Which additional element is included in the fire tetrahedron compared to the fire triangle?

The fire tetrahedron is an extension of the fire triangle, which traditionally includes three essential elements required for fire: fuel, heat, and oxygen. The key additional element in the fire tetrahedron is the chemical chain reaction. This component emphasizes the importance of the energy released during combustion that enables the ongoing reaction to take place.

In a fire, once the initial heat source ignites the fuel, a chemical chain reaction occurs, producing more heat and maintaining the fire as it progresses. This reaction is crucial because it explains how a fire can sustain itself even as fuel or oxygen levels fluctuate. The presence of this fourth element highlights the complexity of combustion and the interdependence of all elements involved in sustaining a fire. Understanding this concept is vital for effectively managing and extinguishing fires, as interrupting the chemical chain reaction can effectively extinguish the fire even if sufficient fuel, heat, and oxygen are still present.