TR19 Explained: A Simple Guide for Commercial Kitchen Operators

When people in commercial kitchens talk about ‘TR19 cleaning’, they usually mean TR19® Grease, the BESA specification covering fire risk management of grease accumulation within kitchen extraction systems. This is separate from TR19® Air, which covers the cleanliness and hygiene of general ventilation systems.

You may have seen it written on a kitchen extraction report or been told your system requires TR19 kitchen extraction cleaning. But what does it actually mean?

If commercial kitchen ventilation is only one small part of your job, the terminology can make something relatively straightforward sound complicated.

The important thing to understand is that cooking produces grease, some of that grease can travel into your kitchen extraction system, and it needs to be managed. TR19 Grease gives the industry a recognised framework for assessing, cleaning and documenting that grease build-up.

Here is what commercial kitchen operators need to know.

What is TR19?

For commercial kitchens, the relevant document is TR19® Grease, published by the Building Engineering Services Association (BESA).

It is an industry specification covering the management of grease accumulation within commercial kitchen extraction systems. It provides guidance around inspecting, measuring, cleaning and reporting on the condition of kitchen extract ductwork.

One important distinction: TR19 is not itself legislation.

However, it is widely used as an industry benchmark and can support organisations in managing their wider fire safety, health and safety, maintenance and contractual responsibilities. Individual insurers, landlords or contracts may also specify particular requirements, so these should always be checked separately.

For the person running the kitchen, the simplest way to think about TR19 is:

It provides a structured way of checking how much grease is accumulating inside your extraction system and managing it before that accumulation becomes excessive.

Why does TR19 matter in a commercial kitchen?

When you fry, grill, roast or cook food, grease isn’t confined to the pans and cooking surfaces.

Tiny droplets and particles can become airborne and are drawn towards the canopy by the extraction system.

Your canopy filters capture part of this contamination. Depending on the system, additional grease filtration may capture more.

But filtration does not necessarily mean that every grease particle disappears.

Some contamination can continue beyond the canopy into the ductwork, fan and other parts of the extraction system. Over time, it can settle on internal surfaces.

Because much of the ductwork is hidden above ceilings, behind walls or in plant areas, you may not see this happening.

That is why a kitchen can appear to be operating normally while grease in kitchen ductwork continues to accumulate.

Excessive grease build-up matters because it can increase kitchen fire risk, make cleaning more difficult, affect equipment and system performance and increase maintenance requirements.

Regular inspection and commercial kitchen extraction cleaning are therefore important parts of good grease management and commercial kitchen safety.

What Does A Grease Or Micron Reading Mean?

This is one of the most confusing parts of many TR19 reports, but the basic idea is simple.

A micron, sometimes written as µm, is a very small unit of measurement.

200 microns = 0.2 millimetres.

That is roughly around half the thickness of a typical business card.

It doesn’t sound like much. But remember: we’re talking about a layer of combustible grease deposited across the internal surfaces of an extraction system, potentially extending through a significant length of ductwork.

A Deposit Thickness Test, or DTT, measures how thick those deposits are at selected points.

BESA’s published TR19 guidance states that grease levels should be controlled so that the mean average does not exceed 200 microns between scheduled cleans.

BESA also states in its guidance that areas which reach 500 microns require immediate spot cleaning.

Your contractor should interpret the measurements in the context of the system and the applicable TR19® Grease specification rather than relying on one isolated number.

The readings help answer an important question:

How quickly is grease building up inside this kitchen extraction system?

That information can then help determine an appropriate inspection and cleaning regime.

BESA have a minimum recommended frequency chart.  This is a clear baseline recommendation from BESA when it comes to TR19 frequency.

Kitchen use	Typical operating hours	BESA minimum cleaning frequency
Heavy	12–16 hours/day	Every 3 months
Moderate	6–12 hours/day	Every 6 months
Light	2–6 hours/day	Every 12 months

Why Can My TR19 Cleaning Frequency Change?

A common question is: “We’ve always had our ducts cleaned at the same interval, so why has that changed?“

Because your kitchen may have changed.

TR19 cleaning frequency should reflect what is actually happening within the extraction system. Factors that can affect grease accumulation include:

• increased cooking volumes;
• longer operating hours;
• changes to the menu;
• new cooking appliances;
• different cooking methods;
• increased frying, grilling or chargrilling;
• changes in the performance or maintenance of filtration equipment.

Imagine a kitchen that previously served a relatively light menu but has moved to higher-volume frying and grilling.

The ductwork hasn’t changed. But the amount and type of commercial kitchen grease entering the extraction system may have changed significantly.

That could mean deposits accumulate more quickly and the previous cleaning interval is no longer appropriate.

If your recommended cleaning frequency changes, the important question isn’t simply “Why is this costing me more?” It is “What has changed inside my kitchen or extraction system?”

Finding the cause may identify opportunities to improve filtration, maintenance or grease management rather than simply accepting increasing levels of ductwork cleaning indefinitely.

Does Having a TR19 Certificate Mean Everything Is OK?

A certificate is important evidence that work has been completed and documented.

But don’t treat receiving a certificate as the final step.

Your post-clean report can contain information that is just as useful.

For example, were all areas of the system accessible? Were any defects identified? Were there sections requiring further work? What were the grease readings? Has the recommended cleaning frequency changed?

Think of it like an MOT report for a vehicle. Passing or completing the process is important, but you would still want to know about observations that could become problems later.

The same principle applies to TR19 compliance and kitchen extraction maintenance.

A report helps you understand the condition of the system, not simply prove that somebody attended site.

Who Should I Use For TR19 cleaning?

Not every company offering commercial kitchen extraction cleaning has been independently assessed to demonstrate that it can work in line with TR19® Grease.

BESA recommends checking the Vent Hygiene Register (VHR) when selecting a contractor, rather than simply accepting a claim that a company can clean your system “to TR19 standards”.

VHR-approved contractors undergo an audit process covering their technical competence and commercial capability. For TR19® Grease work, the VHR also requires appropriately qualified Grease Hygiene Technicians (GHTs) to support the certification of completed work.

Using the VHR gives kitchen operators and facilities managers a straightforward way to check that a contractor is currently registered and approved.

So, before appointing a TR19 duct cleaning contractor, ask a simple question:

“Are you currently approved on the Vent Hygiene Register?”

You can then check the contractor directly using the VHR’s online register rather than relying solely on logos, certificates or statements on a company website.

What should I look for on my TR19 report?

When you receive a report following TR19 canopy and extract cleaning, don’t just file it away.

Check:

• Grease readings: What deposit levels were recorded?
• Photographs: Do the before-and-after images clearly show the condition of the system?
• Inaccessible areas: Were there sections that could not be inspected or cleaned?
• Areas requiring attention: Has anything been highlighted for further investigation?
• Recommended cleaning frequency: Has the interval changed?
• Observations or defects: Were problems found with access, filtration, fans or other equipment?
• Recommended remedial work: Is there anything you need to arrange?
• Changes from previous reports: Are grease levels increasing or are the same problems repeatedly appearing?

If something doesn’t make sense, ask.

A good commercial kitchen duct cleaning provider should be able to explain the findings in straightforward language.

Can Filtration Help Keep Commercial Kitchen Ductwork Cleaner?

Cleaning is only one part of grease management.

Another approach is to ask:

Can we capture more grease before it travels further into the extraction system?

Good commercial kitchen filtration starts at or near the canopy and can include different stages depending on the cooking process and site requirements.

There are several options for improving grease filtration and odour control. Ecofleece Grease Filters fit within the canopy and can prevent up to 98% of grease from entering the extraction system. Canopy UV provides another approach, helping manage grease and odours within the canopy and downstream ductwork to support a cleaner extraction system.

An electrostatic precipitator (ESP), for example, is designed to remove fine grease and smoke particles from the extracted air stream. Correctly specified and maintained ESPs can help reduce the amount of contamination travelling into downstream ductwork.

That can contribute to cleaner ductwork, effective grease and smoke control and better overall system performance.

Filtration equipment needs maintenance too. Grease collected by an ESP doesn’t simply vanish: the equipment requires appropriate ESP cleaning and ESP maintenance to continue performing effectively.

So effective commercial kitchen ventilation maintenance means looking at the complete journey of the air — not just the visible canopy.

Look at the whole system, from canopy to extract

If grease readings are rising, repeatedly cleaning the ductwork addresses the contamination that has accumulated.

But it is also worth asking why it accumulated.

Plasma Clean Air works with commercial kitchen operators, facilities management teams and estates teams to look at the whole extraction system from canopy to extract.

That means helping customers understand what is happening inside their system, why grease levels may be increasing, whether filtration is operating effectively, what maintenance may be required and whether there are opportunities to improve grease, smoke and odour control.

Sometimes the answer is better cleaning or access. Sometimes it is improved maintenance. In other situations, the commercial kitchen filtration systems may need attention.

Understanding the cause helps you make a more informed decision.

The simple takeaway

If you remember only five things about TR19, make them these:

1. Cooking produces airborne grease.
2. Some of that grease can enter your extraction system.
3. TR19 provides a framework for assessing and managing cleanliness.
4. Your report and grease readings tell you what is happening inside the system.
5. Understanding the cause of grease build-up can help you manage fire risk and maintenance more effectively.

Not sure what the readings on your latest TR19 report actually mean?

Plasma Clean Air can help you understand what is happening inside your commercial kitchen extraction system and identify practical steps to keep it clean, safe and operating effectively.

Speak to a Plasma Clean Air expert or request a commercial kitchen extraction assessment to take a closer look at your system.