Commercial kitchen fires: Why grease build up is one of the biggest and most preventable risks.
Commercial kitchens are fast paced, high heat environments. With that comes an increased fire risk, particularly when grease is allowed to build up within extraction systems. While most operators are vigilant about external cleaning of the rangehood and filters, the real danger often sits out of sight, inside the ducting, fans, and discharge points of the extraction system.
Grease build up is one of the most common and preventable contributors to commercial kitchen fires. Understanding why it matters, and how to manage it properly, is essential for protecting people, property, and businesses.
Why grease is such a serious fire risk
Grease is highly flammable. Over time, cooking vapours travel through the extraction system and leave behind layers of grease on internal surfaces. This build up can occur well beyond the visible hood and filters, accumulating deep inside ducting and exhaust fans.
When exposed to heat, sparks, or open flame, these grease deposits can ignite rapidly. Because they are contained within the extraction system, fires can spread quickly and are often difficult to detect until significant damage has already occurred.
This is why extraction systems are included in fire safety and compliance requirements. They are not just about air quality or odour control. They play a critical role in reducing fire risk.
The hidden nature of the problem
One of the challenges with extraction system maintenance is that much of the risk is invisible. A kitchen can appear clean and well maintained on the surface, while significant grease build up exists internally. Filters may be cleaned regularly, benches wiped down, and floors scrubbed, yet grease continues to accumulate in areas that are not accessible without specialist equipment and training. This is where partial or surface level cleaning falls short.
A clean looking kitchen does not always mean a safe extraction system.
Why full system cleaning matters
A proper extraction clean addresses the entire system. This includes the hood, filters, ducting, fan, and discharge point. Each component plays a role in moving heat, smoke, and grease away from the cooking area. If any part of the system is neglected, grease continues to build and the overall fire risk remains. Full system cleaning is designed to remove these hidden fuel sources before they become dangerous. Regular, thorough maintenance also supports system performance, reduces strain on fans, and helps extend the life of the equipment.
Prevention, not blame
Kitchen fires are rarely caused by a single action. They are usually the result of gradual build up and overlooked maintenance. Taking extraction cleaning seriously is not about assigning fault. It is about prevention. Compliance standards exist to protect people and businesses and when followed properly, they reduce risk, support safe operations, and give owners confidence that they are meeting their responsibilities.
A shared responsibility
Maintaining a safe commercial kitchen environment is a shared responsibility between owners, operators, and service providers. Understanding the risks and investing in regular, professional extraction cleaning is a proactive step that protects staff, customers, and livelihoods.
New Zealand councils require commercial kitchen extraction systems to be professionally cleaned at least annually to support BWOF 12A sign off, with higher use kitchens often requiring more frequent cleaning.