5.1 This test method is intended for the determination of the radiant heat performance 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.
5.2 This test method evaluates a material’s heat transfer properties when exposed to a heat exposure at a constant value and systematically varied durations. 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 air movement around the specimen and test apparatus will aid in the repeatability of the results.
5.3 This test method accounts for the thermal energy contained in the exposed test specimen after the radiant heat exposure has ceased. Higher values of Radiant Heat Performance rating determined in this test associate to higher values of radiant energy protection against a predicted skin burn injury.
5.4 This test method maintains the specimen in a static, vertical position and does not involve movement except that resulting from the exposure procedure.
5.5 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.
5.5.1 If a different set of exposure conditions is used, it is likely that different results will be obtained.
5.5.2 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.