Fuel The topic ‘fuel’ is divided into three parts: Fire load Characteristics and availability of fuel determine the size of the fire. Ignition possibilities Characteristics of the fuel that makes it possible to ignite. Combustion products Products produced in a fire.

Fuel Fire load The fire load depends on the amount and characteristics of the fuel: Mass of fuel The amount of fuel available. Energy load The amount of energy in the fuel. Heat of combustion The energy release when a unit mass of material combusts. High Low Light bulb 60 W Paper basket 100 kW Sofa 3-seat 3 MW Total gasoline truck 300 MW

Ignition possibilities Fuel The ignition possibilities depends on: Ignition energy of the fuel The amount of energy needed to ignite the fuel. The greater the energy of the source, the quicker fire growth on the fuel source. Flashpoint of the fuel The lowest temperature at which a flammable vapour/air mixture exists at the surface. Possible surface area The exposed area that are able to burn. A fuel package with large surface area will burn more rapidly than an equivalent with small surface area.

Combustion products The combustion products depends on Fuel The combustion products depends on Type of combustion Flaming, smouldering or thermal degradation (i.e pyrolysis or evaporation) Availability of air An under-ventilated fire, when it is not enough oxygen available to combust all the fuel, produces more toxic combustion products such as carbon monoxide, etc. Chemical structure The chemical structure of the fuel affects the amount of toxic fumes in the fire gases. E.g. plastics emits often very toxic gases in a fire. Addition of fire retardant chemical agents Relatively small fires produces enough soot, to damage items far from the source, and carbon monoxide to kill people in the neighbouring room. Other combustion products e.g hydrogen chloride can cause corrosion leading to failure of electrical components.