Types of Extinguishers

There are six main types of fire extinguishers; water, foam, CO2, powder, water mist and wet chemical. More recently a new innovative technology specifically designed for lithium-ion battery fires has come on to the market to help tackle this fire risk. Different types of fire extinguishers are required for different types of fire, which are also categorised into classes. Find out which fire extinguisher to buy based off the fire extinguisher rating combined with your requirements.

CO2 fire extinguishers

These units contain pure carbon dioxide to suffocate the fire and leaves no residue once the fire has been extinguished. They were originally designed for class B fires, which are flammable liquid fires, such as oil, petrol and solvents. However, these days CO2 extinguishers are mainly used for use on live electrical equipment and are traditionally installed next to water or foam extinguishers where multiple fire risks are present. A specialist version of the CO2 extinguisher is anti-magnetic and is specially designed to be installed in areas of high magnetic activity, such as hospitals' MRI scanner suites.

Powder fire extinguishers

Also called ABC powder or dry powder, these extinguishers are powerful and versatile which can be used for class A (burning solids), class B (burning liquids) and class C (burning gas) fires. Powder extinguishers should not be used in confined spaces (small kitchen or boat cabins), as the powder can cause respiratory issues and impair vision. The residue of the powder makes the clean up after a discharge very difficult. We also stock a special powder fire extinguisher used for class D fires of flammable metals such as burning magnesium swarf.

Water fire extinguishers

These are used on class A fires of solid combustible materials, such as wood, fabric and paper. The water penetrates burning materials to cool down the fire, which extinguishes the fire and stops it re-igniting. Water fire extinguishers are non-toxic and do not contain any harmful chemicals. This makes them safe for use in areas where there are children or pets present, and near vulnerable adults. The firefighting capacity of water is limited, so large water fire extinguishers are required to fight even small fires.

Foam fire extinguishers

Foam fire extinguishers have traditionally been installed in offices and businesses across the UK to tackle class A fires and fires involving electrical equipment. Safelincs have chosen to discontinue AFFF (Aqueous Film-Forming Foam) fire extinguishers due to the toxic chemicals they contain. There are more environmentally friendly options to AFFF foam such as our range of eco-foam fire extinguishers. These are ideal for tackling burning solids (Class A) and liquid fires (Class B) as well as fires involving electrical equipment.

Wet chemical fire extinguishers

Wet chemical extinguishers are used on class F fires such as fat, oil and deep fat fryer fires. The extinguishing agent used in wet chemical extinguishers expands upon contact with the burning oil to form a blanket on top of it, which prevents re-ignition by cooling and smothering the area as well as blocking access to oxygen. They are usually supplied with a long lance which helps the user keep a safe distance from the fire and deploy the media at low pressure, rather than 'spraying' the deep fat fryer which risks causing splashes and spreading the fire.

Water mist fire extinguishers

Water mist extinguishers have a superfine spray nozzle that dispenses microscopic droplets of de-ionised water. The mist curtain reduces the supply of oxygen to the fire and cools the materials, preventing reignition. As they only contain de-ionised water, water mist is an environmentally friendly media and leaves no messy residue to clean up after discharge. Water mist extinguishers displaying the live electrical equipment symbol on the front have been di-electrically tested in accordance with BS EN3 and are suitable for use on live electrical equipment up to 1000 volts at a distance of 1m. Some water mist extinguishers are also certified for class F fires, however, we DO NOT recommend using water mist on anything above a 5F rated fire (equivalent to a domestic deep fat fryer).

Lithium-ion fire extinguishers

With the increase of equipment such as; mobile phones, tablets, laptops, cordless power tools, e-bikes, and e-scooters being charged in our homes and workplaces. It has become necessary for a specifically designed extinguisher for use on lithium-ion batteries and contain a new extinguishing agent, Aqueous Vermiculite Dispersion (AVD). When an AVD extinguisher is dispersed on to the fire it is in the form of a mist which allows for the water to suppress the flames, cooling down the fuel source. When the water cools and evaporates, it creates an insulating film to help prevent re-ignition.

What fire extinguisher do I need?

Fire extinguishers by risk

There are currently six classes of fire, each covering a different fire risk, these have been categorised by the combustible material, liquid, or gas. The classes cover, solid combustibles, flammable liquids, flammable gases, flammable metals, live electricals, and cooking oil.

For example, in a garage you are likely to have the following risks; Flammable Liquids Petrol, oils, paints, tar, ether, alcohol, stearin and paraffin. Flammable Gases Methane, propane, hydrogen, acetylene, natural gas and city gas. Electrical Appliances Computers, electrical heaters, stereos, fuse boxes etc. This would require a fire extinguisher or extinguishers that are capable of tackling Class B (flammable liquids), Class C (flammable liquids), and electrical fires.

Always refer to your fire risk assessment and results of your fire extinguisher survey when purchasing extinguishers.

Fire extinguishers by location

The type of fire extinguisher that are required is based on the risks in that location, for example, the fire risks in a garage are very different to those in an office. In commercial premises, there is a legal requirement to ensure that the correct type and number of extinguishers are present and that they are positioned in the right places.

In domestic properties, it is not a legal requirement in the UK to have a fire extinguisher in your home, it is recommended. Safelincs recommend a water mist fire extinguisher to be kept in homes due to its versatility in being able to put out a range of fire types. Water mist fire extinguishers are suitable for class A, B, C, F and Electrical fires, making them a great all-round fire extinguisher.

What is a fire extinguisher rating?

A fire extinguisher rating defines the type and size fire the extinguisher can put out. For example, a 13A/55B fire extinguisher would be able to combat class A fires up to size 13 and class B fires up to size 55.

For Class A fires the ‘size’ test is conducted using a fire comprising of an open latticework of wooden sticks approx. 40mm square x 500mm long piled 14 high. The number 13 comes from the number of sticks in each row. Fire extinguishers that can put out a fire up to this size are rated 13A.

Class B fires are easier to understand as the number represents how many litres of burning fuel the fire extinguisher can tackle.

Are fire extinguishers a legal requirement?

Fire extinguishers are a legal requirement in all commercial buildings. A fire risk assessment is required by law under Regulatory Reform (Fire Safety) Order 2005 and is for virtually all types of premises, from a small corner shop, offices, hotels, B&Bs, garages and industrial units all come under the RR(FS)O. In fact, there are very few places that don't come under the order, private dwellings (your home or flat), for example. If you operate a business out of your home, you will need to have a fire risk assessment. Part of the FRA is to advise the number, position and types of extinguishers required in your premises. More information for fire safety regulations can be found on the Government website

Are fire extinguishers toxic?

AFFF foam fire extinguishers contain toxic PFAS chemicals and therefore have been discontinued by Safelincs. There are a number of risks associated with the fluorine compounds (PFAS) found in AFFF foam extinguishers making them harmful to the environment and living organisms. Safelincs have an alternative range of eco-friendly foam fire extinguishers that are fluorine free and are available for purchase.

Dry powder fire extinguishers can be toxic to humans if ingested in large quantities. Inhaling or ingesting small amounts of dry powder can lead to symptoms such as an upset stomach and sore throat. Contact with the skin can also cause itchiness and redness. The use of powder fire extinguishers indoors is not recommended by BS 5306-8: 2012 due to the mess powder creates and the potential impairment of vision and respiration it can cause.

CO2 fire extinguishers should be discharged with care as they can cause cold burns if the pressured gas comes into contact with the skin. CO2 also replaces the oxygen in the air when discharged and can lead to risk of asphyxiation if used in a confined space.

Water mist or water fire extinguishers are the most environmentally friendly fire extinguishers as they contain only water. The media in these extinguishers are not harmful to humans, wildlife or the environment and can be used indoors or outdoors.