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Defeat false fire alarms

In most jurisdictions around the world, false alarm reduction remains a key objective. The UK has taken a leading position with, for example, the Fire Industry Association raising awareness and campaigning for best practice, and the industry responding with new solutions.

The FIA reports that the annual cost of false alarms is £1 billion per year. These come from a wide range of sources including detection of ‘incorrect’ signals, malicious damage, poor maintenance and environmental conditions. The cost is not only financial, however, as repeated alarms can reduce the credibility of and response to genuine fire alarms. The latest technology from the active fire protection industry can significantly help reduce false alarms.

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. Advanced’s own technology, AlarmCalm, allows total control and configurability of the false alarm strategy across any site.

Broadly stated, fire panel technologies have focused on two different approaches to false alarm 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. Many forward-looking manufacturers, including Advanced, are bringing these approaches together to combat false alarms from multiple directions.

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.

Detectors also have better physical protection from environmental pollutants and dust/insect ingress than ever before. These should be considered on brand selection as manufacturers spend time and money designing chamber shapes and filters to reduce these false alarms.

The real power of any fire 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. For example, multi-sensor detectors can be switched between heat and smoke modes to confirm a signal. Several detectors can also be combined using double-knock or coincidence programming to fulfil the same purpose.

Modern addressable panels are powerful computers dedicated to fire operation and can match detector signals with powerful cause-and-effect programming, bringing a range verification and investigation delay procedures into play that can significantly reduce false alarms. 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 (Advanced’s is called the 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 that the detector in their apartment has detected a fire, the (trained) 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.

Human involvement in the verification process means that failsafes must be robust, even when the individuals involved have undertaken training. Human input devices must not be permitted to delay a fire signal beyond the pre-programmed period, and the system should only allow them to be used once before a system reset. They should also be superseded by any call point activations or, for example, multiple areas detecting fire signals simultaneously. Verifications must not be permitted in common areas and must be configured to the relevant standards.

While designated responsible people should always have the primary role in signal confirmation, the benefits of involving other trained individuals are hard to ignore.

Attacking further causes of false alarms, the fire panel can work with its loop devices to facilitate easier maintenance, indicate the level of contamination in a detector, allow remote monitoring of device status and faults and build in investigation delays that may be useful on sites where malicious damage is common.

Today’s technology allows fire system networks to become very large and a key consideration in false alarm reduction, is the need to ensure the system can be programmed easily and effectively. Can the false alarm strategy be configured accurately? Can areas within the building, such as apartments, common areas etc be identified and managed? The long-term benefits and savings of this approach make the investment in solutions that are easy to implement worthwhile.

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