Phoenix Journal · Ductwork
A cleaning certificate proves a visit happened, not that your extraction system is safe. Here is the difference between a kitchen that looks compliant and one that can prove it.
Kitchen compliance
A certificate on the wall is not the same thing as a duct you could put your hand inside and find clean.
Plenty of kitchens believe they are compliant right up to the moment someone measures. The paperwork is filed, a cleaning company visits on a tidy schedule, and the hood gleams at the start of every shift. Then a fire risk assessor lifts an access panel further up the run, or an insurer asks for the deposit readings behind the certificate, and the picture changes. The kitchen was compliant in the way a car with a service sticker is roadworthy - assumed, not evidenced.
It is worth being precise about what compliant means, because the word does a lot of quiet work. A kitchen is compliant when the person responsible for it can show, with evidence, that the fire risk from grease has been assessed and controlled. It is not compliant simply because a task was carried out and invoiced. The two can look identical on a noticeboard and be worlds apart the day something goes wrong.
The rules that matter here are not vague. Under the Regulatory Reform (Fire Safety) Order 2005, a named responsible person has to reduce the risk of fire and its spread on the premises, and grease in an extraction system is one of the clearest fire risks there is. The industry benchmark for managing it is BESA’s TR19® Grease specification, which sets a measurable limit for how much grease may build up between cleans. The difference between a kitchen that is genuinely compliant and one that only looks it usually comes down to which of two approaches you have quietly signed up to.
The first approach is the one most kitchens drift into. You clean the extraction system on a fixed interval - quarterly, twice a year, whatever the previous manager arranged - and you keep the certificates. It feels responsible, and compared with doing nothing it is. The trouble is that a date on a calendar knows nothing about how much grease your kitchen actually produces. A wok station running twelve hours a day loads a duct far faster than a sandwich counter, yet both might sit on the same tidy schedule because that is how the contract was written.
Calendar cleaning also tends to clean what is easy to reach. Canopy, filters, the first metre of duct - all visible, all quick. The horizontal runs, the risers and the bends where grease genuinely pools are often left untouched because there are no access panels to reach them, and nobody measured to find out. The certificate still gets issued. It simply does not describe the whole system.
There is a second, quieter problem with the calendar. Because the interval was set once and rarely revisited, it becomes invisible. Menus change, covers double, a second fryer goes in, and the schedule carries on as though nothing has, because no one is measuring and so no one has a reason to challenge it.
The second approach starts from the system, not the diary. A competent contractor surveys the full length of your ductwork, sets a cleaning frequency to match your actual usage - heavy, moderate or light - and then proves the result by measuring. Under TR19® Grease, grease should not exceed a mean average of 200 microns between scheduled cleans, roughly half the thickness of a business card. The only way to know you are inside that is to test, using a Deposit Thickness Test or a Wet Film Thickness Test at defined points along the run.
The output is not a bare certificate but a verification report: before-and-after photographs from matching positions, the deposit readings, a note of any areas that could not be reached and why, a system drawing showing what was cleaned, and a sign-off from a technician holding BESA’s Grease Hygiene Technician qualification. That is the evidence a fire risk assessor and an insurer actually want to see. It also means access panels get fitted where they are missing, so the whole system can be reached next time rather than just the easy end.
None of this is bureaucracy for its own sake. Every element of the report answers a question someone may one day ask you: how clean, how do you know, who says so, and what was done about the parts that could not be reached. Answer those in advance and an inspection stops being something to dread.
When a compliant kitchen turns out not to be, it is almost always because one of these three things was assumed rather than checked. Keep them in view and the gap closes.
None of this is exotic. A brewery taproom kitchen and a two-week street-food residency face the same physics as a full-service restaurant, which is why the same measured approach carries across formats - whether you are running a compliant kitchen inside a brewery or taproom or running a compliant pop-up kitchen. The venue changes; the 200-micron threshold and the need to prove it do not. If your current certificate cannot tell you your last deposit reading, you have your answer about which option you are really on.
Questions
A certificate confirms that a visit took place and that work was invoiced - it does not, on its own, prove your extraction system is within the fire-risk limit. Compliance under the Fire Safety Order 2005 rests on evidence that the grease risk has been assessed and controlled. If the certificate is not backed by deposit readings, before-and-after photographs and a note of what was reached, it may not stand up when an insurer or fire assessor asks the harder question.
TR19 Grease, the BESA specification for kitchen extract fire safety, states that grease should not exceed a mean average of 200 microns between scheduled cleans - roughly half the thickness of a business card. Above that level the fire risk in the ductwork rises sharply. Because you cannot judge it by eye, a contractor confirms it with a Deposit Thickness Test or Wet Film Thickness Test at set points along the run, which is what turns an assumed clean into an evidenced one.
Yes. Insurers commonly expect proof that the extraction system is cleaned and maintained to a recognised standard, and an ineffective or unverifiable regime can give them grounds to challenge or reduce a claim after a fire. Keeping measured verification reports, not just dated certificates, is part of protecting the cover you already pay for. It is also the clearest way to show the responsible person met their duty.
Phoenix Duct Clean · by the numbers
Phoenix surveys and cleans kitchen and building ductwork to the TR19 standard - measured, cleaned and certificated, UK-wide.