Fully functioning fire dampers are a vital safeguard for life and property, as Martin Hembling, Service Delivery Director for Swiftclean Building Services explains.
One of the routes through which a fire can spread is the communal ventilation system. While a single ductwork system to serve multiple dwellings makes good logistic sense, it does also introduce some potential weaknesses and hazards, so it is vital that it is designed well, installed correctly and incorporates correctly installed fire dampers which are properly and regularly maintained for the lifetime of the property.
In a multiple dwelling, it is vital to preserve the compartmentation of each individual dwelling to delay or prevent the spread of fire. Where ductwork crosses an internal fire-resistant rated wall, it creates an opening in that wall through which fire can spread. It is essential, therefore, that this compartmentation is restored by installing a fire damper – a set of louvres which remain open to allow the flow of air, but which will close automatically in the event of fire. By law, all fire dampers must be tested every 12 months in accordance with BS9999: 2017.
The method used is known as drop testing, because it ensures that the louvres of the fire damper will drop into the closed position to form a seal which restores the compartment formed by the fire wall. Unfortunately, this vital area of fire prevention has been overlooked and neglected for years but now, quite rightly, it is being scrutinised and enforced by fire safety offices and should be high on the agenda of Building Control professionals.
One of the major problems with fire dampers has been incorrect installation and lack of commissioning. We have found fire dampers in the wrong place – i.e. not in line with the fire wall – or even upside down, so the louvres would have to defy gravity to close. We have also seen them propped open by objects like cans, bottles, bricks, cable ties and pieces of string, no doubt so that an air flow test for the ventilation system could be completed, but then forgotten about. Clearly, these fire dampers were not working correctly when the building was handed over for use.
Correct installation and commissioning should be scrutinised and confirmed before the building is handed over; but we would also like to see each building have a plan in place for fire dampers to be tested on an annual basis. Without this, in the event of a fire, these louvres may not function correctly. If they don’t, they simply will not prevent the spread of fire.