Fire tetrahedron components

The chain reaction is the least obvious component of the fire tetrahedron since this is occurring at the molecular level and we don t observe it directly. The exact mechanism by which chemicals burn is complicated but we know it involves a catalytic chain reaction. Some extinguishers work not by removing fuel, oxygen, or heat but by interfering with the chemical reaction in a fashion that stops the fire. 

The value of understanding the components of the fire tetrahedron is that removing any one of the components stops the fire. 

During the process of combustion of vapors and gases in which there is a visible flame, a better model is the fire pyramid. Some call this the fire tetrahedron, since there are three sides and a base in the fire pyramid concept. Figure 16-Ib shows a fourth component, production of hydroxyl (OH) radicals. An uninhibited reaction breaks down molecules into hydroxyl radicals. They last for an extremely short time, typically about 1 ms. 

When an ignition source is brought into contact with a flammable gas or a mixture of gases, a combustion chemical reaction will occur at the point of introduction, provided an oxidizer is present, normally oxygen. The combustion components are commonly graphically referred to as a simple fire triangle, fire tetrahedron, or fire square. 

Vandermeer, R. K., Williams, F. D. and Lofgren, C. S. (1981) Hydrocarbon components of the trail pheromone of the red imported fire ant, Solenopsis invicta. Tetrahedron Letters, 22, 1651-4. 

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