- A commercial extract system is canopy, plenum, ductwork and fan — and the fire risk sits mainly in the last two.
- NFPA 96 Table 12.4 sets the inspection intervals: monthly for solid fuel, quarterly for high volume, semi-annually for moderate, annually for low.
- Most Dubai extract systems cannot be cleaned properly because they were installed without adequate access panels.
- Dated before-and-after photographs at each access point are the only practical evidence the middle of the run was reached.
- Hood suppression protects the cooking line, not the duct — the two are complementary rather than alternatives.
A grill restaurant in Karama had its hood cleaned every month. Spotless canopy, clean filters, photographs on file. Above the ceiling, the horizontal duct run to the roof fan had never been opened in seven years, because there were no access panels in it and nobody had asked why.
Clean hood. Seven years of grease overhead.
That distinction is the whole subject. Kitchen duct cleaning in Dubai is routinely sold and bought as hood cleaning, and the two protect against completely different things.
In short: a commercial extract system is canopy, plenum, ductwork and fan, and the fire risk sits mainly in the last two. NFPA 96 is the reference for the work. Frequency follows cooking volume and fuel type, with solid fuel needing the tightest cycle. The first question is not how often, but whether the duct has access panels at all, because without them most of the run has never been cleaned.
Hood, filters, duct, fan
A commercial kitchen extract system has four parts and they foul at different rates.
- The canopy and filters. Visible, cleaned often, the part everyone photographs.
- The plenum behind the filters. Already less accessible, already less often done.
- The ductwork. Horizontal and vertical runs to the roof. The longest, dirtiest and least inspected portion.
- The extract fan. Grease-laden impeller, frequently the worst single item in the system.
The fire risk lives in the third and fourth. A grease fire that starts at the cooking line and reaches an untreated duct has a fuel-lined route through the building's structure, and the hood suppression system that discharged over the range does not reach up there.
Our note on kitchen hood fire suppression covers the suppression side. This page is about the grease it has to work around.
QSERV surveys the full extract route, installs access where it is missing, and cleans to bare metal with before-and-after records.
What sets the frequency
Cleaning intervals follow cooking volume and fuel type rather than a single fixed rule. Dubai Municipality requires kitchen exhaust systems in licensed food establishments to be kept clean, and the UAE Fire and Life Safety Code of Practice treats grease accumulation in ductwork as a fire hazard. The international reference for the work itself is NFPA 96, the standard for ventilation control and fire protection of commercial cooking operations.
| Operation | NFPA 96 inspection interval | Why |
|---|---|---|
| Solid fuel: charcoal, wood-fired | Monthly | Solid fuel produces heavy deposits and carries live embers into the duct |
| High-volume grilling and frying | Quarterly | Continuous heavy grease loading |
| Moderate use, mixed menu | Semi-annually | Steady but lighter accumulation |
| Light or intermittent cooking | Annually | Low deposition rate |
| Twenty-four hour operations | Quarterly, as high volume | Runtime, not just cuisine, drives loading |
Those are the inspection intervals in NFPA 96 Table 12.4, and cleaning follows wherever an inspection finds deposits. The authority having jurisdiction can require tighter. The honest test is not the calendar, it is deposit thickness measured at the worst point in the system.
Access is the thing to check first
Here is the stance, from the systems we survey. Most Dubai kitchen extract systems cannot be cleaned properly, because they were installed without adequate access panels, and no cleaning contract fixes that by turning up more often.
Ductwork needs openings at intervals and at every change of direction. Without them a contractor can reach a metre or two in from each end and no further. The middle of the run stays untouched indefinitely, and the certificate issued afterwards is honest about what was cleaned and silent about what could not be.
> A cleaning certificate covers what the contractor could reach. Ask what they could not.
So the first question is not how often, it is whether the system can be cleaned at all. If access panels are missing, installing them is a one-off cost that makes every subsequent clean meaningful.
What a real clean looks like
- Pre-clean survey with deposit measurement at representative points.
- Full route cleaned: canopy, filters, plenum, all duct runs, and the fan.
- Cleaned to bare metal where achievable, not wiped to look acceptable.
- The extract fan dismantled sufficiently to clean the impeller.
- Before and after photographs at each access point, dated.
- A certificate stating what was cleaned, what was not accessible, and the next due date.
That second-to-last item matters. Photographs at each access point are the only practical evidence that the middle of the run was reached, and they are what an insurer or an inspector will find persuasive.
What the insurer asks for
Fire cover for an F&B operation increasingly depends on evidence of duct hygiene, and the questions asked after a loss are more specific than the questions asked at renewal.
Four things worth having on file before anybody needs them:
- Dated photographs at each access point, before and after. This is the only practical proof that the middle of the run was reached rather than just the ends.
- A record of what could not be accessed, and why. Counterintuitively this strengthens your position: it shows the limitation was known and documented rather than concealed.
- Deposit measurements at representative points, so cleaning frequency can be shown to follow condition rather than habit.
- The access panel history. Where panels were installed, when, and what they opened up.
Keep those with the hood suppression service records rather than separately, because the two are read together after an incident. A file showing monthly canopy cleaning and nothing about the duct invites exactly the question you do not want asked.
None of this changes what the cleaning costs. It changes what the cleaning is worth when somebody examines it.
The honest trade-off
Full duct cleaning to bare metal, with access panels installed where they are missing, costs several times a monthly hood wipe-down. For a small café running a panini press and a coffee machine, that is disproportionate and a lighter regime is the sensible answer.
For anything grilling, frying or burning solid fuel, the cheaper option is not a saving. It is a decision to leave the fuel in place and hope the suppression system, which protects the cooking line rather than the duct, is enough. Insurers increasingly ask for the evidence, and a run of monthly hood photographs with no duct records is a weak answer to that question.
Explore the Kitchen Extract & Suppression Cluster
Each page below covers one part of keeping a commercial kitchen safe in Dubai.
Related reading: restaurant fire AMC scope, and hotel and hospitality fire safety where multiple kitchens share extract routes.
Next step, and it takes ten minutes: walk the duct run from your canopy toward the roof and count the access panels. If there are none between the hood and the fan, nothing in the middle of that duct has ever been cleaned, regardless of how many certificates you hold.
