Which of the following is NOT one of the four main components of the fire tetrahedron?

The correct answer is water, as it is not one of the four main components of the fire tetrahedron, which consists of fuel, heat, oxygen, and a chemical reaction. The fire tetrahedron is a model used to explain the fundamental elements that must be present for a fire to ignite and sustain combustion.

Fuel provides the combustible material, heat raises the temperature to the ignition point, and oxygen supports the combustion process. The chemical reaction is the process that occurs when the fuel and oxygen react in the presence of heat, producing flame and generating energy in the form of heat and light. Water, while commonly used for extinguishing fires, does not play a direct role in the combustion process and is therefore not included as a component of the tetrahedron.