Every commercial kitchen in regional NSW sits on a timebomb when it comes to fire risks, a threat that most operators just don’t know exists. It’s hiding behind the canopy, above the extractor fan filter, and inside the ductwork that runs from the cooking line all the way up to the roof exhaust. Nobody really bothers to take a second look at it during a normal shift, and when it comes to tidying up, a quick wipe-down is all it gets. And in a kitchen where the exhaust system hasn’t been properly serviced in far too long, that out-of-sight section is the most hazardous square metre in the entire building.
The Science Behind How Grease Turns into a Fire Hazard
Every time it’s cooking season, a stream of grease vapour rises right on up into the exhaust system. That vapour then condenses onto every surface it touches inside the canopy, plenum, ductwork, and fan housing, leaving behind a thin film of residue with each pass. Over time, those films start to build up on each other, forming a thick, hard layer that sticks to metal and is much harder to get rid of than pure grease. This is the core challenge that kitchen exhaust cleaning Lismore specialists address every time they service a regional venue.
And once it’s got that far, Fire and Rescue NSW‘s records show that the duct fires that get fed by that residue can reach temperatures of almost 1,000 degrees Celsius in a matter of just minutes. If that temperature warms the walls of the duct enough, it can set off nearby combustible materials in ceiling spaces, wall cavities and even roof structures, all before any fire suppression system has a chance to kick in.
It’s a pretty frightening statistic: about one in five commercial kitchen fires originates in the exhaust hood, the ductwork, or the rooftop fan. If you’re running deep fryers as part of a regular menu, the chances are that you’re building up that hazardous residue a whole lot faster than venues that do less intense cooking.
What AS 1851 Actually Requires, Actually?
The Australian Standard AS 1851-2012 ‘sets the rules’ on how often fire safety systems get treated in this country, and as you might expect kitchen exhaust systems fall within those guidelines. Now, while it doesn’t give a one-size-fits-all schedule for how often to clean the thing, it’s clear that how often you need to do it depends on just how many meals you’re churning out and what kind of kitchen you operate; a real heavy-hitter of a venue will probably need servicing every month, whereas a lower-key operation should be able to get away with a re-clean every six to twelve months.
But just doing a clean and slapping a new compliance certificate over it isn’t enough; a properly issued certificate needs to have some pretty specific stuff in it. For a start, the date and details of whoever did the service, plus some readings and photos showing what the system was like before and after. And just writing “system cleaned” on a piece of paper won’t cut it, that will never stand up to scrutiny from the fire authorities or your insurance company.
Reason Why Both Insurers and Council Filings Need This
Most insurers in NSW demand a current certificate of cleaning as one of the conditions of fire insurance. In case a claim results from a fire in a venue that does not have current cleaning certificates, the claim will be denied without looking into whether grease was the cause of the fire. NSW commercial buildings should also provide an Annual Fire Safety Statement to the council showing that fire safety systems have been maintained to the relevant Australian Standards. Kitchen exhaust systems are part of the fire safety systems, hence having a lack of documentation during filing means there is an issue with both the council and the insurance company.
As of February 2025, NSW will improve its compliance standards as per AS 1851, increasing the responsibility of the operator to demonstrate documented proactive maintenance rather than dealing with the deficiency after receiving a fire safety order.
The Part of the System That Nobody Looks At
Even though operators are cleaning filters and wiping down the outside of the canopy regularly, it does not mean they are using a compliant system. The duct, which includes the bends, horizontal runs, and the rooftop fan housing, is the place where the most dangerous grease accumulation happens. The cleaning report that only shows the status of the filter and the canopy surface does not indicate anything concerning the duct because the duct was not inspected.
Scheduling a full-system clean before AFSS filing period, checking the cleaning schedule after any menu or equipment changes, and maintaining digital records that can be accessed immediately are the ways that distinguish operators from the ones taking risks without realising it.
