TR19 & standards
You don't need to be a technician to check a report. You need to know which numbers, photos and notes actually tell you the job was done.
The short answer
A TR19 report is readable without technical training if you know where to look: grease-thickness readings paired before and after at each point, photographs from identical positions, and honest notes on anything that couldn't be reached. A big drop in the numbers and matching photos means the clean worked; blanks and 'no access' entries tell you what didn't.
The numbers that matter
The heart of the report is the readings. For each test point the report should show a before figure and an after figure in microns. A compliant result has the pre-clean numbers - which might be 200, 300 or more - falling to well under 50 after the clean. What you are checking is the pair: a low after-reading only means something next to the before-reading at the same spot, because it shows how much grease actually came out.
Watch the spread of points, too. Readings should come from across the system - behind the filters, along the duct at set distances, near the fan, at the discharge - not one convenient location. A single glowing figure proves one spot; a set of paired readings across the run is what proves the system.
Photos and access notes
Photographs should come in before-and-after pairs taken from the same position, so the change is genuinely comparable. If the after shots look like different, cleaner sections rather than the same duct cleaned, that is a warning sign. Good reports label each pair to a location on the schematic so you can see the whole system was covered, not just the photogenic parts.
Then read the notes on inaccessible areas - the most honest and most overlooked part. Any section that couldn't be reached should be listed, with a recommendation to add access. This is not a failing to hide; it is the report telling you exactly where the risk still sits. The report should also record the cleaning methods, any faults found, and recommendations for the next visit.
The limit
A report that shows only after-readings, uses photos with no fixed reference, lists no inaccessible areas on a clearly complex system, or carries no BESCA registration is telling you something by omission. None of those on their own proves bad work - but together they mean you cannot evidence a compliant, whole-system clean. Read the report as a document you might one day hand to a loss adjuster, and judge it by whether it would answer their questions.
Questions
Look for paired grease-thickness readings at each test point - a high before figure and an after figure well under 50 microns - plus before-and-after photos from the same positions and notes on any inaccessible areas.
They measure grease thickness. Pre-clean figures show how loaded the system was; post-clean figures should be down near or under 50 microns. The drop between them is the evidence the clean worked.
So the before and after can be compared like for like. Shots from different positions can make any duct look cleaner. Fixed-point pairs, labelled to the schematic, show the actual sections were done.
That a section couldn't be reached, so it wasn't cleaned or measured - a partial clean. It's the honest, important part of the report and usually means access panels should be added.
After-only readings, photos with no fixed reference, no inaccessible-area notes on a complex system, or no BESCA registration. Together they mean a compliant whole-system clean can't be evidenced.
Phoenix Duct Clean · by the numbers
We walk you through every reading, photo and note in your report - and issue ones that are easy to read and stand up to scrutiny.