The two names are often mixed up, and it’s easy to see why. If you’re fitting a new kitchen, refurbishing an old one or reading a specification from a consultant, you may come across both DW172 and TR19. They’re both published by BESA, the Building Engineering Services Association, and both relate to kitchen extract systems. But they cover different stages in the life of a system. This short guide explains how they fit together.
DW172: designing and installing the system
DW172 is BESA’s specification for kitchen ventilation systems. It deals with how a kitchen ventilation system is designed and installed: the canopy, the ductwork and the other parts that make it up. It’s mainly used by designers, consultants and installers when a system is specified or fitted.
If you’re having a new system installed, it’s reasonable to ask your designer or installer which specifications they’re working to. Duct Doctor offers kitchen extraction installation, supplying and fitting canopies and extract systems.
TR19 Grease: keeping it clean
TR19® Grease is BESA’s standalone specification, produced in 2019, for the fire risk management of grease in kitchen extract systems (BESA). It covers the system once it’s in use: how it should be inspected, how grease is measured, minimum cleaning intervals and the records that should be kept.
BESA’s minimum intervals are every 3 months for heavy use (12 to 16 hours a day), every 6 months for moderate use (6 to 12 hours) and every 12 months for light use (2 to 6 hours). Grease should not exceed a mean of 200 microns between cleans, and 500 microns or more needs immediate spot cleaning. See TR19 Grease explained.
Need it done? Duct Doctor cleans and tests kitchen extract and ventilation systems across London and the South East, with a certificate and photo report after every clean. Get a fixed quote.
Why the two are linked
How a system is designed and installed affects how well it can be cleaned for the rest of its life. BESA says that “TR19® emphasises the need for comprehensive access throughout the duct system” (BESA). If a duct is boxed in behind fixed ceilings, has too few access panels or runs through places nobody can reach, every future clean will be harder, and some sections may have to be recorded as inaccessible.
That’s why it pays to think about cleaning at the design stage. Ask how each part of the duct, including any fire dampers, the fan and the discharge, will be reached. A few extra access panels fitted during installation are far simpler than cutting them into a finished duct later. It’s also worth keeping drawings of the duct route, so future cleaning teams know where it goes. See duct access panels explained.
Which one applies to you
- Planning, designing or installing a kitchen extract? The designer and installer will work to the relevant specifications, which may include DW172.
- Running a kitchen with an existing extract? TR19 Grease is the specification for inspection and cleaning that insurers, fire officers and EHOs look to.
- Taking over an existing kitchen? Start with a survey and grease readings to see the condition of the system and whether access is adequate.
Neither is law
Both are industry specifications, not legislation. BESA itself says that “TR19® itself is not legislation” (BESA). The legal duty to manage fire risk comes from the Regulatory Reform (Fire Safety) Order 2005. Following recognised specifications is how you show that duty has been met. See is TR19 a legal requirement?
Quick answers
Is DW172 a cleaning standard?
No. DW172 is BESA’s specification for kitchen ventilation systems. Cleaning is covered by TR19 Grease.
Do I need both?
If you’re installing a system, the installer works to design specifications. Once it’s in use, TR19 Grease applies to cleaning.
Who publishes DW172 and TR19?
Both are published by BESA, the Building Engineering Services Association.
Related services
More advice
- TR19 Explained: Kitchen Extract Cleaning Standard
- Duct Access Panels: Why They Matter for TR19
- Is TR19 a Legal Requirement? What the Law Says
- Pre-Clean Surveys: What to Expect
- All advice
This guide is general information. It isn’t legal or insurance advice: check your own policy wording and lease, and speak to a qualified adviser about your fire risk assessment.