Phoenix Journal · Kitchens
Compliance is cheapest when it is built into the design of your kitchen extraction, not chased afterwards with a certificate. Here is how to make a system cleanable, inspectable and verifiable from day one.
Compliance by design
When compliance is treated as a certificate to chase after the kitchen is built, you inherit every shortcut the design made - and you pay to unpick them for the life of the system.
Most compliance failures in commercial kitchen extraction are not really cleaning failures. They are design decisions that were never revisited. A duct routed with a long inaccessible run, a filter housing chosen for price rather than serviceability, an extract path that no one can physically reach with a brush or a camera - each of these quietly guarantees that grease will build somewhere you cannot measure or remove. By the time a cleaning contractor arrives, the problem is baked in.
The alternative is to design compliance in from the first drawings, so that the finished system is inherently cleanable, inspectable and verifiable. That is not a luxury for new-build projects. It is the difference between a system that passes a post-clean report every time and one that generates a list of "no access" exclusions that your insurer and your fire risk assessor will eventually notice.
Grease is flammable, and it accumulates fastest exactly where extract systems are hardest to reach. The Building Engineering Services Association (BESA) sets the benchmark here: under TR19® Grease, deposits should be controlled so they do not exceed a mean of 200 microns - roughly half the thickness of a business card - between cleans, with 500 microns treated as a point for immediate attention. You cannot hold a system to that standard if you cannot get to the metal.
It means making three questions part of the design brief rather than an afterthought: can every internal surface be reached and cleaned, can grease deposits be measured at representative points, and can the whole thing be evidenced on paper. Get those right and the ongoing compliance almost looks after itself.
In practice, designing compliance in usually comes down to a handful of concrete choices:
None of this is exotic. It is simply deciding, at the design stage, that the people who will later clean, test and certify the system are stakeholders too - not an inconvenience to be engineered around.
Four sit at the centre of a compliant commercial kitchen, and they interlock. Treating them as one design intent - rather than four separate audits - is what "designing compliance in" really describes.
BESA’s TR19® Grease is the specification for fire risk management of grease extract systems, and TR19® Air covers wider ventilation hygiene. They define how deposits are measured - by Wet Film or Deposit Thickness testing at multiple points - and how cleaning frequency is set. As a baseline, heavy-use kitchens running twelve hours or more a day point toward roughly three-monthly cleaning, moderate use toward six-monthly, and light use toward annual, though the deposit measurement always governs.
The design specification for kitchen ventilation systems, now in its 2nd edition with a 2024 addendum. This is where cleanability, access provision, materials and drainage are set. If DW/172 is followed properly at design stage, TR19® compliance later becomes achievable rather than aspirational.
Where the extract also controls exposure to hazardous substances, it is Local Exhaust Ventilation under the Control of Substances Hazardous to Health Regulations. Regulation 9 requires a thorough examination and test at least every fourteen months - a maximum interval, not a target - and records kept for at least five years. Designing in test points and clear duty data makes that examination straightforward instead of a puzzle.
The Regulatory Reform (Fire Safety) Order 2005, reinforced by the Fire Safety Act 2021, makes a responsible person accountable for managing fire risk - and an uncleanable, unverifiable grease duct is a fire risk that a design decision created. Verification matters here: it is worth understanding what "competent person" actually means before you rely on anyone’s sign-off, because the law expects the work to be done and evidenced by people who genuinely have the skills and knowledge.
Design gets you a system that can be kept compliant. Keeping it there is a matter of measuring, cleaning to the standard and holding evidence that stands up to scrutiny. The good news is that a system designed for access makes every one of those steps cheaper and faster.
Build a simple regime around the three things auditors, insurers and fire risk assessors actually look for: a measured deposit level, a clean carried out to TR19® with before-and-after evidence, and a paper trail that names who did the work and to what standard. If a report ever gets challenged, that trail is what protects you - which is exactly why compliance certificates get questioned when the underlying access and measurement were never sound. A certificate is only as strong as the system that let it be earned honestly.
Retrofitting access panels, re-routing an unreachable run or fitting measurable test points is always possible, and it is money well spent - but it costs a multiple of what the same provision would have cost on the drawing board. The lesson is consistent: compliance designed in is quiet and cheap, while compliance bolted on is loud, disruptive and never quite complete.
Questions
No, though it costs more than getting it right on the drawing board. An existing system can be retrofitted with access panels, re-routed where a run is genuinely unreachable, and fitted with measurable test points. The starting point is a thorough survey and deep clean that maps where access and measurement are currently impossible, so you can prioritise the gaps that most affect fire safety and TR19 compliance.
They cover different stages of the same system. DW/172 is the design specification that makes a kitchen ventilation system cleanable and inspectable in the first place. TR19 Grease and Air then govern how that system is cleaned and how deposits are measured through its life. Where the extract also controls hazardous substances, LEV testing under COSHH Regulation 9 adds a thorough examination at least every fourteen months. Designed together, they interlock; treated separately, they leave gaps.
Phoenix Duct Clean · by the numbers
Great equipment still needs a clean kitchen around it. Phoenix deep-cleans commercial kitchens to the standard an inspection scores - UK-wide, around your service.