Fire Extinguishment by Cooling

Extinguishment by cooling is a fundamental firefighting tactic that directly targets the ‘heat’ side of the fire triangle. The goal is to reduce the temperature of the burning material to a point where it no longer produces sufficient flammable vapor to sustain combustion. This point is known as the fire point. Water is the most common cooling agent due to its unique thermal properties. It has a high specific heat capacity, meaning it can absorb a significant amount of thermal energy before its own temperature rises substantially. More importantly, it has a very high latent heat of vaporization. When liquid water turns into steam at 100°C, it absorbs a massive amount of energy from the fire without any change in temperature. This phase change is extremely efficient at drawing heat away from the fuel. The resulting steam also helps to displace oxygen, contributing to extinguishment by smothering. However, using water is not always appropriate. It can be ineffective or dangerous on grease fires (it can spread the burning grease) and electrical fires (due to conductivity), and it can react violently with certain metal fires.