The fire triangle

The fire triangle is a symbol that shows the three things that are required for a fire to burn, namely:

  • oxygen
  • heat
  • fuel
A triangle showing the elements needed for a fire: oxygen, fuel and heat.

Remove just one of these, and the fire can no longer burn. This makes the fire triangle very useful in fire prevention and firefighting.

Removing oxygen

Removal of oxygen from the area around a fire can be achieved with a carbon dioxide extinguisher or a fire blanket. The carbon dioxide extinguisher pushes oxygen away from the fire and replaces it with carbon dioxide, which is inflammable and more dense than air. Fire blankets form a seal around the fire and prevent more oxygen from reaching the fire.

Another example of removing oxygen is closing doors when evacuating a building, which prevents fresh supplies of oxygen from entering the building.

Removing heat

Blowing out the flame on a candle is a good example of this. The fast moving air removes the heat from the candle, stopping it from burning any more.

A useful method of removing heat from a fire is to use water, which absorbs the heat from a fire very effectively. However, water should never be used on electrical fires – due to the risk of electrical shock, or oil fires – as oil and water do not mix, meaning the water only makes the oil form smaller droplets and so makes the fire even worse .

Removing fuel

By using fire-resistant materials, any fire will not have an adequate fuel source to keep burning and so this is a very effective method of fire prevention. Fire-resistant materials can be used for clothes, furniture and building materials.

Forest fires can also be managed more effectively if the trees around a fire can be removed to stop the fire from spreading. This method is known as a firebreak.

RemovalMethodType of Fire
OxygenFire blanket, CO2 extinguisherOil fires, chip-pan fires, electrical fires
HeatWaterHouse fires, wood fires, paper fires
FuelFirebreakForest fires