We have seen a rapid growth of installed automatic fire detection (AFD) and automatic fire alarm (AFA) systems due to their success in providing an early warning in the event of a fire, saving lives and limiting property damage.
While the fire service is dealing with a false alarm they are not available to tackle real fires, they waste essential resources (putting lives at risk) and they disrupt other activities such as training and community fire safety work.
However, the problem is not exclusive to the fire service as false calls (referred to as unwanted fire signals) also erode your confidence in the value and reliability of your AFD systems and can cause costly interruptions to manufacturing work procedures.
What is an "unwanted fire signal"?
Any fire alarm or fire signal other than a genuine fire or test signal.
What can cause the "unwanted fire signal"?
An “unwanted fire signal” can be caused by a variety of reasons, most of which can be eliminated by careful planning. Typical sources of false alarms are:
- activation of a smoke detector by airborne pollutants
- vandalism/malicious action
- human error (generally due to unfamiliarity with the system)
- faulty or non-maintained equipment
What can you do to reduce the “unwanted fire signals”?
If there is definitely no fire:
- silence the fire alarm but do not reset the control panel as this will cancel the indications required for investigation purposes
- check the indications on the control panel and establish the area (zone) of the building where the fire alarm originated from. Your system may also indicate the precise location of the actuated device
- as soon as possible after the unwanted alarm occurred, visit the area and locate the break glass call point, heat or smoke detector that has been actuated
- attempt to establish the reason why the call point or detector was actuated. It is also useful to talk to people who were in the vicinity of the actuated device when the alarm occurred. Ask them if they know what happened and why. However it may be necessary to investigate further to determine the real cause e.g. vandalism or accidental damage to a break glass call point or insects entering a smoke detector
- if the actuated detector cannot be readily located, it may be that it is fitted in a duct or above a false ceiling. Check to establish if the detector location drawings are available and if so, use these to help locate the detector. Break glass call points should be easier to locate as they should be mounted in clearly visible positions
- if the control panel does not indicate the location of the fire alarm or if there is no actuated detector, call in the maintenance company as the problem may be due to an equipment fault
- the occupier should accurately record all the information relating to the fire alarm incident in the system log book irrespective of whether it was a genuine or unwanted alarm. This is very important as the information may be needed at a future date
- if unwanted alarms continue and the cause is not evident or remedial actions are unsuccessful, then it is useful to analyse the times at which unwanted alarms occur and the locations from which they originate. This will help to establish if there is any pattern that may help to identify the cause e.g. cooking prior to meal times or a boiler switching on early in the morning.
The investigations and the analysis should lead to a conclusion that the unwanted alarms are the result of one or more of the following causes:
- Human error. It is likely that the problem can be overcome by a change of existing practices e.g. the issuing of 'permits to work' or the training of building occupiers Examples of this type of problems are:
- smoke caused by building contractors undertaking 'hot work' close to smoke or heat detectors
- alterations to the fire alarm system wiring without isolating the system
- Process induced alarms. Many unwanted alarms result from processes undertaken adjacent to fire detectors, particularly smoke detectors. A well known example being the result of burning toast in a toaster. Such unwanted alarms can be remedied by either changing the location of the offending process, changing the detector type or its location or by changing the way the fire alarm system is configured
- Equipment faults. If there are equipment faults, these will need to be discussed with the fire alarm system maintainer and appropriate action taken to remedy them. Effective, regular maintenance, which includes the internal and external cleaning of smoke detectors, will minimise such faults occurring in the first instance
- Malicious actuation. This cause can be the most difficult to determine and often requires careful analysis of the occurrences. Examples include:
- the malicious operation of break glass call points
- the illicit ownership and use of call point test keys e.g. by school pupils
- the intentional directing of smoke, e.g. from a cigarette into a smoke detector
- actuation of an unsecured control panel usually as a result of the control enable key being left in the panel.
You should consider all these factors in relation to your building and develop a plan to avoid unwanted alarms.