The chemical industry has many explosive sources, such as raw materials, intermediates, and finished products, most of which are flammable and explosive substances; At the same time, there are many ignition sources in the production process, such as open flame, electric spark, electrostatic spark may become the ignition source of explosion. Flammable, explosive substances or its steam and oxygen and other combustion-supporting gases mixed to a certain proportion of the formation of the mixed gas explosion in the ignition source, the degree of damage is no less than the power of high explosives, this feature determines the chemical industry fire prevention and explosion work difficult.