Commercial Kitchen Filtration Specification / Schedule

Every commercial kitchen produces a mixture of smoke, grease, and odours that must be safely extracted and treated before being released outside. Effective air filtration isn’t just about clean air - it’s essential for fire safety, hygiene, energy efficiency, and compliance with standards such as DW172 and BS 6173. This guide explains how modern commercial kitchen filtration systems work, what components are involved, and how restaurants can choose the right setup to protect their staff, customers, and reputation.

Why Commercial Kitchen Filtration Matters & Things To Consider

Cooking creates airborne grease, vapours, and fine particulates. If these aren’t captured effectively, they can cause serious issues: ductwork can become a fire hazard, odours can lead to complaints from neighbours, and HVAC systems can clog, reducing airflow and energy efficiency. A properly designed filtration system ensures that extract air is clean, odour-neutral, and compliant with environmental standards - essential for planning approvals and smooth operation.

The Airflow Path in a Restaurant Extraction System

In a typical system, air passes through several filtration stages, each performing a specific role. First, grease and mesh filters capture large grease droplets directly above cooking equipment. These stainless-steel baffle or mesh filters are designed for easy removal and cleaning. Next, an Electrostatic Precipitator (ESP) removes fine smoke and microscopic grease particles using an electrostatic charge. ESPs are highly efficient and help reduce visible smoke from cooking processes. After that, a UV-O system uses ultraviolet light to generate ozone, breaking down remaining odour molecules in the air and reducing smells from frying, grilling, and charbroiling. Finally, activated carbon filters adsorb any lingering odorous compounds, polishing the air before it is discharged to atmosphere. Together, these components create a multi-stage system that captures particles, removes odours, and keeps the extract clean and compliant.

How Electrostatic Precipitators Work

An Electrostatic Precipitator (ESP) draws contaminated air through an ionising section where particles are electrically charged. These charged particles then pass through collector plates with the opposite charge, where they adhere and are removed from the airflow.Key advantages include:• Excellent fine particle capture (up to 95–98%).• Washable collector cells for long-term use.• Lower pressure drop than disposable filters.Maintenance tip: Clean ESP cells regularly - typically every 2–4 weeks depending on usage - to maintain efficiency and prevent odour build-up.

Understanding UV-O Odour Control

UV-O systems use controlled ultraviolet light to generate ozone, which oxidises and neutralises odour-causing compounds in cooking exhaust air.

This technology is particularly effective at breaking down volatile organic compounds (VOCs) and grease vapours that carbon filters alone can’t handle. By reducing the load on downstream filters, UV-O systems also extend carbon filter lifespan. It’s important to note that ozone generation occurs only inside the duct system - never in occupied areas - ensuring safe and compliant operation.

Activated Carbon for Final Stage Filtration

Activated carbon filters trap odorous gases and vapours through adsorption on their vast internal surface area. They are most effective when used as the final stage of a multi-stage filtration system, once grease and smoke have already been removed by ESPs and UV-O systems. Regular monitoring of odour levels and pressure drop helps determine when carbon filters need replacement or regeneration to maintain optimal performance.

Compliance and Standards

In the UK, kitchen extract and filtration systems are governed by DW172 (HVCA Specification for Kitchen Ventilation Systems) and BS 6173 (Installation of Gas-Fired Catering Appliances). DW172 defines design requirements such as airflow velocities, grease filtration efficiency, and materials, while BS 6173 ensures safe ventilation for gas appliances. Designing systems with these standards in mind ensures compliance, simplifies maintenance, and provides assurance to insurers, landlords, and local authorities.

Maintenance and Servicing

Even the most advanced filtration system requires regular servicing to maintain performance. Routine tasks include cleaning ESP cells, replacing UV lamps annually, and monitoring pressure drops across carbon filters to identify when replacements are due. A full inspection every six months helps prevent issues, extend system lifespan, and keep energy use low.

Choosing the Right Filtration System

Every kitchen is different. The right filtration setup depends on cooking style, equipment type, available space, and local planning requirements. High-grease operations like frying and grilling require robust multi-stage systems with ESP and UV-O technology. Smaller cafés and bistros may only need compact modular units with combined particulate and odour filtration.

Extechnology’s systems are designed to handle every scenario - from high-capacity restaurant kitchens to compact hospitality operations - ensuring compliance, performance, and ease of maintenance.

An effective commercial kitchen filtration system protects against fire risks, controls odours, and ensures clean air discharge. It keeps staff safe, neighbours happy, and your restaurant compliant with UK regulations.

By understanding how each filtration stage works, restaurant owners and consultants can make confident, long-term decisions about system design, maintenance, and upgrades.

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To explore our full product range, including ESPs, UV-O systems, and modular filter units, browse our products here.