What are the different types of fire extinguishers?

15th March 2026

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While passive fire protection measures are crucial for containing a developing fire, active fire protection systems are equally vital. Fire detectors and alarms play a central role in early detection and mobilisation, ensuring a quick response and a safe and effective evacuation.

While employees should never put themselves at risk to fight a fire, fire extinguishers can be an important way to stop a small fire, or to assist in a safe evacuation. Yet when the time comes, many people are unaware of the differences between fire extinguishers, and which one to use on which fire. As such, we’ve explained what the different types of fire extinguisher are below—and everything you need to know to use them in an emergency.

The different types of fires

Contrary to popular belief, fire extinguishers should not be used to fight an established fire. Instead, they are a way to extinguish a small fire before it has a chance to escalate. Fire extinguishers can also be used to suppress a fire if necessary as a means to support evacuation.

Different types of fire extinguishers exist to fight different types of fires. While water fire extinguishers are the most common type, it is not appropriate for all fires. The substances involved in some fires will react negatively to water, while an electrical fire poses a risk of electrocution when using a water extinguisher.

The different types of fires are divided into six classes:

Class A

Class A fires are combustible material fires. These are generally started by a flame or high temperatures coming into contact with easily combustible materials, such as paper or fabric. Class A fires are the most common type of fire due to combustible materials existing in almost every commercial and residential building, and have many firefighting options as a result.

Class B

Class B fires are flammable liquid fires. Class B fires typically involve flammable liquids such as petrol or spirits, and are extremely dangerous, as they can spread quickly and be difficult to fight. As these liquids are also used in many settings—from restaurants to petrol stations to medical facilities—these are also fairly common fires.

Due to the increased risk compared to Class A fires, it’s important to have accurate signage and appropriate fire safety equipment wherever a risk of Class B fires exists.

Class C

Class C fires are flammable gas fires. Class B fires involve substances such as propane, butane, and natural gas. While the risk posed by these substances is extremely high, they are relatively uncommon, despite the presence of gas boilers in many properties. Where significant quantities of flammable gases are stored, proper storage and fire containment systems (such as Durasteel fire barriers) are critical.

Class D

Class D fires are combustible metal fires. Combustible metals include substances like magnesium and lithium, and are thus extremely rare outside of industries such as manufacturing, warehousing, and medical facilities. However, they are also difficult to fight, and require more specific equipment than other fires.

Class E

Class E fires are electrical fires. These may involve a range of appliances or electrical equipment, and pose an obvious danger because of the risk of electrocution along with the risk of fire. Class E fires can only be fought with specific equipment, as certain extinguishers will not only fail to quell the fire, but also pose a risk to the person using them.

Class F

Class F fires are cooking oil and fat fires. Particular to restaurants and kitchens in a commercial setting, oil and fat fires can be extremely long and sustained. These require particular extinguishers to combat, as water reacts violently when used on an oil or fat fire.

Understanding fire extinguishers

The most common types of fire extinguisher in the UK are:

Water extinguishers

Water extinguishers are ideal for fighting Class A fires involving ordinary combustible materials like wood, paper, and cloth, meaning that they feature in many commercial and residential premises. Common applications for a water extinguisher include paper and document fires, wooden furniture, clothing, and other combustible materials.

Foam extinguishers

Foam extinguishers discharge a foam that coats and smothers the fire, preventing oxygen from reaching the fuel. As a water-based extinguisher, they’re ideal for either Class A or Class B fires, including flammable liquids like petrol and oil. Common locations for using foam extinguishers include garages, workshops, and industrial facilities, with use cases including flammable liquids like paint thinners, solvents, and motor oil.

Powder extinguishers

Powder extinguishers release a dry chemical powder that smothers the fire and disrupts the chemical chain reaction. They’re ideal for: Class A, B, and C fires, which involve flammable gases. Common locations for powder extinguishers include industrial facilities, laboratories, and commercial kitchens. They are suitable for fires involving electrical equipment, flammable gases like propane and butane, and cooking oil fires.

CO2 extinguishers

CO2 extinguishers release carbon dioxide, which extinguishes a fire by displacing the oxygen around it, starving it of fuel. The non-reactive nature of carbon dioxide makes them ideal for Class B and C fires, as well as Class E electrical fires. They are a common sight in computer rooms and server rooms, as well as in offices with large numbers of computers, printers, and other electronic equipment.

Wet chemical extinguishers

Wet chemical extinguishers discharge a potassium-based solution that cools fires, and forms a soapy film to prevent reignition. As a non-water based liquid extinguisher, a wet chemical extinguisher is ideal for Class F fires involving cooking oils and fats. They are commonly found in commercial kitchens, restaurants, and other food processing facilities, and are specifically designed for kitchen fires involving cooking oil or fat.

Dry powder extinguishers

Dry powder extinguishers use a dry, non-combustible powder to smother a fire and deprive it of oxygen. Dry powder extinguishers are specifically designed for Class D fires, featuring a large nozzle to allow for a significant amount of powder to be dispensed very quickly. They are usually only found in industrial and medical settings where combustible metals may be present.

Choosing and using fire extinguishers

When selecting fire extinguishers for your workplace, it’s essential to consider the types of fire hazards present. A fire risk assessment by a qualified assessor can help identify the appropriate types and quantities of extinguishers needed. It’s also important to ensure that employees are trained in the proper use of fire extinguishers, and understand the PASS acronym:

Pull: Pull the pin to release the safety lock.
Aim: Aim the nozzle at the base of the fire.
Squeeze: Squeeze the handle to release the extinguishing agent.
Sweep: Sweep the nozzle from side to side, covering the fire.

It’s important that fire extinguishers aren’t just put in place without providing any training or information to staff on what they should be used for, and exactly how to use them. People tend to think less critically in an emergency, making it important that you internalise key fire safety information ahead of time.

Training employees in the different types of fire extinguishers and their appropriate uses will do as much to reduce the risk of fire damage as simply having the extinguishers will, and help to better protect your employees and assets. However, it’s equally important to reiterate that fire extinguishers shouldn’t be used to ‘chase’ a fire, but rather to put out small fires before they escalate, and to support evacuation in case of a major fire.

Four fire extinguishers attached to a white wall

Fire extinguishers and UK fire legislation

UK fire safety legislation for workplaces centres around the Regulatory Reform (Fire Safety) Order 2005, which puts a significant emphasis on fire prevention and early detection. While specific fire safety requirements will vary depending on the industry and type of premises, fire extinguishers are usually mandatory in workplaces to provide a first line of defence against fires.

All extinguishers should be easily accessible and visible, with high-visibility signage that clearly shows the type of extinguisher. The number and type of extinguishers required will depend on the size and nature of the premises, something that’s generally established by a fire risk assessment. Extinguishers also need to be regularly inspected and maintained to ensure they are in working order, with the last date of inspection clearly marked on the extinguisher.

Combining passive and active fire protection

While fire extinguishers are essential tools for combatting fires, in an ideal scenario they should never have to be used—and when they are, it should only be to stop small fires. Extinguishers are just one part of a fire safety strategy that should incorporate both passive and active fire protection measures.

Active fire protection such as alarms and sprinklers offers the best chance of both evacuating safely and stopping a fire at source. Passive fire protection meanwhile, such as Durasteel fire and blast barriers, provides a robust defence against the spread of fire and smoke, trapping the fire at its point of origin until emergency services can respond.

By combining passive and active fire protection, businesses can achieve a higher level of fire safety, and reduce the risk of significant damage and loss. Benefits of this approach include:

Enhanced fire containment. Passive fire protection measures such as Durasteel barriers can create fire-resistant compartments that limit the spread of fire and smoke.
Early detection and response. When a fire occurs, every second counts. Active fire protection systems like fire alarms and heat detectors provide early warnings of a fire, allowing for prompt evacuation and fire suppression efforts.
Effective fire suppression. Fire extinguishers can be used to extinguish small fires before they escalate, preventing a minor event from turning into a damaging and dangerous emergency.
Reduced risk of injury and loss of life. A comprehensive fire safety strategy that combines passive and active fire protection measures will account for personal safety above all other factors, significantly reducing the risk of injury and loss of life.
Compliance with fire safety regulations. By implementing both passive and active fire protection measures, you’ll go a long way to ensuring compliance with fire safety regulations, which demand that all reasonably practicable steps must be taken to protect against a fire.

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Fire extinguishers are an essential component of any fire safety strategy, but they should only be one of a range of fire safety measures. No business is safe from fire, no matter how mundane its activities might seem, and the risk of not preparing can be catastrophic. By following the advice above and combining passive and active protection methods, businesses can protect their property from fire, and create a safer environment for their employees, customers and clients.

Invicta Durasteel is committed to providing innovative and effective fire and blast protection solutions. Our Durasteel barriers offer exceptional fire resistance and durability, making them an ideal choice for a wide range of applications. To learn more about our passive fire protection systems including Durasteel barriers and fire doors, get in touch with us today.