Extraction Fan and Duct Cleaning: Legal Requirements You Must Know

“We didn’t know it was a legal requirement.”

I hear that sentence at least once a month. A restaurant owner, a pub landlord, a care home manager. All running commercial kitchens. None of them aware that their extraction system needs regular professional cleaning by law.

It does. And the consequences of ignoring it range from insurance problems to fires.

Let me break it down.

Why Extraction Cleaning Is a Legal Requirement

Commercial kitchen extraction systems - the canopy above your cooking area, the filters, the ductwork running through your building, and the fan unit on your roof - all collect grease. Every hour that kitchen operates, grease-laden air passes through the system and leaves deposits.

Over time, those deposits build up. Grease is combustible. A grease fire inside ductwork is extremely dangerous because it’s hidden inside your building structure, it’s hard to access, and it spreads fast.

The Regulatory Reform (Fire Safety) Order 2005 requires the responsible person (that’s you, the operator) to take general fire precautions. Allowing grease to accumulate in extraction systems is a failure to manage fire risk. Your fire risk assessment should specifically address extraction system maintenance.

The HSE also expects extraction systems to be maintained under the Health and Safety at Work Act 1974 and COSHH regulations where cooking fumes are concerned.

Your insurance policy almost certainly requires extraction system maintenance. Check the small print. Many policies specifically reference periodic duct cleaning. If you have a fire and your extraction system hasn’t been professionally cleaned, your insurer may refuse the claim. We’ve seen it happen.

Environmental Health Officers check extraction systems during food hygiene inspections too. A filthy canopy and clogged filters will cost you points on your food hygiene rating.

So it’s a fire safety requirement, a health and safety requirement, an insurance condition, and a food hygiene factor. All at once.

The TR19 Standard

TR19 is the industry standard for cleaning ventilation systems. Published by the Building Engineering Services Association (BESA), it sets out how extraction systems should be cleaned, tested, and certified.

For kitchen extraction specifically, TR19 Grease (sometimes called TR19G) applies. This is the version written for grease-bearing kitchen ventilation.

A TR19-compliant clean includes:

• Full internal cleaning of ductwork, removing grease deposits
• Canopy interior cleaning
• Filter cleaning or replacement
• Fan unit cleaning
• Access panel inspection and cleaning
• Post-clean verification, usually with photographs
• A certificate confirming the system meets TR19 standards

The certificate is the important bit. It’s your evidence of compliance. Keep it on file with your fire risk assessment, your insurance documents, and your food safety management records.

Not every company that offers duct cleaning works to TR19. Ask. If they can’t provide a TR19 certificate after the clean, they’re not doing it properly.

How Often: Heavy, Moderate, and Light Use

TR19 Grease sets out cleaning frequencies based on how heavily your kitchen uses the extraction system.

Heavy Use - Every 3 Months

Kitchens cooking with solid fuel (charcoal, wood-fired ovens), high-volume wok cooking, heavy frying operations. These generate the most grease and the fastest buildup.

If you’re running a busy Chinese takeaway, a chargrilled burger restaurant, or a fish and chip shop, you’re in this category. Three-monthly cleaning isn’t optional.

Moderate Use - Every 6 Months

Standard commercial kitchens with a mix of cooking methods. Most restaurants, pub kitchens, hotel kitchens, and canteens fall here. Regular frying and grilling but not exclusively high-grease cooking.

Six-monthly is the most common frequency we deal with in Bristol’s restaurant scene. The harbour-side restaurants, the Gloucester Road independents, the Whiteladies Road bistros. Most of them fall into this bracket.

Light Use - Every 12 Months

Kitchens with minimal grease-producing cooking. Mainly reheating, light cooking, salad preparation. School kitchens, some care homes, and office canteens that do limited cooking might qualify for annual cleaning.

But be honest about your usage. If you’re cooking a full menu with frying and grilling, you’re not light use even if the kitchen is small.

When to Clean More Often

If your filters are visibly saturated with grease between scheduled cleans, your frequency isn’t high enough. If grease is dripping from the canopy or ductwork, you’re overdue. If there’s a noticeable grease smell even when the kitchen isn’t operating, the system needs attention.

Increase your frequency until the system stays clean between services.

What the Cleaning Process Involves

Here’s what happens when we clean an extraction system. No mystery to it.

Preparation

We protect the kitchen. Floors, equipment, and surfaces are covered. Cooking equipment directly below the canopy is covered or moved. We don’t want degreaser or grease residue landing on your prep surfaces.

Filter Removal

Baffle filters are removed, soaked in degreasing solution, scrubbed, rinsed, and inspected. Damaged or warped filters are flagged for replacement. Filters are your first line of defence. If they’re not working properly, more grease gets into the ductwork.

Canopy Cleaning

The canopy interior and exterior are degreased and cleaned. This includes the plenum chamber behind the filters, the grease collection channels, and any internal baffles or turning vanes.

Ductwork Access and Cleaning

Ductwork is accessed through hatches. If there aren’t adequate access panels, we’ll recommend where they should be installed. You can’t clean what you can’t reach.

Inside the duct, we remove grease deposits using scraping tools, specialist degreasers, and in some cases steam cleaning. The method depends on the duct material and the level of buildup.

Fan Unit

The extraction fan is cleaned. Grease on fan blades causes imbalance, reduces airflow, and creates a fire risk. The motor housing and surrounding area are cleaned too.

Verification and Certification

After cleaning, we photograph the system internals to show the condition post-clean. These photos are compared against the pre-clean state. You receive a TR19 certificate confirming the work.

The whole process takes 3-6 hours for a typical restaurant system. Larger or more complex installations take longer.

Honestly, the worst ones we see are the systems that have never been cleaned. Five, ten, sometimes fifteen years of grease buildup inside ductwork. Those are the ones that scare me, because they’re genuine fire risks that nobody’s even thought about.

What BCH Provides

We clean kitchen extraction systems to TR19 standard across Bristol and the South West. Every clean comes with full documentation and certification.

We can set up a scheduled maintenance programme so you never miss a clean. We’ll remind you when it’s due, book it in, and keep your records current.

We’re insured to £2 million and we’ve been doing this for 25 years.

Call 07985 505061 or email hello@bristolcleaningheroes.co.uk.