Abstract: The RPP test principle of radiation heat protection property of fabric was introduced. The relationship between the radiation heat source intensity and the RPP value of the flame retardant fabric was analyzed by 25 kinds of common flame retardant fabrics. The microcosmic changes were characterized by SEM, experimental phenomena and macroscopic changes of the fabric after the experiment were analyzed. The results showed that the physical structure parameters of the fabric are the main factors affecting the radiant heat protection performance of the fabric under the condi⁃ tion of low heat flux density. The RPP value of non-essential flame retardant fabric decreases with the increase of heat flux, while the RPP value of non-essential flame retardant fabric decreases and increases alternately with the increase of heat flux. When the heat flux increases, the burn time decreases more than the radiation heat flux increases, and the RPP decreases. RPP value cannot be used as the only index to evaluate the radiant heat protection performance of fabric. With the increase of radiation heat source inten⁃ sity, the appearance of essential flame retardant fabric hardly changes, and then the carbonization decomposition of finished fabric and blended fabric gradually deepens.

Key words: flame retardant fabric, radiant heat, protective perfor? mance, heat flux intensity, charring