Carbon dioxide (CO₂) controls fires primarily by cutting off the supply of oxygen, which is essential for combustion. Being heavier than oxygen, CO₂ gas blankets the fire, displacing the oxygen around the flames and effectively suffocating the fire by preventing oxygen from reaching the fuel

. Additionally, when CO₂ is released from a fire extinguisher, it expands rapidly and cools down significantly. This cooling effect helps lower the temperature of the burning material, further aiding in fire suppression

. CO₂ fire extinguishers store carbon dioxide as a liquid under high pressure. When discharged, the CO₂ converts to gas and forms a barrier between the fire and surrounding air, cutting off oxygen and cooling the fire simultaneously

. Because CO₂ is non-conductive and leaves no residue, it is especially effective for electrical fires and certain flammable liquid fires, although it is less effective on fires involving solid combustibles like wood or paper

. In summary, CO₂ controls fires by:

• Displacing oxygen around the fire due to its greater density, cutting off the oxygen supply needed for combustion.
• Cooling the fire through rapid expansion and temperature drop when released.
• Forming a blanket that isolates the fuel from oxygen, suffocating the fire.

This dual action of oxygen displacement and cooling makes CO₂ an effective fire suppressant, particularly for electrical and flammable liquid fires

Carbon dioxide covers the fire and cuts off the contact of oxygen and fuel because it is heavier than oxygen. When released, it expands enormously and cools down, bringing down the temperature and helping control the fire