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What Is TR19 Cleaning? A Practical Guide for UK Commercial Kitchens
TR19 GREASE PRACTICAL GUIDE
TR19 is the Building Engineering Services Association (BESA) specification for cleaning ventilation systems. Its kitchen section, TR19 Grease, sets how often a commercial kitchen extract must be cleaned: every 3, 6 or 12 months depending on daily cooking hours. It also sets how much grease can build up: 200 microns on average, with any point over 500 microns needing immediate cleaning. Insurers and fire-risk assessors use a TR19 post-clean report as evidence that the whole system, not just the canopy, has been cleaned. This guide explains the frequencies, the limits, who is responsible and what your report should contain.
What is TR19?
TR19 is published by BESA and is the recognised UK standard for the internal cleanliness of ventilation systems. TR19 Grease is the part written for commercial kitchen extract systems, where cooking vapour carries grease into the canopy, filters, plenum, ductwork, fan and discharge. Grease that builds up inside ductwork is a fire load: a flare-up at the hob can travel into the duct and spread through a building. TR19 Grease gives a measurable way to show the risk is under control: a set cleaning interval, a test of how thick the deposits are, and a report recording what was cleaned. The guidance does not replace the operator’s own fire-risk assessment, insurance conditions or landlord requirements.
“Compliant” should describe evidence, not a vague promise
People often use the phrase “TR19 compliance”, but it is better to ask precise questions. Which parts of the system were inspected? Which parts were cleaned? Were access limitations recorded? Does the report identify the canopy, filter housing, plenum, ducts, fan and discharge route? Were before-and-after photographs taken of the areas actually reached? A useful report should make the scope understandable to someone who was not present. It should not hide limitations behind a general statement. Where a section cannot be safely accessed, the practical next step may be a new access panel, specialist access equipment, coordination with the building manager or a separate return visit.
Why does TR19 matter for restaurants?
- Fire safety: extract ductwork fires are hard to reach and spread quickly between floors.
- Insurance: many commercial insurers require proof of regular extract cleaning. Missing records can affect a claim.
- Fire risk assessment: your assessor will ask for your latest TR19 report.
- Landlords and managing agents: leases for restaurant units often require TR19 cleaning and a copy of each report.
How often does TR19 say a kitchen extract should be cleaned?
TR19 Grease sets minimum cleaning intervals by how many hours a day the kitchen cooks. Kitchens using fryers, chargrills or woks may need cleaning more often, depending on deposit test results. For more detail, see how often kitchen extraction should be cleaned.
| Kitchen use | Cooking hours per day | Clean at least every |
|---|---|---|
| Heavy | 12–16 hours | 3 months |
| Moderate | 6–12 hours | 6 months |
| Light | 2–6 hours | 12 months |
What grease thickness triggers a TR19 clean?
TR19 Grease measures grease with a wet film Deposit Thickness Test (DTT) taken at points along the system.
- 200 microns (µm) mean average: grease should not exceed this between scheduled cleans. If it does, the system needs cleaning and the interval should be shortened.
- 500 µm at any single point: that area needs immediate spot cleaning, whatever the schedule says.
- After cleaning: the report should show readings back below the 200 µm threshold, taken from the same positions as before.
Duct Clean London takes readings before and after every clean, at the canopy, the duct runs and the fan, and records them in your report.
Sources: BESA – Kitchen extract system cleaning, BESA – Duct cleaning best practice.
The whole extraction route matters
A complete kitchen extract route can include the canopy above cooking appliances, removable metal grease filters, the filter housing, the plenum behind the filters, horizontal and vertical ductwork, changes of direction, fire-rated or enclosed sections, an internal or roof-mounted fan and the final discharge point. Each part creates different cleaning and access challenges. Straight duct may be reachable through correctly positioned panels, while a long riser or tight bend may need additional access. Roof plant can require safe roof access and agreed working arrangements. The fan may need isolation before it can be opened safely. The system should be reviewed as a connected route, because leaving a heavily contaminated concealed section untreated can undermine the value of cleaning only the easy, visible areas.
Filters, fans and repairs require different decisions
Filters also need correct identification. Reusable metal grease filters can normally be removed, degreased and refitted if they remain serviceable. Disposable carbon filters are different: they are designed to be replaced, not washed and reused. Damaged, missing or badly fitted filters may allow more grease to travel into downstream ductwork. Cleaning cannot repair defective fan motors, loose belts, damaged ductwork, poor system design or inadequate air volume. If we see an obvious issue during inspection, it should be reported separately so the appropriate ventilation engineer, electrician or equipment specialist can assess it. Keeping cleaning and repair responsibilities clear prevents misleading promises and helps the client plan the right follow-up.
How to decide when cleaning is needed
Cleaning frequency should be based on the kitchen’s actual use and risk profile, not a date chosen without context. Cooking method, oil use, operating hours, menu changes, production volume, filter maintenance and the length and shape of the duct route all affect how quickly deposits can accumulate. A high-volume kitchen using fryers or chargrills may need attention more often than a light-use preparation kitchen. Previous reports, deposit observations, fire-risk documentation and insurer or landlord requirements should be reviewed together. If a kitchen has changed its menu, extended its opening hours or increased output, the earlier cleaning interval may no longer be suitable. The aim is to create a planned schedule supported by evidence rather than waiting until grease becomes visible at the canopy or the system’s performance appears to fall.
Planning access before the visit
Before quoting, Duct Clean London asks for the site address and postcode, kitchen opening hours, clear photographs of the canopy and filters, any visible ductwork, the fan location and available roof or plant-room access. An earlier cleaning report is particularly helpful because it may identify the duct route, access panels and sections that were previously excluded. We also ask about permits, loading restrictions, alarm isolation, security arrangements and the times when cooking equipment can be switched off and allowed to cool. Good preparation reduces disruption and helps the visit focus on agreed work. Evening, overnight and weekend appointments can be discussed where building access and safe working arrangements allow.
What happens during a professional clean
On arrival, the operative should confirm the agreed system and protect the kitchen and nearby equipment. Cooking appliances must be off, cool and safe to work around. Removable items are handled according to the agreed scope. Grease is removed from reachable internal surfaces using suitable manual and mechanical methods and appropriate cleaning products. The method depends on access, deposit condition, duct geometry and the materials involved. It is not responsible to promise that every surface can be reached before the route has been inspected. If unexpected restrictions are found, they should be photographed and explained. The work area should be left orderly, and removed components should be refitted correctly where that is part of the agreed service.
Reports, photographs and honest limitations
The post-clean record is as important as clear communication before the job. A professional report should state the site, date, system cleaned, areas accessed, work completed, limitations, observations and recommended follow-up. Photographs should relate to identifiable locations rather than being an unexplained collection of close-ups. The report can support maintenance planning and conversations with the responsible person, facilities team, landlord or insurer, but it does not replace their assessments or guarantee that unrelated defects are absent. Clients should keep reports together so changes in condition, access and cleaning frequency can be reviewed over time. Consistent records are especially useful when management changes or a building contains several extract systems.
Who is legally responsible for kitchen extract cleaning?
Under the Regulatory Reform (Fire Safety) Order 2005, the “responsible person” for non-domestic premises must assess and reduce fire risks, and that includes ventilation systems. This is usually the business operator; in multi-let buildings it may be shared with the landlord or managing agent. TR19 Grease is guidance rather than law, but it is the standard assessors and insurers use to judge whether that duty has been met.
Do insurers require TR19 cleaning?
Many commercial insurers now require proof that kitchen extract ductwork is cleaned and inspected regularly. If a fire starts in the extract and there is no recent TR19 report, the insurer may refuse or reduce the claim. Check your policy wording for the required interval and keep every report.
What should a TR19 report include?
- Before and after photographs, taken from the same positions
- Deposit Thickness Test readings before and after cleaning, with locations
- A system drawing or site plan marking the areas cleaned and the access points used
- Any areas that could not be reached, with the reason and a recommended fix (for example, a new access panel)
- A written summary of the work and recommendations, including the next cleaning date
- A hygiene certificate showing the date, system location and the competent technician’s name
A report that covers only the canopy, or skips inaccessible sections without saying so, will not satisfy an assessor or an insurer. Every Duct Clean London clean comes with this full report. See our TR19 cleaning in London service.
TR19 cleaning FAQs
Is TR19 a legal requirement?
No. TR19 is BESA guidance. But the Regulatory Reform (Fire Safety) Order 2005 requires you to control fire risks, and TR19 is the standard insurers and fire-risk assessors expect you to follow.
How often should a restaurant extract be cleaned under TR19?
Every 3 months for 12–16 cooking hours a day, every 6 months for 6–12 hours, and every 12 months for 2–6 hours.
What is the TR19 grease limit?
A mean average of 200 microns between cleans. Any single reading of 500 microns or more needs immediate cleaning.
Does cleaning the canopy and filters count as TR19 cleaning?
No. TR19 covers the whole extract route: canopy, plenum, ductwork, fan and discharge. Any parts that were not cleaned must be recorded in the report.
What is a TR19 certificate?
It is the hygiene certificate issued with a post-clean report. It confirms the date, the system cleaned and the technician who did the work, backed by before-and-after photos and deposit readings.
Do you cover my area?
Duct Clean London cleans kitchen extract systems across North West, West and Central London, Zones 1–4. See areas we cover.
How Duct Clean London can help
Duct Clean London provides commercial kitchen extraction, duct, canopy, filter and fan cleaning across North West, West and Central London, including many locations within travel Zones 1–4. Our first step is to understand the property and the route before defining the work. Restaurants and coffee shops may need kitchen extract inspection and cleaning. Laundry and residential enquiries are assessed separately because their ventilation systems and risks are not the same as a grease extract serving a commercial cooking line. We do not describe every ventilation job as TR19 Grease work. The correct service depends on what the system carries, how it is used and what access is available.
Information to send for an accurate review
To request a review, send your full postcode, business or property type, contact details, opening hours, preferred dates and photographs of the visible system. Tell us about roof access, locked plant rooms, ceiling voids, previous access problems and any deadline connected to planned maintenance, an inspection or an insurer’s request. We will use that information to discuss a realistic scope. If a survey or additional information is needed before a firm quotation, we will say so. Clear facts at the start lead to clearer work on site, more useful records and a maintenance plan that matches the actual extraction system.
Discuss your extraction system with us
Call 07843 141416 or email [email protected]. We will review the details you provide and explain the next practical step.