False alarms – also referred to as 'unwanted fire signals' – can divert firefighting resources from real fires, erode your confidence in the value and reliability of your automatic fire detection systems and cause costly interruptions to your business.  

False alarms can be caused by a variety of reasons. You will find a comprehensive list of possible causes in 'Working out the cause' below, but some typical causes 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

Fortunately, most of these can be eliminated by careful planning.

After ensuring there is definitely no fire, follow these steps to find out why there was a false alarm:

1. Silence the fire alarm, but do not reset the control panel as this will cancel the indications required for investigation purposes.
2. Check the indications on the control panel and establish the area (zone) of the building where the fire alarm originated from. If your system is an 'addressable' alarm system, it may also indicate the precise location of the activated device.
3. 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 activated.
4. Attempt to establish the reason why the call point or detector was activated. It is also useful to talk to people who were in the vicinity of the device when the alarm occurred. Ask them if they know what happened and why.
5. You may need to investigate further to determine the real cause for example, vandalism or accidental damage to a break glass call point or insects entering a smoke detector.
6. If the activated 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.
7. If the control panel does not indicate the location of the fire alarm or if there is no activated detector, call in the maintenance company as the problem may be due to an equipment fault.

• 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 you cannot find the cause, or attempts to rectify it 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 see if there is any pattern, which may help to identify the cause e.g. cooking prior to meal times or a boiler switching on early in the morning.

For free advice on how to reduce unnecessary fire calls caused by false alarms, please contact our team by:

• phone on:  01622 212 427   
• email to: buildingsafetyenquiry@kent.fire-uk.org

These investigations and the analysis should point to the unwanted alarms being caused by one or more of the following :

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, for example 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.

We advise that you consider all these factors in relation to your building and develop a plan to avoid unwanted alarms.

The Fire Industry Association have published helpful Guidance for Responsible Persons regarding the management and ultimate reduction of false fire alarms. This guidance looks at the classification of false alarms, system compliance, action plans, keeping records, maintenance, and more.  

View or download 'Guidance for Responsible Persons on False Alarm Management of Fire Detection and Alarm Systems' from the Fire Industry Association.

Please note this Guidance is currently only available in PDF format.