Engineering Ventilation for Commercial Kitchens

Commercial kitchens produce some of the most intense thermal, humidity, and particulate loads of any environment. Strong extraction, precise make-up air, and integrated cooling are essential not only for staff comfort but for food safety, duct hygiene, and fire protection.

This article dives into the engineering principles behind professional kitchen ventilation, focusing on airflow balance, filtration, and HVAC system integration.

---

Extraction: The Primary Driver

Extraction hoods directly above cooking equipment must capture:

• grease vapour

• heat

• smoke and fumes

• moisture

• combustion products

The capture rate is defined by:

• hood type

• canopy height

• equipment power

• cookline length

• airflow velocity

Typical UK extraction rates range from 1,500 to 5,500 m³/h per canopy, depending on equipment.

Improper canopy design results in:

• grease escaping into the kitchen

• poor air quality

• odours spreading to dining areas

• increased risk of fire

---

Make-Up Air: The Most Important Yet Overlooked Component

For every cubic metre of air extracted, the same volume must enter the kitchen — otherwise negative pressure forms.

Negative pressure causes:

• hood performance collapse

• smoke recirculation

• doors slamming

• poor cooling performance

• unsafe gas appliance operation

Make-up air supply should provide 60–80% of extraction volume through:

• ceiling diffusers

• wall supplies

• fresh-air AHUs

To maintain comfort, supply air is often cooled, especially in high-output kitchens.

---

Filtration and Grease Management

Filtration levels:

1. Baffle Filters

Trap larger grease droplets; easy to clean.

2. Electrostatic Precipitators (ESP)

Capture fine grease particles using ionisation — essential for high-volume restaurants.

3. Activated Carbon Filters

Remove odours; used for urban areas or recirculation.

4. Pre-Filters

Protect coils and ducting.

Without proper filtration:

• ducts become grease-coated

• fire risk increases

• coils clog

• airflow declines

• maintenance costs spike

---

Airflow Balance and Pressure Control

Correct airflow balance ensures:

• smoke is captured

• kitchen remains safe

• conditioned air is not wasted

• comfort is stable

Engineers calculate:

• supply vs extraction ratio

• static pressure

• duct resistance

• diffuser velocities

Laminar, low-turbulence airflow reduces interference with hood capture.

---

Cooling Integration

Because extraction removes so much air, kitchens often require supplemental cooling via:

• ducted AC

• high-static indoor units

• cooled make-up air from AHU systems

Cooling must NOT:

• blow directly onto flames

• disrupt hood capture

• create turbulence

• interfere with gas equipment

This requires CFD airflow modelling in large kitchens.

---

Codes and Standards

UK standards include:

• BS EN 16282 (kitchen ventilation)

• DW/172 (HVCA kitchen ventilation systems)

• fire damper requirements

• duct cleaning intervals

Compliance protects staff, customers, and property.

---

Conclusion

Professional kitchen ventilation demands precise engineering. Extraction, make-up air, filtration, and conditioned supply must work as a unified system. When correctly designed, the kitchen remains safe, cool, odour-free, and energy-efficient. When poorly engineered — everything fails.