Process & access
Ductwork can only be cleaned where there is a way in. With no access panels, whole lengths of duct stay sealed, greasy and uncleaned - and there is nothing to verify at the end.
The short answer
Access panels are the openings a cleaner uses to reach inside the ductwork. Without them, there is simply no way into that length of duct - so it cannot be inspected, cannot be cleaned, and the grease inside it stays where it is. TR19 Grease calls for access at a minimum of every two metres and at strategic points precisely so the whole run can be entered. Where panels are missing, the clean stops at the last opening and everything beyond it is left untouched, however good the canopy looks afterwards.
Why the gap matters
The lengths with no access are usually the concealed runs - above ceilings, in risers, across roof voids - and those are exactly the places grease builds up out of sight. Around seventy per cent of commercial kitchen fires are linked to the extract system, and it is the hidden, un-cleaned grease that carries the risk, not the visible canopy. A system cleaned only where it opens leaves the fire load in place in the very areas nobody can see.
There is a compliance problem too. A clean has to be verified to below fifty microns and documented in a report, but you can only verify a surface you can reach and measure. Duct with no access cannot be checked, so it cannot honestly be signed off. A certificate that quietly covers only the accessible parts is not the same as a clean, whole system - and an insurer or fire risk assessor may treat the untouched sections as though they were never cleaned at all.
The fix
The answer to missing access is to fabricate and fit access panels so the whole system can be reached. Under DW144 they should be made of the same material as the duct, sealed against leaks and fitted with quick-release catches, and sized to the duct without weakening it - up to a maximum of 460mm by 610mm. Fitted at a minimum of every two metres and at direction changes, they turn a sealed run into one that can be cleaned and, just as importantly, re-cleaned on schedule.
On fire-rated ductwork this needs extra care: a new panel must not compromise the duct's fire integrity, so it should be a certified, fire-rated panel installed with the manufacturer's or a fire specialist's guidance and the client's agreement. Done properly, adding access is a one-off that makes every future clean possible. Left undone, it means paying for cleans that can never actually reach the whole system.
Access first, then a clean that means something
Because you can only clean what you can reach, access is the stage that makes the rest of the job real. If the survey finds none, fitting compliant panels comes first - then the whole run can be cleaned to bare metal and verified. Without it, any clean is partial by definition, and any certificate covers only what happened to be open.
Questions
Only where there is another way in, such as a removed fan or filter. Any concealed length with no access cannot be inspected or cleaned, so the grease inside it is left in place.
TR19 Grease calls for access at a minimum of every two metres and at strategic points such as changes of direction, so the whole system can be reached and cleaned.
They stay greasy. That is a fire risk in the hidden runs where grease builds up, and it also means those sections cannot be verified or honestly included on a compliance certificate.
Yes. Compliant panels are fabricated in the same material as the duct, sealed and fitted with quick-release catches. This is usually the first step before a full clean where access is missing.
It can be, but it must maintain the duct's fire integrity using a certified fire-rated panel, installed with manufacturer or fire-specialist guidance and the client's agreement.
Phoenix Duct Clean · by the numbers
We survey the runs, identify where access is missing and fit compliant panels so the whole system can be cleaned and verified - not just the parts we can reach.