What is the correct order of the four stages of fire development?

• A. Incipient, Growth, Fully Developed, Decay.
• B. Incipient, Fully Developed, Growth, Decay.
• C. Ignition, Growth, Maturity, Extinction.
• D. Beginning, Accelerated, Peak, End.

Answer: (A)

Understanding how a fire progresses through stages helps you predict behavior and risk. In the incipient stage, ignition has just occurred and flames are small, with heat and smoke beginning to build. In the growth stage, the fire releases more heat and spreads to more fuels, increasing flame size and involvement of the space. When the fire has reached the fully developed stage, most combustibles in the area are burning and the heat release rate is at its peak, making conditions extremely hazardous. In the decay stage, fuel is running out or ventilation limits slow the burn, and temperatures fall as the fire subsides. Therefore the order is incipient, growth, fully developed, decay. The alternative that places growth after fully developed contradicts how a fire expands—growth must come first as the fire expands to involve more fuel. The other option uses different terms that describe a similar idea but do not align with the standard four-stage model.