Phoenix Journal · Ductwork
Most kitchen extraction quotes look identical until you ask the right questions. Here are the ones that separate a genuine TR19 Grease specialist from a jet-wash-and-run operator - before any money changes hands.
Choosing a contractor
Hiring a duct cleaner should feel less like buying a service and more like appointing someone you trust with your fire risk, your insurance cover and your kitchen's downtime.
The trouble is that most kitchen extraction quotes look identical on paper. Same promises, similar prices, the same reassuring line about being "fully compliant". What separates a genuine specialist from a jet-wash-and-run operator is not the sales pitch - it is the answers they give when you ask a few pointed questions before any money changes hands. Get those answers wrong and you can pay for a clean that leaves grease where the fire risk actually sits, then discover the paperwork will not stand up when your insurer or an environmental health officer asks to see it.
This guide sets out the questions worth asking, why each one matters, and what a good answer sounds like. None of it requires you to be a ventilation engineer. It just requires you to know what "done properly" means in the UK, so you can tell the difference between a contractor who cleans to a recognised standard and one who hopes you will never look inside the duct.
The standard question
Start with the one that reveals everything: which standard do you clean and certify to, and who signs it off? In the UK the reference point for commercial kitchen extract is TR19® Grease, published by the Building Engineering Services Association (BESA). It is the document your insurer, your fire risk assessor and any environmental health officer will expect a contractor to work to. A specialist will name it without hesitating and explain what it asks of them. If the answer is vague, or leans on the older catch-all "TR19" without the Grease distinction, treat that as your first warning.
Follow it with a question about people, not just process. TR19® Grease sets minimum competency levels for the technicians doing the work, and the recognised qualification is the BESA Grease Hygiene Technician (GHT). Only a suitably qualified person should be carrying out deposit thickness testing and issuing your post-clean verification. Ask who will actually be on site, what they hold, and whether the same person signs the report. "Our lads know what they are doing" is not an answer. A name and a qualification is.
Prove it was clean
The single biggest gap between a good clean and a bad one is verification. Anyone can spray a canopy until it shines. What matters is whether the inside of the ductwork - the long, hidden runs where grease actually feeds a fire - has been brought back to standard, and whether there is evidence to prove it. So ask directly: how will you measure and record that the system is clean, and what will I receive afterwards?
A proper answer involves testing, not just a photo of a gleaming filter. TR19® Grease expects a cleaned system to be brought below 50 microns of residual grease - roughly half the thickness of a human hair - and this is checked with a wet film thickness test for soft deposits, or a deposit thickness test where grease has carbonised into a harder crust. Between cleans, the standard works to a mean average that should not exceed 200 microns, with any localised build-up of around 500 microns or more flagged for immediate attention. You do not need to memorise those figures, but you should hear your contractor volunteer them, because a firm that measures against numbers is a firm that cannot quietly cut corners.
Then pin down the paperwork. After a compliant clean you should receive a detailed post-clean verification report that records the date, the areas cleaned, before-and-after evidence and the test results, ideally lodged on the Ventilation Hygiene Register so the certificate is traceable rather than a PDF knocked up in a spreadsheet. This is the document that does real work for you. Many insurers now make TR19-compliant cleaning an explicit condition of cover - some, such as Aviva, will only indemnify a kitchen fire where a recognised compliant provider was used - and a claim can be refused if you cannot produce a valid certificate, even when you genuinely paid someone to clean. The report is your protection, so confirm you get one before you book, not as an afterthought you have to chase. It is exactly the sort of record that appears on the list of documents an inspector will ask for, and having it filed and current turns an awkward visit into a five-minute formality.
Access, scope and honesty
A clean is only as good as the parts of the system the cleaner can actually reach. Long horizontal runs, bends and risers hide the worst grease, and if there is no way in, they simply do not get touched. Ask how you will access the full length of the ductwork, and what happens where there are no access panels? A capable contractor surveys the system first, tells you honestly which sections are currently unreachable, and offers to fit properly sealed access hatches at sensible intervals so the whole run can be cleaned now and maintained in future. Beware anyone who quotes a flat price without ever asking about your duct layout - they are pricing the bits they can see and quietly ignoring the rest.
Scope and frequency are worth settling in the same conversation. TR19® Grease ties cleaning intervals to how hard the kitchen works: broadly, heavy use of twelve to sixteen hours a day points to roughly quarterly cleaning, moderate use of six to twelve hours to around every six months, and light use to about once a year. Those are baselines, not guarantees - a competent person should set your interval from an actual assessment of your cooking style, your menu and how fast grease builds. A contractor who asks what you cook and how long your extraction runs is thinking about your real risk. One who reels off "annual" before seeing the kitchen is guessing. It is also worth timing a clean and a system check ahead of your busiest trading, so the extraction is pulling properly when it matters most; if you are planning to stress test the kitchen before a big event, the state of the ductwork belongs on that checklist.
Finally, do not forget the wider ventilation picture. If your kitchen or plant relies on local exhaust ventilation to control fumes and airborne contaminants, that system sits under COSHH and needs a thorough examination and test at least every fourteen months, carried out by a competent examiner working to the HSE's HSG258 guidance, with records kept for at least five years. A well-rounded contractor will understand where grease cleaning ends and LEV testing begins, and will not blur the two to win the job. Ask them to be clear about what your quote does and does not cover, get it in writing, and you will have hired on evidence rather than on the promise printed at the top of the page.
Questions
Ask which standard they clean and certify to, and who signs it off. A genuine specialist will name TR19® Grease from BESA without hesitating and explain that a qualified Grease Hygiene Technician carries out the work and issues the report. Vagueness here, or a reluctance to say who actually attends site, usually means the deeper answers on testing and paperwork will be just as thin.
A compliant clean should be verified by testing, not judged by how shiny the canopy looks. Ask for a post-clean verification report showing the date, the areas cleaned, before-and-after evidence and thickness test results confirming the system is below 50 microns of residual grease. Ideally the certificate is lodged on the Ventilation Hygiene Register so it is traceable rather than a document that could be typed up after the fact.
Many commercial policies now make TR19-compliant kitchen extract cleaning an explicit condition of cover, and some insurers will only indemnify a kitchen fire where a recognised compliant provider was used. If a fire is linked to grease build-up and you cannot produce a valid certificate, a claim can be refused even though you paid for a clean. That certificate is your evidence, so confirm you will receive one before you book the work.
Phoenix Duct Clean · by the numbers
Phoenix surveys and cleans kitchen and building ductwork to the TR19 standard - measured, cleaned and certificated, UK-wide.