It’s easy to treat kitchen exhaust cleaning as a line item: book it, pay the invoice, file it. But kitchen exhaust is covered by AS 1851 (opens in a new tab), the Australian standard for servicing fire protection systems, and keeping grease from building up in it is the food business’s responsibility. A good place to start is knowing what AS 1851 actually says, and what it doesn’t.
This post is a plain-English summary of the standard as it applies to commercial kitchen exhaust: what it covers, the minimum schedule it sets, and what it leaves to other guidance.
What is AS 1851?
AS 1851, Routine service of fire protection systems and equipment, is the Australian standard for servicing fire protection systems and equipment. It covers a lot of things, including the fire and smoke control features of mechanical services, which is where kitchen exhaust sits. For kitchen exhaust it sets a minimum schedule of checks and cleans for the grease filters, the hood and plenum, the grease gutters and the exhaust duct.
The standard isn’t law on its own, but your lease, centre rules or building approval paperwork may refer to it, and some insurance policies include a condition about the exhaust being maintained, so read yours. Even where nothing points to it, it is a sensible minimum to plan around.
How often does the standard say to clean?
AS 1851 sets a minimum, not a tailored interval:
| Interval | What AS 1851 calls for |
|---|---|
| Monthly | Check the grease filters, hood, plenum and grease gutters for excessive accumulation, and check the filters are secured and undamaged |
| 12-monthly | Clean the hood and plenum, and inspect and clean the exhaust duct |
That 12-monthly clean is the floor, and AS 1851 doesn’t shorten it for a busier kitchen. For a tailored interval, the AIRAH Commercial Kitchen Exhaust Management Best Practice Guide (2022) (opens in a new tab) sets a starting point from daily cooking hours and how much grease the cooking produces: every two months for heavy frying or grilling over 16 hours a day, up to every twelve months for light use. Solid fuel cooking has its own, shorter schedule. The guide then adjusts the interval from measured grease thickness, so the average across the system never reaches 200 microns (0.2 mm), the point at which it calls for the whole system to be cleaned. It also calls for urgent cleaning of any single point that reaches 2,000 microns (2 mm), whatever the average, and for no more than 50 microns (0.05 mm) at any point after a clean. It is best practice, not law, and it is free from AIRAH.
The City of Wanneroo (opens in a new tab) and the City of Cockburn (opens in a new tab) publish exhaust hood guidelines calling for ducts to be cleaned at least every six months. They’re a guide only, so check what applies to your venue. If your lease, centre rules or insurance policy name an interval, add it to the list, and plan around the tightest one that applies. Inspections can show a kitchen needs cleaning sooner than that, but they don’t make a longer interval acceptable. The right interval depends on what you cook, how much, for how many hours a day, whether your own team keeps up the filters and grease trays between cleans, and how the system is built.
What “a clean” actually includes
A full kitchen exhaust clean is more than a wipe of the hood. It covers the whole system, from the hood to the fan discharge:
- Hood: the capture surfaces and grease gutters
- Grease filters: cleaned, exchanged or replaced, depending on type and condition
- Plenum: the space behind the filters
- Duct: horizontal runs and risers leading to the fan, reached through access panels
- Exhaust fan: impeller and housing, usually on the roof
- Fan discharge: the outlet after the fan, where the exhaust leaves the building
A shiny canopy tells you little about the duct above it. Our kitchen exhaust cleaning covers the canopy and filters, plus the duct and fan wherever we can safely reach them. If a section can’t be safely reached, we tell you in writing before any work is booked, and we never claim a section was cleaned when it couldn’t be reached.
The reporting matters as much as the cleaning
A clean you can’t show is hard to rely on. The Food Act 2008 (WA) (opens in a new tab) adopts the Food Standards Code, and Standard 3.2.2 (opens in a new tab) requires a food business to keep its fixtures, fittings and equipment free of any accumulation of grease. FSANZ’s guidance (opens in a new tab) counts ventilation ducts as fixtures and fittings, and your council’s environmental health officers enforce it. Whoever asks, whether that’s the council, your landlord or your insurer, these are the records worth being able to show:
- A current maintenance schedule
- Cleaning records covering the prior 12 months
- Before and after photos for each visit
- Who did the work, and when
- Evidence that any defects flagged were actioned
Keep them together where you can find them quickly. What each party wants can differ, so ask them.
What we recommend
Put your interval in writing, book the cleans ahead and keep the records in one place. We book the work around your trading hours and agree any downtime before we book, and every clean ends with a photo report: before and after photos of what we clean, and written notes on anything needing attention.