Commercial Kitchen Ventilation Australia | AS 1668 Guide

Commercial kitchen ventilation is one of those things you only notice when it goes wrong. A well-designed canopy and exhaust system capture and remove heat, smoke, grease and steam quietly all day; a poor one leaves staff in a hot, hazy room, deposits grease through your ducting and turns ordinary cooking into a fire hazard. In Australia, the design rules sit in the Australian Standards — specifically AS 1668 — which most owners hear about during fit-out and then never read. This guide explains commercial kitchen ventilation requirements in plain English, so you know what your designer is talking about, what your council is checking for compliance, and where the real costs sit when installing commercial exhaust hoods and ventilation systems in an Australian commercial kitchen.

⚠️ This guide is general information only. Mechanical ventilation in a commercial kitchen must be designed by a qualified ventilation engineer and certified to AS 1668 by your local council and certifier. Use this as a primer, not a substitute for professional design.

Why commercial kitchen ventilation matters

Cooking equipment doesn't just put out heat. A busy chargrill or fryer produces visible steam, fine particulate smoke, oil aerosols (grease) and combustion by-products from any gas appliance. Without a properly designed exhaust hood and ventilation system to capture and remove that air — and replace it with clean makeup air — four things start to slide:

• Staff comfort and indoor air quality. Temperatures climb fast in a poorly ventilated commercial kitchen, fatigue rises, and indoor air quality drops below what Safe Work Australia would consider reasonable. Proper ventilation systems keep indoor air quality compliant and the kitchen workable.
• Fire hazards. Grease vapour rises with the hot air and condenses in the ducting. Built-up grease is the leading cause of commercial kitchen fires — well-sized exhaust hoods and regular grease-filter cleaning exist specifically to limit how much grease ever reaches the duct.
• Equipment performance. Fridges and freezers near a hot cooking line work harder if there's nowhere for the heat to go, which costs energy and shortens their life. Combustion-fuelled cooking equipment also needs adequate makeup air to burn cleanly and efficiently.
• Compliance with Australian Standards. Councils across Australia require commercial kitchen exhaust systems to be designed and certified to AS 1668 before a venue can open or trade. Skip it and you don't get your Certificate of Occupancy.

In short, ventilation isn't a nice-to-have you bolt on at the end of the fit-out — it's part of how the kitchen works, how it stays safe, and how it lands a clean compliance sign-off.

AS 1668 explained — the two standards that matter

The Australian Standard that governs mechanical ventilation in buildings is published in parts; for commercial kitchens, two parts are doing the heavy lifting.

AS 1668.1 — fire and smoke control

AS 1668.1 sets the requirements for the fire and smoke control aspects of mechanical systems in buildings. For your kitchen, this is the part of the Australian Standards that covers how the exhaust system behaves in a fire — how the ducting is constructed and fire-rated, where dampers go, how the commercial exhaust fan is interfaced with the fire-suppression system, and what stops a flame travelling up the duct from a cooking surface. It's the layer you hope you never test.

AS 1668.2 — ventilation design and indoor air quality

AS 1668.2 sets the ventilation design and indoor air quality requirements. This is the part your engineer reaches for to calculate the extraction rate needed for each piece of cooking equipment, the makeup-air balance, the ducting sizing, and the minimum performance the canopy must deliver. It is, in practical terms, the maths behind every canopy above an Australian commercial kitchen.

The two parts are read together. AS 1668.2 sets the air-handling requirements that keep the kitchen liveable, the air quality acceptable and the equipment working; AS 1668.1 keeps the system safe under fire conditions. Both are referenced by the National Construction Code (NCC) and treated as the baseline by councils right across Australia.

The components of a compliant commercial kitchen exhaust system

A commercial kitchen ventilation system is a chain of components — change any one and the rest have to be redesigned around it. Knowing what each does helps you read a quote or a design, and makes it easier to compare options for commercial exhaust hoods and the surrounding kitchen exhaust system.

Exhaust hood (canopy)

The exhaust hood — usually a stainless steel canopy — sits directly above the cooking line and is sized to capture and remove the heat, smoke, steam and grease coming off it. Canopy size, height and overhang are all specified to catch the thermal plume rising from the equipment below. Commercial exhaust hoods generally fall into two categories:

• Type 1 hood — used over cooking equipment that produces grease-laden vapour (fryers, chargrills, woks, salamanders, ranges, ovens, griddles). Type 1 hoods include grease filters and are fire-rated; their ductwork must meet stricter fire-construction requirements.
• Type 2 hood — used over cooking equipment that produces heat and steam only, with no significant grease (combi steam ovens used only with steam, dishwashers, kettles, pasta cookers). Type 2 hoods don't need grease filters and have less onerous duct requirements.

You can't put non-grease equipment under a Type 1 hood and call it a saving — you need Type 1 wherever any grease-producing appliance lives, and Type 2 over the heat-and-steam zones (often a passthrough dishwasher area).

Grease filters

Inside a Type 1 hood, grease filters (typically stainless steel baffle filters) catch oil aerosols before they enter the duct. They must be commercial grade, removable for daily cleaning, and sized so the kitchen doesn't lose extraction performance as they load up. Cheap mesh filters in a commercial kitchen are a fire hazard waiting to happen.

Exhaust fan and ducting

The exhaust fan — usually mounted on the roof and selected for the calculated extraction volume — pulls air through the canopy, filters and ducting. The ducting is rigid (typically welded stainless or galvanised steel for grease ducts), runs the shortest practical path, and is built so it can be cleaned periodically. AS 1668.1 dictates the construction, fire rating, supports and access requirements for grease ducting in particular. Sizing the commercial exhaust fan correctly is what lets the rest of the system actually move air — undersize it and the canopy underperforms; oversize it and you waste energy and lose efficient operation.

Makeup air

You can't extract air without bringing the same volume back in. Makeup air is the supply side of the equation — outside air drawn in (usually through a tempered supply unit) to balance what the exhaust pulls out. Without enough makeup air, the kitchen goes into negative pressure: doors slam, gas appliances starve for combustion air, the back office becomes a wind tunnel, and the exhaust fan can't actually move the air it was specified for. A correctly balanced ventilation system is one of the clearest signs a ventilation engineer knew what they were doing, and it makes the canopy hoods over your cooking line genuinely effective rather than just present.

Fire suppression

For Type 1 hoods over grease-producing cooking, a wet-chemical fire suppression system integrated into the hood is now the norm in Australia. Detector heads sit above each appliance; if a flame is detected, the system shuts off the fuel supply to that appliance, trips the exhaust fan, and discharges suppressant directly into the hood and onto the cooking surfaces. This is the safety net that turns a chip-fryer flare-up from a venue-closer into a quickly contained event.

Hood sizing and exhaust rates — what your engineer is calculating

You won't size a canopy yourself, but knowing what shapes the numbers helps you sanity-check a design and compare quotes for commercial exhaust hoods.

• Overhang. The canopy should extend beyond the cooking equipment on the sides and front so the thermal plume is captured before it spills out — typically a generous overhang on each open side rather than sitting flush with the appliance edge.
• Mounting height. Higher hood = wider plume to catch and more air needed to capture it. Designers keep the hood as low as practical above the cooking surface (within clear access for staff).
• Face velocity. The average air speed across the open face of the hood. Too low and the plume escapes; too high and the system is wasteful and noisy. AS 1668.2 sets the framework; the engineer picks the right velocity for your appliance mix.
• Exhaust rate. The total volume of air (L/s or m³/s) being pulled through the hood, derived from face velocity and hood area, and validated against the heat load of the equipment below.
• Equipment mix. Chargrills, woks and open-flame ranges produce the largest plumes and drive higher extraction; combi steam ovens with closed cooking cycles produce far less. The hood is specified for the worst-case combination running together, not the average.

You'll see all of this on a mechanical ventilation drawing — and the council certifier will check it before sign-off.

How much does commercial kitchen ventilation cost in Australia?

Mechanical ventilation is one of the larger line items in any fit-out, and it varies more than any other category — because every kitchen is different.

These are planning bands — your actual cost depends on the cooking equipment, the duct run length, the building (heritage facades and high-rise tenancies cost more), fire engineering required, and whether you're starting from scratch or modifying an existing system. Get a ventilation engineer involved early; it almost always saves money to design the kitchen and the canopy together rather than retrofit one to the other.

Ventilation systems for different kitchen layouts

Not every Australian commercial kitchen ventilates the same way. Commercial exhaust hoods, the exhaust fan and the ducting are all sized to the cooking equipment beneath them, and the layout of that equipment shapes the design — so different kitchen layouts call for different ventilation systems.

• Single-line cooking suite. The most efficient ventilation system to design — one continuous canopy above a single row of cooking equipment, one exhaust fan, one main duct run. Common in cafes and small restaurants.
• Island cooking suite. Equipment in the middle of the kitchen needs a four-sided island canopy (or two back-to-back canopies) — more demanding on extraction because the thermal plume can drift on any side. Air quality and makeup-air balance become trickier here.
• Wall-mounted with back-shelf appliances. A standard canopy works well; just confirm the back-shelf appliances (salamanders, hot-holding cabinets) sit inside the canopy footprint so their plume is captured and removed too.
• Mixed-fuel layouts. Gas chargrills next to electric induction next to a combi steam oven — each appliance contributes a different thermal load, and the engineer balances the exhaust rate across the canopy zones accordingly.
• Multi-zone kitchens. Larger venues often run separate canopy hoods over the hot line, the warewashing, and the prep/finishing area — each tuned for its own extraction needs (Type 1 above grease cooking, Type 2 above steam appliances).

If your floor plan is still moving, lock the cooking-equipment positions before the ventilation engineer prices the canopy. Every move costs a redesign.

How cooking equipment choice changes your ventilation requirements

The cleanest way to control your ventilation cost is at the equipment-selection stage. A few practical levers:

• Group grease-producing equipment together. A continuous cooking line under a single Type 1 hood is more efficient than scattering fryers, chargrills and ranges across separate hood runs.
• Use combi steam ovens for low-grease cooking. Where the menu allows, a combi steam oven reduces the open-flame, high-grease footprint of the cooking line — which can shrink the Type 1 hood area.
• Match capacity to your menu. A double chargrill running half-empty produces the same plume as a full one — but a correctly sized single unit uses less extraction. Don't over-size cooking equipment "just in case".
• Plan for ovens and ranges that vent cleanly. Modern commercial ovens and ranges from our oven range are designed with sealed combustion and efficient burners — the engineer's calculations will be tighter and the running cost lower.

A good supplier will help you map the cooking line so the ventilation designer can work to a clean, efficient layout.

Maintenance and ongoing compliance

Compliance doesn't end at hand-over. Three habits keep the system safe and certified through the life of the venue:

• Daily filter cleaning. Pull out the grease filters at the end of service and run them through the dishwasher, or wash by hand with hot water and detergent. A clogged baffle filter reduces extraction and increases the grease load going into the duct.
• Quarterly checks of the hood and fan. Look (or have a service tech look) at the fan condition, the grease tray under the canopy, suppressant cylinder pressure, and obvious signs of grease build-up beyond the filters.
• Professional duct cleaning every 6–12 months. A specialist cleaner removes accumulated grease from the duct run itself — the bit you can't see. Many insurers require evidence of regular professional duct cleaning, and AS 1851 (Routine Service of Fire Protection Systems and Equipment) sets the framework for the fire-rated parts of the system. Keep the certificates on file.

Done consistently, these are inexpensive habits that prevent the kind of fire and shutdown costs that close venues for weeks.

Common ventilation mistakes — and how to avoid them

• Sizing the hood to fit the budget rather than the cooking line. Under-extracting at design stage is the most expensive mistake you can make — the kitchen never works properly and the fix is a complete redesign.
• Forgetting makeup air. A perfectly specified exhaust system without enough supply air is a system that doesn't move air. Plan both together.
• Cheap filters and ductwork. Domestic-style filters and undersized ducts may pass an initial inspection but fail under load and accelerate grease build-up. Use commercial-grade components throughout.
• Mixing Type 1 and Type 2 zones. Putting a heat-only appliance under a Type 1 hood is wasteful; putting a grease-producing appliance under a Type 2 hood is a fire risk and a compliance fail.
• Skipping the engineer. Ventilation is not a place to DIY. Even small venues need a certified design — the cost of getting one is far smaller than the cost of failing inspection or, worse, having a fire.

How to plan ventilation for a new commercial kitchen

A reliable sequence keeps the design clean and the certifier happy:

1. Finalise the cooking line. Confirm equipment, brand and capacity — your hood is sized to this list, so changes later mean rework.
2. Engage a ventilation engineer early. They produce the mechanical drawing and the AS 1668 calculations the certifier needs.
3. Co-ordinate with the building and fire engineer. Duct routing, roof-fan location, fire-rated penetrations and makeup-air paths all interact with the building works.
4. Check council requirements. Some councils have local provisions on top of AS 1668 — particularly around odour, noise and discharge location.
5. Get the suppression system designed alongside the canopy. The two must integrate at install, not be retrofitted.
6. Commission and certify. Air-balance readings, suppression sign-off, and AS 1851 documentation for ongoing fire-system servicing should be in the handover pack.

Done in this order, ventilation stops being a fit-out crisis and becomes a quiet, compliant system that runs all day.

Where Commercial Kitchen Appliances fits in

We don't design or install ventilation systems — your mechanical engineer and certifier handle that. What we do is supply the cooking equipment that drives your ventilation design, and we'll happily share product datasheets (heat output, gas input, dimensions) with your engineer so the hood and exhaust system are specified accurately.

Browse our commercial cooking equipment collection to see chargrills, salamanders, gas cooktops, deep fryers and combi steam ovens — all from Australian-supported value brands. Compare specs side by side, and we'll back it with our price-match guarantee on like-for-like commercial equipment. If you're funding the fit-out, SilverChef finance is available for eligible operators — see our payment and finance options.

Looking at the rest of your compliance picture? Our Food Safety & Compliance hub covers related operating-standard guides for Australian commercial kitchens.

Ready to spec your kitchen for clean, compliant ventilation?

We help operators across Australia choose cooking equipment that fits within real-world ventilation budgets — without compromising on the line.

• 📞 Call 1300 000 927 — talk through your cooking line and ventilation plan
• 📍 Visit us: showroom at 151 Parramatta Road, Granville NSW 2142
• 💳 SilverChef finance available for eligible operators
• ✅ Price-match guaranteed on like-for-like commercial equipment
• 📋 Datasheets on request for your mechanical engineer

Warranty varies by product (1–5 years parts and labour, manufacturer-backed) — see our warranty information for the specifics.

Frequently asked questions

What is AS 1668 in commercial kitchen ventilation?
AS 1668 is the Australian Standard that governs mechanical ventilation in buildings. For commercial kitchens, the two parts that matter are AS 1668.1 (fire and smoke control — how the duct, dampers and exhaust system behave under fire conditions) and AS 1668.2 (ventilation design and indoor air quality — the calculations that size your hood, exhaust rate and makeup air). Both must be referenced in a certified mechanical-ventilation design.

What's the difference between a Type 1 and Type 2 hood?
A Type 1 hood is used over cooking equipment that produces grease-laden vapour — fryers, chargrills, salamanders, ranges, woks and griddles. It includes grease filters, fire-rated ductwork and usually a wet-chemical suppression system. A Type 2 hood handles heat and steam only (combi steam ovens used with steam, dishwashers, kettles), with no grease filters and lighter duct requirements. The wrong hood type over the wrong equipment is both wasteful and a compliance risk.

How much does commercial kitchen ventilation cost in Australia?
Indicative bands are roughly $8,000–$15,000 for a small cafe, $15,000–$25,000 for a mid-size restaurant, and $25,000+ for large or high-volume kitchens. The drivers are the cooking equipment mix, duct run length, building constraints, the fire and suppression systems, and your council requirements — get a ventilation engineer to quote against your actual cooking line.

How often do commercial kitchen exhaust ducts need cleaning?
Professional duct cleaning is typically scheduled every 6–12 months depending on cooking volume and menu (heavy fryer use shortens the interval). Grease filters should be cleaned daily, fire-suppression systems serviced to AS 1851, and the canopy and fan checked routinely. Keep cleaning certificates on file — insurers often request them.

Do I need an engineer to design my commercial kitchen ventilation?
Yes. A compliant commercial kitchen exhaust system must be designed by a qualified mechanical/ventilation engineer and certified to AS 1668 — councils across Australia require this before issuing a Certificate of Occupancy or a building approval for a fit-out. Cooking-equipment suppliers like CKA provide datasheets to support the design, but the design itself sits with the engineer.