OPINION
the actuation originates from an automatic detector or a manual call point. Advanced twowire systems can go even further by offering the option to respond differently to signals from alarm devices based on their type and location. For example, in our apartment block, consider the benefits of the following set-up option; a fire signal from a manual call point or automatic detector in a common area can be arranged to instantly trigger sounders and beacons throughout the entire premises, whereas a fire signal from an automatic detector in one of the apartments can be arranged to initially trigger the sounders and beacons in that apartment only. If, however, the fire signal from the apartment persists for, say, one minute, the alarm is raised throughout the premises.
This arrangement is useful as a fire signal from a single apartment may well mean nothing more than someone has burnt their toast, in which case raising a general alarm is unnecessary and disruptive. This complies fully with Part 1 and Part 6 of British Standard BS5839. It’s also worth noting that the detectors used in two-wire systems are by no means all the same. The most useful are types with both smoke and heat sensors. In most instances, a combination of heat and smoke detection will give the optimum balance between fast response to a real fire and freedom from false alarms. However, there are locations where it is preferable to reduce the influence or even disable one or other of the detection functions, and good detectors will allow the installer to do this.
more contracts and improve profits, while at the same time gaining satisfied customers! To receive a free pocket guide on installing twowire systems which are fully compliant with BS5839 standards, please email karen.evans@ fike.com, or visit www.fikesafetytechnology. co.uk/twinflex.html to download a pdf version.
Hopefully this short article has shown that, in all but the very simplest and most complex of fire protection installations, the two-wire option offers the best value for money. These types of systems make it easier for contractors to win
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