Phoenix Journal · Ductwork
A commercial kitchen that never closes still needs its extract system cleaned to standard. Here is how a phased, out-of-hours clean removes grease to TR19® Grease without ever shutting you down.
Kitchen extract cleaning
A hospital canteen, a hotel that serves through the night, a motorway site, a care home - plenty of commercial kitchens simply never go dark, and that makes the idea of pulling the whole extract system offline for a deep clean feel impossible.
Here is the reassuring part - a full TR19® Grease clean does not need you to shut the doors. It needs planning. The system that carries grease-laden air away from your cookline is the same system that most concerns your insurer and your fire risk assessor, so letting it slide because there is never a convenient moment is the worst outcome of all. The good news is that a well-run team can clean around a live 24/7 operation in stages, using quiet windows, cook-side isolation and a sequence that keeps food service running while the ductwork is opened, scraped, verified and closed back up.
This page walks through exactly how that is done - the practical steps we take to remove grease to standard without switching your kitchen off, and how we keep the certificate honest at the end of it.
Every site is different, but the sequence below is the backbone of a no-downtime clean. The aim is simple - isolate a section, clean it properly, prove it is clean, and move on, all while the rest of your kitchen carries on cooking.
The reason phased cleaning matters so much is that fire risk does not respect a convenient schedule. Grease in a kitchen extract system is fuel, and a duct run that has been left because there was never a good time to stop is precisely the kind of concealed hazard a fire risk assessor looks for. TR19® Grease is published by BESA, the Building Engineering Services Association, and it is the specification your insurer almost certainly points to when they ask for evidence that the system is being managed. Miss it, and a grease-fuelled fire can turn into a declined claim.
That is why the honesty of the post-clean report matters as much as the scrubbing. It is depressingly common to inherit a system with a drawer full of certificates and a duct interior that tells a very different story - long horizontal runs that no cleaner ever reached because there were no access panels, signed off year after year as though they had. We have seen exactly that pattern in an audit that found years of missed cleaning hiding behind paperwork that looked perfectly in order. A no-downtime clean is only genuine if the report states, section by section, what was cleaned, what was measured and what still needs access cut into it.
Frequency is the other half of the picture. TR19® Grease ties how often you clean to how hard the kitchen works - a heavy-use site running twelve to sixteen hours a day is looking at roughly quarterly attention, a moderate kitchen at around six-monthly, and lighter use annually. A genuinely round-the-clock operation sits at the top of that range, so the case for a repeatable, phased routine that never needs a full shutdown is stronger for you than for almost anyone else. Get the access right once and each subsequent visit is quicker, cleaner and easier to slot into a quiet hour.
The canopy and filters deserve a mention of their own, because they are the first line of defence and the part most exposed to a live cookline. Keeping them clear is not just housekeeping - it feeds directly into your fire risk assessment, and pairing extract cleaning with regular canopy cleaning and fire risk assessment is the tidiest way to keep the whole cooking environment defensible on paper and in practice.
Cleaning around a 24/7 operation is not a compromise - done properly it is simply better project management. You get a system cleaned to TR19® Grease, an honest certificate that names every section, and a kitchen that never stopped serving. The one thing you should never accept is a signed-off clean that quietly skipped the parts nobody could reach, because that is the version that fails you on the night it matters.
Build the access in once, agree the zones and the quiet windows, and a live-system clean becomes a routine you can rely on rather than a disruption you keep postponing.
Questions
Yes. We split the system into zones and clean them one at a time, so only a small part of the cookline is ever isolated while the rest keeps serving. By scheduling the heaviest work into your quietest windows - often overnight or between service peaks - a genuinely 24/7 kitchen can be cleaned to TR19® Grease with no full shutdown. The trade-off is planning time, not lost trading.
TR19® Grease links frequency to how hard the kitchen works. A heavy-use site running twelve to sixteen hours a day typically needs cleaning around every three months, moderate use around every six months, and lighter use annually. A round-the-clock operation sits at the top of that range, so a repeatable phased routine that never needs a shutdown is usually the most practical way to stay compliant.
That is one of the most common problems we find, especially on older systems with no access panels along long horizontal runs. Where a section is genuinely unreachable, we cut and fit compliant removable access panels so it can be cleaned properly, and we state clearly in the report what was and was not reached. A certificate that hides missed sections is worse than useless - it can invalidate an insurance claim after a fire.
Phoenix Duct Clean · by the numbers
Phoenix surveys and cleans kitchen and building ductwork to the TR19 standard - measured, cleaned and certificated, UK-wide.