These three elements refer to

The three elements of fire are combustible, combustion-supporting substance and fire source. The harm of fire accidents is extremely serious. 1. Combustible: Any substance that can burn with oxygen or oxidant in the air, such as combustible solid gas and liquid.

2. Combustion-supporting substance: any substance that helps to support and cause combustion, such as air oxygen oxidizer.

3. Fire source: all thermal energy sources that cause the combustion of combustible materials, metal impact sparks, electric sparks, electrostatic discharges, lightning and the spontaneous combustion of concentrated chemicals.