Phoenix Journal · Ductwork
A proper site survey does not glance at the canopy and email a number - it opens the ductwork, measures the grease in microns and writes it all down. Here is what a good one looks like before any quote lands.
A good survey is quiet, methodical and slightly inconvenient - and that is exactly how you know it is worth having.
Picture the person who turns up to price your kitchen extract clean. If they stand in the doorway, glance at the canopy, nod at the fan on the roof and email a figure by lunchtime, you have not been surveyed - you have been guessed at. A proper survey looks different. Someone opens the access panels that already exist, notes the ones that should exist and do not, and runs a gloved finger along the inside of the horizontal duct where the grease likes to settle. They ask when the system last ran, what you cook, how many covers you turn on a busy night, and whether the fan has ever tripped on a warm evening.
None of that is showmanship. Kitchen extract cleaning in the UK is governed by TR19 Grease, the specification published by the Building Engineering Services Association (BESA) in 2019, and a survey done to that standard is measured, photographed and written down. The difference between a scribbled estimate and a real survey is the difference between a number you hope is right and a scope you can actually hold a contractor to. Here is what the good version looks like when it walks through your door.
The heart of a TR19 Grease survey is a periodic inspection carried out before any cleaning is priced or booked. Its job is not to sell you the biggest possible clean - it is to establish how much grease is in the system, where it sits, and whether your current cleaning interval is keeping the fire risk in check. That means the surveyor has to get inside the ductwork, not just look at the outside of it.
Grease is measured, in microns, using recognised test methods rather than a raw eyeball. Soft, fresh deposits are read with a Wet Film Thickness Test (WFTT); harder, carbonised build-up is read with a Deposit Thickness Test (DTT). TR19 Grease works to a mean average of 200 microns across the system as the trigger point - if the average deposit exceeds that, the full system should be cleaned - and after cleaning any remaining deposit should sit under 50 microns. A surveyor who takes readings at several points and records them is giving you evidence. One who says "looks pretty greasy, we’ll deep clean the lot" is giving you a sales pitch. If you want to understand exactly what those readings capture and why the numbers matter, it is worth reading up on what a grease loading survey measures before you compare quotes.
Extract systems fail as a whole, so they have to be surveyed as a whole. A thorough surveyor traces the full route - canopy and filters, the plenum behind them, the vertical riser, every horizontal run, the fan chamber and the discharge point on the roof. They will be looking for the pinch points where grease concentrates and fire is most likely to start and spread, and for the places where nobody can currently reach to clean. Expect them to open things, shine a light and take photographs from fixed positions so the same views can be repeated after the work.
The site visit is only half the value. A survey earns its keep in what it leaves behind - a written picture of your system that lets you compare quotes fairly, plan a realistic interval and prove to an insurer or fire officer that the risk is being managed. If all you receive is a headline price, you have no way to check whether the job you are paying for is the job your system needs.
A good survey report tells you which sections can be cleaned to standard today and which cannot be reached until access is improved. That distinction matters enormously. If a stretch of duct has no panel within reach, no honest contractor can certify it as clean - they can only certify what they could get to. A survey that quietly ignores the unreachable sections is setting you up for a certificate that does not cover your whole system. The good version flags those gaps up front, prices the extra access panels needed, and makes clear what "fully cleaned" will and will not include.
Under the Regulatory Reform (Fire Safety) Order 2005 the responsible person has to manage fire risk, and grease build-up in extract ductwork is a well understood ignition and spread risk. That is why the paperwork matters as much as the graft. A TR19 Grease clean is documented with before-and-after grease readings and photographs, and the record can be lodged on BESA’s national database so it can be produced if an insurer or authority asks for it. Insurers increasingly treat that evidence as a condition of cover, not a nicety. A survey should also recommend a cleaning frequency that reflects how hard you actually run - heavy use, solid fuel and long hours all push the interval shorter - rather than defaulting to an annual visit that may be far too infrequent for your kitchen.
When you line those things up, a good survey stops feeling like an obstacle between you and a price. It becomes the thing that protects you - from underquoting, from a certificate that does not mean what you think it means, and from a fire risk sitting quietly above the ceiling. If a survey is quick, dry and cheap to produce, be a little suspicious. The one worth having takes time, gets its hands dirty, and leaves you holding proof.
Questions
Longer than a doorway glance. A surveyor working to TR19 Grease has to open access panels, trace the full run from canopy to fan, and take grease readings at several points along the ductwork. For a typical single-kitchen system that is usually the best part of an hour or more on site, plus the time to write it up with photographs and readings afterwards. If someone quotes in five minutes without opening anything, they have estimated, not surveyed.
Many reputable contractors carry out the initial survey as part of quoting, at no charge, because it is how they scope the work accurately. What matters more than the fee is what you receive: measured grease readings in microns, photographs, a clear scope separating what can be cleaned now from what needs extra access, and a recommended interval based on your actual usage. A free number with no evidence behind it is worth far less than a thorough survey you can hold a contractor to.
Phoenix Duct Clean · by the numbers
Phoenix surveys and cleans kitchen and building ductwork to the TR19 standard - measured, cleaned and certificated, UK-wide.