The protection of aircraft fuel tanks against explosion hazards using inert combustion products

Within certain ranges of temperature and pressure, the air-vapour mixture produced above the liquid fuel in aircraft fuel tanks will support combustion, and will burn explosively on the addition of the necessary energy for ignition. Although the danger zone for each type of aviation fuel can be clearly defined under equilibrium conditions, the many transient factors involved in practice make it difficult to find completely safe operating conditions for any fuel.