In a restaurant kitchen the extract works as hard as the chefs. Every service sends grease-laden vapour up into the canopy, and some of it settles in the filters, plenum and ductwork as it cools. Left alone, that grease becomes fuel for a fire, blocks airflow and starts to smell. This guide covers what a proper clean includes, how often you’ll need one and how to plan it so you don’t lose a single cover.
What a full clean covers
A TR19® Grease clean covers the whole system, not just the parts you can see. That means:
- the canopy, inside and out, and the grease filters
- the plenum behind the filters
- horizontal duct runs and vertical risers
- the extract fan and its housing
- attenuators, where fitted, and the discharge
Ductwork is reached through access panels. Grease is removed by hand scraping and with degreasers, hot water or steam, depending on the deposit. If parts can’t be reached, they should be recorded on the report, so you know exactly what was and wasn’t cleaned. Our guide to canopy-only versus full cleans explains why this matters.
How often a restaurant needs cleaning
BESA gives minimum cleaning intervals based on how many hours a day the kitchen is in use: every 3 months for heavy use (12 to 16 hours a day), every 6 months for moderate use (6 to 12 hours) and every 12 months for light use (2 to 6 hours) (BESA). Many restaurants serving lunch and dinner fall into the moderate or heavy bands.
These are minimums. What you cook matters too. Grills, woks, fryers and charcoal produce more grease than steaming or baking. Grease thickness readings tell you the real picture: BESA says grease shouldn’t exceed a mean of 200 microns between cleans, and 500 microns or more anywhere needs spot cleaning straight away. See how often to clean a kitchen extract.
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.
Fitting it around service
Extract cleaning happens when the kitchen is closed. For most restaurants that means overnight after the last cover, early morning before prep, or on the day you’re shut. Cooking equipment is switched off and allowed to cool, the kitchen is sheeted to protect surfaces, and the grease and water from cleaning are contained and taken away. Our guide to overnight extract cleaning explains how keys, alarms and handover usually work.
Daily and weekly habits that help
- Clean or swap grease filters regularly. Clogged filters slow extraction and push more grease into the duct. See our grease filter guide.
- Wipe the canopy and empty grease channels and cups.
- Never run the range without filters in place.
- Report changes: louder fans, smoke hanging in the kitchen or grease dripping from the canopy are all warning signs.
Make these jobs part of the closing checklist, with a name against each one. That way they don’t slip when the kitchen is short-staffed. See signs your extract needs cleaning for more to watch for.
The paperwork to keep
After each clean you should receive a certificate and a report showing what was cleaned, grease readings, any areas that couldn’t be reached, photos and the recommended next clean date. Keep them together in your maintenance log for your insurer, fire risk assessor and EHO. Duct Doctor provides a TR19® certificate and a before-and-after photo report with every clean, and we work evenings, overnight and weekends across London and the South East. See our restaurants and pubs page.
Quick answers
Do we need to close for the clean?
No service is lost if the clean is booked for when you’re closed, such as overnight or before prep.
How long does a clean take?
It depends on the size of the system and how much grease there is. A survey first gives you a clear plan.
Can we stay on site?
Usually yes, but the kitchen itself needs to be clear while the team works.
Related services
More advice
- How Often Should a Kitchen Extract Be Cleaned?
- Overnight Kitchen Extract Cleaning: What to Expect
- Canopy-Only Cleaning vs a Full TR19 Clean
- TR19 Certificates: What They Should Show
- 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.