Commercial kitchens are one of the highest fire risks in any business. Hot oil, open flames and grease build-up are a dangerous mix – but most kitchen fires can be prevented.

Common Causes

  • Overheated oil in fryers, and oil spilt onto hot surfaces.
  • Grease building up in canopies, filters and extract ducts.
  • Cooking left unattended.
  • Faulty thermostats and electrical faults.
  • Oily cloths heating up on their own.

Extinguishers and Fire Blankets

  • Wet chemical extinguisher – the right type for Class F fires (cooking oils and fats). Under British Standard BS 5306-8, no one should have to travel more than 10 metres to reach one.
  • Fire blanket – for small pan fires. Use a larger size for commercial kitchens – see Fire Blankets: Where and How to Use Them.
  • CO2 – for electrical equipment.
  • Never use water on burning oil – it can cause an explosive fireball.

Which Size of Wet Chemical Extinguisher, and How Many?

The number on the label (for example, 75F) shows the size of test fire the extinguisher put out, measured in litres of cooking oil. It isn't the size of fryer it can cover.

British Standard BS 5306-8:2023 bases the choice on the largest area of hot oil exposed in a fryer – the length times the width of the oil surface:

  • Up to 0.015 m² – one 5F extinguisher
  • Up to 0.04 m² – one 25F
  • Up to 0.06 m² – one 40F
  • Up to 0.11 m² – one 75F

For example, a fryer with an oil surface of 30 cm × 30 cm has an area of 0.09 m², so it needs a 75F extinguisher. No one should have to travel more than 10 metres to reach one. If you have several fryers, or a larger oil surface, ask us – you may need more than one extinguisher, or a fixed suppression system.

Kitchen Fire Suppression Systems

Many commercial kitchens have an automatic suppression system over the cooking range. It detects a fire, cuts off the gas or electricity and sprays wet chemical onto the appliances, canopy and duct. Systems are commonly approved to LPS 1223 (a Loss Prevention Certification Board standard) or designed to BS EN 17446, and should be serviced at least every six months.

Is there a level at which you must have one? No law sets a size or type of kitchen that must have a suppression system. The decision comes from your fire risk assessment and, very often, your insurer. Many insurers require one where cooking produces more than a moderate amount of grease in the extraction system, typically an LPS 1223-approved system installed by a BAFE SP206-certified company. Your lease or landlord may require one too – so check your insurance policy and lease.

Extract Duct Cleaning

Grease in extract ducts is a major cause of serious kitchen fires. The industry guide, TR19 Grease (published by BESA, the Building Engineering Services Association), recommends professional cleaning of the whole extract system – not just the filters – at least:

  • Every 3 months for heavy use (12–16 hours a day).
  • Every 6 months for moderate use (6–12 hours a day).
  • Every 12 months for light use (2–6 hours a day).

Clean canopies and filters at least weekly. Keep the cleaning certificates – insurers often ask for them.

Gas Safety

Gas cooking appliances should have an interlock that cuts off the gas if the extract ventilation fails, and a clearly labelled emergency gas shut-off on the way out.

Training

Make sure all kitchen staff know how to use the wet chemical extinguisher and fire blanket, how to shut off the gas, and when to just get out.

Worth remembering… your fire risk assessment is what decides what your premises need. This guide is general advice, not a substitute for it.

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