Using a Carbon Dioxide (CO2) Fire Extinguisher

Fire outbreaks in premises can pose significant risks to human lives and properties. Thankfully, you can protect people and buildings from certain fire emergencies using a carbon dioxide (CO2) fire extinguisher.

Previously, we covered different classes of fires and types of fire extinguishers in line with Australian standards. In this guide, you’ll learn how carbon dioxide fire extinguishers work, how to use them in case of emergencies, and how to ensure their fire safety maintenance & inspection.

How to Identify a Carbon Dioxide Fire Extinguisher?

If you’re in the market looking for a new CO2 extinguisher, you’ll notice that all fire extinguishers have a rich red paint called “Signal Red.” But how do you differentiate CO2 extinguishers from other fire extinguishers?

Generally, all CO2 fire extinguishers feature a black colour band running around the top of the cylinder. These colours make it identifiable in the market and distinctive in darker rooms.

Carbon dioxide fire extinguishers in Australia are available in three main portable sizes: 2 KG, 3.5 KG, and 5 KG. You can find a mobile fire extinguisher of 45 KG if you’re looking for a larger fire extinguisher. Information about the size and type of fire extinguisher is in large font on a label imprinted on the cylinder.

Both portable and mobile CO2 fire extinguishers have a maintenance tag showing when they were last tested and inspected.

However, portable CO2 extinguishers are made of aluminium and can be hand-held during use. They also have a discharge time ranging between 8-16 seconds. The discharge time varies depending on the size used, with larger sizes having a higher discharge time.

On the other hand, a mobile CO2 extinguisher is made of steel, has a hose for emitting the extinguishant and comes with a mounting trolley; mobile extinguishers have a net weight of 150kg, making them significantly heavier than portable extinguishers.

When Should You Use a CO2 Fire Extinguisher?

In the case of a fire outbreak, it’s crucial to understand the kind of fire before using a CO2 extinguisher. The truth is, a CO2 extinguisher on its own won’t put out all types of fires. After understanding the type of fire, you should identify the kind of extinguisher to use for optimum fire protection.

So, what are carbon dioxide fire extinguishers used for?

You can use CO2 fire extinguishers to combat Class E and B fires. However, the effectiveness of the CO2 extinguishers on the two fire types differ.

CO2 fire extinguishers are commonly used to combat Class E fires. It’s no wonder people refer to these extinguishers as electrical fire extinguishers.

Class E fires result from electrical equipment used in homes, workplaces, and laboratories. Overheating household appliances such as heaters, aircon, washing machines, and other industrial appliances can be the major causes of electrical fires.

A CO2 fire extinguisher for electrical fires can be used in offices, labs, schools, hospitals, electric switch rooms, and server areas. Since CO2 is a gas, you can use the fire extinguisher without worrying about destroying your electrical appliances. The extinguisher can safely put out fires linked to computers, fans, heaters, switchboards, power generators, and machinery.

The use of CO2 extinguishers on Class B fires is limited and not as effective as with Class E fires. You can use the extinguisher with flammable liquid fires caused by petrol, ethanol, turpentine, paint, thinners, kerosene, and diesel.

When Should you NOT use a CO2 Fire Extinguisher?

CO2 fire extinguishers can’t smother all fires and may cause re-ignition or create an explosion in some circumstances. Avoid putting out the following fires with a CO2 fire extinguisher:

Class D fires: Avoid using CO2 extinguishers on Class D fires that involve flammable metals such as magnesium, potassium, sodium, and titanium. It’s advisable to combat Class D fires using a dry powder chemical fire extinguisher.
Class C fires: CO2 extinguisher is not suitable for Class C fires involving flammable gases such as methane, propane, and butane. To combat Class C fires effectively, use a chemical dry powder fire extinguisher.
Class A fires: Class A fires involve ordinary flammable materials such as wood and combustible carbon solids like plastics. These are the fires you’re likely to light or deal with regularly. If faced with a Class A fire outbreak, a CO2 extinguisher can’t be effective. It’s advisable to put out the fire using water fire extinguishers or foam fire extinguishers.
Class F fires: CO2 fire extinguishers can’t be effective in Class F fires. These fires result from igniting cooking oils or fats. Though closely related to Class B fires, Class F fires require extremely high temperatures to ignite. When putting out Class F fires, you may consider a dry powder BE or wet chemical fire extinguisher.

How Do Carbon Dioxide Fire Extinguishers Work?

For any fire to combust, sustain itself, and spread, it needs fuel, heat, and oxygen. Fire extinguishers work by eliminating any of these three elements to put out the fire.

CO2 displaces or reduces the amount of oxygen in the fire. Without oxygen, the fire may not continue burning. CO2 fire extinguishers store carbon dioxide in a liquid form. CO2 is very cold upon discharge and comes out as a cloud or dry ice. The cold CO2 can help cool down the fire by reducing its temperatures.

Removing oxygen and heat can stop further combustion. However, it’s crucial to continue spraying the site of fire with CO2 to prevent chances of re-ignition. CO2 extinguishers discharge the cold CO2 relatively fast and cover a limited area. If you’re putting out a fire in a windy area, the CO2 may be ineffective.

Dangers of CO2 Fire Extinguishers

When using a CO2 fire extinguisher, you should be aware of its associated risks. These risks include:

Asphyxiation: If you’re putting out a fire in a confined space, people present may experience asphyxiation. The discharged CO2 fills the area and lowers the amount of oxygen in the atmosphere. High concentrations of CO2 and low oxygen may result in CO2 poisoning, unconsciousness, or even death.
Frost burn: The extinguishing agent discharged is freezing, and if it comes into contact with your skin, it may cause a frost burn. When spraying, direct the extinguishant toward the fire only. You should also ensure that the horn of your extinguisher is made of frost-resistant material.
Loud noise: CO2 extinguishers generate a loud noise when discharging the extinguishing agent which is known to shock some people.

Cleaning Up After a CO2 Fire Extinguisher

The good thing about CO2 extinguishers is that they have minimal discharge effects. The CO2 evaporates into the atmosphere, leaving no residue behind. You, therefore, don’t have to worry about cleaning your equipment and property.

Maintenance of CO2 Fire Extinguisher

Regulations dictate that all fire extinguishers must get serviced every six months. They should also feature a fire extinguisher maintenance tag indicating the most recent inspection date.

Since fire extinguishers have a 5-year lifespan, you should discharge and recharge your CO2 extinguisher every five years.

Ensure your CO2 extinguisher pressure remains at optimum level by pressure testing it. Inspect the needle to see if it’s in the green zone, and check the safety pin to ensure it’s in place. Check the nozzle for any obstructions or signs of damage. Lastly, check the seal to ascertain that it’s still intact.

Storage determines how intact and effective your CO2 extinguisher remains. Store your CO2 extinguisher in a safe place where it can’t catch fire easily. However, ensure it is easily accessible in case of fire emergencies.

Prioritise Fire Safety

You now know how a CO2 fire extinguisher works and how to use one. Remember, only trained people can use fire extinguishers in times of emergency. Avoid using your fire extinguisher before confirming the type of emergency. Conduct regular maintenance, inspection, and testing of fire extinguishers and fire protection services to provide effective fire safety to people and places.