How many distinct stages are identified in the fire growth process?

The fire growth process is commonly divided into five distinct stages, which are ignition, growth, fully developed, decay, and extinguishment.

During the ignition stage, the fire begins, and combustible materials reach their ignition temperature. In the growth stage, the fire spreads as it consumes more fuel and generates heat, leading to an increase in temperature. The fully developed stage represents the peak of the fire’s intensity, characterized by maximum heat output and the spread of flames. After reaching this peak, the fire enters the decay stage, where the available fuel begins to diminish, leading to a decrease in temperature and flame size. Finally, the extinguishment stage involves the complete and effective suppression of the fire, marking its conclusion.

Understanding these five stages is crucial for fire investigators as it allows them to evaluate how a fire developed and identify contributing factors, which can be essential in determining the cause and accidental or intentional nature of a fire incident.