Why extract systems need specialist cleaning
Every commercial kitchen extraction system – canopy, filters, ductwork and fan – collects grease from cooking vapour. Filters catch some of it, but a lot passes into the ducts, where it builds up out of sight. Grease deposits are highly flammable; a flare-up on the range can ignite them, and fire can travel through the ductwork to other parts of the building.
Kitchen fires spreading through ductwork are a well-known cause of serious commercial fires. Under fire safety law, the responsible person for the premises must assess and reduce fire risks, and keeping extraction systems clean is a key part of that.
What TR19 Grease is
TR19 Grease is a specification published by BESA (the Building Engineering Services Association) for cleaning kitchen extract systems. It sets out how systems should be inspected and cleaned, how grease levels are measured, recommended cleaning frequencies, and how cleaning should be recorded and certified.
Many insurers require extraction systems to be cleaned to TR19 Grease (or an equivalent standard) and may refuse or reduce a claim after a fire if records can't be shown. Check your policy wording.
How often extract systems should be cleaned
TR19 Grease recommends cleaning frequencies based on how heavily the kitchen is used. As a general guide:
| Kitchen use | Typical hours per day | Indicative cleaning frequency |
|---|---|---|
| Heavy | 12–16 hours | Every 3 months |
| Moderate | 6–12 hours | Every 6 months |
| Light | 2–6 hours | Every 12 months |
Typical TR19 Grease cleaning frequencies by daily use. Measured grease levels and your insurer's requirements take priority.
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What a TR19 clean involves
A specialist ventilation hygiene contractor surveys the system, identifies access points, and measures grease thickness at intervals along the ductwork using a wet film thickness test. They clean the canopy, plenum, ductwork and fan, using scraping, degreasing chemicals, steam or other methods depending on the system. Additional access panels are sometimes fitted where ducts can't otherwise be reached.
Afterwards, they provide a post-clean report and certificate with before-and-after photos, grease measurements, a diagram of the system showing what was cleaned, and any areas that couldn't be accessed. Keep these records – insurers and fire safety inspectors may ask for them.
Daily and weekly tasks for kitchen staff
Between specialist cleans, kitchen staff play a big part in reducing grease build-up:
- Clean or swap canopy grease filters regularly – often daily or weekly depending on use
- Wipe the inside of the canopy and grease troughs
- Never run the cooking line without filters in place
- Keep cooking under the canopy and don't block airflow
- Report any fan noise, vibration or reduced extraction
Choosing a contractor
Look for a ventilation hygiene specialist with experience of TR19 Grease, appropriate insurance, and membership of BESA's ventilation hygiene scheme or an equivalent. Ask for sample reports, how they'll work around your opening hours, and what's included – canopy, ducts, fan and access panels. General commercial cleaning companies usually handle canopies and kitchens but subcontract ductwork to specialists.
For the rest of the kitchen and front of house, see restaurant and pub cleaning. Domestic kitchens are different – a home cooker hood is covered in our extractor hood guide.
