The upsurge in large-scale residential schemes and commercial towers with fire fighting shafts has created the need for much more sophisticated control systems with highly complex sequences of operation for their smoke ventilation schemes.
In searching for solutions, the industry has looked at the possibility of using existing systems, such as fire alarm control systems, for smoke ventilation. In a previous post, I analysed the key functionalities that are necessary for a smoke ventilation control system to perform effectively.
Do fire alarm control systems deliver on all the functionalities you need?
- A fire alarm control system is reasonably robust, generally has multiple back up features and, in this respect, is a good match for this type of application.
- The principal drawback is that the fire alarm protocol structure often doesn’t know how to say no: by its very nature, it is designed to record and react to events – it would be a rare case when you would want a system to detect a fire and not to react.
- For a multi compartment smoke ventilation system, it is the opposite. If more than one zone is opened, firstly the ventilation rate is reduced and so the performance is adversely affected. Secondly the compartmentation between the zones is compromised, increasing the potential for smoke and fire spread to other areas of the building.
- Fire alarm control systems may not offer any form of override capability to allow a fire officer, for example, to cancel the original event and activate an alternative operation depending on the system parameters and the conditions at the time.
While fire alarm control systems do meet the all-important requirements of robustness and reliability, their inability to “say no” is an important drawback. They can offer an adequate solution for simple applications such as large single storey buildings or even simple atria or shopping malls, where the mode of operation is the same regardless of the fire location. However, in the case of multi compartment smoke ventilation systems for high rise residential or commercial buildings for example, where the sequence of operation is dictated by the fire location, they are not the answer.
Conor Logan is Associate Technical Director of Colt UK, Smoke and Climate Control Division.