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Extraction cleaning - extent
The honest answer is all of it - canopy to fan, including every hidden run. The reason people ask is that the hidden runs are exactly the parts a cheaper clean quietly leaves out.
The short answer
TR19 Grease is a whole-system standard. It expects the entire kitchen extract run cleaned and verified - the canopy and filters, the concealed horizontal ductwork, the vertical risers, the plenum and the extract fan - with grease measured by deposit thickness before and after. Any section that cannot be reached is recorded as a partial clean, which is exactly the gap a fire and an insurer care about.
Where the grease actually is
It is natural to judge a kitchen extract system by the canopy, because that is the part you can see and wipe. But the grease that sets the fire risk is deposited along the concealed ductwork - the horizontal runs above ceilings, the vertical risers between floors, and the blades of the extract fan. That is where a flare-up on the cookline finds fuel and a route to travel.
So a clean that stops at the canopy and filters leaves the actual hazard untouched, however bright the stainless steel looks afterwards. TR19 Grease exists precisely to close that gap: it treats the system as one thing, from the point of capture to the point of discharge.
How completeness is proven
TR19 Grease does not rely on the eye. Grease is assessed by deposit thickness, taken at set points across the system, before and after cleaning, so the result is recorded rather than asserted. That measurement is what turns a clean into evidence - a figure your insurer and fire risk assessor can rely on.
It also settles arguments about extent. If a run genuinely cannot be reached, the report says so and records it as inaccessible, rather than quietly pretending it was done. A certificate that covers the whole measured system is a very different thing from one that covers only what was easy to reach.
Access is what makes it possible
The reason so many older systems get only a partial clean is access. Ductwork that runs sealed through ceiling voids and risers has no way in unless access panels are fitted. Without them, whole sections stay uncleaned and unmeasured - and the report has to say so.
Fitting compliant access panels where the run is sealed is what turns a partial clean into a full one. It is a one-off addition that every future clean then uses, so the whole system can be reached, cleaned, measured and certified each time rather than only the accessible parts.
The partial-clean trap
When one extract quote is markedly cheaper than another, the difference is frequently extent. A canopy-and-filters clean is quick and cheap; a full TR19 Grease clean of the concealed ductwork, risers and fan takes longer and costs more, because there is far more system to reach and measure.
That is fine as long as you know which you are buying. The problem is a quote that looks like a full clean, and a certificate that looks complete, covering only the visible parts. The way to avoid it is to ask what proportion of the system will be reached and measured, and to read the access notes on the certificate you are given.
What the certificate really says
A TR19 Grease certificate is only as meaningful as the extent it covers. Two certificates can both say the work was done to the standard, yet one covers the entire measured system and the other quietly covers only the sections that were accessible on the day. The difference is in the detail - the schedule of what was cleaned, the grease-depth readings, and the notes on any inaccessible runs.
This is why it pays to read a certificate rather than just file it. If it records large sections as inaccessible, your system has not really been cleaned to the standard - it has been partially cleaned and honestly documented, which still leaves the fire risk in the parts that were skipped. The certificate is evidence, and evidence of a partial clean is not the same as evidence of a compliant one.
Why partial cleans persist
Much older ductwork was installed with no thought to how it would ever be cleaned - long sealed runs, risers with no openings, fans buried behind fixed panels. For years those systems could only ever get a partial clean, because there was no way into most of them, and that became the accepted norm on a lot of premises.
The standard has not changed to accommodate that; the fix has. Retrofitting access to an old system - cutting and fitting compliant panels at sensible intervals - is what brings a historically half-cleaned system up to a full one. It is a one-off piece of work that turns every future clean from partial to complete, which is usually far cheaper over time than repeatedly paying to clean only what can be reached.
The insurer's view
From an insurer's point of view, the extent of cleaning is not a technicality - it is the whole point. If a policy requires the extract system cleaned and a fire starts in a section that was never reached, a certificate that records that section as inaccessible is unlikely to protect the claim. The uncleaned run is exactly the kind of gap a loss adjuster looks for.
So completeness is not perfectionism; it is the difference between cover that holds and cover that fails when it is needed. Cleaning the whole system, and holding a certificate that says so without a list of skipped sections, is what makes the paperwork worth having.
Questions
Yes. It expects the entire extract run cleaned and measured - canopy, filters, concealed ductwork, risers, plenum and extract fan - not just the visible canopy.
No. It leaves the concealed ductwork, risers and fan - where the fire risk actually sits - untouched. TR19 Grease treats the system as one whole, from capture to discharge.
By measuring grease deposit thickness at set points before and after cleaning, and by recording any section that could not be reached as inaccessible on the report.
Compliant access panels are fitted where the run is sealed, so every section can be reached and measured. Without them, unreachable sections are logged as a partial clean.
Often because it covers less of the system - a quick canopy-and-filters clean rather than the full ductwork, risers and fan. Ask what proportion will be reached and measured.
A certificate with before-and-after grease-depth readings, photographs of each section and an access report noting anything inaccessible.
We will survey the full run, tell you what can be reached, and clean and measure the whole system to TR19 Grease.
