Which of the following is NOT one of the three sides of the fire triangle?

The three sides of the fire triangle are oxygen, heat, and fuel. Each side represents a component that is essential for combustion to occur. Without any one of these three elements, a fire cannot ignite or sustain itself.

Oxygen is crucial because it supports the chemical reactions that occur during a fire. Heat provides the energy necessary to raise the material to its ignition temperature. Fuel is the substance that burns and produces heat, light, and other products of combustion.

Pressure, while it can influence fire behavior and its spreading, is not a fundamental component of the fire triangle itself. Therefore, identifying pressure as the element that is not part of the triangle is correct. The fire triangle is foundational knowledge for understanding how fires start and spread, and recognizing the absence of one of its components can help in fire prevention and suppression strategies.