Introduction to CO2 fire extinguishers

CO2 fire extinguishers contain carbon dioxide gas (CO2) under very high pressure (about 55 bar at room temperature) and can be easily recognised by their flute-shaped discharge horn. CO2 extinguishers are colour coded with a black field on the otherwise red extinguisher.

CO2 fire extinguishers suppress fires by replacing oxygen, without which there can be no fire, with the inert CO2 gas. Although the CO2 is very cold when it comes out of the extinguisher, this does not make it a suitable choice for tackling Class A fires, such as solid combustibles like paper, wood and fabrics. Class A fires require water-based extinguishers that penetrate/saturate the burning materialwork to prevent re-ignition. A still smouldering Class A fire could simply re-ignite once the CO2 gas has dispersed.

CO2 extinguishers are these days mainly used in office environments, where they can be used to extinguish fires in electrical equipment.  This is due to carbon dioxide being non-conductive and not leaving any harmful residue that may contaminate sensitive circuitry. Please note, though, that the use of CO2 gas on electronics can still damage the circuits through static or temperature shock.

CO2 extinguishers can also be used by experienced operators on Class B fires which consist of flammable liquids such as petrol, oil and diesel, (not including cooking oil).

The properties of CO2 also make the extinguisher a good protective fire fighting device in places like laboratories, clean rooms, engine compartments, generator rooms, boats and flammable liquid storage spaces.

It is not easy to verify whether a CO2 extinguisher is still filled or has suffered a loss in pressure and content. At a filling pressure of 55 bar and room temperature the CO2 in the extinguisher is neither a liquid nor a gas. What this means in practice is that you cannot hear any ‘sloshing’ when you are shaking a CO2 extinguishers. It just feels as if it were empty! The only way to verify that the extinguisher is still charged is to measure its weight and compare it with its manufactured weight stamped on the cylinder. You need very precise scales for this. Also, the discharge horn of the extinguisher has to be removed for this purpose. This is dangerous and should not be done without prior training, as an accidental discharge without the horn can lead to serious injury. The Horn acts as a pressure reducer; when it is removed the CO2 extinguisher discharges like a rocket should the handle be operated!

When ordering CO2 extinguishers, make sure you buy a model with a frost-free horn, as the horn gets so cold that skin could stick to it.

Call our customer hotline now on 0800 6126537 to find out more about the benefits of CO2 extinguishers or take some time to explore our web pages and see our impressive range of affordable fire safety products in greater detail.

How to protect a kitchen with heat detectors

Kitchens produce great amounts of steam and cooking smoke and ordinary smoke alarms are not able to cope with these confusing signals. An ionisation smoke alarm or even an optical smoke alarm would quickly be set off when a kitchen is being used. At the same time fires regularly start in the kitchen, so rapid fire detection is important.

Luckily, there is an easy solution available. Heat alarms or heat detectors work by detecting either rapidly rising temperatures or trigger when a certain temperature is reached. Heat detectors do not get set off by steam or smoke or the normal cooking tempreatures. The thermistor in the heat detector head only detects the temperature changes mentioned above and ignores all other influences.

To notify the rest of the house of a fire in the kitchen you do not need to rely solely on the siren in the heat detector. You can interconnect the heat detectors with other smoke alarms in the house either with wire or through radio-frequency. The latter avoids you having to lay cables between alarms.

Heat detectors are also installed in garages and other areas where smoke or gases are present (with exception of bathrooms).

More information about the workings of heat detectors and other smoke alarms can be found in our smoke alarm guide.

Retrofitting or Replacing Fire Door Seals

Following a fire risk assessment, doors are sometimes re-designated as fire doors if the door and frame are substantial enough to be justifiably counted as a nominal fire door. The same applies to older fire doors which do not follow the latest specifications. In these cases, fire door seals are retrofitted, and to avoid having to cut a rebate in either the door or the frame, surface mounted fire door seals can be fitted. These are stuck to the frame or door with their self-adhesive backing and sometimes nailed as well to give them increased longevity.

Where a fire door rebate already exists, or the existing rebated fire door seal has been damaged, rebated intumescent fire door seals can be fitted.

We offer a range of fire door seals: fire only, or combined fire and smoke. Both variants contain intumescent material that swells if a fire breaks out to seal the gap around the fire door. Seals that cover smoke also contain a brush-type smoke seal to stop smoke travelling through the gap before the intumescent material expands. There are some applications where a gap should not have smoke seals: e.g. if the fire door has been installed on the exit of a room which has no smoke detectors on its own. In this case, the fire alarm system can only be triggered if smoke can leak out around the fire door and set off the fire alarm system in the circulation spaces, but these cases are quite rare.

Fire door seals are fitted on three sides of a fire door with the gap underneath the door not being covered, though there are products available to prevent smoke from escaping under doors if necessary.

If new fire door seals are fitted for the first time, make sure that fire door hinges, fire door closers and, where necessary, intumescent door lock protection are fitted as well.

CO Alarm for Caravans and Motorhomes

Prepare for the summer season by installing a CO alarm for caravans. Because caravans are a confined space, the potential for the build-up of deadly carbon monoxide gas is greater. If you have already fitted a CO detector, ensure that you carry out your pre-holiday safety checks. This should include checking or replacing the batteries and testing smoke, heat and CO alarms. It is also advisable to check when your alarms need replacing. Sensors in these types of alarms become less effective over time and will need to be replaced after 10 years.

Kidde 7DCO for caravans and motorhomes
The Kidde 7DCO CO Alarm for caravans and motorhomes

Choosing a CO alarm for caravans and motorhomes

Not all carbon monoxide alarms are suitable for use in caravans or motorhomes. Choosing a suitable alarm is important because if the CO alarm you have isn’t recommended for use in camping environments, you may not be alerted to dangerous levels of CO gas. Choose an alarm that is:

  • Kitemarked to British Standard BS EN50291-2
  • Certified for use in caravans
  • Suitable for wall mounting
  • Battery operated
  • CE marked

Kidde 7DCO

The Kidde 7DCO is ideal for caravans. It can be easily wall mounted using the fixings included in the pack. The digital display shows readings taken every 15 seconds and will indicate any changes to the level of CO gas detected. The alarm is supplied with 3 x AA batteries that are easy to replace when the warning chirp indicates that the power is low.

The Kidde 7DCO is certified for use in caravans and has a warranty for the full 10 year lifespan of the product.

Caravan fire extinguisher and CO alarm
Kidde 7DCO can be easily wall mounted in your caravan or motorhome
Kidde Carbon Monoxide Alarm - 7DCO / 7DCOC
Kidde Carbon Monoxide Alarm - 7DCO / 7DCOC
  • Product Life: 10 years
  • Battery: replaceable AA alkaline batteries included
  • Warranty: 10 year warranty
  • Displays CO levels from 10ppm
  • Peak Level Memory - recalls highest CO levels
  • Ideal for domestic use and camping, caravans & boats
  • Kitemarked to BS EN50291-1 and BS EN50291-2
  • Also suitable for the 2022 Welsh legislation
£15.21 ex VAT
£18.25 inc VAT
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Free Water Mist Extinguishers for Qwackers Pre-School

Qwackers Pre-School in Alford, Lincolnshire has been part of the life of generations of local people. It started off in a hall at the side of a babbling brook where ducks swam. The group then moved to a second-hand prefab building that was erected on the site of the John Spendluffe School.

This building has served a good purpose but with many years of wear and tear it became apparent that it was no longer viable to repair the structure any longer. After several years of campaigning Qwackers have now moved into a brand new building on their old site.

We always like to support local causes and as Qwackers is a registered charity we wanted to show our support by installing new extinguishers for them and maintaining the extinguishers on a yearly basis in the future completely free of charge.

We chose to install Water Mist extinguishers, which when deployed will leave no residue and will not cause water damage as with conventional water extinguishers. The Water Mist extinguishers are fitted with a supersonic nozzle, creating a microscopic mist curtain. The water mist removes oxygen from the fire and also cools the material that is alight, reducing the chance of re-ignition. Because the extinguisher is creating a fog rather than a jet, the water mist extinguishers are ideal for schools and nurseries, as children cannot hurt themselves, should they ever set off an extinguisher.

Water Mist extinguishers are also perfect for home, offices, shops and kitchens, and their testing credentials mean they can even be used on electrical equipment too!