TR19 Grease: kitchen extract cleaning frequencies, insurers and what drives the cost

What does TR19 Grease cover, and is it a legal requirement?

TR19 Grease is a stand-alone BESA specification for the fire risk created when grease builds up inside a commercial kitchen extract system. BESA's publications page calls it the definitive specification for that job and lists a published date of 1 August 2020. It replaced section 7 of the third edition of TR/19.

The scope is the whole route. BESA says a clean covers the canopy, the fan and the full length of the ductwork, not just the filters staff can see.

It is a specification, not a statute. The legal duties sit in the Regulatory Reform (Fire Safety) Order 2005, whose articles legislation.gov.uk marks for England and Wales. The responsible person must make a suitable and sufficient assessment of the risks (article 9), take general fire precautions (article 8) and keep the premises and their fire safety equipment under a suitable system of maintenance (article 17). BESA says grease in the ductwork is a hazard the assessment has to cover.

Failing a fire safety duty is an offence when it places people at risk of death or serious injury in case of fire. Article 32 sets the penalty on summary conviction at a fine not exceeding the statutory maximum, and on indictment at a fine, up to two years' imprisonment, or both.

How often should a kitchen extract be cleaned?

BESA publishes minimum intervals by how many hours a day the kitchen cooks.

Use	Hours of cooking a day	BESA minimum interval
Heavy	12 to 16	Every 3 months
Moderate	6 to 12	Every 6 months
Light	2 to 6	Every 12 months

Treat the table as a floor. BESA says the actual interval should be set by a competent person's cleanliness risk assessment, weighing the type of cooking, seasonal menu changes, how fast grease accumulates and the deposit readings from earlier cleans. It adds that intervals must be reviewed so grease stays at safe levels.

Article 9 requires the fire risk assessment to be reviewed after a significant change. A new fryer line or longer trading hours can move a kitchen into a different band, so the cleaning interval belongs in that review.

How is grease thickness measured and reported?

BESA says TR19 Grease controls grease so that it does not exceed a mean average of 200 microns between scheduled cleans, and that deposits of 500 microns or more need immediate spot cleaning. The readings come from a Wet Film Thickness Test or a Deposit Thickness Test taken at various points along the duct.

The readings therefore test the schedule. If a visit finds the mean well above 200 microns, the gap between cleans is too long for that kitchen, whatever the table says.

BESA says each clean should end with a verification report. The items it lists are:

• before-and-after photographs taken from matching positions;
• the thickness test results;
• a written summary of the work;
• notes on any access limits or recommendations;
• a hygiene certificate giving the date, the system location and the name of the competent technician.

BESA's FAQ says only properly qualified technicians should carry out deposit testing and sign off the report, and names the BESA Grease Hygiene Technician qualification. Its pages use two names for the audited contractor scheme, BESCA's Vent Hygiene Elite and the Vent Hygiene Register, so check a contractor against the register rather than a logo.

Why do access panels and fire-resisting ductwork matter?

A duct that cannot be reached cannot be cleaned or measured. BESA says TR19 expects access panels at regular intervals, typically every 2 to 3 metres wherever possible, and of a size that gives unrestricted access to the inside surfaces.

BESA says that after a fire insurers will look at whether areas flagged as uncleaned or inaccessible in earlier reports were dealt with. A report line reading "not accessible" is a job to schedule, not a pass.

BESA's FAQ also says fire dampers are not acceptable in kitchen extract systems under BS 9999, so fire-resisting ductwork is used where the discharge cannot be immediate. General ventilation ducts are different (see the dampers guide), and kitchen extract design sits in the kitchen extraction guide.

Why do insurers and fire risk assessments rely on it?

BESA's certification arm reported in January 2021 that RISCAuthority, the body that carries out research on behalf of insurers, had designated TR19 Grease as best practice. It said RISCAuthority's guidance RC68, produced with the Fire Protection Association, recommends cleaning grease extract systems to TR19 using contractors whose competence a third party has verified. BESA's register pages say TR19 appears in sections 5.1.4, 5.6.13 and 5.7.8 of RC68. RC68 itself was not read for this page.

Fire and rescue guidance points the same way. London Fire Brigade's page for takeaways, cafes and restaurants says kitchen ducting should be cleaned regularly because grease could ignite and spread fire, and it links its guidance note GN86 on catering kitchen extract systems, which BESA says was updated with TR19 Grease.

BESA also warns that non-compliance with TR19 can lead to denied claims even where a cleaning contractor had been employed. That is a trade body's statement, not policy wording, so ask the insurer or broker which standard the policy names and what evidence to keep.

What drives the cost of a TR19 Grease clean?

No official source publishes a price per clean, so this page gives none. What can be sourced is the scope, because a quote only means something once it says what is cleaned and what evidence comes back. BESA's list of what a cleaning contract should specify makes a checklist:

BESA contract element	What to look for in a quote
Scope of work	Canopies, filters, risers, horizontal ductwork, fans and discharge points all named
Frequency	An interval at or above the BESA minimum for the kitchen's hours, with the reason
Access	Existing panels listed, limited-access areas flagged and a way to resolve them
Verification	Photographs and thickness readings after every clean
Certification and reporting	Hygiene certificate and a full report each time
Responsibilities	Who provides access, isolates equipment and reinstates services afterwards

Quotes that differ in scope are not comparable. A filter-only visit and a canopy-to-discharge clean with readings are different jobs, and a duct short of panels needs work before it can be cleaned to the specification. The kitchen extraction cost guide sets the cleaning interval beside fan power and other yearly costs, and you can send an enquiry through the form on this site to ask for quotes that follow this scope.

Where can I read the TR19 Grease document?

BESA Publications lists the 42-page document with a preview link and a PDF download option. When checked on 22 October 2026 the listing showed "Sold out", so ask BESA or a BESA contractor member how to get a copy. The specification is licensed, so this page summarises it and does not reproduce it. Check any threshold here against the document itself.

TR19 Air, the general-ventilation specification, is covered in the duct cleaning guide. Interlocking gas appliances to the extract is a separate safety system, explained in the gas interlock guide, and the restaurant ventilation page shows how the pieces fit together.

Sources

• TR19 Grease: specification for fire risk management of grease accumulation within kitchen extraction systems, BESA Publications, published 1 August 2020, checked 22 October 2026
• Kitchen extract system cleaning for fire safety compliance, BESA, 5 January 2026, checked 22 October 2026
• About the Vent Hygiene Register, BESA, checked 22 October 2026
• Insurers call for improved ventilation safety, BESCA, 14 January 2021, checked 22 October 2026
• Regulatory Reform (Fire Safety) Order 2005, article 8, legislation.gov.uk, checked 22 October 2026
• Regulatory Reform (Fire Safety) Order 2005, article 9, legislation.gov.uk, checked 22 October 2026
• Regulatory Reform (Fire Safety) Order 2005, article 17, legislation.gov.uk, checked 22 October 2026
• Regulatory Reform (Fire Safety) Order 2005, article 32, legislation.gov.uk, checked 22 October 2026
• Fire safety in restaurants, takeaways and cafes, London Fire Brigade, checked 22 October 2026

Common questions

Can a kitchen team clean its own extract ductwork?

Daily filter cleaning is the operator's job, but BESA says filters alone cannot control the risk because grease vapour passes through and around them. BESA also says TR19 Grease sets minimum competency levels and that only qualified technicians should test deposits and issue the report. A kitchen that wants the certificate should use a contractor who can produce it.

Does TR19 Air cover the kitchen extract as well?

No. BESA describes TR19 Air as the specification for general ventilation systems and TR19 Grease as the separate one for kitchen extraction. A TR19 Air certificate does not cover a grease extract.

What should happen when the report says part of the duct could not be reached?

BESA says the report should record access limits and recommendations, and that cleaners should make inaccessible areas reachable by fitting access panels. Treat the note as an action with an owner and a date, because insurers look at whether earlier flags were dealt with.

Does the Fire Safety Order apply to every commercial kitchen?

London Fire Brigade says all businesses require a fire risk assessment under the Order. The articles are marked for England and Wales on legislation.gov.uk, so a kitchen in Scotland or Northern Ireland should confirm the local rules with its fire and rescue service.

Related guides

• Can air conditioning spread legionella?
• Air conditioning in listed buildings and conservation areas
• Commercial air conditioning noise: limits, assessments and complaints
• Do you need planning permission for commercial air conditioning?