Carbon Dioxide (CO2) Fire Extinguishers

by Curtis Worthington
co2 carbon dioxide fire extinguisher

Carbon Dioxide (CO2) Fire Extinguishers

In the case of a fire, the most important thing you can have to hand, whether you’re at home or at work, is a fire extinguisher.

Previously we’ve taken you through the various types of extinguishers available, while also highlighting the types of fires and how each extinguisher can be used on a particular one.

Going a little more in depth, here’s everything you need to know about CO2 fire extinguishers.

What is a CO2 Fire Extinguisher?

Also known as a carbon dioxide fire extinguisher, these are the fire extinguisher of choice when it comes to electrical fires.

However, they can sometimes be found paired alongside foam extinguishers, as they can be used on Class B fires; those started by flammable liquids such as petrol, diesel, paints and alcohol.

Electrical fires can happen everywhere from the office to the home but if you happen to own business premises that could become susceptible to Class B fires, especially if you have a lot of electrical equipment, having a few of these CO2 extinguishers on site would be extremely beneficial.

You can also use these on Class B fires, so if a fire does break out that involves paints or petrol and you only have a CO2 extinguisher close by, it’s safe to use.

How to Identify a CO2 Fire Extinguisher

Being able to distinguish between fire extinguishers is highly important, especially if you’re within a working environment – as you could end up being the closest to an extinguisher in the case of a fire.

However, if the extinguisher isn’t suitable for the fire that’s happening, then this could in fact make matters worse.

Therefore, if an electrical or Class B fire does break out you should be looking for a fire extinguisher that has a black coloured label stating ‘CO2’, or a fire extinguisher ID sign that identifies a nearby CO2 extinguisher.

However, in the frantic moments that can occur during the outbreak of a fire, you may not immediately be able to spot this. Other things you should look for include:

  • An extinguisher with a nozzle that has a distinctive black horn at the end

Taking a fire training course could also be extremely useful, even if you aren’t the designated fire marshal for your company as it could come in handy in such situations.

If you own a business, ensuring all your staff are all well-equipped with the knowledge on how to tackle a fire could prove pivotal in the long-term.

How CO2 Fire Extinguishers Work

Knowing how fire extinguishers work is key to understanding how to use them.

The basics everyone knows about an extinguisher is, you aim it at a fire and spray – but it isn’t as straight forward as that. This is why knowing everything there is to know could help out more than you realise in the event of a fire.

These CO2 extinguishers discharge CO2 gas, which you’ll also know simply as carbon dioxide. Stored within the main canister of the extinguisher, which can come in both 2kg and 5kg sizes and is a liquid while contained.

It only becomes a gas when put under pressure, which is what happens when the handle of the fire extinguisher is squeezed.

When the handle is held together this will cause the CO2 gas to emerge from the nozzle at an extremely high speed.

This is why it is highly recommended that you not use a CO2 fire extinguisher on fires created by chip pans, as the end result could see the flames blasted into the surrounding areas rather than extinguishing them as chip pans are often used in confined spaces, such as your home kitchen, you can see why this could only make matters worse.

CO2 fire extinguishers also work differently to others. Whereas fire extinguishers that emit foam or water work to cool the fire, CO2 extinguishers don’t operate this way. Instead these CO2 fire extinguishers work by replacing the oxygen that surrounds and feeds the flame with carbon dioxide, which means the fire can no longer burn and spread due to oxygen restriction.


How to use a CO2 Fire Extinguisher

Now that you’ve got some background on how these CO2 extinguishers work, knowing how to actually use one is key.

As mentioned, just picking one up, aiming and squeezing just won’t cut it as you should be equipped with the know-how on how to operate a fire extinguisher safely.

Firstly, avoid holding a CO2 fire extinguisher by the horn, as this could cause cold burns, resulting in a nasty injury and the risk of you dropping the extinguisher. If this happens it could render the extinguisher useless and the fire could spread.

Therefore, you need to handle it with care.

Whenever you use any fire extinguisher you should firstly remove the safety pin in order to break the anti-tamper seal, which will activate the extinguisher. You should then stand back from the fire and hold the extinguisher by the nozzle pipe.

The next thing you should do is aim the horn, without holding the horn, towards the base of the fire and squeeze to release the liquid, which will become a gas as it exits the extinguisher.

Then you should move the jet of CO2 backward and forwards until the fire is extinguished. For electrical fires you should switch off the appliance in question if it is safe to do so.

If you’re using one on a liquid fire take care not to splash any burning liquid onto any nearby areas.

If the fire isn’t extinguished when the extinguisher has run out, use another if there’s one to hand. Otherwise get out of the building quickly and safely, ensuring everyone knows not to go there by sounding the alarm.

How long does a CO2 Fire Extinguisher last?

Keeping an eye on your equipment is key when it comes to fire safety. After all, the last thing you want is for your fire extinguisher not to work in the case of a fire.

Most professional fire extinguishers are designed to last for 10 years, and these should be checked regularly to ensure seals aren’t broken or the extinguisher isn’t damaged in any way. Learn more about fire extinguisher servicing.

Whereas foam, powder and water extinguishers need to be refilled after every five years, CO2 extinguishers last twice as long as this and only need to be refilled after every 10 years.

The Pros and Cons of a CO2 Fire Extinguisher

You may know how to use one and what they do, but just like all other fire extinguishers there are pros and cons that come with CO2 extinguishers. And knowing these can be as beneficial as everything else there is to know about them.


  • Extremely effective on electrical fires
  • Can also be used on Class B fires
  • Do not leave any residue behind after using


  • They’re less environmentally friendly when compared to other types of extinguishers
  • Can run the risk of asphyxiation if used within confined spaces due to the restrictions of oxygen – if the space where the fire is occurring is too small, evacuation may be a better option than running this risk

Who should have a CO2 Fire Extinguisher?

As we’ve mentioned throughout the article, CO2 extinguishers are powerful tools of protection from electrical fires, which makes them an essential in near enough all buildings/businesses.

Therefore the following places should ensure that they have CO2 extinguishers on the premises:

  • Office buildings – especially offices that have high volumes of electrical equipment such as call centres
  • Shops – even though all shops should have extinguishers, ensuring one of these is on hand should a fire break out caused by a computer is crucial
  • Schools – with schools becoming even more reliant on computers/electrical equipment, more and more of these should be added
  • Hospitals – As above, due to the high volume of electrical equipment these should be on all hospital grounds - there is also a Non-Magnetic/Anti-Static CO2 extinguisher designed for hospital use

It’s important to note that wherever there’s a chance of an electoral fire, which in this day and age is most places and venues, a CO2 fire extinguisher should be present.

It is also recommended that CO2 fire extinguishers are purchased in pairs, especially in environments such as the ones mentioned above, as this will make sure you’re fully equipped in such an event should it happen.

In Synopsis

These are just the basics that you should know about fire extinguishers, as no one knows when a fire could break out.

From your home to your place of work and even places you’re visiting it’s important to know what types of fires there are, and the types of extinguishers that can be used for each.

Should an electrical fire break out, you’ll now be skilled with enough knowledge to help you out. If you do own a business or want to equip yourself even further then there are courses you can attend.

For those who own business premises, we have a whole range of CO2 fire extinguishers or you can see our Special Offers.

If you aren’t sure which extinguishers you need for your business, or you want a little extra guidance, then you can contact us on 0800 316 1469.

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