The Phenomenon of Fire
Fire is the visible heat energy being released from rapid oxidation of afuel. Something is
'on fire' when the exothermal release of heat from the oxidation reactionreaches visible light level.
Basically, combustion takes place within two modes-flaming andflameless. The flaming mode can be viewed as a tetrahedron, with each siderepresenting one of the four basic
components of flaming combusion: fuel, heat, oxygen and uninhibited chainreaction. Here the practical emphasis is on extinguishing an existingfire.
The classic fire triangle illustrates the flameless mode, the three legsrepresenting fuel, oxygen and heat. Air provides oxygen forcombustion. The heat required for ignition varies with the characteristicsof the fuel. Fuel is any substance that will sustain combusion after theinitial application of heat to start it. Here the practical emphasis is onpreventing a fire from starting by prohibiting the formation of thetriangle.