Ductwork is the part of a ventilation system nobody sees, which is exactly why it gets neglected. Out of sight, grease, dust and debris build up inside the ducts until the system is not only running inefficiently but has become a genuine hygiene and fire risk. TR19 is the standard that governs how that ductwork should be cleaned and how you prove it is clean.
What TR19 is
TR19 is the specification published by the Building Engineering Services Association for the internal cleanliness of ventilation systems. It sets measurable standards for how clean ductwork must be, how cleanliness is tested, and how often systems should be inspected. Its sister standard, TR19 Grease, deals specifically with kitchen extract systems, where grease accumulation is a serious fire hazard.
For most commercial buildings, TR19 matters for two reasons: air hygiene and fire safety. Both carry legal weight.
The hygiene case
Ventilation ductwork that has never been cleaned recirculates whatever has settled inside it. In an office, that means degraded air quality and the dust-and-stuffiness complaints that follow. In food premises, healthcare or any environment with hygiene obligations, it can mean a direct breach of duty. TR19 provides the benchmark — a measured level of cleanliness — and the verification method to prove you have met it.
The fire case
This is the one that carries the most risk. Under the Regulatory Reform (Fire Safety) Order, the responsible person for a building must manage fire risk, and grease-laden or heavily fouled ductwork is a recognised fire pathway. In commercial kitchens especially, extract ductwork coated in grease is one of the most common causes of serious fires. Insurers increasingly require TR19-compliant cleaning records, and a claim can be challenged without them.
What compliance looks like in practice
A TR19 regime means: an initial inspection to assess the current state of the ductwork, cleaning to the specified standard where required, post-clean verification with photographic and measured evidence, and a schedule of ongoing inspection at intervals set by how the system is used. A busy kitchen extract needs far more frequent attention than a low-use office supply system.
The documentation is not an afterthought — it is the point. Being able to show a dated, verified record of ductwork cleanliness is what satisfies insurers and fire risk assessors.
We inspect, clean and verify ventilation ductwork to TR19, and just as importantly we set the right inspection frequency for how your system is actually used, so you are neither under-cleaning and carrying risk nor over-cleaning and wasting money.
If your ductwork has not been inspected against TR19, that is the place to start.
