Technical Talks is our series of risk management articles, produced by our in-house team of portfolio underwriting, risk managers and surveyors, offering support and guidance for you and your clients in relation to everyday business solutions.
Losses involving fire within or spread by grease extraction ducting continue to pose a signifcant problem. It is not just the major newsworthy incidents that occur, The London Fire Brigade reports that there is a kitchen extract ductwork fire, on average, every 9 days in the Greater London area. This equates to approximately 40 significant duct fires per year.
It is estimated that due to the expansion of the leisure industry and the increase in volume of fast-food outlets, pubs, wine bars and restaurants the numbers of such fires will keep growing.
Major incidents, however, have some common features that should be noted:
- Staff looking after the kitchen/frying facilities tend to be inexperienced and lack training.
- The extract ducting spreads the fire rapidly to other areas of the building.
- Cleaning of the extract systems had gone past the recommended period.
- Extinguishing the fire is made more difficult by poor access facilities to the extract ducting.
- Business interruption losses will generally far exceed the material damage loss.
Common Causes of Fires involving Grease Extract Systems
- Flames, sparks or hot gases can ignite combustible deposits within the duct
- Superheated oils leading to spontaneous combustion
- Fan motor failure or overheating
- Lack of adequate thermostats
- No high temperature safety thermostat
- Equipment left on after close of business
- Conduction through the ducting to combustible materials close to the ducting
- Solid fuel cooking – barbeques etc
- Tandoori ovens without igniters or flame failure devices
- Cooking equipment left unattended
- Gas torches used for browning
- Flexible hoses/housings connecting the fan motors fail in fire conditions allowing spread.
- Positioning of fat fryers next to other cooking ranges which can cause a flash over fire if the frying vapour becomes overheated.
The list could go on, but the primary common cause continues to revolve around the human element i.e. lack experience, leaving equipment unattended, not having sufficient maintenance and cleaning schedules.
Risk Reduction Measures
Please review our comprehensive guidance below. The highlighted sections represent our key priorities and essential requirements for your consideration.
- Extract filters to be cleaned daily. This is dependent on use but should never exceed a weekly clean.
- Extract ducting to be completely cleaned down by a BESA (Building Engineering Services Association) https://www.thebesa.com/ approved company on the following basis: Use of between 12-16 hours per day — every 3 months
- Use of between 6-12 hours per day — every 6 months
- Use of 2-6 hours per day or less — annual
- Once cleaned the work is to be proven by certificate and/or photographic proof provided.
- Ensure that access to the ducting is relatively easy.
- Consider the compartmentation of the ducting, particularly where compartment walls are breached by the ducting. Is there fire damping but more importantly would it work? If there is no damping, then the extract needs to form its own compartment.
- Kitchen extract ductwork should ideally run directly to the exterior without passing through combustible floors or voids. Where bends or dips are necessary, they must include access points for cleaning as these areas naturally collect grease. When ductwork must penetrate combustible materials, a safety clearance of 150mm is required around the duct, with this space filled completely with non-combustible insulation to create a fire-resistant barrier and prevent fire spread through the building structure.
- Power supplies to the extract fans need to be easily isolatable, switches to be in a known and safely accessible position preferable of an automatic shut off type.
- Gas supplies to be easily isolatable with isolation being in a known safely accessible position, again preferably of an automatic shut off type.
- Staff to be trained in the risks associated with cooking, fat frying etc and in the correct and safe use of extinguishing equipment.
- Specialist extinguishers such as Chubb Fire Fry should be installed.
- Fat fryers need to include, thermostats, flame failure devices and a high temperature limit stat of a non-self-resetting type (thermal cut out) operating to prevent the heat of the fat exceeding 230 degrees C.
- Fat fryers should not be placed next to cooking ranges such as gas cookers, where there is no alternative a stainless-steel baffle between the fryer and the cooker needs to be fitted.
- Consideration needs to be given to fitting active chemical suppression systems
- Consideration needs to be given to linking the power supply to the fan motors and possibly the gas supply to an automatic shut off in the event of the heat detection in the kitchen being activated.
Finally, remember, it is not just restaurants, fast food outlets and hotels where such extraction is found. Businesses such as commercial manufacturing may contain staff restaurants and kitchens and will have extraction equipment that requires maintenance and cleaning. Property owners should also give careful consideration in relation to the presence and management of food exposures.
Note: Information detailed in Technical Talks has not been verified for accuracy by a third party. None of the information should be taken as legal or professional advice.