DW172 and BS6173 What You Need To Know

Whether you operate a restaurant, pub, hotel, or central production kitchen, your commercial kitchen filtration, extraction and ventilation system must do more than just remove smoke and heat. It has to be safe, efficient, and fully compliant with the UK’s key industry standards - DW172 and BS 6173.These two documents form the backbone of commercial kitchen design and operation. While they’re often referenced together, they serve different purposes. Understanding how they work - and how they overlap - helps operators, consultants, and landlords make informed decisions about design, upgrades, and compliance.

What DW/172 Covers

DW/172, published by the Building Engineering Services Association (BESA), is the Specification for Kitchen Ventilation Systems. It’s the definitive reference for how commercial kitchen extract and supply systems should be designed, built, and maintained.It sets out best practice for:• Airflow and capture efficiency at cooking canopies.• Minimum filtration performance for grease and particulates.• Ductwork construction materials, thickness, and fire ratings.• Maintenance and cleaning access points (in line with TR/19).• Discharge heights and odour-control requirements.

Essentially, DW/172 defines what a safe, hygienic, and efficient kitchen extraction system looks like. It ensures contaminated air is captured, treated, and safely discharged - protecting both the kitchen and the surrounding environment.

What BS 6173 Covers

BS 6173 focuses on gas safety in catering environments. Officially titled “Installation and maintenance of gas-fired catering appliances for use in all types of catering establishments,” it provides strict guidance for how gas appliances and ventilation systems should operate together.It addresses:• Air supply rates for safe gas combustion.• Correct positioning and interlocking of gas appliances with extract fans.• Automatic shutdown procedures if airflow or extraction fails.• Safety controls, alarms, and commissioning requirements.

While DW/172 governs how air is extracted and filtered, BS 6173 governs how gas appliances safely interact with that airflow - ensuring both people and property remain protected.

How the Two Standards Work Together

DW/172 and BS 6173 are complementary, not competing.In a compliant commercial kitchen:• DW/172 ensures that grease, smoke, and odour are safely removed through effective extraction and filtration.• BS 6173 ensures that gas appliances operate safely within that ventilated environment.Together, they deliver a complete safety framework covering:• Fire prevention through effective grease removal.• Safe operation of gas appliances and air balance.• Clean, odour-free discharge to the environment.• Ease of inspection, maintenance, and insurance compliance.For consultants, combining both standards during design guarantees a system that performs reliably and meets all stakeholder expectations - from planning approval to final sign-off.

Why Compliance Matters

Non-compliance with either standard can quickly lead to serious operational, financial, and safety risks:• Fire hazards from unfiltered grease deposits in ductwork.• Health and safety breaches if gas appliances operate without adequate extraction.• Environmental complaints from odour or visible discharge.• Insurance issues where systems are not built to recognised standards.Designing, installing, and maintaining to DW/172 and BS 6173 isn’t just about ticking a box - it’s about protecting staff, customers, and business continuity.

Signs Your Commercial Kitchen May Not Be Compliant

If you’re unsure whether your current system meets both standards, look for tell-tale signs such as:• Persistent odours outside or within the building.• Heavy grease build-up in canopies or ducts.• Excessive fan noise or unstable airflow.• Lack of electrical interlock between gas and extract systems.• Missing or inadequate maintenance records.These issues usually point to design gaps, poor servicing, or outdated equipment - all of which can be resolved with proper assessment and upgrades.

How Extechnology Ensures Compliance

At Extechnology, every commercial kitchen extraction and odour control system is engineered with DW/172 and BS 6173 compliance at its core. Our multi-stage filtration solutions - including Electrostatic Precipitators (ESPs), UV-O systems, and activated carbon filters - are designed to deliver clean, safe, and odour-free discharge air.

From concept design to installation support, we help consultants and operators ensure that each system meets performance, safety, and environmental standards across restaurants, hotels, pubs, and wider hospitality facilities.

DW/172 and BS 6173 together define the gold standard for safe and efficient commercial kitchen ventilation. Understanding the difference between them - and how they complement one another - helps every operator stay compliant, protect their team, and maintain a professional reputation.A well-designed, properly maintained extraction system doesn’t just meet regulations - it creates a cleaner, safer, and more comfortable kitchen for everyone who works within it.

For more technical information and compliance insights, visit our Extechnology Blog.To explore our full range of DW/172 and BS 6173-compliant filtration systems, browse our products here.