Kitchen Hood Exhaust Ducting — The Nextgen Mall
An external galvanised exhaust ducting riser designed and installed for a multi-storey kitchen tenant at The Nextgen Mall in Nairobi, routing cooking extraction safely clear of the building's façade and upper floors.
EMOST Techniques Ltd designed, fabricated, and installed an external galvanised exhaust ducting riser for a kitchen tenant at The Nextgen Mall in Nairobi, carrying grease-laden cooking extraction from ground level to above roofline without compromising the building's façade, structure, or fire safety.
Project overview
- ClientThe Nextgen Mall
- Client industryRetail / Commercial Property
- LocationNairobi, Kenya
- Service categoryHVAC Systems + Metal Fabrication
- ScopeExternal galvanised exhaust riser, ducting run, structural support brackets, weatherproofing
The challenge
A multi-storey commercial building with ground-floor kitchen tenants has to route grease-laden cooking extraction up and clear of the building without the ducting becoming a structural or fire-safety liability, and without ruining the mall's façade. The Nextgen Mall needed an exhaust route for one of its kitchen tenants that could carry sufficient extraction volume from ground level, run externally past several storeys, and terminate safely above roofline — all while withstanding weather exposure and vibration from continuous kitchen operation.
How the ducting system was built
Surveyed the building's exterior, existing kitchen extraction point, and available riser path to plan a route that cleared windows, signage, and structural elements at every floor.
Ducting diameter and gauge were sized to the kitchen's extraction volume, with a support bracket spacing plan calculated for wind load and vibration at a multi-storey height.
Galvanised steel ducting sections were cut, formed, and seamed in the workshop, sized to match the riser route's bends and floor-to-floor runs.
Support brackets were fixed to the building's exterior wall at calculated intervals, and ducting sections were lifted and joined floor by floor.
Joints and wall penetrations were sealed against water ingress, with flashing installed where the riser passes through any overhangs or ledges.
Extraction airflow was checked along the full run before handover to confirm the kitchen's hood was drawing correctly at the new riser height.
Unit specification
| Ducting material | Galvanised steel |
|---|---|
| Installation type | External, multi-storey riser |
| Support method | Wall-mounted brackets at calculated intervals |
| Weatherproofing | Sealed joints, flashing at wall penetrations |
| Termination | Above roofline, clear of adjacent structures |
| Client | The Nextgen Mall, Nairobi |
What was delivered
EMOST Techniques Ltd designed, fabricated, and installed a complete external exhaust ducting riser for a kitchen tenant at The Nextgen Mall, carrying cooking extraction safely from ground level to above roofline. The system was sized to the tenant's extraction volume, secured against wind load across multiple storeys, and weatherproofed at every wall penetration.
Before hiring a ducting contractor in Kenya
- Route survey first. A contractor should assess the actual building exterior and floor layout before proposing a route — not quote from a generic diagram.
- Gauge and diameter. Confirm the ducting gauge and diameter match your kitchen's actual extraction volume, not just the size of the existing kitchen hood outlet.
- Wind load on tall runs. For multi-storey risers, ask how bracket spacing and support were calculated for wind exposure.
- Weatherproofing. Confirm how wall penetrations and joints are sealed — this is where leaks typically start.
- Fire and building compliance. Confirm the ducting route and materials meet local fire-safety and building requirements for commercial kitchen extraction.
Frequently asked questions
This project shows how EMOST Techniques Ltd approaches commercial kitchen extraction for multi-tenant buildings in Kenya: a ducting route surveyed and engineered to the building itself, as delivered for The Nextgen Mall in Nairobi.
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