The ASTM F1939-15 (2020) standard test method is used to evaluate the radiant heat resistance of fireproof clothing materials under continuous heating conditions. This method measures the thermal conductivity properties of materials by exposing them to a standardized radiant heat source to determine their protective performance in a radiant heat environment. During the test, the material remains in a static vertical state and is exposed to a continuous and constant radiant heat source. This standard is applicable to the evaluation of fireproof clothing materials used to protect workers from radiant heat hazards. It is important to note that this test method is not applicable to non-fireproof materials. In addition, the test results should not be used directly to predict skin burn injuries, as it does not take into account the residual thermal energy in the specimen after exposure.