A ventilation clean is only as good as the report that proves it.
Nobody sees the inside of a supply duct once the access panels go back on. The client, their facilities manager and the next contractor see one thing: the report. Under TR19® Air (Version 2, March 2026) that report has a name, a deadline and a list of things it must carry. Most of the reports that fall short do so on the same few points.
The report has a name and a deadline
TR19 Air calls it the Post-Work Verification Report (also "Post Clean Report") (8.16, 9.2, 9.4). It is needed for ventilation cleans, for hygiene inspections or surveys, and for post-installation surveys of new ductwork (8.17).
It goes to the client within 30 days of the last cleaning visit (8.16, 9.1). One building per report; several systems are fine, as long as each is clearly separate (8.16, 8.21).
Every report ends in one of four outcomes (9.2):
- Full Clean
- Partial Clean - scope set before starting; the report says it is not a full clean and names the areas still to do
- Inspection - outcome "Clean"
- Inspection - outcome "Not Clean"
One trap: cleaning an air handling unit, a fan or one component on its own is a Partial Clean, never a Full Clean (9.2).
What the report should show - a checklist
| On the report | TR19 Air clause |
|---|---|
| A summary page: Full, Partial or Inspection for each system, the scope, and each system's class (Low, Medium, High) | 9.4, 8.21 |
| How the clean was verified: visual, or measured (EVT, DTT) | 9.4 |
| Before and after photos at the sampling locations | 9.4, 8.7 |
| Test results for each system, at those locations | 9.4 |
| Areas not cleaned, why, and what would allow a full clean | 9.1, 8.16 |
| Other hazards, and access limits, for each system | 9.4 |
| Methods used, faults that affect future work, additional work, recommendations | 8.21 |
| A schematic or as-installed drawing: areas cleaned and not, access panels added, test points | 8.19, 8.21, 8.22, 9.4 |
| The signing-off engineer's name and date of attendance (qualified to BESA AHT3 or equivalent) | 9.4, 8.18, 9.3 |
The figures behind "verified"
- Visual comes first. Surfaces must be visibly clean in every case (8.1, 8.10).
- Measured verification is by EVT only. The deposit thickness test is not suitable after a clean (8.11).
- The pass mark is under 0.3 g/m² by EVT - every class, every service (8.13, Appendix F). Exactly 0.3 does not pass.
- Whether to test depends on the class. Low: the client decides. Medium: testing is recommended, the client has the final say. High: testing must go ahead (Table 9).
- Same day. The post-clean test is taken the same day as the clean of that section (8.4, 8.15).
- How many points. Up to 250 m of system, 3 points (beginning, middle, end); up to 500 m, 4; up to 1,000 m, 6; up to 1,500 m, 8; then one more per extra 250 m - plus at least one per air handling unit (8.7, Table 10).
Where reports usually fall short
The class is missing. If nobody sets it, TR19 Air assumes Medium (2.3). A report that never states the class leaves the client unable to tell whether testing was optional or required.
"Full Clean" on a partial job. The fan and the AHU were cleaned, the ductwork was not. That is Partial, and the report has to say what is left.
The lab result arrives after the report. EVT samples are weighed by an independent lab (E2.13). If the report goes before the result, the client gets a "verified" clean with no verification attached.
Results that cannot be traced. A table of figures with no clear location means the next contractor cannot sample the same points.
How SMART Reports handles it
TR19 Air is now a report type in SMART Reports, built for firms working to TR19 Air:
- The office sets each system's class (Low, Medium, High) and air service (supply, extract, recirculation), so the class is on the report, not in someone's head.
- The app suggests the minimum number of test points from the system's length and air handling units. It is a suggestion the engineer can go past, never a block.
- On an inspection, the engineer names each test point with its deposit reading and photos, and the outcome is worked out from the readings and the visual check - never picked from a list.
- On a clean, the engineer records how it was verified - checked by eye, or verified by lab sample. High-class systems always go to the lab.
- Lab results wait for the report, not the other way round. The office records each result as it arrives and attaches the lab's certificate. Send waits until they are in.
- The verification report and certificate go from the office, locked, in your firm's branding, the same way as grease and fire damper reports.
One thing it does not do yet: the schematic is not drawn inside the TR19 Air report type.
TR19 Air is £90 a month, or £200 a month with TR19 Grease and fire damper testing and inspections together. Every engineer and office user included. No VAT charged. Start your firm online today, or book a call.
Read next: The kitchen extract post-clean report, explained - the grease equivalent - and The kitchen extract schematic.
Source: BESA, TR19® Air - Specification for internal cleanliness and hygiene management of ventilation systems, Version 2, March 2026. Clause numbers given so you can check each point in your own copy; no text of the specification is reproduced.