What is TR19?


TR19 is the required standard to which ductwork should be cleaned, tested, and inspected. All employers have a legal obligation to ensure working environments are clean and safe as well as meet the requirements of insurance companies. The Building Engineering Services Association defined TR19 in 1988 to ensure duct cleaning and other extraction system maintenance would meet an industry-approved set of criteria. Requirements for ductwork cleaning have been categorised under high, medium, and low depending on the environment. Different organisations will need varying levels of ductwork cleaning depending on the type of company and air quality specifications. Facilities that require high levels of cleanliness, such as a hospital will have a “high” classification whereas an office space would likely fall under the “medium” category. Duct cleaning companies use the guidance outlined in the TR19 standard to determine the level and frequency of maintenance and testing required.

What does the TR19 Standard Entail


The TR19 Standard is a protocol that sets out how to properly and comprehensively clean kitchen extract and ventilation ductwork systems. It’s the most commonly used standard for this kind of cleaning and is recognised by most insurers and building engineering service providers. 

The key elements of the TR19 standard are:


Access Mechanisms


The ductwork should be designed in such a way that it can be easily accessed for cleaning purposes. This typically involves having easily accessible and removable access panels or hatches that allow cleaners to get inside the ductwork to clean it properly.


It’s vital to ensure that all parts of the access mechanism are cleaned thoroughly to prevent dirt and grease from building up and causing blockages.


The TR19 regulations state that all access mechanisms must be cleaned:

  • At least once a year
  • More frequently if there is evidence of excessive dirt or grease build-up
  • Whenever the system is serviced or repaired


Inspection Mechanisms


Ductwork must be inspected regularly to ensure that it is still clean and meets the required standards. This typically involves using a borescope or other visual inspection tool to look inside the ductwork and check for any dirt, debris or grease build-up. Tests such as Wet Film Thickness (WFT) can also be used to measure the amount of grease build-up on surfaces, while Deposit Thickness Ratio (DTR) can be used to assess the level of debris in the ductwork.


TR19 duct cleaning standards advise that inspections should be carried out periodically and not exceeding 12-month intervals.

Cleaning Processes


There are a number of different cleaning processes that can be used to clean ductwork, depending on the type of system and the level of contamination. The most common methods recommended by TR19 guidance include:


  • Manual Cleaning
  • Air-washing
  • Brush Cleaning
  • Vacuuming
  • Chemical Cleaning


In order to ensure that the cleaning process is effective, the TR19 regulations require that all cleaners are trained and competent in using the chosen cleaning method. They must also have the appropriate personal protective equipment (PPE) to protect themselves from any potential hazards.

Post-Cleaning Verification Methods


Once the cleaning process is complete, it’s important to verify that the system has been cleaned effectively and meets the required standards. This involves carrying out another visual inspection using a borescope or other similar tool. The surfaces should be visibly clean with no evidence of dirt, debris or grease build-up. Further WFT and DTR tests can also be used to verify that the system has been cleaned effectively.


A Post Cleaning Report should be generated after each duct cleaning session, detailing the methods used, the results of any inspections or tests, and any actions that need to be taken. This report should be signed off by both the cleaners and the building owner/manager. This report can provide evidence that the system has been cleaned to the required standard should it ever be requested by an insurer or other organisation.

Meet TR19 Standards & Regulations


At Deduct, our professional teams are equipped with the training and experience needed to meet TR19 standards and regulations. We’ll provide a no-obligation quote that’s bespoke to your requirements. Our highly recommended and reputable service makes use of the latest duct cleaning processes and technologies to deliver outstanding results.

clean hospital

Legal Requirements


The Health and Safety at Work Act and Occupiers Liability Act stipulate a legal requirement for working environments to be safe and healthy. These legislations include air quality which can be greatly affected by ductwork. Duct cleaning is needed to ensure a suitable system of maintenance is in place for each working environment in relation to TR19 regulations and guidance.

Why Clean Ductwork?


Ductwork and ventilation systems gradually build up dust, bacteria and mould over time. These pollutants can become harmful if left unchecked and cause health problems if air quality is compromised. In addition, the efficiency of ductwork can be reduced if systems are not cleaned or maintained, which can be both dangerous and costly if not regularly managed.

office block

Contact Us


Speak to our team today to ensure your working environment meets TR19 standards. If you’d like more information about any of our duct cleaning services or have a question regarding safety standards, please get in touch.