Which element is NOT part of the fire triangle?

The fire triangle is a fundamental concept in fire science that illustrates the three essential elements required for a fire to ignite and sustain combustion. These elements are fuel, heat, and oxygen. When any one of these components is removed, the fire cannot continue to burn.

Fuel represents the material that can combust, such as wood, paper, or gasoline. Heat is necessary to raise the temperature of the fuel to its ignition point, allowing combustion to occur. Oxygen supports the chemical reaction of combustion, enabling the fire to maintain itself.

Carbon dioxide, on the other hand, does not belong to the fire triangle. In fact, carbon dioxide is often used as a fire suppressant because it can displace oxygen in the surrounding environment, effectively suffocating the fire by limiting its access to one of the three vital components needed for combustion. This role as a suppressive agent is why carbon dioxide is not part of the fire triangle but is instead a byproduct of combustion.