How does a CO2 extinguisher extinguish fires?

A CO2 extinguisher extinguishes fires by displacing oxygen with carbon dioxide gas. When this gas is released, it creates an environment where the concentration of oxygen is significantly lower. Since most fires require oxygen to sustain combustion, reducing the available oxygen effectively suffocates the fire, leading to its extinguishment.

This method is particularly useful for fires involving flammable liquids and electrical fires, as CO2 does not conduct electricity and does not leave residue that could cause further damage. Other types of extinguishing agents function differently; for example, water cools the fire, foam can smother flames, and certain agents interrupt the chemical reactions involved in combustion. However, the hallmark of CO2 extinguishers is their ability to eliminate oxygen, thereby halting the fire's ability to sustain itself.