When specifying a smoke control system, designers devote a lot of attention to choosing the right equipment - fans, vents and smoke barriers - for the job. They follow the standards set by EN 12101 for fans, vents and smoke barriers so that when the time comes, whatever the circumstances, the equipment will be capable of the job expected.
Electrical wiring – the vital link
But if this equipment relies on power supplies and signals to operate and continue operating during a fire, specifying the right equipment is not enough: designing and specifying the cabling linking the elements of the smoke control system requires just as much attention. Electrical wiring is the vital link between the control system and the equipment, the source of power and backbone of the smoke control system on which success or failure depends.
A life could depend on the right cable selection
We know that the majority of smoke control systems will only ever have to operate during commissioning and then during testing and maintenance. Only a very few will ever have to work in a fire. But, every so often a smoke control system has to operate at the limits of its capability – and someone’s life could depend on it. It is for this circumstance that the system needs to be properly designed, and this includes the electrical wiring connecting it to the control system.
Cable selection – a complex subject difficult to navigate
Cable selection is a complex subject, often not fully understood by specifiers and practitioners. Guidance is available, but it is distributed in a large number of standard documents and codes of practice, which adds further to the complexity.
Update to BS 8519
BS 8519: 2010, ‘Selection and Installation of Fire Resistant Power and Control Cable Systems for Life Safety and Fire Fighting Applications – Code of Practice’, covers a lot of what is needed to be known.
Work is about to commence on an update to this standard. Hopefully if the standard for cables is to be raised, it will be with a full evidence based justification. Too often standards are re-written introducing ever increasing levels of testing and certification which have no correlation with the way in which the end-product will be used or applied.
Navigate the complexities of cable selection with our whitepaper
Download our whitepaper, which can help you navigate this complex subject: Cable selection for smoke control – Making the right connections.
Conor Logan is a Technical Manager of Colt UK, Smoke and Climate Control Division. Conor designs innovative smoke control and HVAC systems and is also Chairman of the Smoke Control Association.