Fire Extinguisher Types & Use: What Every Office / Remote Worker Should Know
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Fire Extinguisher Types and Uses: A Practical UK Guide
Fire extinguishers are a vital first line of defence in workplaces, offices, and home working environments. However, using the wrong type of extinguisher can make a fire significantly worse and place lives at risk. This guide is for business owners, office managers, and anyone responsible for fire safety in the UK. In this article, we will cover the types of fire extinguishers and their uses to help you make informed decisions. Choosing the correct extinguisher can prevent injuries, property damage, and ensure compliance with UK fire safety laws.
Understanding the different types of fire extinguishers and their uses allows you to respond safely to small fires while remaining compliant with UK fire safety legislation. This guide explains fire classes, extinguisher types, and where each should be used, helping you make informed fire safety decisions.
Why Fire Extinguisher Types Matter
No single fire extinguisher is suitable for every fire. Each extinguisher is designed to tackle specific fuels, known as fire classes. Applying the wrong extinguishing agent can spread flames, cause explosions, or introduce serious electrical hazards.
In the UK, extinguisher selection forms part of a fire risk assessment under the Regulatory Reform (Fire Safety) Order 2005. Correct placement, clear labelling, and basic staff awareness are essential for safe and effective use.
Understanding Fire Classes
Fires are classified into different classes based on the type of material that is burning.
Fire classes are defined by the material burning:
- Class A – Solid combustibles (wood, paper, textiles)
- Class B – Flammable liquids (petrol, solvents, paints)
- Class C – Flammable gases (LPG, propane, butane)
- Class D – Flammable metals (magnesium, lithium, sodium)
- Electrical fires – Live electrical equipment
- Class F – Cooking oils and fats
Each class requires a specific extinguishing method. Selecting the correct extinguisher depends entirely on identifying the fuel involved.
Main Types of Fire Extinguishers and Their Uses
There are five main types of fire extinguishers: water, foam, dry powder, CO2, and wet chemical.
Fire extinguishers are classified by the type of fire they extinguish, identified by colour-coded labels. UK fire extinguishers follow BS EN3 colour labelling, making identification easier during emergencies.
Water Fire Extinguishers (Red Label)
Water extinguishers are classified as Class A and are best for fires involving ordinary combustibles like wood, paper, and textiles.
Primary Use:
Water extinguishers are designed for Class A fires and are best for fires involving ordinary combustibles such as wood, paper, and textiles.
Best for:
- Class A fires (wood, paper, textiles)
Do not use on:
- Electrical fires
- Flammable liquids
- Cooking oils or gases
Water extinguishers cool burning materials, reducing the risk of re-ignition. They are common in offices, corridors, and general accommodation areas.
Foam Fire Extinguishers (Cream Label)
Foam fire extinguishers are suitable for both Class A and Class B fires.
Primary Use:
Foam extinguishers are effective on Class A and Class B fires, making them suitable for both solid combustibles and flammable liquids.
Best for:
- Class A fires
- Class B flammable liquid fires
Limitations:
- Not suitable for Class F fires
- Generally not recommended for live electrical equipment
Foam forms a blanket over burning liquids, cutting off oxygen and reducing vapour release. These are widely used in garages, workshops, and mixed-risk areas.
Dry Powder Fire Extinguishers (Blue Label)
Dry Powder extinguishers are classified as Class A, B, and C and are versatile for use on solids, liquids, and gases.
Primary Use:
Dry powder extinguishers are versatile and can be used on Class A, B, and C fires, making them suitable for solids, flammable liquids, and gases.
Best for:
- Class A, B, and C fires
- Some electrical risks
Drawbacks:
- Powder clouds reduce visibility
- Residue damages electronics and machinery
- Not ideal for offices or enclosed spaces
Dry powder extinguishers interrupt the chemical reaction of a fire, making them effective outdoors or in industrial settings. Specialist powders are required for Class D metal fires.
CO₂ Fire Extinguishers (Black Label)
CO2 fire extinguishers are primarily used for electrical fires and Class B fires involving flammable liquids.
Primary Use:
CO2 extinguishers are ideal for electrical fires and small Class B fires involving flammable liquids.
Best for:
- Electrical fires
- Small Class B fires
Key considerations:
- No cooling effect (re-ignition possible)
- Risk of frostbite from discharge horn
- Less effective outdoors
CO₂ extinguishers displace oxygen and leave no residue, making them ideal for server rooms, offices with IT equipment, and electrical plant areas.
Wet Chemical Fire Extinguishers (Yellow Label)
Wet chemical fire extinguishers are specifically designed for Class F fires involving cooking oils and fats.
Primary Use:
Wet chemical extinguishers are essential for Class F fires, particularly those involving cooking oils and fats.
Best for:
- Class F fires involving cooking oils and fats
Wet chemical extinguishers cool burning oil and create a sealing layer to prevent re-ignition. They are essential in commercial kitchens, takeaways, canteens, and food vans. Where deep-fat fryers are present, wet chemical extinguishers are typically a legal requirement.
Water Mist and Specialist Extinguishers
Water mist extinguishers use fine de-ionised water droplets, allowing limited use near electrical equipment while reducing residue. They are suitable for care homes, heritage buildings, and mixed-risk environments.
AVD extinguishers are specialist units designed for lithium-ion battery fires, increasingly relevant where large battery storage or charging is present.
How to Use a Fire Extinguisher Safely (PASS Method)
Only attempt to fight a fire if:
- It is small and contained
- You have the correct extinguisher
- You have a clear escape route
PASS Method:
- Pull the pin
- Aim at the base of the fire
- Squeeze the handle
- Sweep side to side
If the fire grows, evacuate immediately and call emergency services.
Inspection, Maintenance, and Legal Duties
Routine Checks
Fire extinguishers must be maintained in line with BS 5306. Typical requirements include:
- Monthly visual checks by the responsible person
Annual Servicing
- Annual servicing by a competent technician
- Extended servicing or replacement, depending on the extinguisher type
Legal Responsibilities
Under UK law, the Responsible Person must ensure that extinguishers are appropriate, maintained, and supported by a current fire risk assessment.
Conclusion: Right Extinguisher, Right Place
Effective fire safety is not about having more extinguishers — it’s about having the right extinguishers in the right locations.
Understanding fire classes, extinguisher types, and basic usage principles helps reduce risk and prevent costly mistakes. Combined with training, servicing, and professional assessment, correct extinguisher selection plays a crucial role in protecting people and property.
Frequently Asked Questions
Can one extinguisher cover all fire risks?
No. Different fire classes require different extinguishing agents.
How many extinguishers does a small office need?
This depends on the fire risk assessment, building layout, and hazards present.
Do lithium-ion batteries need special extinguishers?
Only where large-scale storage or charging is present.
Is it safe for untrained staff to use extinguishers?
Staff should only attempt to extinguish small fires if confident and safe to do so.
