Carbon dioxide (CO2) controls fire primarily by removing one of the essential elements required for combustion: oxygen. Here is how CO2 is able to control and extinguish fires:
- Oxygen Displacement: CO2 is heavier than oxygen and when released, it blankets the fire, displacing the oxygen around it. Since oxygen is necessary for combustion, reducing its concentration below a critical level starves the fire and causes it to go out
- Smothering Effect: By covering the fuel with a layer of CO2, the gas prevents oxygen from reaching the combustible material, effectively suffocating the fire
- Cooling Effect: When CO2 is released from a pressurized container, it expands rapidly and cools down. This cooling effect lowers the temperature of the fuel and surrounding gases, further inhibiting the fire’s ability to sustain itself
- Chemical Interruption: CO2 can interfere with the chemical reactions in the combustion process by reducing the temperature and free radical population necessary to maintain the flame chemistry, thus disrupting the chain reaction of the fire
- Non-Conductive and Residue-Free: CO2 is electrically non-conductive and leaves no residue, making it ideal for use in areas with sensitive equipment such as data centers, electrical rooms, and industrial settings
In summary, CO2 extinguishes fire by rapidly displacing oxygen, smothering the flames, cooling the fire environment, and interrupting the combustion chemical reactions, which collectively halt the fire’s progression without damaging sensitive equipment
