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Kitchen Fires

Kitchen Fires


Understanding the Risk

Cooking facilities are present in a vast range of commercial premises including hotels, schools, restaurants, fast food outlets and public houses plus less obvious examples such as work canteens in factories or offices. Causes of fires are varied and include electrical faults in fixed wiring or the numerous appliances that can be present plus the cooking process itself, especially with the presence of hot cooking oils in deep fat fryers.

The resultant loss of a facility and disruption to the business can have a severe and immediate impact especially where cooking is the core activity. Where cooking is an ancillary activity in a ‘host’ occupancy, a fire starting here can spread to more important areas of a premises and cause widespread damage.

The risk where cooking is undertaken needs to be understood, managed and controlled in order to reduce the likelihood of a fire starting in the first place or mitigating the extent of damage should the worse happen.

In order to do this, it is necessary to firstly consider the inherent risks associated with cooking facilities before deciding on an effective program of risk control measures.

One of the biggest hazards in a kitchen is the use of cooking oils which are typically used at temperatures of around 200ºC. If the temperature the oil is heated to is too high, either by operator error or failure of the thermostats, then self-ignition can result in a fierce fire which unless controlled can spread easily to surroundings and into hard to reach hidden areas such as extract plenums and ducts.

The safety margin between cooking and self ignition temperatures reduces as the oil is used due to oxidation processes and contamination so regular replacement with fresh oil is important.

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During the cooking process, grease laden fumes are produced which will deposit on surfaces especially in extract hoods, plenums and ducts.

If these grease deposits are left to accumulate over time and are ignited, the fire will be difficult to extinguish manually especially if it spreads to hidden or inaccessible areas.

Fire spread through greasy ducting can be rapid and will jeopardise other portions of the building which can potentially result in significant direct damage and consequent interruption to the business.

Controlling the Hazard

Controls that can be in place generally fall into 2 categories which are:

  • Human Element - relating to the management procedures primarily aimed at reducing the likelihood of an event occurring or how to react to an emergency event.
  • Physical Element - relating to protection or design principles aimed at reducing or mitigating the effect should an incident occur.

The following issues under these 2 headings should be considered fully to create an integrated risk control program:

Human Element
  • Undertake fire risk assessments to identify hazards and develop self-inspection checklists
  • Maintain good housekeeping regimes to eliminate unnecessary combustibles
  • Provide and maintain up to date record of induction and refresher training to employees in the correct use of protection equipment and emergency fuel isolation switches or valves
  • Develop written emergency plans and have regular fire drills
  • Clean extract filters, grease traps and canopies at frequency determined by risk assessment (normally weekly) and keep record
  • Regularly replace the cooking oil based on risk assessment – replacement or replenishment should not be undertaken when the oil is hot
    • Arrangements should be in place for full length deep clean of extract duct-work by specialist contractor at a frequency determined by risk assessment (at least annually for light use). This is to remove greasy fat deposits within the duct-work which if left unchecked would assist fire spread.
    • Arrange for cooking equipment & electrical installations to be inspected and maintained by competent company
    • Ensure deep fat fryers are not left unattended when in use and the fuel supplies to all cooking equipment is switched off at the end of the working day
    Physical Element
    • Eliminate the use of combustible materials in the construction of kitchens
    • Locate kitchens (where possible) in a separate fire compartment providing at least 1-hour fire separation
    • Arrange the layout of the kitchen to ensure appliances and equipment are readily accessible to facilitate regular maintenance
    • Ensure deep fat fryers are provided with a separate non-self-resetting high temperature limit control device in addition to the normal operator thermostat
    • Deep fat fryers should be provided with metal lids
    • Interlocks should be provided to ensure the cooking ranges cannot be operated without the extract systems in operation
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    • Provide easily accessible and identifiable manual emergency shut off switches and valves preferably on exit routes
    • Provide a suitable portable fire extinguisher designed specifically to fight fires involving fat. This is in addition to fire blankets.
    • Extract ducting should be provided with runs kept as short as possible avoiding horizontal runs. Material should be stainless steel or galvanised metal, have liquid tight seams and have adequate inspection openings to facilitate a full length deep clean.
    Fire Suppression Systems

    In view of the speed and severity of deep fat fryer fires, the provision of a suitably designed and installed automatic wet chemical kitchen fire suppression system is one of the most effective solutions. These systems will provide a safe and effective means of controlling kitchen fires that if uncontrolled, can result in significant damage and consequent interruption to operations.

    For further information, please contact your RMC Engineer

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