ASTM D5470-01

Standard Test Method for Thermal Transmission Properties of Thin Thermally Conductive Solid Electrical Insulation Materials

SCOPE
1.1 This standard covers a test method for measuring thermal impedance of thin electrical insulation materials.
1.2 This test method is useful with either homogeneous or composite thermally conductive sheet material ranging from 0.02 to 10 mm in thickness.
1.3 This test method measures steady-state heat flux through a flat specimen. Calculations are made as if the specimens were homogeneous. In fact, these materials are usually not homogeneous, but the assumption does not detract from the usefulness of the test methods.
1.4 The term "thermal conductivity" applies only to homogeneous materials. Thermally conductive electrical insulating materials are usually heterogeneous since they typically include fillers, binders, reinforcements such as glass fiber mesh, or a layer of polymeric film. To avoid confusion, this test method uses "apparent thermal conductivity" for measurements of both homogeneous and non-homogeneous materials.
1.5 A limitation of using this test method to calculate apparent thermal conductivity is the problem of accurately determining the specimen thickness. To reflect the commercial practice of measuring thickness as manufactured rather than measuring thickness in an assembly, thickness is determined from measurements made at room temperature in accordance with Method C of Test Methods D 374.
1.6 Thermal impedance test data are influenced by contact pressures, specimen surface characteristics, and the existence of alternate paths for heat transmission which are not through the specimen. This test method determines thermal conduction properties under a specific set of conditions (including a 50°C average test temperature) which may not agree exactly with the conditions in an application. As a result, the degree of correlation between this test method and any particular application needs to be determined.
1.7 The values stated in SI units are to be regarded as standard.
1.8 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.
Note 1—Earlier versions of this document included a Method B (the Roiseland Method). This method is now deleted because of a lack of general support.

General Information

• Status: Historical
• Publication Date: 09-Sep-2001
• ICS: 29.035.01 - Insulating materials in general
• Technical Committee: D09 - Electrical and Electronic Insulating Materials

Relations

• Replaces: ASTM D5470-95 - Standard Test Methods for Thermal Transmission Properties of Thin Thermally Conductive Solid Electrical Insulation Materials
• Effective Date: 10-Sep-2001
• Replaced By: ASTM D5470-06 - Standard Test Method for Thermal Transmission Properties of Thermally Conductive Electrical Insulation Materials
• Effective Date: 01-Apr-2006
• Referred By: ASTM D6343-14(2018) - Standard Test Methods for Thin Thermally Conductive Solid Materials for Electrical Insulation and Dielectric Applications
• Effective Date: 10-Sep-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
An American National Standard
Designation:D5470–01
Standard Test Method for
Thermal Transmission Properties of Thin Thermally
1
Conductive Solid Electrical Insulation Materials
This standard is issued under the fixed designation D 5470; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 1.7 The values stated in SI units are to be regarded as
standard.
1.1 This standard covers a test method for measuring
1.8 This standard does not purport to address all of the
thermal impedance of thin electrical insulation materials.
safety concerns, if any, associated with its use. It is the
1.2 This test method is useful with either homogeneous or
responsibility of the user of this standard to establish appro-
composite thermally conductive sheet material ranging from
priate safety and health practices and determine the applica-
0.02 to 10 mm in thickness.
bility of regulatory limitations prior to use.
1.3 Thistestmethodmeasuressteady-stateheatfluxthrough
aflatspecimen.Calculationsaremadeasifthespecimenswere
NOTE 1—Earlier versions of this document included a Method B (the
homogeneous. In fact, these materials are usually not homo- Roiseland Method). This method is now deleted because of a lack of
general support.
geneous, but the assumption does not detract from the useful-
ness of the test methods.
2. Referenced Documents
1.4 The term “thermal conductivity” applies only to homo-
2.1 ASTM Standards:
geneous materials. Thermally conductive electrical insulating
D 374 Test Methods for Thickness of Solid Electrical Insu-
materials are usually heterogeneous since they typically in-
2
lation
clude fillers, binders, reinforcements such as glass fiber mesh,
E 691 Practice for Conducting an Interlaboratory Study to
or a layer of polymeric film. To avoid confusion, this test
3
Determine the Precision of a Test Method
method uses “apparent thermal conductivity” for measure-
E 1225 Test Method for Thermal Conductivity of Solids by
ments of both homogeneous and non-homogeneous materials.
Means of the Guarded-Comparative-Longitudinal Heat
1.5 A limitation of using this test method to calculate
3
Flow Technique
apparent thermal conductivity is the problem of accurately
2.2 Military Specification:
determining the specimen thickness. To reflect the commercial
MIL-I-49456 Insulation Sheet, Electrical, Silicone Rubber,
practice of measuring thickness as manufactured rather than
4
Thermally Conductive, Fiberglass Reinforced
measuring thickness in an assembly, thickness is determined
from measurements made at room temperature in accordance
3. Terminology
with Method C of Test Methods D 374.
3.1 Definitions of Terms Specific to This Standard:
1.6 Thermal impedance test data are influenced by contact
3.1.1 average temperature (of a surface), n— the area-
pressures, specimen surface characteristics, and the existence
weighted mean temperature.
of alternate paths for heat transmission which are not through
3.1.2 composite, n—a material made up of distinct parts
the specimen. This test method determines thermal conduction
whichcontribute,eitherproportionallyorsynergistically,tothe
properties under a specific set of conditions (including a 50°C
properties of the combination.
averagetesttemperature)whichmaynotagreeexactlywiththe
3.1.3 homogeneous material, n—a material in which rel-
conditions in an application. As a result, the degree of
evant properties are not a function of the position within the
correlation between this test method and any particular appli-
material.
cation needs to be determined.
1
This test method is under the jurisdiction of ASTM Committee D09 on
2
Electrical and Electronic Insulating Materials and is the direct responsibility of Annual Book of ASTM Standards, Vol 10.01.
3
Subcommittee D09.19 on Dielectric Sheet and Roll Products. Annual Book of ASTM Standards, Vol 14.02.
4
Current edition approved Sept. 10, 2001. Published December 2001. Originally AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
published as D 5470 – 93. Last previous edition D 5470 – 95. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D5470–01
3.1.4 thermalconductivity(l),n—thetimerateofheatflow, against cumulative thickness permits the determination of
understeadyconditions,throughunitarea,perunittemperature thermal conductivity without regard to thermal interfacial
grad
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