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Defeat false fire alarms

Unfortunately, false alarms are common and when they occur, can cause major disruption and major financial penalties. Furthermore, as buildings become more complex with many occupants and users with different needs, safe evacuation can become complicated, putting occupant safety at risk. As a result, false alarm reduction and the signalling of evacuations only when alarms are genuine is now a top priority in many countries. The latest generation of intelligent fire systems do more than ever to help and use a variety of methods.

The design and planning of effective false alarm management starts with the fire risk assessment and the specification of a fire system that can cope with the demands that will be placed upon it.

The fire industry has implemented two different approaches to the false alarm issue, both focusing on signal verification. The first is based around detector technology, which functions by screening false signals in the detector heads themselves. The second focuses on the fire panel, analysing the signals received from sensors and interpreting this information to determine if the fire signal is real and take further action. Advanced and other forward-looking manufacturers are bringing these approaches together to combat false alarms from multiple directions.

Advances in the capabilities of detectors, particularly point devices, have been a driving force in the reduction of false alarm incidents. The latest detectors use smart algorithms to distinguish a real fire from a false signal, which may be caused by steam or cooking smoke. Some detectors have operating modes designed for particular areas or likely fire types. The detectors themselves are becoming more complex and can detect and analyse more signals from more on-board sensors.

The real power of any system comes from combining detector data with an intelligent fire panel. At a basic level, this allows individual detectors to be used in combination or in different modes to help prevent false alarm incidents.

A well-designed system can achieve much automatically, or with very minimal human input. However, in recent years the involvement of building occupants in certain verification models has been shown to be very effective, and some manufacturers have developed dedicated false alarm input devices to facilitate this.

Taking the form of loop devices, such as Advanced’s AlarmCalm Button, or restricted repeaters, these allow the validation of a local alert by the occupant of a room or apartment. The cause and effect is set such that each apartment has a pre-set verification time in which the alarm system will monitor a signal detected from a device within it. If the signal clears before the end of the verification period the system resets, if it is still present the next stage of the alarm is implemented, usually a full fire signal.

On hearing a local alert and being made aware the detector in their apartment has detected a fire, the occupant can press the AlarmCalm Button, (if they believe the signal is a false alarm), to extend the automatic verification time, by a pre-programmed period. This gives additional time for a false signal to clear, possibly allowing the fire system to reset. Again, if the signal persists beyond the second stage verification time, the system will progress to a full alarm, likely evacuation and all associated outputs.

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