TR19 & standards
A standard is only as good as who stands behind it. TR19 Grease is trusted because of who writes it, who backs it, and how it's checked.
The short answer
TR19 Grease is written by BESA, the engineering body that has set duct-cleaning standards since the 1990s, developed with the RISCAuthority and industry experts. Insurers trust it because it is recognised by the Association of British Insurers, gives a measurable pass mark, and is backed by independent BESCA audit and a national record - not just a contractor's word.
Who actually writes it
The standard comes from the Building Engineering Services Association - BESA - founded in 1904 and long the trade body for the people who design, install and maintain building ventilation. Its duct-cleaning guidance runs back to TR/17 in 1998, so TR19 Grease is the latest step in a lineage the industry has followed for a quarter of a century.
Crucially, it was not written in isolation. TR19 Grease was developed alongside the RISCAuthority - the fire-risk research body backed by insurers - and a panel of industry experts who contributed the test methods. That collaboration is why it reads as a practical fire-risk document rather than an academic one, and why the people who ultimately pay for fires had a hand in shaping it.
Why insurers rely on it
Insurers trust TR19 Grease for the same reasons any assessor does: it turns 'clean enough' into a number. A defined micron limit, a required test method, a competence qualification and a certificate give an insurer something objective to ask for and check, instead of a subjective claim that the ducts were done.
The standard is recognised by the Association of British Insurers and its members, and is backed by independent oversight: BESCA audits Ventilation Hygiene Elite members and can remove those who fall short, and each clean is recorded on BESA's national Elite database. So when an insurer asks for proof, there is an independent record to point to. It is not law - but buildings and contents cover can be treated as invalid where a kitchen can't show a TR19-approved cleaning schedule, which gives it real force.
There is a practical upshot for you in all this. When cover is quoted or a claim is assessed, the insurer is effectively asking whether your extract was maintained to a standard they already recognise - and a TR19 Grease certificate on the accredited route answers that in their own terms. It is the difference between offering an opinion that the ducts were clean and handing over a record they can verify, which is exactly what tends to smooth both premiums and claims.
The limit
The weight behind TR19 Grease makes it the benchmark to meet - but the backing protects you only if your clean is genuinely done and recorded to it. A certificate from an unaudited source, or one with no BESCA registration, borrows the standard's name without its substance. The trust insurers place in TR19 Grease flows through the accredited route and the independent record; a document outside that chain does not inherit it.
Questions
BESA, the Building Engineering Services Association - founded in 1904 and the long-standing UK body for ventilation engineering. Its duct-cleaning guidance runs back to TR/17 in 1998.
Yes. It was developed with the RISCAuthority, the insurer-backed fire-risk research body, and a panel of industry experts who contributed the test methods - which is why it works as a practical fire-risk specification.
Because it is measurable and independently checked: a defined micron limit, a required test, technician qualifications, BESCA audit of accredited contractors, and a national record insurers can request as proof.
It is recognised by the Association of British Insurers and its members. While not a legal requirement, buildings and contents cover can be treated as invalid without evidence of a TR19-approved cleaning schedule.
Only one on the accredited, audited route. A certificate with no BESCA registration or from an unaudited source uses the name without the independent record that insurers actually rely on.
Phoenix Duct Clean · by the numbers
We clean and certify to the standard insurers recognise, with the independent record behind it. Ask us how our certificates support your policy.