Original Text

SMTE Version

Fire is the product of a chemical reaction known as combustion

Combustion is a rapid oxidation of a fuel accompanied by the evolution of heat and light

For combustion to occur the molecules of the fuel must have adequate contact with oxygen molecules and this only occurs in the gaseous state

It is the vapours emitted by a fuel that burn

However, the vapour from a fuel will only burn if mixed with oxygen in the correct proportions and raised to its ignition temperature

The fire triangle is the basic structure showing the three elements necessary for combustion – oxygen, fuel and heat

Combustion is initiated by a source of ignition – heat energy

Once initiated, the combustion is sustained by the chemical chain reaction of the oxidation of fuel vapour

Heat given off shortly after ignition causes more fuel vapour to be released which in turn burns producing more heat

This chemical chain reaction is shown here in the fire tetrahedron and is the fourth element necessary for fire

Removal of any one part of the fire tetrahedron will stop the combustion process and the fire will be extinguished

Fire is a chemical process called Combustion. 

Combustion is when Oxygen reacts quickly with a Fuel giving off heat and light 

For combustion to happen the Heat starts the burning. 

Heat makes the fuel turn into a gas or vapour. 

The mixture of fuel vapour (gas) and Oxygen must be heated to its ignition temperature. 

This is shown in the fire triangle: Fuel + Oxygen + Heat 

After ignition, the combustion continues because heat causes more fuel to turn into vapour, and the vapour burns creating more heat. 

This continuous combustion is called a Chemical Chain reaction. 

These four parts — fuel, oxygen, heat, and the chain reaction — form the fire tetrahedron. 

If you remove any one part, the fire stops.