Commercial kitchen extract is the highest-consequence ventilation in most buildings. It handles grease-laden vapour at temperature, and when neglected it becomes a fire path running through the structure. It's also one of the most common inspection failures in the UAE restaurant sector.
What accumulates, and where
Cooking vapour carries aerosolised fat that condenses on every internal surface as it cools along the duct run. The hood is visible and gets wiped. The horizontal duct, the vertical riser and the fan housing are not visible and frequently don't. That's where the load builds.
Volume and cooking style drive the rate. A high-turnover kitchen doing significant frying or char-grilling loads its system far faster than a bakery or a salad-focused operation, and intervals should reflect that rather than a generic annual schedule.
Realistic cleaning intervals
- High-volume frying and grilling: every three months, sometimes more often.
- Moderate-volume mixed kitchens: every three to six months.
- Low-volume or low-grease operations: every six months.
Your licence conditions may specify the interval directly. Where they do, that governs.
Ecology units
Where exhaust discharges near occupied areas or residential neighbours, an ecology unit — electrostatic precipitator plus carbon filtration — is generally required to control grease and odour before release.
These need attention far more often than most operators expect. Electrostatic cells lose efficiency once grease-loaded, which in a busy kitchen is weeks rather than months. Carbon media saturates and stops controlling odour entirely. A neglected ecology unit produces exactly the neighbour complaints it was fitted to prevent.
What usually triggers a problem
In our experience: kitchens that clean the hood but never the duct run; ecology units serviced annually when they need quarterly attention; extract fans losing performance gradually until the kitchen is uncomfortably hot and staff prop doors open; and missing documentation at inspection even where the work was done.
Documentation
Keep the service certificate and the before-and-after photographs. Being able to produce dated evidence at inspection is as important as the cleaning itself.
Related: kitchen exhaust duct cleaning, ecology units explained, restaurant compliance.
Need this looked at?
inspection, fixed written price before any work begins, and a before/after photo report on every job.