What Is TR19 Kitchen Extract Cleaning? A Complete Guide for UK Business Owners

What Is TR19 Kitchen Extract Cleaning?

If you run a commercial kitchen in the UK, you have almost certainly been told that you need "TR19 cleaning" — usually by your insurer, your environmental health officer, or your landlord. What is rarely explained is what TR19 actually is, what a compliant clean involves, and how to tell whether the certificate you have been handed is worth anything at all.

This guide explains TR19 in plain English.

TR19 is a standard, not a law

TR19 is a technical specification published by the Building Engineering Services Association (BESA). Its full title is Guide to Good Practice: Internal Cleanliness of Ventilation Systems. The section that concerns commercial kitchens is commonly referred to as TR19 Grease.

TR19 itself is not legislation. You will not be prosecuted for "breaching TR19". What makes it matter is that it is the recognised benchmark that everyone else measures you against:

Fire safety law. The Regulatory Reform (Fire Safety) Order 2005 places a duty on the "responsible person" to carry out a suitable fire risk assessment and to take general fire precautions. Grease build-up in an extraction system is a well-recognised fire risk, and TR19 is the accepted method of demonstrating you have controlled it.
Insurance. Most commercial kitchen policies contain a condition requiring extraction systems to be cleaned at appropriate intervals by a competent contractor. Insurers overwhelmingly reference TR19 as the yardstick.
Food safety and enforcement. Environmental health officers routinely ask to see extraction cleaning records as part of a wider hygiene inspection.

In short: TR19 is voluntary in the same way that an MOT is voluntary. Nothing forces you to have one — but a great deal stops working without it.

Why grease is the whole problem

Every time you cook, airborne grease particles are drawn into the canopy, through the filters, along the ductwork and out through the fan. Filters catch some of it. The rest condenses and settles on the inside of the system as a sticky, flammable film.

That film is the hazard. It is highly combustible, it sits directly above open flames and hot surfaces, and it lines a duct that runs through the structure of your building. A flare-up at hob level can ignite deposits in the canopy, and the ductwork then behaves like a chimney — carrying fire quickly into voids and roof spaces where it is extremely difficult to fight.

This is why TR19 is measured rather than eyeballed. A duct can look acceptable through an access panel and still carry a dangerous depth of deposit.

How TR19 measures cleanliness

TR19 Grease is built around measurement, and this is the single most important thing to understand about it. Grease deposit is quantified in microns (thousandths of a millimetre), typically using a deposit thickness test taken at multiple points across the system.

A compliant clean requires that measurements are taken before and after the work, at defined points, and recorded. The post-clean figures are what prove the system was actually cleaned to standard — not simply wiped where it was visible.

The practical consequence: a TR19 certificate with no measurements in it is not evidence of anything. If a contractor hands you a single-page certificate with a logo and a date, you have a receipt, not a compliance record.

What a compliant TR19 clean actually covers

TR19 addresses the whole system, from the point where air enters to the point where it leaves the building:

System component — What the clean involves
--- — ---
Canopy and plenum — Full degrease of internal and external surfaces, including the plenum chamber behind the filters
Grease filters — Removed, deep-cleaned or replaced; filters are the first line of defence and are often the most neglected
Ductwork — Internal cleaning along the full accessible run — the part most often skipped
Access panels — Existing panels used and resealed; additional panels installed where the duct cannot otherwise be reached
Extract fan — Impeller, housing and blades degreased — a heavily fouled fan loses performance and draws more current
Discharge point — Cleaned and checked, including any external termination

The phrase to watch for is "accessible". Many older kitchens were built with ductwork that has no access panels at all, which means large stretches cannot be reached or verified. A competent contractor will tell you this and quote for fitting panels. A poor one will quietly certify only what they could reach and leave you believing the whole system is clean.

How often does it need doing?

TR19 sets frequency by how hard the kitchen works. The widely applied guideline is:

Usage level — Typical operating hours — Recommended frequency
--- — --- — ---
Heavy use — 12–16 hours per day — Every 3 months
Moderate use — 6–12 hours per day — Every 6 months
Light use — 2–6 hours per day — Every 12 months

Cooking style matters as much as hours. A fish and chip shop or a charcoal grill generates far more airborne grease per hour than a kitchen doing mostly boiling and steaming, and should be treated as heavier use than the clock alone suggests.

If you are unsure which band you fall into, a survey settles it — and your grease measurements will tell you quickly whether your current interval is right.

What you should receive afterwards

A proper TR19 job produces a Post Clean Verification Report (PCVR), not just a certificate. It should contain:

Pre-clean and post-clean grease depth measurements, by location
Photographs of each area before and after, with identifiable reference points
A schematic or description of the system, noting any areas that could not be accessed and why
The date, the technician, and the standard worked to
A clear statement of compliance, and a recommended date for the next clean

Keep these. When your insurer asks for evidence after an incident — and that is exactly when they ask — this report is what protects your claim.

The most common mistakes we see

Filter-only cleaning sold as TR19. Cleaning the filters is maintenance. It is not a TR19 clean and does not cover the ductwork where the real risk sits.
No access panels. If the duct cannot be reached, it cannot be cleaned or verified. Panels are a one-off cost that makes every future clean possible.
Certificates with no data. No measurements, no photographs, no named technician. Worthless in a claim.
The wrong interval. A heavy-use kitchen on an annual clean is accumulating risk between visits, whatever the certificate says.
Assuming the landlord handles it. In many leases the tenant is responsible for the extraction system. Check your lease rather than assume.

Getting it right

TR19 compliance is not complicated, but it is specific. You need the whole system cleaned, the results measured, and the evidence documented in a form your insurer will accept.

BlueTick Extraction Hygiene carries out TR19 kitchen extract cleaning across Peterborough, Cambridge, Northampton, Lincoln and the wider East Midlands. Every job includes full grease measurement and a photographic Post Clean Verification Report as standard.

Not sure whether your current certificate would stand up? Get in touch for a free site survey — we will assess your system, tell you honestly what condition it is in, and set out what compliance would involve.