Which phase of a fire typically requires the most water to extinguish effectively?

• A. The smouldering phase
• B. The incipient phase
• C. The fully developed phase
• D. The cooling phase

Answer: (C)

The fully developed phase of a fire is when the fire is at its peak intensity, consuming the maximum amount of fuel and producing the most heat and smoke. This phase typically involves large volumes of flames and high temperatures, making it extremely challenging to combat effectively. The amount of water needed to extinguish a fire during this phase is significantly greater compared to other phases because of the established and widespread combustion, which requires substantial cooling and smothering to bring the fire under control.

In contrast, during the smouldering, incipient, and cooling phases, the fire is less intense and therefore requires less water. The smouldering phase often involves slow combustion without flames, mainly burning materials that are already charred. The incipient phase is the very beginning of a fire, where it can often be extinguished quickly and easily with little water. The cooling phase occurs after the fire has been controlled, where the main objective is to prevent re-ignition by cooling down hot spots, which generally requires less water than actively fighting a fully developed fire.