This test method is intended for the determination of the radiant heat resistance value of a material, a combination of materials, or a comparison of different materials used in flame resistant clothing for workers exposed to radiant thermal hazards.

This test method evaluates a material’heat transfer properties when exposed to a continuous and constant radiant heat source. Air movement at the face of the specimen and around the calorimeter can affect the measured heat transferred due to forced convective heat losses. Minimizing the air movement around the specimen and test apparatus will aid in the repeatability of the results.

This test method maintains the specimen in a static, vertical position and does not involve movement, except that resulting from the exposure.

This test method specifies two standard sets of exposure conditions: 21 kW/m² [0.5 cal/cm²s] and 84 kW/m² [2.0 cal/cm²s]. Either can be used.

5.4.1 If a different set of exposure conditions is used, it is likely that different results will be obtained.

5.4.2 The optional use of other conditions representative of the expected hazard, in addition to the standard set of exposure conditions, is permitted. However, the exposure conditions used must be reported with the results along with a determination of the exposure energy level stability.

This test method does not predict skin burn injury from the standardized radiant heat exposure.

Note 4—See Appendix X4 for additional information regarding this test method and predicted skin burn injury.

1.1 This test method rates the non-steady state thermal resistance or insulating characteristics of flame resistant clothing materials subjected to a continuous, standardized radiant heat exposure.

1.1.1 This test method is not applicable to clothing materials that are not flame resistant.

The determination of a clothing material's flame resistance shall be made prior to testing and done in accordance with the applicable performance standard, specification standard, or both, for the clothing material's end-use.

1.1.2 This test method does not predict skin burn injury from the standardized radiant heat exposure as it does not account for the thermal energy contained in the test specimen after the exposure has ceased.

See for additional information regarding this test method and predicted skin burn injury.

1.2 This test method is used to measure and describe the response of materials, products, or assemblies to heat under controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials, products, or assemblies under actual fire conditions.

1.3 The values stated in SI units are to be regarded as standard. The values given in brackets are mathematical conversions to inch-pound or other units that are commonly used for thermal testing.

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.