What is the purpose of CO2 fire suppression on a ship?

• A. To displace nitrogen in the space and extinguish the fire.
• B. To displace oxygen in an enclosed space and suppress the fire.
• C. To humidify the air to make firefighting easier.
• D. To create a visible fog for cleanup.

Answer: (B)

CO2 extinguishes fires by starving them of oxygen in a confined space. CO2 is heavier than air, so when released it blankets the area and pushes out the breathable air, lowering the oxygen level enough to suppress combustion. This makes it well-suited for enclosed spaces where water or other agents could damage equipment.

Because of this, it’s used in spaces that can be evacuated or strictly controlled for safety; CO2 can be dangerous to anyone still inside, so proper procedures are essential.

The other ideas don’t fit: CO2 doesn’t work by displacing nitrogen, it doesn’t humidify the air, and it doesn’t create a visible fog for cleanup.