FIRE SAFETY
Why a dirty grease duct is the biggest fire risk in your kitchen
A kitchen fire rarely starts in the duct. It often ends up there, and that is exactly the problem: the moment the fire reaches the extraction system, a manageable pan fire turns into a fire running through the whole building. Below is how that works, what Dutch law has to say about it, and what your insurer expects of you.
Grease is fuel, and the duct is the route
Every time you fry or grill, grease travels into the extraction system as vapour. Where the air cools, it settles: on the filters, against the walls of the duct, on the fan impeller. Layer on layer, a little more every service.
That layer is flammable, and unlike wood or paper it does not need a flame — it ignites from heat. If it gets hot enough inside the duct, the build-up catches along its entire length at once. Not in one spot, but everywhere it sits.
And the duct is precisely what runs through the whole building: past ceilings, through floors, up to the roof. It is also an enclosed shaft with air moving through it, so the fire gets a draught behind it and nobody can reach it from the inside. That is why a fire that started in a pan can end with a building lost.
Putting it out helps only so much. Burning grease cannot be doused with water; water on hot oil evaporates explosively and spreads the fire instead. Anyone who has ever smothered a pan fire with a fire blanket knows how fast that goes — in ten metres of ducting, you cannot.
What the law says, and what it does not
There is no Dutch regulation obliging you to have your grease duct cleaned at fixed intervals. No deadline, no inspection, no stamp you have to be able to produce.
What does exist is the specific duty of care for fire-safe use, set out in article 6.4 of the Besluit bouwwerken leefomgeving (the Dutch buildings decree). It requires you to take the measures that can reasonably be expected of you to prevent situations that pose a fire hazard. Maintenance and cleaning of installations are not named separately in it.
So it is an open standard. It does not say how often, but it does say you must act on what is reasonable — and a grease layer allowed to grow for years while you know what that means is not reasonable.
The practical consequence: nobody comes to remind you, and you only find out how that standard gets interpreted once something has happened.
Careful: your HACCP plan does not cover this
Every hospitality business works with an HACCP food safety plan, usually the hygiene code published by its trade association. Many owners assume maintenance of the extraction system automatically falls under it.
It does not. HACCP is about food safety: temperatures, storage times, cross-contamination, cleaning work surfaces. It is a hygiene system, not a fire safety system. The Dutch food authority's own information about the hygiene code does not mention grease extraction ducts at all.
So your cleaning schedule can be entirely in order while ten metres of grease build-up hangs above your head. These are two separate obligations with two separate pieces of evidence, and only the first one comes up by itself during a food safety inspection.
The gebruiksmelding: does it apply to you?
If more than fifty visitors can be present in your premises at the same time, you are required to file a gebruiksmelding — a notification of use — with your municipality. For hotels the threshold is lower: it applies as soon as you provide accommodation to more than ten people commercially.
You file it through the Omgevingsloket, at the latest four weeks before you start using the premises. Your municipality can attach additional requirements that apply to your building alone.
If you are under those thresholds, you do not have to notify anyone. The duty of care under article 6.4 still applies in full — there is simply nobody dropping by unannounced to remind you of it.
What an inspector actually looks at
Once a gebruiksmelding has been filed, the municipality and the fire service may come and check whether you are using the premises safely. Such an inspection covers the whole picture, not one installation.
What comes up in any case: measures that prevent and limit fire, such as rules on smoking and open flames. Working smoke and fire detectors. Escape routes that are clear and passable, with an evacuation plan that holds up. Firefighting equipment that is present and tested, such as extinguishers and hose reels. And access for the emergency services themselves.
Your electrical installation may also be covered, through an inspection. On top of that, your municipality's local plan can add requirements of its own, for instance about access and water supply for firefighting.
What is not on such a list as a separate item is the cleaning of your grease duct. That falls under the open standard: are you preventing situations that pose a fire hazard? An inspector who finds a duct that has silted up will have something to say about it, but that is not what brought them there.
The inspector comes before, the insurer after
That is the difference that counts. An inspector visits while you can still do something about it, and tells you what needs to happen. Your insurer only looks once it has already gone wrong, and then the question is not what you intended but what you can prove.
So a passed inspection is not proof that your duct is clean, and a clean duct is no guarantee that you will pass the inspection. They are two different things, and you need both.
Your insurer is stricter than the legislator
Where the law names no interval, almost every hospitality fire policy does. The conditions state how often the extraction system must be cleaned, and that you must be able to prove it. That is not advice — it is a condition of cover.
After a fire, that is exactly what it comes down to. The question is not only what caused it, but whether you can show the maintenance was carried out. If you cannot, the insurer is entitled to reduce or refuse the payout — leaving you with the damage and without cover.
So check what your own policy says. The required interval differs per insurer and per type of kitchen, and it is one of the few documents that tells you in black and white what is expected of you.
Make sure you can prove it
You prove it with paperwork. After every cleaning you receive a cleaning certificate from us, with the date, the parts that were cleaned, what we found, and a photo report of the before and after situation. That is the document you forward when your insurer or landlord asks for it.
Keep them in order. A run of certificates with unbroken dates shows something a single sheet of paper cannot: that the maintenance was not an incident but a habit.
The certificate is evidence of work carried out — not a guarantee towards your insurer, and not an indemnity. What it does do is answer the first question anyone asks after a fire.
Not sure what condition your duct is in?
Answer three questions about your kitchen and see which cleaning interval fits. If you want to know for certain, we will come and look, free and without obligation.