The importance of extractor fans in commercial kitchens for fire safety

Commercial kitchens are among the highest fire-risk areas in any workplace. Heat, naked flames, cooking oils, electrical equipment and continuous use combine to create conditions where a small failure can escalate quickly. While cooking appliances often receive the most attention, one of the most critical fire safety controls in a commercial kitchen is frequently overlooked: the extractor fan and ventilation system. Extractor fans are not simply about comfort, odour control or meeting catering standards. They play a fundamental role in controlling fire risk, smoke spread and heat build-up.

Why commercial kitchens present a unique fire risk

Commercial kitchens operate very differently from domestic ones. Cooking often runs for long periods, appliances are used intensively, and oil or grease is present in significant quantities. This creates an environment where ignition sources are constant and combustible residues can accumulate quickly. When heat and grease are not effectively removed, fire risk increases in three key ways: the likelihood of ignition rises, fires grow more rapidly once started, and smoke spreads faster through the building. Extractor fans are central to controlling all three. We will now go into the detail of these.

Grease build-up and hidden fire spread

During normal cooking, grease-laden vapours are drawn into extractor hoods and ductwork. If these systems are not adequately designed, maintained or cleaned, grease accumulates inside hoods, filters and ducts. Grease is highly combustible. Once ignited, fire can travel rapidly through ductwork, spreading beyond the kitchen and into roof voids or upper floors. Many serious commercial kitchen fires do not remain confined to the cooking area for this reason. An effective extraction system, combined with regular professional cleaning, reduces the amount of combustible material present and limits the potential for unseen fire spread. This video by Fire RID demonstrates a kitchen hood/duct fire scenario and is one of the best publicly-available clips that imitates what happens when grease inside an extractor system ignites:

Heat control and ignition risk

Excess heat is a key contributor to kitchen fires. Poor extraction allows heat to build up around appliances, increasing the chance of oils reaching ignition temperature or equipment overheating. Extractor fans remove hot air at source, helping to stabilise temperatures and reduce stress on cooking equipment. This is particularly important in kitchens with gas appliances, deep-fat fryers or solid fuel equipment, where heat output can be intense and sustained. From a fire safety perspective, controlling heat is as important as controlling flames.

Smoke management and safe evacuation

In the event of a fire, smoke poses a greater risk to life than flames. Poorly ventilated kitchens can fill with smoke rapidly, reducing visibility, delaying evacuation and affecting escape routes beyond the kitchen itself. Well-designed extraction systems can slow the spread of smoke into adjacent areas, buying valuable time for occupants to evacuate and for staff to respond appropriately. While extractor fans are not a substitute for smoke control systems, their role in limiting early smoke spread should not be underestimated.

Interaction with fire alarm and suppression systems

Extractor fans also influence how other fire safety systems perform. Poor ventilation can increase nuisance fire alarms, particularly heat and smoke detectors located near kitchens. This often leads to complacency or inappropriate interference with alarm systems. Conversely, well-designed extraction helps detectors operate as intended and supports the effectiveness of kitchen fire suppression systems, such as wet chemical extinguishing systems installed within hoods. Fire safety systems do not operate in isolation. Extraction is part of a wider fire strategy.

Management, maintenance and fire risk assessment

From a legal and practical standpoint, extractor fans must be considered within the fire risk assessment for any commercial kitchen. This includes their design, condition, cleaning regime and suitability for the type of cooking taking place. A system that was adequate when installed may no longer be suitable if menus change, cooking volumes increase or equipment is replaced. Fire risk assessments should reflect how the kitchen is actually used, not how it was originally intended to operate. Regular inspection and professional cleaning of extractor systems is not just a hygiene issue. It is a core fire safety control.

What to do next

If your premises includes a commercial kitchen, your fire risk assessment should explicitly consider extractor systems, grease build-up and ventilation performance, not just cooking appliances. Fletcher Risk provides competent, practical fire risk assessments for commercial kitchens across Chester, the North West and North Wales. If you would like your current arrangements reviewed or need independent advice, please speak to our team.

Disclaimer

This article provides general fire safety information only and does not constitute legal or professional advice. Fire safety requirements vary depending on building type, cooking processes and local enforcement expectations. A competent fire risk assessment should always be carried out for individual premises.

(C) Fletcher Risk Team - 25 February 2026