What is one of the elements of the fire tetrahedron that supports combustion?

The fire tetrahedron is a model that expands on the traditional fire triangle by including a fourth element that is essential for combustion to occur—an uninhibited chemical chain reaction. This fourth element is crucial because it represents the ongoing sequence of reactions that continually produce heat and additional reactive substances needed for fire.

In a fire, the initial heat from a fuel and an ignition source facilitates the combustion process. Once the fire starts, the chemical chain reaction maintains itself as the heat generated breaks down fuel molecules into volatile gases that ignite and further fuel the fire. This self-sustaining reaction is critical, as it ensures that the fire continues to burn as long as there is sufficient heat, fuel, and oxygen available.

While oxygen, fuel, and heat are all necessary components in any fire scenario, the uninhibited chemical chain reaction is what allows the fire to sustain itself and grow in intensity. Thus, without this specific element functioning correctly, combustive processes would dissipate, and the fire would extinguish.