CO2 fire extinguishers, also known as carbon dioxide fire extinguishers, are one of the most effective solutions for fighting class B (liquids such as petrol or oil) fires. Their operating principle is based on the displacement of oxygen and the cooling of the burning material.
In this article, we explain how a CO2 fire extinguisher works, what components it contains and why it is the first choice in certain situations.
A CO2 fire extinguisher releases gaseous carbon dioxide (CO2) when used. This gas has two key properties that make it ideal for fighting fires:
Cooling: The CO2 stored under pressure is extremely cold (usually around -78 °C) when it is released. This coldness lowers the temperature of the burning material and thus prevents the fire from flaring up again.
Another advantage of the CO2 fire extinguisher is that the gas leaves no residue. This makes it particularly suitable for sensitive electrical devices such as computers or control panels.
A CO2 fire extinguisher consists of various components. The container is made of steel to hold the high pressure of the liquid CO2. The CO2 is stored in the container at around 50 to 60 bar.
The valve regulates the release of the carbon dioxide. It is equipped with a safety device that prevents the gas from escaping unintentionally. The extinguisher also has a triggering device, usually in the form of a lever, which opens the valve and releases the CO2. The escaping CO2 is fed through an extinguishing nozzle opening. These nozzles are specially designed to efficiently direct and expand the gas onto the fire. A horn is often attached to the end of the nozzles, which acts as a diffuser and makes it easier for the gas to spread. An ergonomic handle makes transporting and operating the extinguisher easier and safer.
There is a riser pipe inside the container which ensures that the liquid CO2 is transported to the valve when the extinguisher is activated.
Important instructions for use:
- Do not use CO2 fire extinguishers in small, unventilated rooms without breathing protection, as the gas can also have a suffocating effect on people.
- Hold the fire extinguisher by the handle or pipe and avoid direct contact with the extinguishing nozzles, as they become extremely cold when released and can cause frostbite.