Fire Basic Knowledge Collection 1Basic concepts: Combustion refers to the exothermic reaction of combustibles with oxidants, usually accompanied by flame, luminescence and/or smoke. 2Because of incomplete combustion and other reasons, some small particles will be produced in the combustion products, thus forming smoke. 3Combustion can be divided into flaming combustion and flameless combustion according to whether there is flame or not. 4Combustion must have three necessary conditions, namely, fuel, combustion aids and ignition source, commonly known as the three elements of combustion. 5The sufficient conditions for combustion can be expressed as having sufficient quantity or concentration of combustibles; having sufficient data or concentration of combustion aids; having sufficient energy of ignition source. 6Combustibles are substances that can react with oxygen or other oxidants in the air, such as wood, hydrogen, gasoline, coal, paper, sulfur, etc. 7According to chemical composition, it can be divided into inorganic combustibles and organic combustibles; according to its state, it can be divided into combustible solid, combustible liquid and combustible gas. 9Combustion AIDS refer to substances that combine with combustibles to cause and support combustion, such as oxygen in the air. 10The ignition source refers to the external heat source (energy) that can make the material start to burn.Common sources of ignition are: Open fire: stove fire, candle fire, welding fire, smoking fire, motor vehicle exhaust pipe Mars, flying fire, etc. Arc, spark: electrical equipment, electrical circuit, electrical switch and leakage spark, fixed telephone, mobile phone and other communication tools spark, static spark, etc. Lightning stroke: High voltage discharge can ignite any combustible substance at the moment of lightning strike. High temperature: high temperature heating, baking, heat accumulation, mechanical equipment failure heating, friction heating, heat accumulation, etc. 11Combustion can be divided into fire and explosion. (1) Fire Ignition refers to the phenomenon that combustibles and combustion aids coexist, and the ignition source contacts to cause combustion, and can continue to burn after the ignition source leaves. The ignition mode can generally be divided into ignition and spontaneous combustion. (1) Ignition Ignition refers to getting energy from external energy sources (electric coil, spark, hot particle, ignition flame, etc.), which makes the local area of the mixture heated intensely and ignited. (2) Spontaneous combustion Spontaneous combustion refers to the combustion of combustible substances which are heated or self-heated and regenerated without external fire source. (1) Chemical spontaneous combustion, which does not require heating, occurs according to its own chemical reactions, such as friction ignition of matches and explosive explosion by impact. (2) Hot spontaneous combustion, the mixture of combustible and combustion- supporting material is pre-uniformly heated, and will automatically burn as the temperature rises to a certain extent. (2) Explosion Explosion refers to the rapid transformation of substances from one state to another, and in the instant release of enormous energy in the form of mechanical work, or gas, vapor in the instant occurs drastic expansion and other phenomena. 12Classification according to the morphology of combustibles Combustions can be divided into gas combustion, liquid combustion and solid combustion according to their forms. (1) Gas combustion Combustible gases are easy to burn and fast. According to the state of mixture of combustible gases and oxygen, they are divided into diffusion combustion and premixed combustion. (1) Diffusion combustion Diffusive combustion refers to the diffusion of combustible gases and vapor molecules with gas oxidants, and combustion while mixing. Diffusion combustion is characterized by stable combustion, relatively low flame temperature and no movement of diffusion flame.The mixture of combustible gas and gas oxidant is carried out at the combustible gas nozzle, and no tempering occurs during combustion. (2) premixed combustion Premixed combustion refers to the combustion of combustible gases and vapors mixed with air (or oxygen) in advance, which produces impact when ignited.There are two modes of f