Comprehensive Overview of the TR19 Regulation & Standards

No matter the industry your business operates in, if you have ductwork in your building, you must ensure it is compliant with TR19 regulations or risk invalidating your insurance. 

But what is TR19, and why is it important? We answer these questions in this blog post and explain in detail the various components of TR19 that ensure your property is compliant with the required industry standards. 

We also explain why Deduct is perfectly positioned to carry out ductwork cleaning on your behalf to ensure your business is TR19 compliant. 

What are TR19 Regulations? 

TR19 regulations are best practice guidelines issued by the Building Engineering Services Association (BESA) regarding the maintenance of ductwork. The regulations stipulate in detail how you should maintain your building’s ductwork to ensure the workplace is safe for the health and well-being of your employees. 


What Should I Know About TR19 Regulations? 

For 20+ years, the TR19 guidelines have been the gold standard when it comes to ductwork cleaning. Most insurance companies require a certificate that stipulates ductwork has been cleaned to TR19 standards before issuing insurance.

Essentially, if you own or operate a commercial or industrial building, it’s imperative that you clean your ductwork in compliance with TR19 and document the paperwork to prove it.


What Does the TR19 Standard Entail? 

Ensuring your ductwork is compliant with TR19 guidelines is so important, as it ensures your building is safe and compliant with Health & Safety and Fire Safety regulations. But what does TR19 actually entail? We take a look at some of the crucial aspects of TR19 below, so you can see what is expected of you from a cleaning and maintenance perspective.


Access Mechanisms 

Access is comprehensively covered within TR19. You must ensure that access to and the inside of your ductwork is clear and free from irregularities. This is crucial to ensuring that grease, dust, and other pollutants can’t accumulate and degrade the quality of air circulating within. 

What’s more, your ductwork must be fitted with sufficient access points so that the system can be regularly inspected and cleaned. This should have been taken care of at the time of installation of your ducts, as access is largely determined by the position of the ducts and the design of your building. 

But access panels for inspection must be comprised of the same material as the ducts themselves and should include the likes of seals and quick release catches, which are vital safety and maintenance features. The panels should also be installed at a position that is easy to access, typically on the top or at the side of the ductwork. 


Inspection Mechanisms

The next vital component of TR19 refers to the inspection of your ductwork. It’s incumbent upon building owners to regularly check and inspect the interior of their ductwork and decide whether they need to be cleaned. This is so important to prevent the accumulation of grease and other dirt, which affects the quality of airflow. In terms of the actual inspection, it’s recommended that you perform the following two tests regularly: 

  • Wet Film Thickness Test (WFTT) 
  • Deposit Thickness Test (DTT)


These tests allow you to check for the build-up of grease, soft deposits, and harder, carbonised deposits at the same time. It’s recommended that these tests be performed at least once every twelve months, but it’s advisable to test more regularly than this if your ducts are in constant use. 

TR19 also stipulates that inspection should occur at the following points within your ductwork: 

  • Canopy/extract plenum behind the filters 
  • Duct one metre from the canopy 
  • Duct three metres from the canopy 
  • Duct midway between the fan and canopy 
  • Duct upstream of the fan
  • Discharge duct downstream of the fan


Cleaning Processes 

In addition to regular inspections, TR19 provides stringent guidelines on how to clean your ducts. This includes: 

  • Hand wiping the system manually 
  • Hand scraping the system and removing heavy deposits of dirt or grease 
  • Using chemicals to soften or dissolve stubborn deposits 
  • Utilising a high-pressure washer to dislodge particular deposits 
  • Blasting contaminants off duct and component surfaces 


It’s important to clean your ductwork in accordance with TR19 guidance. Specifically, when you use chemicals, you must ensure they’re removed from the surfaces when you’re done. How often you clean your ductwork depends on their usage, which TR19 classifies in the following way: 

  • Heavy use (12-16 hours per day): every three months 
  • Moderate use (6-12 hours per day): every six months 
  • Light use (2-6 hours per day): every twelve months 


Post-Cleaning Verification Methods 

Just as important as cleaning and maintaining your ductwork is keeping the required documentation to ensure it can later be assessed by the relevant parties. You must, for instance, receive and keep a post-cleaning report that stipulates: 

  • The systems and surfaces that have been cleaned 
  • Pre & post-clean measurements 
  • Photographic records 
  • Details of any additional work that has been carried out relating to the ductwork 
  • COSHH data regarding the use of cleaning chemicals 
  • Recommendations about cleaning your ductwork in the future 
  • General observations on the cleanliness and performance of your ductwork system 
  • Schematics that indicate any uncleaned areas with an explanation why it remains uncleaned 


How to Ensure your System is Cleaned to TR19 Standards 

While it’s possible to clean and maintain the ductwork within your building internally, considering the stringent stipulations within TR19, it’s advisable to work with a trusted ductwork cleaning company that ensures all of the requirements are met. 

At Deduct, we specialise in cleaning and maintaining ductwork for businesses throughout the UK and ensure your systems are cleaned in relation to TR19 guidance.

You can get in touch with us to arrange the cleaning of your ductwork or to ask us any questions you have about TR19. Drop us a message via our website, or call us directly on 0333 772 0089.