The growing global concern for the ecology, resulting in the worldwide ban on using the principal halogenated fire suppressants, has stimulated extensive research of new, environmentally acceptable substances. However, it has evidently been very difficult to create a chemical agent that meets all the desirable and contradictory properties.
An ideal agent naturally must be highly effective at ignition and flame suppression, yet also be environmentally friendly, stable, and non-toxic for humans during and after application.
Fire prevention and control has long dealt with the familiar fire triangle consisting of heat, fuel, and oxygen which are required to initiate and support combustion. Nitrogen, constituting 79% of atmospheric air, can significantly influence combustion. Furthermore, increasing the
nitrogen content in the gaseous mixture affects its molecular kinetic properties, reducing the availability of oxygen molecules for combustion.
Air with partial pressure of oxygen at an altitude of 9,000ft. (2700 m) can easily support the burning of a candle or the ignition of paper. However, if a corresponding normobaric environment is created with the same partial pressure of oxygen, candle will not burn and paper will not ignite. Even a matchstick will be instantly extinguished after the depletion of the oxygen-carrying chemicals on its tip.
Consequently, any fire that is introduced into this breathable normobaric, hypoxic atmosphere is instantly extinguished. Kerosene fuel, gas lighter or propane gas torch will not ignite in this environment either.