Forbrændingstrekanten

Forbrændingstrekanten, or the fire triangle, is a conceptual model used to explain the elements necessary for a fire to exist. It illustrates that fire requires three components: fuel, oxygen, and heat. If any one of these components is removed or is insufficient, combustion cannot occur or will be extinguished.

Fuel is the material that will burn. This can be anything from wood, paper, and cloth to flammable liquids and gases. The type and form of the fuel greatly influence how easily a fire can start and how intensely it will burn.

Oxygen, also known as an oxidizer, is necessary for the chemical reaction of combustion. In most fires on Earth, the oxygen is supplied by the air, which is approximately 21% oxygen. A fire typically requires at least 16% oxygen to sustain itself.

Heat is the energy required to raise the fuel to its ignition temperature. This is the temperature at which the fuel will begin to burn continuously. Heat can be introduced by an external source, such as a spark, flame, or friction. Once a fire starts, the burning process itself generates more heat, which then heats more fuel, creating a self-sustaining cycle.

Understanding the fire triangle is fundamental to fire prevention and firefighting. By removing or controlling any of the three elements, one can prevent a fire from starting or extinguish an existing one. For example, removing fuel prevents a fire from having anything to burn. Cooling the fuel below its ignition temperature removes the heat. Smothering a fire, such as with a fire blanket or by displacing oxygen with inert gas, removes the oxygen component.