If you run a commercial kitchen, sooner or later someone will ask whether your extract is cleaned to TR19. It might be your insurer, a fire officer, an environmental health officer or a landlord. The question is simple. The answer is worth understanding properly, because it affects your fire risk, your cover and your paperwork.
This guide explains what TR19® Grease is, who writes it, which parts of the system it covers, how often it says a kitchen extract should be cleaned, how grease is measured and what a proper certificate looks like. It also clears up the most common misunderstanding: TR19 is not the law, but the law still expects you to keep grease under control.
What TR19® is and who writes it
TR19® is a specification published by BESA, the Building Engineering Services Association. It sets out how ventilation systems should be inspected and cleaned. There are now two separate parts:
- TR19® Grease, a standalone specification produced in 2019 for the fire risk management of grease in kitchen extract systems.
- TR19® Air, which covers general supply and extract ventilation, such as the ductwork and air handling units in offices, schools and hospitals. Our guide to TR19® Air covers that side.
BESA explains both in its guides on kitchen extract system cleaning and ventilation hygiene standards. BESA writes the specification. It does not certify individual cleaning firms.
Which parts of the system TR19 Grease covers
The key word is system. TR19 Grease is about the whole route the cooking fumes take, not just the parts you can see. A full clean covers:
- the canopy, inside and out;
- the plenum, the space behind the grease filters;
- the grease filters themselves;
- horizontal duct runs and vertical risers;
- the extract fan and its housing;
- attenuators, where fitted;
- the discharge, where the air leaves the building.
Ductwork is reached through access panels. Where there aren’t enough panels to reach every section, the parts that couldn’t be cleaned must be recorded on the report. New panels can be fitted to close those gaps. See access panel installation for how that works, or read duct access panels explained.
Who TR19 Grease applies to
Any premises with a commercial kitchen extract is in scope. That includes restaurants and pubs, hotels, school and college kitchens, hospital and care home kitchens, staff restaurants in offices, and food production sites. The size of the kitchen changes how often it needs cleaning, not whether the specification is relevant.
If your building has a kitchen extract that serves a business, it’s worth treating TR19 Grease as the benchmark. Our sector pages for restaurants and pubs, hotels and schools and colleges explain how the work usually fits around each type of kitchen.
How often TR19 Grease says to clean
BESA gives minimum cleaning intervals based on how many hours a day the kitchen cooks. These are taken from BESA’s guidance on kitchen extract cleaning:
| Kitchen use | Typical daily cooking | Minimum cleaning interval |
|---|---|---|
| Heavy | 12–16 hours a day | Every 3 months |
| Moderate | 6–12 hours a day | Every 6 months |
| Light | 2–6 hours a day | Every 12 months |
These are minimums, not targets. A competent person’s risk assessment, backed by grease readings taken in the system, sets the real interval. A busy kitchen frying all day may need cleaning more often than the table suggests. Our guide on how often a kitchen extract should be cleaned goes into the detail.
Need it done? Duct Doctor cleans and tests kitchen extract and ventilation systems across London and the South East, with a certificate and photo report after every clean. Get a fixed quote.
How grease is measured
TR19 Grease uses measured thickness, not guesswork. Grease deposits are measured in microns (thousandths of a millimetre) using a Wet Film Thickness Test (WFTT) or a Deposit Thickness Test (DTT).
BESA’s guidance gives two figures to work to:
- grease should not exceed a mean of 200 microns between cleans;
- a reading of 500 microns or more at any point needs immediate spot cleaning.
Readings are taken before and after a clean, and they’re what turn a cleaning schedule from a guess into evidence. Read more in grease thickness testing explained or on our grease thickness testing page.
The certificate and report
A TR19 clean should end with paperwork you can show to someone else. A good post-clean certificate and report records the date, the location and the technician, what was cleaned, the grease readings, before and after photos, any sections that couldn’t be reached and the recommended date for the next clean.
BESA advises keeping certificates in your maintenance log. If an insurer or fire officer asks, that log is your evidence. Our guide to what a TR19 certificate should show lists the details to check.
Is TR19 the law?
No. BESA says plainly that TR19® itself is not legislation. The law in England and Wales is the Regulatory Reform (Fire Safety) Order 2005. It puts a duty on the “responsible person” for the premises to assess fire risks and take reasonable steps to reduce them. GOV.UK has a plain summary of workplace fire safety responsibilities.
In a commercial kitchen, a build-up of grease in the extract is an obvious fire risk. TR19 Grease is the recognised way to show you’ve dealt with it. So although the specification isn’t law, it’s the yardstick most people will measure you against. Our short guide is TR19 a legal requirement? covers this in more depth.
TR19 and your insurance
Many insurers ask for proof of regular kitchen extract cleaning, and many policies refer to TR19 by name. BESA notes that without that proof, an insurer can refuse or reduce a claim after a fire. Policies vary, so read your own wording and check what it asks for.
Keep every certificate, every photo report and a record of any inaccessible sections. Our guide to what insurers want to see explains how to build that evidence pack.
How Duct Doctor works to TR19
Duct Doctor has been cleaning kitchen extract systems since 2009. We are a BESCA Vent Hygiene Elite member, cleaning to BESA TR19® Grease. Every job follows the same order: we survey the system first, give a fixed quote, clean the whole system out of hours, then issue a TR19® certificate and a photo report. Think of it as a diagnosis, a treatment and a clean bill of health.
If you’re not sure where your system stands, our kitchen extract cleaning page explains the service, or you can get in touch for a quick quote.
Quick answers
What does TR19 stand for?
TR19® is the name of BESA’s technical specification for ventilation hygiene. TR19® Grease covers kitchen extract systems; TR19® Air covers general supply and extract ventilation.
Is TR19 cleaning a legal requirement?
TR19 itself isn’t law. The Regulatory Reform (Fire Safety) Order 2005 is. It requires the responsible person to reduce fire risk, and TR19 Grease is the recognised way to show grease in the extract is under control.
Does TR19 cover the whole duct or just the canopy?
The whole system: canopy, plenum, filters, ductwork, risers, extract fan and discharge. Any section that can’t be reached should be recorded on the report.
How often does TR19 say to clean?
BESA’s minimums are every 3 months for heavy use, 6 months for moderate use and 12 months for light use. Grease readings and a risk assessment set the actual interval.
Does BESA certify cleaning companies?
No. BESA writes the specification. Contractors can belong to BESCA’s Vent Hygiene Elite scheme, now the Vent Hygiene Register, which issues TR19 certificates through its portal.
Related services
- Kitchen extract cleaning
- TR19 inspections and grease testing
- Ductwork cleaning
- Canopy and hood cleaning
More advice
- How Often Should a Kitchen Extract Be Cleaned?
- TR19 Certificates: What They Should Show
- Kitchen Extract Insurance: What Insurers Want to See
- Is TR19 a Legal Requirement? What the Law Says
- TR19 vs DW172: What’s the Difference?
- All advice
This guide is general information. It isn’t legal or insurance advice: check your own policy wording and lease, and speak to a qualified adviser about your fire risk assessment.