ASTM-E1225 Historical Revision Information
Standard Test Method for Thermal Conductivity of Solids by Means of the Guarded-Comparative-Longitudinal Heat Flow Technique

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Standard Test Method for Thermal Conductivity of Solids Using the Guarded-Comparative-Longitudinal Heat Flow Technique


1.1 This test method describes a steady state technique for the determination of the thermal conductivity, [lambda], of homogeneous-opaque solids (see Notes 1 and 2). This test method is for materials with effective conductivities in the approximate range 0.2 ∧ [lambda] ∧ 200 W/ [dot]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, [lambda] , 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 [lambda] 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 [lambda] . Note 2-This test method may also be used to evaluate the thermal conductance/resistance of materials in contact.

1.2 This standard does not purport to address all of the safety concerns 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.


Alloys; Austenitic steel; Carbon; Ceramic materials; Comparison techniques; Copper; Copper alloy; Glass; Graphite; Guarded heat flow technique; Heat flow; Heating tests-chemicals/materials; Insulation; Iron; Metals and metallic materials; Meter bar materials; Polymers; Refractories (general); Sensors; Silica content; Solid phase materials; Thermal conductivity; Thermal insulating materials; Thermal transmission properties; Tungsten; thermal conductivity of solids, by guarded-comparative-longitudinal heat; flow technique, test; ICS Number Code 17.200.10 (Heat. Calorimetry)

To find similar documents by ASTM Volume:

14.02 (General Test Methods; Forensic Psychophysiology; Forensic Sciences; Terminology; Conformity Assessment; Statistical Methods; Nanotechnology; Forensic Engineering; Manufacture of Pharmaceutical Products)

To find similar documents by classification:

17.200.10 (Heat. Calorimetry)

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Document Number


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Modification Type


Publication Date

March 10, 1999

Document Type

Test Method

Page Count

8 pages

Committee Number