Kitchen Extraction & Ventilation Requirements for Kenyan Commercial Kitchens

Cooking produces heat, grease-laden air, fumes, moisture and odours that build up quickly in an enclosed kitchen. Left uncontrolled, this affects staff working conditions, increases fire risk from grease build-up in ductwork, and can push heat and smells into dining areas or neighbouring units. Mechanical extraction captures these contaminants at source — at the cooking line — before they spread into the rest of the space, rather than relying on general room ventilation to dilute them.

The extraction canopy or hood is positioned directly over the cooking line to capture heat and fumes as close to the source as possible — positioning and sizing matter as much as the fan behind it. Grease filtration, typically baffle or mesh filters, sits at the canopy to strip grease from the airstream before it reaches the ductwork, reducing both fire risk and duct fouling.

Kitchen extraction ductwork is typically stainless or coated to withstand grease, moisture and cleaning agents, with duct access panels built in for cleaning and inspection. Routing is planned to keep runs as short and direct as practical, since duct length and bends affect both fan sizing and how much grease accumulates along the way.

Fan and duct sizing is matched to the heat and contaminant load of the cooking line rather than a fixed figure — an oversized system wastes energy and creates noise, while an undersized one fails to clear heat and fumes effectively. Airflow planning also has to account for how extraction interacts with the rest of the building's ventilation, so the kitchen doesn't end up pulling air (and smells) from adjoining spaces in ways that weren't intended.

Extraction removes air from the kitchen, and that air has to be replaced — without adequate make-up or fresh air supply, extraction fans struggle to perform, doors become hard to open, and outside air gets pulled in through uncontrolled gaps. A balanced design sizes fresh air supply to match extraction volume, filtering incoming air and, in some layouts, tempering it before it reaches the kitchen. This is planned together with extraction, not bolted on afterward.

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Where exhausted air is discharged matters. Discharge points are sited to avoid re-entrainment — exhaust air being pulled back into fresh air intakes, windows or neighbouring properties — and to keep grease-laden air away from occupied outdoor areas. This is a design decision made early, since it affects duct routing and fan location as much as the equipment specification does.

Kitchen layout affects where extraction and make-up air can practically be routed, and changes to layout after a system is designed often mean re-working ductwork. Noise is a related consideration — larger centrifugal fans can be intrusive in occupied spaces, so fan selection, location and acoustic treatment of ductwork are considered where the kitchen sits close to dining areas, offices or guest rooms.

Grease filters need regular cleaning, and full duct grease cleaning is needed periodically — how often depends on cooking intensity, grease loading, system condition and the operating environment, so intervals vary between a light-use office kitchen and a high-volume commercial kitchen. As a general planning reference, filter cleaning weekly to monthly and duct cleaning roughly every 3–12 months is common in busy commercial kitchens, but the appropriate schedule for your kitchen should be set from its actual cooking volume and risk category, and confirmed against applicable maintenance procedures rather than treated as a fixed rule. Fan and motor inspection and discharge point checks are part of a routine maintenance plan. Regular cleaning is one of the main ways commercial kitchens manage the fire risk that grease-laden ductwork can otherwise create.

Kitchen extraction and ventilation is a system, not a single piece of equipment — the canopy, ductwork, fan, discharge point and make-up air supply all have to work together, sized to the specific cooking line and building. Extraction and fresh air are best designed together rather than in isolation, since undersizing one undermines the other.

We don't claim to certify compliance with every applicable building, fire or health code — those requirements vary by county, building type and use, and should be confirmed with the relevant authority for your project. What we can offer is sound engineering design: sizing extraction and make-up air to the actual load, specifying grease filtration and fire-rated ducting where the application calls for it, and building in the access needed for ongoing cleaning and maintenance.

Involve a ventilation contractor early — ideally during kitchen layout planning, not after equipment is installed and the extraction is an afterthought. This is especially true for new-build kitchens, major refurbishments, or any kitchen where cooking equipment, seating capacity or the building's use is changing, since all of these affect the heat and contaminant load the system needs to handle.

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