Which sequence correctly orders the four stages of fire growth from earliest to latest?

• A. Incipient Stage, Growth Stage, Fully Developed, Decay Stage
• B. Incipient Stage, Fully Developed, Growth Stage, Decay Stage
• C. Growth Stage, Incipient Stage, Fully Developed, Decay Stage
• D. Decay Stage, Incipient Stage, Growth Stage, Fully Developed

Answer: (A)

Understanding how a fire evolves requires following its stages from ignition to burnout. The earliest phase is the incipient stage, where the fire has just begun and heat release is limited. As it grows, it enters the growth stage, with flames spreading and heat release increasing as more fuels catch fire. When the fire reaches its peak involvement, all available fuels and oxygen are engaged—the fully developed stage, marked by maximum heat release and widespread fire inside the compartment. Finally, as fuels are consumed and conditions change, the fire enters the decay stage, with diminishing heat and smoke production as the fire burns out. This sequence—incipient, growth, fully developed, decay—best fits the progression of a fire over time. Other sequences misplace the stages (such as putting growth before incipient or placing decay before full development), which does not reflect how a fire naturally evolves.