Wet Chemical Fire Extinguishers

The need for a wet chemical fire extinguisher

All Class F fire extinguishers must conform to British Standard BS7937. For fat fryers holding more than three litres of oil, you must have a Class F wet chemical fire extinguisher as a legal requirement under the Regulatory Reform (Fire Safety) Order 2005.

Wet chemical fire extinguishers are the only type of fire extinguisher suitable for a large volume of cooking oil – nothing else can be used safely. They work through a unique two-step process that makes them incredibly effective:

Instant cooling: The mist effect released from the nozzle cools the flames and partially removes the 'heat' side of the fire triangle.

Saponification: A chemical reaction occurs between the potassium salts and burning oil or fat, creating a soapy layer of foam that forms on top of the burning liquid, cutting off oxygen to the fire.

Businesses that need wet chemical fire extinguishers

You'll most commonly find wet chemical fire extinguishers in restaurants, hotels, chip shops and burger vans. Any business that uses cooking oil or fat that might combust requires this essential safety equipment.

Our customers include:

• Commercial restaurants and kitchens
• Fast food outlets and takeaways
• Hotels and hospitality venues
• Catering companies and mobile food vendors
• Care homes and institutional kitchens
• Schools and workplace canteens

What size wet chemical fire extinguisher do you need?

2L or 3L wet chemical extinguishers are suited for domestic kitchens, small commercial kitchens, or catering vans. A larger commercial kitchen or one with large quantities of oil, such as deep fat fryers, would require a 6L wet chemical fire extinguisher.

One 6-litre Wet Chemical Fire Extinguisher is sufficient to contain a 75-litre fat fire burning at a blistering 340 degrees.

What fires can wet chemical fire extinguishers tackle?

All of our wet chemical fire extinguishers can also be used to tackle Class A fires and fires involving live electrical equipment, making them ideal for use in a kitchen environment.

Class F fires: Cooking oils, fats, and grease. Class A fires: Paper, wood, cardboard, and textiles. Some models: Certain wet chemical fire extinguishers are also approved for use on Class B fires – those involving flammable liquids, such as gasoline, diesel, and paint.

Recognising a wet chemical fire extinguisher

Wet chemical fire extinguishers have a yellow-coloured label stating 'Wet Chemical' and a longer-than-usual hose with a 'lance' attachment. This design allows you to apply the extinguishing agent from a safe distance.

What makes Safelincs' wet chemical fire extinguishers different?

At Safelincs, we pride ourselves on offering the latest, most innovative products, competitive pricing, and a commitment to ensuring that each and every customer is satisfied with their purchase.

British Standard compliance

All Class F fire extinguishers must conform to the British Standard BS 7937. Our range meets and exceeds these requirements.

Expert advice

Our UK-based customer service team is highly trained and is committed to supporting you and your unique requirements.

Complete solutions

Wet chemical fire extinguishers are often paired with fire blankets for full coverage of kitchen fires. We offer combination packages for total kitchen protection.

Are wet chemical fire extinguishers environmentally friendly?

Wet chemical extinguishing agents contain special additives that break down oil and fat compounds as they spread, producing less smoke and unpleasant smells that linger. Most fire extinguishers often leave dust residues or waste that cannot be washed away, but this is not a concern with wet chemical extinguishers.

Necessary regulations to note for 2025

From July 2025, fire extinguishers containing perfluorooctanoic acid (PFOA) will no longer be permitted in the UK. This affects some older foam extinguishers and may affect wet chemical extinguishers - historically they do contain fluorine compounds. Newer wet chemical extinguishers will shortly be subjected to regulation as they contain PFAS chemicals which will be phased out. We have a new P50 wet chemical fire extinguisher that does not contain PFAS.

How often do wet chemical fire extinguishers need servicing?

Steel wet chemical fire extinguishers (like all steel fire extinguishers) require a service every year by a qualified technician and an extended service every 5 years (like foam, water and powder).

P50 Service-Free Wet Chemical Fire Extinguishers do not require annual servicing or an extended service at 5 years. They need only a service-exchange after 10 years.

Safelincs extinguisher technicians are BAFE certified and will carry out extinguisher servicing in accordance with the relevant British Standard. We offer transparent pricing with no hidden costs.

Ready to protect your kitchen? Browse our comprehensive range of wet chemical fire extinguishers below, or contact our expert team on 0800 612 6537 for personalised advice on the ideal fire safety solution for your business.

Frequently Asked Questions (FAQs)

What fires can wet chemical fire extinguishers tackle?

The primary use of a wet chemical fire extinguisher is tackling class F cooking oil fires.

What size wet chemical fire extinguisher do I need for my kitchen?

2L or 3L wet chemical extinguishers are suited for domestic kitchens, small commercial kitchens, or catering vans. A larger commercial kitchen or one that had large quantities of oil, for example, in deep fat fryers, would require a 6L wet chemical extinguisher.

The size depends on the scale of your cooking operations and the amount of oil or fat present. Smaller units work well for home kitchens and mobile catering, whilst larger commercial operations need more substantial protection.

How do wet chemical fire extinguishers work?

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.

This process works in two stages: first, the agent cools the burning oil to reduce the temperature, and second, it creates a protective barrier that prevents oxygen from reaching the fuel source, effectively suffocating the fire.

Why is it dangerous to use the wrong type of fire extinguisher on cooking oil fires?

Using the incorrect extinguisher on a Class F fire can cause the burning oil to splash, potentially spreading the fire. This can turn a contained fire into a much more dangerous situation.

Class F fires involving cooking oils and fats must only be tackled by extinguishers that have been certified for this use. Standard water-based extinguishers can cause the burning oil to splatter and spread the fire throughout the kitchen.

What's the difference between wet chemical extinguishers and water mist extinguishers for kitchen fires?

Some small Water Mist extinguishers are certified for use on cooking oil fires. These extinguishers have a small Class F rating, indicating that they are effective in fighting small, domestic kitchen fires.

Water mist extinguishers are suitable for small domestic kitchen fires, but wet chemical extinguishers are essential for commercial kitchens and situations involving larger quantities of oil.