A minimum of three samples (230 mm x 70 mm) will be tested for each material or set of materials.

Test: A sample of fabric is submitted to a radiant heat incidental flux of 20-40 kW/m2 ± 5%. Heat passing through the sample is measured by a calorimeter placed behind the fabric and in conctact with it. Radiation must be stopped when the clometer's heat raising reaches 10ºK or after 5 minutes. Needed time must be measured in seconds, in order to produce a heating of the temperature in the calorimeter, which means the average time a person takes to feel hot due to second degree burns produced by this heating of temperature.