How to Extinguish a Class F Fire (Cooking Oils & Gas)

It might be hard for most of us to distinguish between one fire and another but we want to explain the cause of a Class F fire because they’re entirely feasible in all buildings that have kitchens. This month, Target Fire Protection are here to explain how best to extinguish this type of fire to ensure that you and all others in the same building remain safe and sound.

What is a Class Fire F?

A Class F fire involves fat or cooking oil and although this is technically a sub-class fire because they’re the cause of flammable liquids or gases, this type differs from conventional fires because they burn at incredibly higher temperatures.

Flammable liquids, like petrol, have low auto ignition and flash temperatures, whereas fats and cooking oils need temperatures of around 340°C to burst into flames. These liquids have such unique characteristics because of their unusual flash point, that they have been placed into their very own category.

Due to the nature of the liquids, Class F fires take place in kitchens and the majority of these fires occur because of negligence within food preparation facilities. These fires happen when pans are left unattended, oil/fat spillages are left on surfaces and when oil hasn’t been changed in deep fat fryers.

How to Extinguish a Class F Fire

When extinguishing a fire like this, one of three elements must be removed; so either the fuel, oxygen or heat. Normally if the fuel is a burning liquid, the heat is the element that needs to be reduced – to below the flash point. However, in this case because the fat and oil burns at an extreme temperature, this is hard to achieve.

The majority of fire extinguishers are inadequate for Class F fires and can potentially be much more dangerous than just leaving the fire. If you were to use a water fire extinguisher for a Class F fire, it’s very likely that this will cause a massive explosion and help the fire to grow, by spreading the oil further with water. The same goes for CO2 fire extinguishers and powder extinguishers, these can also cause more problems than solutions – increasing danger to yourself and the building.

What does fire protection involve?

Fire protection is a term covering a broad spectrum of techniques, equipment and procedures. Whilst it is vital for all premises to have some form of fire protection in place according to the UK’s fire legislation for those living in, working at or simply visiting the building, there are a variety of different types of fire protection available, and here we run through exactly what these are.

Active or passive fire protection

There are two types of fire protection, active and passive, both of which refers to a different way of handling fire safety.

1. Active fire protection – This is the manual and automatic detection and suppression of fires, including the use of fire sprinkler and fire alarm systems.
2. Passive fire protection – Passive protection includes the installation of firewalls at a premises, as well as fire rated floor assemblies in order to form fire compartments which will limit the spread of fire, high temperatures and creation of smoke, through isolating the outbreak.

Education

This is, of course, a vital aspect of fire protection. The provision of information regarding both active and passive fire protection systems is a sure fire way to ensure that operators, occupants and emergency staff and personnel have a full, working knowledge and understanding of the systems in place and how to perform the fire safety plan at the premises in question.

Classifying fires

Of course, a vital aspect of putting a fire protection system in place is having a full understanding of different types of fire. The fire types are ‘classed’ under the letters A-F, and are as follows (within Europe):

Class A – Fires that involve flammable solids such as wood, cloth, rubber, paper and some types of plastics

Class B – Fires that involve flammable liquids or liquefiable solids such as petrol/gasoline, oil, paint, some waxes & plastics, but not cooking fats or oils

Class C – Fires that involve flammable gases such as natural gas, hydrogen, propane, butane

Class D – Fires that involve combustible metals, such as sodium, magnesium and potassium

Class E – Fires that involve any of the materials found in Class A and B fires, but with the introduction of an electrical appliance, wiring or other electrically energised objects in the vicinity of the fire, with a resultant electrical shock risk if a conductive agent is used to control the fire

Class F – Fires involving cooking fats and oils. The high temperature of the oils when on fire far exceeds that of other flammable liquids, making normal extinguishing agents ineffective

Fire protection engineering

Fire protection engineering simply refers to the application of science and engineering principles to premises which are designed to protect people and the environment in which they are in from the destructive nature of fire. It can include:

1. Analysis of fire hazards
2. Prevention of fire damage by proper design and construction of buildings, materials, structures, industrial processes and transportation systems
3. Design, installation and maintenance of fire detection, suppression and communication systems
4. Post-fire investigation and analysis