Abstract: The gas film reinforced concrete structure dome grain silo （hereinafter referred to as "gas film grain silo"） has been applied in China due to its advantages of high safety, strong airtightness, good thermal insulation, and energy conservation and environmental protection. However, there is no consensus on the fire safety and reliability research of gas film granaries. Therefore, this study constructed a simulated fire scenario to analyze the possibility and causes of fire in an gas film grain silo, and studied the characteristics of fire spread on the outer wall of the silo. The experimental results indicate that the outer PVDF layer and polyurethane insulation layer of the gas film granary can be ignited and spread by a fire source. The maximum heat flux at a distance of 2.5 meters from the wall is less than 1.0 kW/m2, which does not reach the heat flux required to ignite ordinary combustibles. In addition, the temperature 2.5 m away from the wall does not exceed 100 ℃, and does not reach the ignition temperature of 270 ℃ for flexible polyurethane foam. Considering a certain safety margin, it is recommended that the fire separation distance should not be less than 3.0 meters. At the same time, this article also proposes fire protection measures suitable for gas film granaries.

Key words: gas film reinforced concrete structure grain silo, fire propagation, fire separation distance