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Turning the screw on fire dampers
Gary Nicholls, managing director of ductwork risk experts Swiftclean, looks at why the latest version of the BESA’s (Building Engineering Services Association’s) VH001 (version 3) guidance document on testing fire dampers, issued this summer, advises that a fire damper installed using self- drilling screws could now be deemed a test failure
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istorically we have not, as a building services industry, given enough focus to what happens inside ventilation ductwork once it
is installed. This has been addressed in more recent years with the advent of TR19®, but one aspect, that of fire damper maintenance, still lags behind, remaining something of a challenge. We have long known that ductwork hygiene can affect indoor air quality and therefore the health and wellbeing of a property’s occupants. However, what has been overlooked far too frequently, and neglected for far too long, is the very real prospect that an incorrectly installed or non-functioning fire damper can mean the difference between life and death.
It is disappointing to note that, many years since the annual testing of fire dampers became a legal requirement, not only is this not yet on the regular maintenance schedule for all building managers; there are still far too many incorrectly installed fire dampers which come to light at their first inspection and testing.
When visiting new clients, we often find
fire dampers installed at the wrong point in the ductwork, so they don’t reinstate the compartmentalisation provided by an internal fire- resistant wall through which ductwork passes. Some have been installed upside down, so their steel louvres won’t close as required to create a barrier in the event of a fire. Still more have been left propped open for airflow testing, and then forgotten, so that obstructions will not allow them to close in a fire situation, as they are designed to do. Currently under the spotlight is the worrying use
of self-drilling screws, where fire safety breakaway joints are required. Large numbers of spring- loaded fire dampers in particular, have been found within existing ductwork, installed with self-drilling screws. Many fire dampers are designed to be fixed using fittings, which melt in the event of a building fire. This is necessary so that the fire damper stays strategically in place, even if the ductwork distorts
Gary Nicholls, managing director of ductwork
around it due to the heat. A self-drilling screw, on the other hand, does not melt as the temperature rises and the fire intensifies. So the fire damper can be pulled out of place from the fire barrier it is designed to protect as ductwork distorts, and even if its louvres do close, the all-important fire-resistant barrier could be breached as the fire damper enclosure may be ripped out of the fire barrier due to incorrect fasteners being used. Version 3 of the BESA’s VH001 guidance document on fire damper testing, released in August 2022, reiterates that self-drilling screws should not be used at all when installing fire dampers. Whilst a damper may function in its performance test, the client should be advised of the potential risk in a fire situation on the discovery of self-drilling screws. Therefore, any detection of self-drilling screws during an inspection and test of the fire damper should result in the recording of an advisory note that the self-drilling screws should be scheduled to be replaced, where a breakaway joint was required. On first tests and inspections, the presence of
self-drilling screws is one of the aspects that skilled technicians are now being trained to observe and report on. This does mean that this additional fire risk should be gradually addressed and resolved as more fire damper tests are carried out. Finding and replacing them is good news for the safety of each building, so we do urge more building managers to prioritise and adequately budget for fire damper testing and resultant remedial works. We still face some of our greatest challenges in gaining full access to the ductwork. This is frequently a problem when cleaning ductwork for compliance with TR19®, but is also something that we hope will be borne in mind during the current revision to DW144, the standard which governs the design and installation of ductwork. Clearly, being able to access the entire length of the ductwork is essential for successfully cleaning the ventilation system to ensure cleanliness and to help promote good indoor air quality. It is, arguably, even more vital that we are able to access and test fire dampers, which can be truly life critical. This is an issue that we really can’t afford to screw up.
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Ductwork & ductwork cleaning
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