Abstract: A flexible fireproof cover system material for valve actuators was developed. The fireproof cover consists of a fire-resistant outer layer, a thermal insulation layer, and a wear-resistant inner layer. Using glass fiber cloth as the base fabric and coating it with benzyl methyl silicone resin, the outer layer material of the fireproof system was obtained. The influence of the fiber type and thickness of the thermal insulation layer fiber mat in the composite fabric on its thermal insulation performance was explored. The results show that after ablation at 500 °C for 30 minutes, the coated fabric maintains intact structural performance, exhibits liquid repellency and moisture resistance, is resistant to ultraviolet rays, acids, and alkalis, and its smoke toxicity meets the AQ2 level in GB/T 20285. Coated fabrics prepared with quartz fabric and high-silica glass fiber fabric as the base fabric can withstand ablation by butane fire for 10 minutes. When using high-silica coated fabric as the protective outer layer and 48 mm glass fiber mat or alumina fiber mat as the thermal insulation layer, the composite material remains unburned through after 30 minutes of butane fire ablation at 1 100 °C, and the temperature on the back of the composite material is lower than 80 °C，which is the failure temperature of general valve actuators.

Key words: flexible fireproof cover, ablation resistance, thermal insulation material, smoke toxicity