ASTM F1868-23

1.1 This test method covers the measurement of the thermal resistance, evaporative resistance, and total heat loss under steady-state conditions of fabrics, films, coatings, foams, and leathers, including multi-layer assemblies, for use in clothing systems.

1.2 The range of this measurement technique for intrinsic thermal resistance is from 0.002 to 0.5 K·m²/W and for intrinsic evaporative resistance is from 0.0 to 1.0 kPa·m ²/W. The total heat loss range is from 0.0 to 1300 W/m².

1.3 The values in SI units shall be regarded as standard. Other units of measurement are provided in this standard but are not regarded as standard.

1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.