Taking Over an F&B Unit: What to Check About the Existing Kitchen Exhaust Before You Sign

Taking over an existing F&B unit is attractive for one obvious reason: the kitchen is already there. The hood is up, the duct is run, the fan is on the roof, and the previous operator was trading. What is easy to miss is that you are also taking over whatever condition that system is in, and whatever the authorities think of it. We are called into these units regularly — usually a few weeks after the lease was signed, when the new operator has discovered the system does not do what they assumed.

This is what to look at before you sign, in the order we would look at it.

1. Was the system built for your cooking, or theirs?

This is the first question and the one that decides the most money. A ventilation system is designed around the cooking line beneath it — the equipment, its intensity, and the grease it throws off. A hood sized for a bakery or a sandwich counter is not a hood for a wok range, no matter how new it looks.

So go with your own equipment schedule in hand and compare it to what was there. If the previous operator ran a cafe and you are opening a zi char, assume the system needs redesigning rather than reusing. If your line is lighter than theirs, you are usually fine, and you may even be over-provisioned.

The equipment is what matters, not the floor area. We set out how cooking type drives the whole design in designing a compliant commercial kitchen ventilation system.

2. Open a filter and look inside the hood

You do not need to be a specialist to learn a great deal in sixty seconds. Lift out a baffle filter and look at the plenum behind it, then look up into the duct collar if you can see it.

What you are looking for:

• Grease depth. A film is normal between cleans. A layer you can scrape with a fingernail means cleaning has been skipped for a long time, and that grease is inside the duct too, not just the hood.
• The filters themselves. Missing filters, mesh where baffles should be, or gaps between filters all mean grease has been going straight into the duct.
• Rust and pitting on the hood body and the grease gutter, especially at the joints. Corroded stainless is old stainless that has been sitting wet and greasy.
• The grease gutter and cup. Overflowing or missing tells you how the kitchen was run.

A dirty hood is cleanable. What it really tells you is how likely the ductwork behind it is to be heavily loaded — and duct cleaning, not hood cleaning, is the part that costs.

3. Follow the duct, all the way to the discharge

The duct is where the risk lives, and it is the part nobody inspects before signing.

• Where does it discharge, and how high? Discharge location is a common reason a kitchen gets complaints and a common reason a system has to be changed.
• What is near the discharge? Residential windows, a neighbour's fresh-air intake, a walkway. If the previous operator had complaints, they will land on you the moment you start cooking.
• Are there access panels? A duct with no access panels cannot be properly cleaned, which means it cannot be properly maintained, which means it is a fire risk that grows.
• How many bends, and how sharp? A duct that fights the airflow will underperform whatever fan you put on it.
• Does it pass through anything it should not? Grease ductwork has fire-resistance and clearance requirements. A run that passes another tenancy or a means of escape is a serious question, not a detail.

4. Find out where the make-up air comes from

Every cubic metre you exhaust has to come back in. If nobody can tell you where the make-up air enters, the answer is usually "around the doors" — which means the kitchen sits in negative pressure, the hood loses capture efficiency, and the kitchen is hot and smoky even with the fan running.

This is the single most commonly skimped part of an existing system, and it is also the one most often blamed on the fan. Replacing a fan on a system with no make-up air makes noise, not airflow.

5. Ask for the paperwork — and notice what is missing

Ask the outgoing operator, the agent and the landlord for:

• Cleaning records. Dates, scope and who did it. A system with no records should be assumed uncleaned.
• Any approvals or submissions relating to the ventilation system, and any correspondence with the authorities.
• Any complaint history — odour or noise complaints from neighbours are the ones that resurface.
• Fire suppression records, if a system is fitted over the cooking line: the service history and whether it was matched to the equipment layout that is actually there now.
• What the landlord requires at reinstatement. If you have to remove or restore the system at the end of your lease, that is a cost to know about at the start.

Missing paperwork is not automatically a deal-breaker. It is a price negotiation — and it tells you to survey rather than assume.

6. Check the suppression system against the layout you plan

Fire suppression is designed around specific appliances in specific positions. Move a fryer, add a wok burner or change the line and the coverage may no longer match. If you are changing the cooking line at all, the suppression arrangement has to be looked at with it, not after the kitchen is built. Our scope on that is on the fire suppression systems page.

What we would do before you commit

A survey before signing costs a fraction of what discovering the problem afterwards costs, and it changes your negotiating position while you still have one. We look at the hood against your intended cooking line, open the duct at the access points, check the discharge and the make-up air arrangement, and tell you plainly which of three situations you are in:

• Clean and reuse — the system suits your line and needs a deep clean and some maintenance.
• Modify — the bones are usable, but the hood, the fan, the filtration or the make-up air needs work.
• Replace — the system was built for a different kitchen, and reusing it will cost more than starting properly.

We will tell you when it is the first one. Design and installation work is quoted after that survey — there is no price list, because there is no standard kitchen. Full scope is on kitchen exhaust design and build, and if the answer is a deep clean, that is on kitchen exhaust cleaning.

Get it surveyed before you sign

Tell us where the unit is, what you intend to cook, and when you need to open. We will arrange a survey and give you a straight answer on what you are inheriting — and if something goes wrong once you are trading, our 24/7 standby team is available.

WhatsApp BC Air 8989 2833 for a pre-lease survey →

Related reading: signs a hood is overdue a deep clean · what NEA expects · what SCDF looks for · neighbour odour complaints and how they are fixed