Phoenix Journal · Ductwork
A clean you cannot evidence is a clean that never happened in the eyes of an insurer or fire officer. Here is how to make your photos and post-clean reports carry real weight.
Compliance evidence
Under the Regulatory Reform (Fire Safety) Order 2005 the responsible person has to show that fire risk is being managed, and for a commercial kitchen that means proving the extract system has actually been cleaned - not just that someone attended.
Grease is a fuel. When it builds up inside canopies, filters, ductwork and the fan, it turns an ordinary flare-up into a fire that travels the length of the duct run. That is why insurers, environmental health officers and fire safety inspectors all want the same thing after a clean: objective proof of the condition of the system before work started and after it finished. A verbal assurance or a line on an invoice is not proof. A set of dated, matched photographs and a properly structured post-clean verification report is.
The industry benchmark for that proof is BESA's TR19® Grease specification, and its 2024 technical bulletin TB/009 has sharpened what a compliant record looks like. Major insurers such as Aviva and AXA now expect kitchen extract cleaning to be carried out and evidenced to TR19® Grease, and some will decline a fire claim where that evidence is missing. So your photos and reports are not paperwork for its own sake - they are the difference between a defensible position and an argument you will lose.
Photographs are the most immediate part of the evidence pack, but a phone snap of a shiny filter proves very little on its own. To carry weight, an image has to be honest about what it shows and repeatable by anyone who checks it later. That comes down to a few disciplines your cleaning provider should follow every visit.
Get those four things right and a stranger reviewing the file months later can see, without taking anything on trust, that the system was dirty, was cleaned, and reached the standard.
Photographs show condition; the report proves the clean was measured and verified. A post-clean verification report built to TR19® Grease is a structured document, not a certificate with a logo on it. When you receive one, check it contains the following.
One more marker separates a genuinely compliant report from a lookalike: registration. To be fully compliant with TR19® Grease, each post-clean report should be logged on the BESCA Vent Hygiene Register (VHR) or an equivalent recognised scheme. That independent record is hard to dispute and easy for an insurer or auditor to verify - which is precisely the point of holding evidence at all.
Evidence you cannot find is no better than evidence you never collected. The moments when these records earn their keep - an insurance renewal, a fire risk assessment review, an environmental health visit, or worst of all the aftermath of a fire - are rarely convenient, so the file needs to be complete and retrievable at short notice.
Keep the photographs and the post-clean verification report together for every visit, and hold onto them well beyond the current cleaning cycle. There is no single statutory retention period written into the Fire Safety Order, but the practical test is simple: you should be able to demonstrate an unbroken history of cleaning across the whole period your insurer or a fire investigator might reasonably look back over, which in practice means holding several years of records, not just the latest one. A gap in the timeline reads as a gap in the cleaning.
These records also sit alongside the wider paper trail a facilities manager is expected to hold, so file them with the rest of your fire and hygiene documentation rather than in a separate silo. It is worth knowing which of these documents matter most and how long to keep each - our guide to the compliance documents every FM should keep sets that out. Stored together, dated and cross-referenced, your photos and reports stop being loose files and become a defensible record.
Questions
Not really. A certificate confirms an event took place, but insurers and fire officers want to see the condition it certifies. The photographs and the post-clean verification report - with micron readings, matched before-and-after images and a statement of what was cleaned - are what demonstrate the system actually reached the standard. Treat the certificate as the cover sheet, not the evidence itself.
There is no single fixed period set in law, but you should hold enough history to show an unbroken cleaning record across the span an insurer or fire investigator might review. In practice that means keeping several years of photos and post-clean verification reports rather than only the most recent one. A missing year in the timeline can be read as a missing clean, so retain the full sequence.
Phoenix Duct Clean · by the numbers
Phoenix surveys and cleans kitchen and building ductwork to the TR19 standard - measured, cleaned and certificated, UK-wide.