Common Causes of Kitchen Fires

Insurance company data shows that of all property losses in restaurants exceeding EUR 100 000 are a direct result of a fire.

Approximately 40% of restaurant and hotel fires start in the kitchen and 19% starts at the stove. In addition to the risk of injury the cost of property and material damage is significant, often more than EUR 50 000 per restaurant. It also leads to further heavy costs due to loss of revenue while the restaurant is closed. The insurance may, or may not, cover this lost revenue.

Gasoline bottles must be removed at an adjacent fire due to risk of the fire spreading. A fire that started in a neighboring area threatens to take off if it manages to ignite the fat in a polluted duct.

Restaurant fire

Common Causes of Kitchen Fires

  • Too high temperature in the fryer
  • Vegetable, more flammable, oils
  • Old, more flammable oil, in the deep fryer
  • Fat deposits in the flue and ventilation ducts
  • Misalignment sprinklers due to equipment moved around
  • Clogged melting links of the sprinklers leading to impaired function

What is needed for a fire to start?

It may sound obvious, but there are three conditions that must be met in order for a fire to start; heat, oxygen (air) and fuel.

Remove one or more factors and the fire can be avoided.

All of these factors are present in varying degrees in a kitchen.

Fire Extinguishing System

The systems available on the market are mainly based on “suffocation”, ie. oxygen removal, by either spraying a foaming solution or a powder/carbon dioxide over the fire to shut out the oxygen supply. A secondary benefit is that the solution is supposed to cool the fuel, removing some of the heat.

Preventive Measures against the Spread of Fire

Fuel is required to keep a fire alive, when heat and oxygen are already present. As long as there is fuel the fire will live on.

A fat removal system aims to reduce the accumulations of fuel (fat) in the parts of the ventilation system which is exposed to fire, including the kitchen flue duct.

Flue Ducts and Fire Prevention
Stainless steel ducts are safest from a fire standpoint. The reason is partly explained due to its high heat resistance in case of a grease fire in the kitchen flue. With a built-in exhaust air cleaning system, eg. ozone or UV, you reduce the fire hazard and may, depending on the local fire code, use less costly channel materials in the installation.

Flue fires are increasing. The greatest risk is at the fryer, wok and cooking table.

Animal fat and cooking oil have a high energy value of 10 kW/kg (36 MJ) (12.5 kW/liter = 45 MJ) and burns with very high temperatures (900-1100 °C). The energy value can actually be compared with ordinary fuel-oil!

Animal fat melts at 40 degrees and vaporized (smoke) at 120-220 °C. The flash point is 280 °C, the odors spontaneously combust at 310 – 360 °C.

Regular cooking oil begins to smoke at 150 -250 ° C, which means that the oil degrades and makes the oil combustible.

Vegetable oil burns with a hotter flame than animal fat.