Method for Measuring the Thermal Conductiv-
the apparent thermal conductivity of the specimen, λ , does not vary with
A
ity of Plastics by the Evaporation-Calorimetric Method
changes of thickness or cross-sectional area by more than 65%. For
3
composites or heterogeneous systems consisting of slabs or plates bonded
(Withdrawn 1990)
together, the specimen should be more than 20 units wide and 20 units
E220Test Method for Calibration of Thermocouples By
thick, respectively, where a unit is the thickness of the thickest slab or
Comparison Techniques
plate, so that diameter or length changes of one-half unit will affect the
E230Specification and Temperature-Electromotive Force
apparent λ by less than 65%. For systems that are non-opaque or
A
(EMF) Tables for Standardized Thermocouples
partially transparent in the infrared, the combined error due to inhomo-
geneityandphotontransmissionshouldbelessthan 65%.Measurements
F433Practice for Evaluating Thermal Conductivity of Gas-
onhighlytransparentsolidsmustbeaccompaniedwithinfraredabsorption
ket Materials
coefficientinformation,ortheresultsmustbereportedasapparentthermal
conductivity, λ .
A
3. Terminology
NOTE 2—This test method may also be used to evaluate the contact 3.1 Descriptions of Terms and Symbols Specific to This
thermal conductance/resistance of materials.
Standard:
3.1.1 Terms:
1.2 The values stated in SI units are to be regarded as
3.1.1.1 thermal conductivity, λ—the time rate of heat flow,
standard. No other units of measurement are included in this
understeadyconditions,throughunitarea,perunittemperature
standard.
gradient in the direction perpendicular to the area;
1.3 This standard does not purport to address all of the
3.1.1.2 apparent thermal conductivity—when other modes
safety concerns, if any, associated with its use. It is the
of heat transfer through a material are present in addition to
responsibility of the user of this standard to establish appro-
conduction,theresultsofthemeasurementsperformedaccord-
priate safety and health practices and determine the applica-
ing to this test method will represent the apparent or effective
bility of regulatory limitations prior to use.
thermal conductivity for the material tested.
1 2
ThistestmethodisunderthejurisdictionofASTMCommitteeE37onThermal For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Measurements and is the direct responsibility of Subcommittee E37.05 on Thermo- contact ASTM Customer service at service@astm.org. For Annual Book of ASTM
physical Properties. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved March 15, 2009. Published April 2010. Originally the ASTM website.
3
approved in 1987. Last previous edition approved in 2004 as E1225–04. DOI: The last approved version of this historical standard is referenced on
10.1520/E1225-09. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E1225 − 09
3.1.2 Symbols: temperature, T (z). A temperature gradient is imposed on the
g
column by maintaining the top at a temperature, T , and the
T
λ (T) = thermal conductivity of meter bars (reference
M
bottom at temperature T .T (z) is usually a linear temperature
B g
materials) as a function of temperature, (W/
gradient matching approximately the gradient
...
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:E1225–04 Designation:E1225–09
Standard Test Method for
Thermal Conductivity of Solids by Means of the Guarded-
1
Comparative-Longitudinal Heat Flow Technique
This standard is issued under the fixed designation E1225; 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
1.1 This test method describes a steady state technique for the determination of the thermal conductivity, l, of homogeneous-
opaque solids (see Notes 1 and 2).This test method is for materials with effective thermal conductivities in the approximate range
0.2 < l < 200W/(m·K) over the approximate temperature range between 90 and 1300 K. It can be used outside these ranges with
decreased accuracy.
NOTE 1—Forpurposesofthistechnique,asystemishomogeneousiftheapparentthermalconductivityofthespecimen, l ,doesnotvarywithchanges
A
of thickness or cross-sectional area by more than 65%. For composites or heterogeneous systems consisting of slabs or plates bonded together, the
specimen should be more than 20 units wide and 20 units thick, respectively, where a unit is the thickness of the thickest slab or plate, so that diameter
or length changes of one-half unit will affect the apparent l by less than 65%. For systems that are non-opaque or partially transparent in the infrared,
A
the combined error due to inhomogeneity and photon transmission should be less than 65%. Measurements on highly transparent solids must be
accompanied with infrared absorption coefficient information, or the results must be reported as apparent thermal conductivity, l .
A
NOTE 2—This test method may also be used to evaluate the contact thermal conductance/resistance of materials.
1.2
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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 appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
C177 Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the
Guarded-Hot-Plate Apparatus
C408 Test Method for Thermal Conductivity of Whiteware Ceramics
C1045 Practice for Calculating Thermal Transmission Properties Under Steady-State Conditions
3
D4351 Test Method for Measuring the Thermal Conductivity of Plastics by the Evaporation-Calorimetric Method
E220 Test Method for Calibration of Thermocouples By Comparison Techniques
E230 Specification and Temperature-Electromotive Force (EMF) Tables for Standardized Thermocouples
F433 Practice for Evaluating Thermal Conductivity of Gasket Materials
3. Terminology
3.1 Descriptions of Terms and Symbols Specific to This Standard:
3.1.1 Terms:
3.1.1.1 thermal conductivity, l—the time rate of heat flow, under steady conditions, through unit area, per unit temperature
gradient in the direction perpendicular to the area;
3.1.1.2 apparent thermal conductivity —when other modes of heat transfer through a material are present in addition to
1
This test method is under the jurisdiction of ASTM Committee E37 on Thermal Measurements and is the direct responsibility of Subcommittee E37.05 on
Thermophysical Properties.
CurrenteditionapprovedMay1,2004.PublishedJune2004.Originallyapprovedin1987.Lastpreviouseditionapprovedin1999asE1225–99.DOI:10.1520/E1225-04.
Current edition approved March 15, 2009. Published April 2010. Originally approved in 1987. Last previous edition approved in 2004 as E1225–04. DOI:
10.1520/E1225-09.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerserviceatservice@astm.org.For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Withdrawn. The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
E1225–09
conduction,theresultsofthemeasurementsperformedaccordingtothistestmethodwi
...
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