Ventilation – access all areas

Despite a growing awareness of the issues surrounding ventilation hygiene and safety, there are still an alarming number of potential barriers to compliance throughout the lifetime of some ventilation systems, as Gary Nicholls, Managing Director of Swiftclean and co-author of TR/19, explains.

Many more building owners and managers are now becoming aware that to run a safe and healthy building, there are a number of ventilation compliance issues to tackle. As well as complying with TR/19, the leading industry guidance document on ventilation hygiene issued by BESA, they also have to tackle the annual testing and ongoing maintenance of fire dampers within the ventilation system, which is covered by BS:9999.

A poorly maintained ventilation system can adversely affect indoor air quality which, in turn, can negatively impact the wellbeing of a building’s end users. In a residential setting, it can exacerbate conditions such as asthma, so it is essential that ventilation ductwork is cleaned thoroughly at regular intervals in accordance with TR/19. In a commercial setting, poor air quality can have a detrimental effect on concentration and productivity and has frequently been linked with raised sickness and absenteeism levels, so TR/19 compliant ductwork also makes good commercial sense.

The ductwork itself is often routed through fire resistant internal walls which are designed to delay or prevent the spread of fire. Potential openings through fire rated walls present an opportunity for fire to travel to other parts of the building, so it is essential that these openings can be sealed in the event of fire by installing fire dampers, a set of steel louvres which will close automatically should a fire occur. Obviously, it is also essential that these are regularly tested, using a method called drop testing. In 2017 BS:9999 drop testing became an annual requirement, to ensure that fire dampers will work properly if needed, and this is an area in which fire officers are, understandably, clamping down.

In the case of kitchen extract ductwork systems, regular TR/19 cleaning also helps prevent fires by removing the flammable grease deposits which are an unavoidable result of cooking. The second edition of TR/19 includes helpful tables which lay out the necessary cleaning frequency, according to each system’s classification (high, medium or low). Heavily used systems such as commercial kitchen extracts will need cleaning the most often and here the rate of deposit accumulation will define the cleaning frequency requirements.

Despite a legal requirement to comply with both TR/19 and BS:9999, which Swiftclean provides, we continue to experience physical barriers to compliance. Clearly, in order to achieve compliance, we must be able to access all areas of the ventilation system, but there are still some fundamental reasons why this is not always possible.

Ventilation systems must be designed and installed in accordance with DW144 for ordinary ductwork or DW172 for kitchen extract ductwork. TR/19 is not a design or installation requirement, but a guideline (and a legal requirement) for ongoing compliance. Ironically, DW144 and DW172 do not include the full remit of access points which are required by TR/19. A new version of TR/19 will be published in 2019 following a review of the issues concerning kitchen extract systems, and this is expected to increase the minimum access door frequency requirement from every 3 meters to every 2 meters. As there are currently no plans to review DW172, the discrepancy between the two is set to grow.

A new ventilation system can, therefore, be designed, installed and commissioned in full compliance with DW144 and DW172, but in order to achieve ongoing compliance with TR/19, we may well have to retrofit additional access doors at the very first clean. In a busy commercial kitchen, we all too frequently have to install further access points when the system is just a few months old.

In order to effectively clean an ‘elbow’ in the ductwork, we need to be able to approach the angled section from both directions, but we often find that there are insufficient access points close enough to allow a thorough clean. Again, we can usually retrofit an additional door, but it seems nonsensical to have to do this during a new system’s first clean.

This is all very well if the ductwork itself is accessible. This is not always the case. When we are carrying out TR/19 cleaning, we often encounter situations in which a solid ceiling or false wall has been added after the ventilation system was installed. We cannot then tell whether access points exist and have been covered over, or were never included. In many cases, we cannot install additional access points even if we need to, or the client would wish us to. Gaining sufficient access to the ventilation system to achieve TR/19 compliance may involve expensive major remodelling or an unsightly ceiling access hatch. A solid ceiling may look more attractive, but a suspended ceiling is usually better for achieving compliance. There are no building regulations which stipulate that the construction of ceilings or walls should preserve access to essential services for ongoing compliance. Perhaps there should be.

Since TR/19 compliance is required by law, we would argue that it should be designed into the system’s construction from the outset. This would mean updating DW144 and DW172 to include the principles in TR/19. There should also be measures in place to prevent the permanent covering of the ventilation system (and other essential services that will need ongoing maintenance) so that it remains accessible.

System design regulations ought to include sufficient access to conduct fire damper testing to BS:9999. In the event of a fire, smoke and flames can travel through the ductwork to other parts of the building, so it is life critical that fire dampers close as designed to restore the compartment created by the fire-resistant wall. This delay allows vital time to evacuate the building’s users. Fire dampers are often installed in hospitals, care homes, hotels and halls of residence, so the need to be able to evacuate residents and guests is obvious.

If your system is not compliant with TR/19, or does not allow fire damper testing, you will probably find that your buildings insurance cover is compromised. Insurers expect that in managing your building you will comply with the law so, if you don’t, you may not receive a pay-out. In the event of a fire, the legal consequences for any responsible persons can include prosecution and, if found guilty of negligence, can result in a custodial sentence.

Most of these potential problems would be solved if we designed and installed ventilation systems in accordance with TR/19 and with BS:9999 in mind from the outset. Retrofitting additional access points is more expensive than installing them during initial construction, so it makes commercial sense to provide for ongoing compliance at the design stage. If we also ensured, perhaps with a new building regulation, that any further ceiling construction and aesthetic remodelling did not interfere with safe access, we could achieve ongoing system compliance without problems. All of this is surely common sense. Why would we ignore this when good health, and even lives, may depend on it?