Fire triangle
The fire triangle is a model stating that combustion requires fuel, heat, and oxygen. Removing any one of these three elements can extinguish a fire.
Combustion: A chemical reaction in which a fuel reacts rapidly with an oxidizer, releasing heat and often light. Fire is sustained by combustion, which depends on the triangle’s three elements.
Fire extinguisher: A portable device that discharges an agent to suppress or extinguish a fire. Different extinguisher agents cool fuel, displace oxygen, or interrupt combustion.
Fire tetrahedron: A fire model that adds a self-sustaining chemical chain reaction to fuel, heat, and oxygen. It expands the triangle’s three-part account with a fourth sustaining factor.
Oxidizing agent: A substance that accepts electrons in a chemical reaction and enables another substance to be oxidized. Oxygen is common in fires, but other oxidizing agents can also support combustion.
Fuel: A material that releases usable energy through a chemical or physical process. Fuel supplies the combustible material required for a fire.
Water as a fire suppressant: Water suppresses many fires chiefly by absorbing heat and cooling burning material. Cooling removes the heat needed to sustain combustion.
Smoldering combustion: A slow, flameless form of combustion occurring on the surface of a solid fuel. Smoldering shows that fire can persist without the visible flames often associated with the triangle.
Exothermic reaction: A chemical or physical process that releases energy, often as heat, to its surroundings. Combustion releases heat that can maintain ignition and warm nearby fuel.
Ignition temperature: The minimum temperature at which a material can ignite under specified conditions. Heat must bring fuel to ignition conditions before combustion can begin.
Carbon dioxide fire suppression: A fire-control method that releases carbon dioxide to dilute oxygen around a fire. Oxygen displacement can suppress fires where water would cause damage.