KITCHEN EXTRACT systems provide an ideal environment for the propagation of fire due to the presence of heat from the cooking process, oxygen injected by the extractor fan, and fuel resulting from an uncontrolled accumulation of deposits created by the cooking process. The risk of fires in kitchen extract ductwork affects more than just the hotel, restaurant and fast food industries. Wherever there is a commercial kitchen in regular use, there will be an accumulation of fat, oil and grease (FOG) inside the ductwork.
Even with healthy menus, some atomised FOGs will be produced during cooking and, as they travel into and through the extract ductwork and cool, they become solids that are deposited on the inner surfaces of the extract ductwork and internal system components. A thick layer can build up and, in the event of a fire, can provide fuel to promote and spread the blaze to other parts of the building.
Ductwork fires
Whether the ductwork is clean or laden with FOGs can often make the difference between a small kitchen fire being brought under control quickly or it raging unchecked through other parts of the building. During such fires, burning FOGs or excess heat can spread to the contents and structure of the building, and destroy other areas along the duct route. In some cases this can cause the loss of the entire building. Forensic fire investigators estimate that at least 25% of kitchen fires are made dramatically worse due to a failure to maintain proper cleanliness and the subsequent presence of excess fat, oil and grease in kitchen extract ductwork. This is far too high a figure, as it is possible to reduce the risk of these fires through routine maintenance. However, awareness of this is not yet great enough.
The accumulation of FOGs in ductwork is a fairly obvious and prevalent problem in the food industry, but it also affects, schools, prisons, hospitals, care homes, leisure centres, public transport terminals, factories, or any building with a commercial kitchen that uses extract ductwork. Because the ductwork can act as a channel through which fire can spread, it also represents a further risk to an organisation’s core activity. In some circumstances this can also be life critical.
In a restaurant, it is fairly easy to evacuate kitchen waiting staff and diners, but in other contexts this will not be so easy. For example, in a hospital, there may be a large number of people to evacuate, many of whom will have limited mobility and are resident due to some kind of infirmity. The speed with which they can be evacuated will obviously increase the risk to their safety. In a prison setting, there would be the added challenge not only of evacuating residents, but also of keeping them secured, which could pose a huge logistical problem.
Fast food outlets
A frequent scenario in a high street or university campus location is for fast food outlets and restaurants to be located at street level, with residential accommodation on the floors above. A fire may start in the food outlet due to causes other than cooking; an electrical fault for example, when the premises are unattended. If the FOG deposits in the extract ductwork ignite, the occupants of the accommodation above are at particular risk, especially if sleeping. Quite apart from the flames being a hazard, there is a very great possibility of residents being overcome by smoke before the alarm is raised and they can be evacuated.
The floors above commercial kitchens may also house offices, which can be the sole premises of small businesses. A fire can be enough to put these out of business permanently, so not only may the food outlet fail as a result of fire, but other businesses may close and further jobs can be lost too. Even larger companies with branch or satellite offices in these locations can suffer a great deal of disruption and loss of business continuity.
Public transport
There can be an even greater impact in the case of public transport hubs such as train stations or airports, the vast majority of which have catering facilities. The constant traffic of people through these locations makes fire a very pressing danger. Not only does evacuation have security implications; it is also almost impossible to say how many people are present in a terminal. In the event of a disaster, establishing whether everyone is accounted for is not practical. Passenger lists will not tell you names or numbers of people transporting friends and family to and from the station or airport. Flights, trains and buses will also be cancelled or delayed, and this too will have a knock-on effect on personal and business activity.
Complying with legislation
Preventing these ductwork fires is astoundingly simple, through kitchen extract fire safety cleaning. Yet we still find that too few businesses that use kitchen extract ductwork apply the solution in a diligent manner. Each commercial property should, of course, have a legally responsible person appointed in accordance with Regulatory Reform (Fire Safety) Order 2005 [FSO]. Part of their legal responsibility is to ensure that kitchen grease extract systems are cleaned in accordance with the FSO to control the risk of fire and fire spread.
They will also need to make sure that cleaning is conducted in compliance with buildings insurance policies, and health and safety regulations. It is worth noting that quite apart from the risk to life and property, there is also a very real possibility that buildings insurance may be compromised if this regular ductwork cleaning is not carried out. Statistics from the Association of British Insurers have indicated that pay-outs on fires caused by improperly maintained extractor ducts totals around £65m a year. There is also a growing number of cases in which insurers have refused to pay out as a result of fires that have been made worse due to poorly cleaned ductwork.
The Building and Engineering Services (B&ES) Association publication, TR/19: Internal Cleanliness of Ventilation Systems, is an industry guide to good practice in ensuring that kitchen extract fire safety cleaning is done to a sufficiently high standard to remove this fire risk. Section 7 of this is a guidance document for controlling fire risk in kitchen extract systems. It suggests that a kitchen extract system in use for 12 to 16 hours a day should be thoroughly and effectively cleaned at least quarterly, with all the FOG deposits completely removed. Those in moderate use (six to 12 hours a day) should be cleaned half-yearly. Finally, those in light use (two to six hours a day) should be cleaned at least once a year.
Cleaning methods
This type of cleaning is a legal requirement and must be certified with post-clean photographic evidence to prove that it has been done correctly, so it is worth employing a specialist rather than a general cleaning company. The FOG deposits must be completely removed at each clean, even from the least accessible parts, so in an older extract system this can mean retrofitting access hatches at the regularly prescribed intervals to effect the initial clean and facilitate future ones. This is best done by a specialist, and this is insisted on by many insurers, as they will also help to document that cleaning process with before and after cleaning photographs.
In a new building or refurbishment, if the responsible person is able to influence the design of an extract system, there is a distinct advantage in considering its regular ongoing cleaning needs. When constructing a ductwork system, under the Construction (Design and Management) Regulations 2007 (CDM), access doors should be installed at critical points such as turns in the ductwork, so that operatives can access the system to clean thoroughly at the regular intervals prescribed under industry guidelines TR/19. There should
be inspection/cleaning access at minimum intervals of three metres throughout the length of the run of ductwork, in accordance with B&ES Association advice.
Criminal negligence
If a fire caused by fat deposits that have not been cleaned results in a fatality, the failure to clean could even result in a charge for corporate manslaughter. Even more alarming, if gross negligence manslaughter is proved when individual officers of a company by their own grossly negligent behaviour cause death, the offence is punishable by a maximum of life imprisonment.
The risk of grease fires has been well known for years, as there have been some high profile dramatic cases. In 1997 a fire at a fast food outlet at London’s Heathrow Airport caused the closure of Terminals 1, 2 and 3 for an hour while it was brought under control. Over 300 flights were cancelled and thousands of passengers were evacuated and suffered significant delays. The cause was found to be grease deposits in ductwork in the space above the food outlet.
In 2007, Grade II listed Orsett Hall, then a country house hotel, suffered a fire in its extract ductwork system. The house, which had stood in some form since 1614, was burnt to the ground and its remains had to be demolished. A new building has been constructed in similar style, but a piece of the nation’s heritage is lost forever. While this disaster may have been historic, unfortunately the problem is not.
In 2010, a fire at a burger outlet in London’s Liverpool Street Station caused a three-hour closure and the evacuation of more than 1,000 passengers. Fine cuisine causes FOG deposits just as easily as fast food. Last year no fewer than three London catering establishments, two restaurants and a fast food outlet, all suffered extract ductwork fires within a couple of weeks of warm weather in July. Warmer weather does pose a further threat as the grease deposits are warmed by the elevated temperature
of the ductwork in sunny conditions, ready to catch fire even more easily.
As recently as February, exclusive Chelsea restaurant Daphne’s, a member of the same restaurant group as The Ivy, was closed and several surrounding streets in Kensington and Chelsea were cordoned off as 20 firefighters fought a blaze in the building’s ductwork. Due to the inaccessibility of the fire raging within the restaurant’s ductwork, the fire crew took almost 12 hours to subdue it.
Fire statistics
Despite numerous serious incidents, fire statistics do not currently report the presence of FOG deposits as a contributory factor in ductwork fires. The methodology of the recording of fire statistics is currently under review and Swiftclean has launched a ‘Make Hidden Grease Visible’ campaign. This is to achieve the twin aims of altering the statistics so that they do record the presence of FOGs in ductwork fires, and to make building managers and responsible persons more aware of the pressing need to make safe cleaning a regular part of a building’s maintenance.
The campaign is requesting that the following metrics be recorded within the newly formulated fire statistics:
• evidence of fire having extended into the duct system
• evidence of fire being made significantly worst as a result of it having propagated through the duct system
• evidence of the presence of accumulated grease over 200 microns in extract ductwork (burnt or not)
• the presence of or lack of inspection access at minimum intervals of three metres, in accordance with B&ES Association advice
• documented evidence (with photographic evidence) of recent kitchen extract fire safety cleaning, in compliance with TR/19 of the B&ES Association guide to good practice
Political support
If the campaign succeeds – it has already had some support from MPs and an acknowledgement from the Incident Recording System Working Group for the Department for Communities and Local Government that it will consider these suggestions – these metrics will be officially recorded. This will make it possible for targets to be set for a reduction in fires made significantly worse by the presence of grease deposits in kitchen extract ductwork.
With both an official government record of the scale of the problem and greater awareness of this fire hazard, we would hope to see a reduction in the incidence of fires associated with the build-up of grease in kitchen extract ductwork systems.
Whether the statistics are changed or not, the legal obligation to ensure that kitchen extract fire safety cleaning is carried out on a regular basis should be at the front of every responsible person’s mind. Hopefully, 2014 might be the year we begin to see progress in this area, which will ultimately lead to a reduction in fires
Gary Nicholls is managing director of Swiftclean Building Services.