subject: The Fire Triangle and Fire Tetrahedron [print this page] The Fire Triangle and Fire Tetrahedron The Fire Triangle and Fire Tetrahedron
The fire triangle is a way of visualising the three elements required to create and sustain a fire. The fire triangle is sometimes also referred to as the combustible triangle but they're the same thing.
The three elements of the fire triangle are as follows: Heat, Fuel and Oxygen.
All three of these elements are required for a fire to exist, so to prevent or extinguish an existing fire we simply have to remove at least one of the elements.
The different fire extinguisher types are designed to remove one or more of these elements in order to extinguish a fire.
For example, water removes heat and foam can prevent oxygen from reaching a fire by covering it like a blanket. To remove the fuel source is a little more tricky.
Fire Triangle and Heat
Without heat a fire cannot be created and it cannot continue to burn. As mentioned earlier the best method of removing heat is to use water.
We can also remove heat (the ignition source) in an electrical fire by turning off the power.In a burning structure the hot embers are often scraped away from the fire, again removing one of the heat sources and making the fire easier to extinguish.
Fire Triangle and Fuel
Without fuel a fire cannot continue to burn. Eventually a fire will naturally burn itself out over time as the available fuel is used up.
However, in the case of a fire we want to extinguish it as quickly as possible to minimise any damage so if the fuel can safely be removed it should be.
The fuel can either be removed physically, which may be dangerous to attempt or it can be removed chemically with the correct fire extinguisher type.
Removing nearby fuel sources can also prevent the fire spreading or prevent new fires from starting.
Fire Triangle and Oxygen
Without sufficient oxygen a fire cannot be created or continue to burn. Oxygen can be prevented from reaching a fire by using something like a foam fire extinguisher or even a fire blanket in certain conditions.
A fire won't often burn itself out due to a lack of oxygen like it will if it runs out of fuel. There's usually a plentiful supply of oxygen to keep a fire going indefinitely.
Fire Tetrahedron
The fire tetrahedron is a variation of the fire triangle. It introduces the requirement for the chemical reaction which is the process which creates and sustains a fire.
Halon fire extinguishers can be used to reduce this fourth element because they interfere with the chemical reaction.
