Intelligent Fire Alarm SystemsConventional fire alarm systems provide an adequate and cost effective fire alarm system for many small buildings. In larger, more complex building however, more sophisticated “intelligent” fire alarm systems tend to be used. These systems offer benefits in speed of detection, identification of the location of a fire and easier maintenance. Intelligent systems also offer tolerance to faults in the system wiring, which allows a single pair of wires to be used to connect a large number of devices to the system, allowing cost savings in the wiring of large systems. In larger installations, the benefits of improved maintenance and reduced cabling cost are overwhelming. Currently, the point at which an intelligent system becomes economical is around 6 zones.
Figure above demonstrates an example of single loop intelligent fire system layout. The wiring is looped, and connects to the control panel at each end. All detectors, call points. Sounder and interface modules are wired directly to the loop, each having its own address.
The control panel communicates with each device on the loop, and if an alarm or fault condition is signalled, or if communications are lost with one or more detectors, the appropriate response is triggered. The loop can be powered from each end so that if the loop is broken at any point, no devices are lost. In addition the use of short circuit isolators minimises the area of coverage lost in the case of a short circuit.