How Often Does Kitchen Extract Ductwork Need Cleaning Under TR19?

One of the most common questions we receive from Scottish catering operators is: how often do we actually need to clean our kitchen extract system? The answer depends on how you cook — and getting it wrong can leave you uninsured.

The TR19 Risk Categories

TR19 Grease (the current BESA standard) does not set a single cleaning frequency for all commercial kitchens. Instead, it defines four risk categories based on the type and volume of cooking carried out. Your cleaning frequency is determined by which category applies to your operation.

Heavy Use — Every 3 Months

Heavy use applies to kitchens operating for 12 or more hours per day, or kitchens that produce large volumes of grease-laden vapour. This typically includes:

• High-volume restaurants and takeaways with continuous fryer use
• Fast food outlets with heavy char-grilling or deep-frying
• Large hotel kitchens serving multiple sittings daily
• Contract catering operations serving hundreds of covers per day

For heavy-use kitchens, TR19 requires cleaning every three months. This is the most demanding schedule and reflects the rate at which grease accumulates in high-output operations.

Moderate Use — Every 6 Months

Moderate use applies to kitchens operating for 6 to 12 hours per day with a mixed cooking profile. This covers the majority of Scottish commercial kitchens, including:

• Restaurants and cafes with standard service hours
• Pub kitchens serving lunch and dinner
• Care home kitchens serving three meals per day
• School canteens operating during term time

Six-monthly cleaning is the most common schedule for Scottish operators. It balances compliance requirements with operational practicality.

Light Use — Every 12 Months

Light use applies to kitchens operating for 2 to 6 hours per day, or kitchens with low grease output. Examples include:

• Small cafes or coffee shops with limited hot food preparation
• Office kitchens used for light catering
• Community halls and function rooms used occasionally
• Kitchens producing predominantly low-fat food

Seasonal or Occasional Use — Every 12 Months or as Required

This category covers kitchens used for less than 2 hours per day, or kitchens that operate only during certain periods of the year — for example, seasonal hospitality venues or event catering facilities. Annual cleaning is the minimum, but the system should be inspected before each period of use.

Grease Depth Measurements Override the Schedule

The risk categories above are minimum frequencies. TR19 also requires that grease depth is measured before and after each clean. If measurements show that grease is accumulating faster than the standard schedule allows — for example, if a kitchen classified as moderate use is showing heavy grease levels at the six-month inspection — the cleaning frequency must be increased.

This is why it matters to use a contractor who actually measures grease depth rather than simply cleaning on a fixed schedule. The measurements are the evidence that your system is being maintained to standard.

What Happens If You Miss a Clean?

Missing a scheduled TR19 clean does not just create a compliance gap — it creates a paper trail that can be used against you. If a fire occurs and your cleaning records show a missed or overdue clean, your insurer will use that as grounds to reduce or refuse a claim. EHOs can also issue improvement notices and, in serious cases, close a premises where fire risk is not being managed.

The practical advice is straightforward: book your next clean before the current one is complete, and keep your TR19 certificates on file for at least three years.

How Deep Clean Scotland Can Help

We work with Scottish operators to establish the right cleaning schedule for their operation, based on actual grease depth measurements rather than guesswork. After every clean, we issue a TR19 compliance certificate and a full written report — and we will remind you when your next clean is due.

If you are unsure which risk category applies to your kitchen, or if you have not had a TR19 clean recently, contact us for a no-obligation assessment.