What safety precautions should be taken when using a carbon steel CO₂ fire extinguisher, particularly in enclosed spaces?

In confined spaces, the discharge of CO₂ gas from a fire extinguisher can rapidly reduce the oxygen levels, leading to a risk of asphyxiation. This is especially concerning in spaces that lack proper ventilation, as the displaced oxygen can create dangerous conditions for anyone in the vicinity. Therefore, before deploying a CO₂ extinguisher, ensure that the area is well-ventilated. This can be achieved by opening windows, doors, or using mechanical ventilation systems like fans to help circulate air. In high-risk environments such as industrial facilities or basements, ensure the area is equipped with exhaust fans or ventilation systems that can quickly remove CO₂ from the air. By maintaining a healthy oxygen level, you mitigate the risk of suffocation and ensure that the fire can be dealt with effectively without endangering those present.

One of the unique features of CO₂ fire extinguishers is the extremely low temperature of the gas when it is discharged. When CO₂ is expelled, it expands rapidly and causes a significant drop in temperature, making the nozzle and hose extremely cold. Direct contact with the nozzle or hose during discharge can cause frostbite or cold burns to the skin. To avoid injury, always hold the nozzle or discharge horn by the insulated handle, not by the nozzle itself. Maintain a safe distance between the nozzle and the fire to avoid freezing of nearby surfaces, and never point the discharge nozzle directly at people or animals. When using the extinguisher, apply the CO₂ in short bursts to control the discharge and minimize exposure to the extremely cold gas.

CO₂ extinguishes flames by displacing oxygen in the vicinity of the fire. However, unlike other fire extinguishing agents, CO₂ does not lower the temperature of the surrounding materials. As a result, the area may still be hot enough to reignite the fire if left unchecked. After applying CO₂ to the fire, carefully monitor the area for potential re-ignition. Always stay clear of the fire zone after discharge to avoid getting caught in a possible flare-up. CO₂ fire extinguishers are most effective on electrical fires, liquid fires, and gasoline fires, but they must be used with caution in areas where heat persists even after the flames are extinguished. For this reason, have a secondary method of fire suppression on hand (such as a fire blanket or another type of extinguisher) in case the fire re-ignites.

One of the biggest dangers of using CO₂ fire extinguishers in confined spaces is the potential for oxygen deprivation. As CO₂ is heavier than air, it can quickly accumulate at ground level and displace breathable oxygen. If you begin to feel dizzy, lightheaded, or short of breath while using the extinguisher, it is critical to exit the area immediately and get to fresh air. Prolonged exposure to high concentrations of CO₂ can lead to hypoxia (low oxygen levels) or even unconsciousness, which could result in serious injury or death. This is why it is essential to maintain a clear escape route and ensure that anyone using the fire extinguisher is trained to recognize early symptoms of oxygen deprivation.