One of the most overlooked fire risks across a number of industry sectors is the hidden fat, oil and grease deposits which naturally accumulate in the extract systems of commercial kitchens. The second edition of the industry’s leading guidance document TR/19: Internal Cleanliness of Ventilation Systems (Second Edition 2013) which was issued by B&ES in July 2014, helps to highlight the simple measures that can help to reduce the number of fires associated with kitchen extract ductwork.
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.
Wherever there is a commercial kitchen in regular use, there will be an accumulation of fat, oil and grease, or FOG, as it is known, 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 which are deposited on the inner surfaces of the extract ductwork. A relatively thin layer, exceeding an average of 200 microns, can provide fuel and help to spread fire to other parts of the building. This equates to about half the thickness of a standard business card.
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 transfer the duct fire to the contents and structure of the building; in some cases, causing loss of the entire building. Forensic fire investigators estimate that at least 25% of kitchen fires investigated are made dramatically worse due to a failure to maintain proper cleanliness, and the subsequent presence of excess FOGs in kitchen extract ductwork.
The accumulation of FOGs in ductwork is a fairly obvious problem in the food industry, but also affects schools, prisons, hospitals, care homes, leisure centres, public transport termini and factories; any building with a commercial kitchen which uses extract ductwork.
A frequent scenario in a high street 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.
Preventing these ductwork fires is astoundingly simple, through Kitchen Extract Fire Safety Cleaning; this is a legal obligation as well as a vital measure to preserve business continuity. Each commercial property should have a legally Responsible Person appointed in accordance with the 2005 Regulatory Reform (Fire Safety) Order, and part of their legal responsibility is to ensure that kitchen grease extract systems (canopies, filters, ductwork, risers and fans) are cleaned in accordance with Fire Safety Regulations 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 Workplace (Health, Safety and Welfare) 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 regular ductwork cleaning is not carried out. Statistics from the Association of British Insurers indicate that pay-outs on fires caused by improperly maintained extractor ducts run at around £65m a year. There are also a growing number of cases in which insurers have refused to pay out in the case of fires which have been made worse due to poorly cleaned ductwork.
The second edition of TR/19 now contains tables which give exact guidance on how frequently each type of ventilation ductwork should be cleaned, according to its use. For kitchen extract ductwork, it outlines cleaning intervals depending on how many hours each day the kitchen is in use. The FOG deposits must be completely removed at each clean, including from the least accessible parts; in an older extract system this can mean retrofitting access hatches at the regularly prescribed intervals. This is best done by a specialist, many insurers insist on this, as they will also help to document that cleaning process with before and after cleaning photographs. If the kitchen operator keeps to a regular cleaning schedule and has evidence to prove it, they will keep on the right side of the law on ductwork cleaning and the management of related fire safety.
If, in a new building or refurbishment, the responsible person is able to influence the design of an extract system, there is a distinct advantage in bearing in mind its regular ongoing cleaning needs prescribed by TR/19, which advises that there should be inspection/cleaning access at minimum intervals of 3 meters throughout the length of the ductwork.
If a fire caused by fat deposits which have not been cleaned results in a fatality, the failure to clean can result in a charge for corporate manslaughter for the business. Even more alarming, if gross negligence manslaughter is proved when individual officers of a company (directors or business owners) 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 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 1997 a fire at a fast food outlet at London’s Heathrow Airport caused the closure of Terminals 1, 2 and 3 while it was brought under control. Over 300 flights were cancelled and thousands of passengers were evacuated.
In 2007, Orsett Hall, then a Grade II listed 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 was constructed in similar style, but a piece of the nation’s heritage was lost forever. This disaster may have been historic, but unfortunately the problem isn’t.
Fires are often more prevalent in warmer weather, but this is a year round hazard. In February 2014, 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 some 20 firefighters fought a blaze in the building’s ductwork. This took almost twelve hours to subdue due to the inaccessibility of parts of the building’s ductwork.
At present, this is still far too often a hidden problem, but the legal obligation to ensure that Kitchen Extract Fire Safety cleaning is carried out on a regular basis should be front of mind for every Responsible Person. Hopefully, 2019 might be the year we begin to see more awareness of the kitchen extract FOG issue and, with it, fewer serious fires.
For more information, go to www.swiftclean.co.uk
About the Author
Gary Nicholls is Managing Director of Swiftclean.
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