In addition to the well-known fire classes A to D, fire class F is particularly important in kitchen environments. It describes fires caused by burning cooking oils and fats—an underestimated but dangerous risk. In this article, you will learn:
- Which substances belong to fire class F
- Where such fires typically occur
- Which extinguishing agents and fire extinguishers are suitable
What is included in fire class F?
Fire class F covers fires caused by overheated cooking fats or oils. When heated, these substances reach a so-called auto-ignition temperature – at this point, they ignite without an external ignition source.
The fire spreads quickly, is intense, and is difficult to control, as burning fats are very hot and conventional extinguishing attempts—such as using water—can have fatal consequences.
Typical substances are:
- Sunflower oil, rapeseed oil, palm oil
- Clarified butter, frying fat
- Other vegetable or animal fats
Where do Class F fires occur?
Fires of this type often occur in commercial kitchens, canteens, restaurants, and snack bars—in other words, anywhere where large quantities of fat or oil are heated. Fat fires also occur regularly in private households, e.g., due to unattended heating during deep-frying or frying.
Typical locations:
- Commercial kitchens and communal catering facilities
- Restaurants
- School and company cafeterias
- Food trucks and snack bars
- Private kitchens
Which extinguishing agents are suitable?
Water is completely unsuitable and life-threatening when used on grease fires. It evaporates instantly, spraying the burning grease in all directions and potentially causing a grease explosion. Therefore, only special extinguishing agents are permitted.
Suitable extinguishing agents are:
- Special extinguishers with salt or foam solution
- Kitchen fire extinguishing systems, e.g., with Ansul
These agents work by means of a chemical reaction (saponification) that forms a foam-like insulating layer over the grease and prevents the supply of oxygen. In addition, the cooking oil or grease is cooled below the auto-ignition temperature. This prevents the fire from reigniting or reigniting.
Which fire extinguishers are suitable for fire class F?
For class F fires, there are specially developed grease fire extinguishers that are equipped with a particularly powerful extinguishing agent.
Suitable fire extinguishers:
- Grease fire extinguishers (class F): specially developed for cooking fats/oils
- Combination extinguishers (ABF): also suitable for class A and B fires
Not suitable:
- Water extinguishers
- Powder extinguishers (cause strong recoil and can spread the flames)
- CO₂ extinguishers (only effective to a limited extent, no cooling effect)
Grease fires: Invisible heat, high risk
Grease fires often produce flames that are barely visible, but generate extreme heat. Just a few drops of water are enough to cause a dangerous deflagration. Therefore:
- Never pour water on burning grease!
- Keep special grease fire extinguishers handy.
- Never leave deep fryers and pans unattended.
- Check thermostats regularly.
Fire safety in kitchens: Safety is no accident
A grease fire can cause significant damage within seconds – not only to property, but also to health. With the right equipment, regular maintenance, and trained personnel, you can effectively prevent such incidents.
CWS Fire Safety supports you with:
- Suitable grease fire extinguishers and kitchen protection solutions
- Professional advice and risk analysis
- Training for your team
- Regular maintenance of your extinguishing systems