Phoenix Journal · Ductwork
A cladding law, on the face of it - but the Building Safety Act reset how every building proves it is safe. Here is what changed, and where your greasy kitchen extract ductwork sits inside it.
Regulation · What changed
The Building Safety Act 2022 was born from the Grenfell Tower tragedy, and although the headlines fixed on cladding and tall residential blocks, the shift in thinking it set off now reaches into places you might not expect - including the extract system above your cooking line.
If you run or maintain a commercial kitchen, it is easy to read "building safety" and assume none of it lands on your desk. The Act is aimed at higher-risk buildings, the argument goes, so unless you cook at height it is somebody else's problem. That reading is too comfortable. Some of the Act's duties really are reserved for the tallest, most complex buildings. But the broader machinery it created - a named person who is accountable, a continuous record of safety information, and a hard expectation that whoever touches a system is competent to do so - has quietly reset the standard the whole industry is measured against.
Grease-laden extract ductwork is one of the most under-managed fire risks in any building that serves hot food. The Act did not write a new rule about kitchen cleaning. What it did was change the climate around evidence, ownership and competence, and that is exactly the climate a hidden fire load thrives or dies in. This piece walks through what actually changed, and where a kitchen extract system sits inside it.
The three things that moved
Strip the Act back and three ideas do most of the work. The first is accountability. For higher-risk buildings - defined as at least 18 metres tall or seven storeys, containing two or more residential units - the Act names an Accountable Person, and where there are several, a Principal Accountable Person carrying overall responsibility. This is deliberate. Diffuse responsibility was one of the failures Grenfell exposed, so the law now insists on somebody whose name is against the safety of the structure and its systems.
The second idea is the golden thread. Under Section 88, the Accountable Person for a higher-risk building must create, hold and keep current a digital record of the information that keeps the building safe - and hand it over intact when responsibility passes on. It is not a filing cabinet of old certificates. It is meant to be a living, structured record that anyone can interrogate to understand how a building performs and what has been done to it. Failing to pass it on is a criminal matter, carrying a fine and up to two years' imprisonment.
The third, and the one that reaches furthest, is competence. From 1 October 2023 the Building Regulations gained a new dutyholder regime that applies to all regulated building work in England, not only to tall buildings. Clients, designers and contractors must plan, manage and monitor their work, cooperate with one another, and appoint only people with the skills, knowledge, experience and behaviours - or, for a company, the organisational capability - to do the job properly. Anyone who assumed those duties were reserved for higher-risk buildings has, in the words of the lawyers who read the small print, reason to reconsider.
Where the kitchen sits
Here is the part that catches operators out. The kitchen extract system, the greasy duct run above the canopy that most people never see, has always been a fire safety obligation - the Building Safety Act simply raised the temperature around how that obligation is evidenced. The duty itself sits under the Regulatory Reform (Fire Safety) Order 2005, which makes a responsible person assess and control fire risk in non-domestic premises. Accumulated grease is a textbook fire load: highly flammable, invisible until you open a panel, and capable of carrying flame the full length of a duct in seconds.
The recognised way to manage that risk is BESA's TR19 Grease specification, now a stand-alone standard for the fire risk management of grease in kitchen extraction. It sets a mean grease limit of 200 microns across the system between cleans, and it ties cleaning frequency to use: a heavy-use kitchen running twelve hours or more a day is looking at quarterly cleaning, moderate use around every six months, light use annually. Crucially, TR19 also expects access panels roughly every two metres so the whole run can actually be reached, and it expects post-clean verification - matched before-and-after photographs, deposit measurements below the threshold, drawings of what was cleaned, and a certificate naming the qualified technician who did it.
Read that alongside the Act and the alignment is hard to miss. The golden thread wants structured, current, transferable evidence rather than a folder of assurances. TR19 verification produces exactly that kind of evidence for one of a building's genuine hidden risks. The competence regime wants demonstrably capable people; TR19 defines what capable looks like for extract cleaning. Even where your kitchen sits well below any higher-risk threshold, the expectations set at the top of the industry have a way of becoming the benchmark an insurer, a fire officer or a landlord holds you to. Many insurers now ask for proof of TR19-standard cleaning before they will meet a claim, and will trace a fire back to poor maintenance to decline one.
What to do about it
The most useful thing the Act changed is not a clause you can point to. It is a shift in expectation - away from the annual scramble for a certificate and towards a continuous, honest record of how a building and its systems are actually kept safe. That is a mindset, and mindsets are contagious across a sector. The same move is playing out elsewhere: in the way building ventilation has been reassessed since the pandemic, where fresh-air performance and CO₂ monitoring became things you evidence rather than assume, and in the argument that real protection comes from a safety culture rather than a folder of documents. A dust-covered TR19 certificate from three years ago is a folder. A live schedule, matched photographs and measured deposit readings are a culture.
For a kitchen operator, the practical response is refreshingly concrete. Know who is accountable for the extract system in your building and write it down. Set a cleaning frequency that matches how hard you actually cook, not the cheapest interval you can negotiate. Insist that whoever cleans it can reach the whole run through proper access panels and hands back TR19-compliant verification you can file and, if asked, pass on. Do that and you are not just chasing a standard - you are holding evidence that stands up when a fire officer, an insurer or an incoming tenant asks the one question the Building Safety Act taught everyone to ask: can you show me?
None of this requires you to become a compliance specialist. It requires a partner who treats your ductwork as the fire risk it is and leaves you with proof, not promises. That is the whole point of the change - the burden of "trust us" has shifted to "show us", and a properly cleaned, properly documented extract system is one of the easier places to show it.
Questions
The Act's headline duties - the Accountable Person and the golden thread - apply to higher-risk buildings, meaning those at least 18 metres or seven storeys with two or more residential units. But the new dutyholder and competence rules that came in on 1 October 2023 apply to all regulated building work in England, not only tall buildings. And your extract system's fire safety duty sits under the Fire Safety Order regardless of height, so the direction of travel reaches your kitchen either way.
The golden thread is the digital, continuously updated record of safety-critical information that an Accountable Person must hold and pass on for a higher-risk building, created by Section 88 of the Act. Kitchen extract cleaning is not named in it by law, but the thinking behind it - structured, current, transferable evidence rather than a drawer of old certificates - is exactly what a good TR19 verification report provides. Treating your extract records the same way is sensible practice whether or not your building formally falls in scope.
TR19 Grease is BESA's specification for managing the fire risk of grease in kitchen extraction, setting a 200-micron mean limit and requiring photographic, measured post-clean verification. The Act did not create TR19, but it hardened the culture of evidence and competence that TR19 already embodies. A properly cleaned, properly documented extract system is one of the clearest ways to demonstrate the accountability and proof the Act now expects across the built environment.
Phoenix Duct Clean · by the numbers
Phoenix surveys and cleans kitchen and building ductwork to the TR19 standard - measured, cleaned and certificated, UK-wide.