April 3, 2025

Fire extinguishers. We’re used to seeing these red tanks everywhere, but what do you know about them? They’re essential safety devices, specifically designed to fight small fires in emergency situations. The correct selection, installation, and maintenance are vital to ensure safety. This guide looks at the different types of fire extinguishers, the regulations governing their use in the United Kingdom, as well as how they fit into the wider safety landscape.

Fire extinguishers. We’re used to seeing these red tanks everywhere, but what do you know about them? They’re essential safety devices, specifically designed to fight small fires in emergency situations. The correct selection, installation, and maintenance are vital to ensure safety. This guide looks at the different types of fire extinguishers, the regulations governing their use in the United Kingdom, as well as how they fit into the wider safety landscape.

How Do Fire Extinguishers Work? The Science Explained

To understand how fire extinguishers work, let’s take a step back and look at the science of fire itself. You might remember from school that fire requires three key elements to ignite and sustain itself – we often call this the Fire Triangle:

Heat – A source of ignition, such as a spark, open flame, or high temperatures.
Fuel – A combustible material like wood, paper, petrol, or gas.
Oxygen – A sufficient supply of oxygen (usually from the air) to support combustion.

Fire extinguishers work by disrupting at least one of these elements, stopping the fire from burning. Different extinguishing agents achieve this in different ways:

Cooling: Water-based extinguishers reduce the heat of the fire, lowering the temperature below the ignition point.
Smothering: Foam, carbon dioxide (CO₂), and dry powder extinguishers create a barrier that cuts off the oxygen supply.
Interrupting Chemical Reactions: Dry chemical and wet chemical extinguishers interfere with the chemical processes that sustain combustion.
Displacement of Oxygen: CO₂ extinguishers replace the oxygen in the surrounding area, suffocating the flames.

Choosing the right extinguisher for the fire type is crucial for it to work effectively.

Types of Fire Extinguishers and Their Uses

Fire extinguishers are categorised based on the type of fires they are designed for. You need to understand these classes to choose the right extinguisher for your situation.

Fire Classes: What They Are and Why They Matter

Class A: Fires involving ordinary combustible materials such as wood, paper, cloth, rubber, and many plastics.
Class B: Fires involving flammable liquids like petrol, oil, grease, and oil-based paints.
Class C: Fires involving flammable gases such as propane, butane, and methane.
Class D: Fires involving combustible metals like magnesium, titanium, and sodium.
Class F: Fires involving cooking oils and fats, commonly occurring in kitchens.

Fire Extinguisher Types and Their Best Applications

Water Extinguishers: Suitable for Class A fires. They work by cooling the burning material. Not suitable for Class B (liquids), Class C (gases), or electrical fires due to the risk of spreading the fire or causing electrical shock.
Foam Extinguishers: Effective on Class A and B fires. They form a blanket over flammable liquids, preventing vapours from escaping and re-igniting. Not recommended for electrical fires unless they are dielectrically tested.
Dry Powder Extinguishers: Versatile and can be used on Class A, B, and C fires. They work by interrupting the chemical reaction of the fire. However, they are not ideal for enclosed spaces due to reduced visibility and potential inhalation hazards.
Carbon Dioxide (CO₂) Extinguishers: Ideal for Class B and electrical fires. CO₂ displaces oxygen, suffocating the fire. They do not leave residue, making them suitable for areas with sensitive equipment. However, they have limited cooling properties, so re-ignition is possible.

Wet Chemical Extinguishers: Specifically designed for Class F fires involving cooking oils and fats. They cool the fire and form a soap-like solution, sealing the surface and preventing re-ignition. They can also be effective on Class A fires but are not suitable for Class B, C, or D fires.

UK Fire Extinguisher Colour Codes: A Quick Guide

In the UK, fire extinguishers are colour-coded for easy identification:

Red: Water
Cream: Foam
Blue: Dry Powder
Black: CO₂
Yellow: Wet Chemical

This standardisation means that individuals can quickly identify the appropriate extinguisher type during an emergency.

UK Fire Extinguisher Regulations: What Businesses Need to Know

To ensure quality across industries, the use and maintenance of fire extinguishers in the UK are governed by several regulations.

Fire Safety Law: The Regulatory Reform (Fire Safety) Order 2005

This legislation mandates that all non-domestic premises conduct a fire risk assessment to identify potential hazards and implement appropriate fire safety measures, including extinguishers. It places a duty on the 'responsible person' (normally the employer, owner, or occupier) to ensure that adequate fire-fighting equipment is provided and maintained.

BS 5306-8: 2023 Fire Extinguisher Guidelines Explained

This standard provides guidance on the selection and installation of portable fire extinguishers. The 2023 update aligns with current best practices, ensuring that extinguishers are appropriately selected based on the specific risks present in the environment.

Key Requirements:

Provision of Class A Extinguishers: A minimum of two Class A fire extinguishers should be available on every storey of a building. This ensures that basic fire-fighting equipment is readily accessible.
Additional Extinguishers: Depending on specific risks identified in the fire risk assessment, additional extinguishers suitable for other fire classes (B, C, D, F) should be provided.
Installation and Signage: Extinguishers must be mounted on walls or placed in stands and accompanied by clear signage indicating their type and intended use.

Fire Extinguisher Maintenance: Inspection and Servicing Requirements

The moment you need to use an extinguisher is not the time to find out if it works as it should. Regular maintenance can ensure that fire extinguishers function correctly during emergencies when they are most needed.

Annual Inspections: Extinguishers should undergo a basic service annually by a competent person to check for any signs of damage, corrosion, or pressure loss.
Extended Service: Every five years, water, foam, and powder extinguishers require a more thorough examination, including a test discharge and recharging.
CO₂ Extinguishers: These should be overhauled and pressure tested every ten years to ensure their integrity.
Records: All maintenance activities must be documented, and records should be kept on-site for reference.

Flare’s 20+ point Annual Firefighting Equipment Service covers all these points and more, ensuring your equipment is properly maintained and ready for us if needed. As well as giving you peace of mind, it will ensure you remain compliant with all the legislation.

Fire Extinguisher Training: Why Staff Must Know How to Use Them

You can provide the very best equipment, but if no one knows how to use it properly, you may end up with an expensive door stop. Ensuring that staff and occupants are trained in the proper use of fire extinguishers is essential.

Fire Safety Training: Regular training sessions should be conducted to educate individuals on identifying fire classes, selecting the appropriate extinguisher, and using it correctly.
Fire Drills: Conducting regular fire drills helps reinforce training and ensures that everyone knows their role in an emergency.

Fire Risk Assessments: A Key to Fire Safety Compliance

A comprehensive fire risk assessment is the foundation of effective fire safety management. It involves:

Identifying Fire Hazards: Recognising sources of ignition, fuel, and oxygen.
Evaluating Risks: Assessing the likelihood and potential impact of a fire starting and spreading.
Implementing Measures: Introducing controls to eliminate or reduce risks, such as installing appropriate extinguishers and implementing safe working practices.
Reviewing and Updating: Regularly reviewing the assessment, especially after any significant changes to the premises or operations.

Fire Extinguisher Limitations and Common Mistakes to Avoid

Fire extinguishers are crucial safety tools. In an emergency situation it’s far better to have one than not. However, they do have limitations:

Size & Duration: Portable extinguishers contain only a limited amount of extinguishing agent, most lasting 10-30 seconds of discharge.
Fire Severity: They are effective only on small fires in their early stages. If a fire spreads, evacuation is the safest option.
Misuse: Using the wrong type of extinguisher can worsen a fire. For instance, using water on an electrical or oil fire can spread flames or cause electrocution.

Key takeaway: Always match the extinguisher type to the fire class and ensure users are properly trained.

Fire Extinguisher Placement Rules: Best Practices for Compliance

Proper extinguisher placement is critical for effective fire response as well as legal compliance. Best practices include:

Location: Place extinguishers near high-risk areas (e.g., kitchens, electrical rooms, fuel storage areas).
Visibility: Install extinguishers in clear, unobstructed locations with appropriate signage.
Spacing: one should be more than 30 metres from an appropriate extinguisher.
At least two Class A extinguishers per floor of a building.

UK regulations recommend:

Regular inspections ensure extinguishers remain in working order and easily accessible.

Fire Extinguisher Disposal: Safe and Eco-Friendly Options

Fire extinguishers contain chemical agents that must be disposed of responsibly:

Recycling: Many components (metal cylinders, plastic parts) are recyclable.
Hazardous Waste Handling: Expired extinguishers must be disposed of through licensed waste handlers.
Refilling: Some extinguishers can be refilled instead of discarded, reducing environmental impact.

Never dispose of a fire extinguisher in general waste or landfills due to pressurised contents.

Fire Safety at Sea: Fire Extinguisher Requirements for Offshore & Marine Use

Fire safety is particularly critical in offshore and marine environments, where the risk of fire can be heightened due to the presence of flammable materials, confined spaces, and remote locations.

Regulations: Offshore installations must comply with SOLAS (Safety of Life at Sea) regulations and UK Health & Safety Executive (HSE) guidelines, ensuring the correct selection and maintenance of extinguishers.
Specialist Extinguishers: CO₂ and dry powder extinguishers are commonly used due to their effectiveness on fuel and electrical fires. Water mist systems may also be deployed for enhanced coverage.
Challenges: Corrosion from saltwater exposure and limited access for servicing require marine-grade equipment and rigorous maintenance schedules.
Training: Personnel working in offshore and marine environments must undergo specialised fire safety training to handle emergency situations effectively.

Fire extinguishers are just one element of a complete fire safety system. Other critical measures include:

Fire alarms & smoke detectors – Early detection saves lives.
Automatic suppression systems – Sprinklers or gas-based suppression systems for high-risk areas.
Emergency escape plans – Clearly marked exits and regular fire drills.
Fire-resistant materials – In construction, using flame-retardant walls and doors to contain fire spread.

A holistic fire safety approach ensures maximum protection for both property and lives. The Hierarchy of Controls model allows us to see where fire extinguishers fit.

Fire Safety Compliance: Choosing, Using, and Maintaining Fire Extinguishers

Understanding the different types of fire extinguishers and adhering to UK regulations is essential for maintaining a safe environment. By selecting the appropriate extinguishers, ensuring their proper installation and maintenance, and providing adequate training, organisations can significantly reduce the risks associated with fires. Regular fire risk assessments and staying updated with current standards further enhance fire safety measures, protecting both property and lives.

About the Author

Keith Robertson is a trusted leader in offshore, wind farm, and marine safety, with over 40 years in the industry. Known for his expertise in fire and safety systems, Keith has a proven track record of driving growth through direct sales, product innovation, and streamlined safety solutions that reinforce operational efficiency and core business values.