The true cost of false fire alarms

More than 75% of automatically generated fire alarms in the UK are false or unwanted. That’s a big problem when you consider the huge number of commercial and industrial premises that are fitted with automatic alarm detection systems and the number of unnecessary call-outs they cause for the fire and rescue services.

It’s good news for public safety that automatic alarms and detection systems are widely installed. But 75% inaccuracy means that the UK fire brigade can’t cope with the number of alarms it receives. Ideally, a team would respond immediately to every alarm and check for fire, so they can take life-saving action if needed. But there are so many alerts that they don’t have enough firefighters or appliances to do this.


That’s why fire services often use triage to find out if alarms are real or false. Specialist operators phone the alarm site and ask a member of staff to confirm if there is a fire. But this may not be accurate, if the person can’t monitor or check the whole building. Or there may not be anyone on site to check.


Fire safety experts agree that an acceptable target would be 10-20% false alarms, or 80-90% genuine alarms. 

The cost of false alarms in the UK

Every time the Fire Service sends a team out to a false alarm, it causes unnecessary expense. And there’s an extra overhead in funding the call centre teams. The Welsh Government reported on false alarms in June 2015, finding that responding to them was a “wholly unproductive activity” that costs £3m a year. Assistant Chief Fire Officer for South Wales Fire and Rescue Services, Andrew Thomas, said, “What we need to do is to understand how to reduce the number of alarms being generated, and once you’ve done that, that stops us being called.”


According to Home Office (government) statistics, England’s fire and rescue services alone attended around 226,000 false fire alarms in the year 2017/18 ending June 2018. That’s 41% of total call-outs. The Fire Industry Association (FIA) estimates that false alarms cost the UK over £1bn per year.

The human risk of false alarms

Because teams are sent out on so many false alarm calls, it means they don’t get to the genuine incidents as quickly. The risk to human life because of this is a cause for enormous concern.


An independent media investigation found that each call-out in North and West Yorkshire takes one fire engine and four firefighters out of service, costing between £323 and £355 per hour. “The practical cost is in the loss of this lifesaving resource,” said David Williams, chairman of the Yorkshire Fire Brigade’s Union. “That’s time you can’t get back. That’s when it’s critical.”

There’s also a dangerous effect on people’s behaviour, if they inhabit or use buildings that have a lot of false alarms. After a while, they will feel that there’s no need to react to an alarm. But for the one in ten or a hundred alarms that’s genuine, complacency could be fatal.

There’s a cost to businesses too

For building and business owners, false alarms disrupt everyday activities. They’re inconvenient and sometimes stressful for building users. They can cause customers to stop using the building or business. For example, a hotel that has frequent false alarms during the night will quickly deter its guests from booking again. Some English fire services have begun to charge the worst offenders for false alarm call-outs in an attempt to recover the cost of their time and resources. 

What causes false alarms?

Many false alarms are caused by stimuli that trick sensors into thinking there’s a fire. Cooking – like grilling bacon or burning toast in a restaurant, cafeteria or hotel kitchen – is one culprit. Industrial processes like welding and grinding can trigger false alarms in factories. Steam from showers in hotel rooms is another common cause. In all kinds of public environments, cigarette smoke, dust, vaping, aerosols and cleaning products can trick detectors into automatically reporting a fire. 

Technology can reduce false alarms

Alarm and detection providers are using smarter technology to help tackle this problem. A recent report from the Association of British Insurers (ABI) highlighted the results of comparison tests of single-sensor and multi-sensor devices (see “ABI/FPA sensor tests in the UK: the alarm immunity test” below). The multi-sensor devices had much better immunity to false alarms.


Multi-sensor detectors can sample a combination of different fire indicators, including heat, smoke, carbon monoxide and light. Individually, these are unreliable markers, but a device that can sense some or all of them is far more accurate. The new, intelligent systems can also be calibrated for the environment, applying the right level of sensitivity to detect and filter stimuli that can be present without posing a fire risk. These might include cigarette smoke, dry ice or cooking fumes.


Responsible alarm manufacturers have developed multi-sensors that can be dropped into existing systems, replacing single sensors. This makes it easier and more affordable for building owners to adopt the new technology.

Making a difference in public environments

For one Edinburgh hospitality group, the latest technology has made a difference to the safety and comfort of staff and guests. G1 Group’s nightclub Cabaret Voltaire uses dry ice, which can deceive alarm sensors. Its Grassmarket Hotel experienced many false alarms because of shower steam, aerosols and cooking activity. With built-in ASAtechnology TM (ASA = Advanced Signal Analysis), Siemens detection systems installed by our partner Black Box Fire & Security now detect real fire and smoke early and reliably, filtering out deceptive signals. The result is no more false alarms or costly business interruptions on G1 Group’s premises.

ABI/FPA sensor tests in the UK: the alarm immunity test

The Fire Protection Association (FPA) conducted tests on behalf of the Association of British Insurers (ABI) in a dedicated smoke detector demonstration facility at the Fire Service College in Moreton in Marsh. The stimuli tested were welding, steam from a kettle, toasting bread, smouldering wood, burning heptane and welding that ignited heptane.


Four Siemens models were tested. There were two traditional smoke detectors and two intelligent devices. The intelligent devices were tested with different settings designed for three different environments:

  • Sensitive/fast response in clean environments (offices, sleeping accommodation)
  • Medium response, suitable for everyday environments
  • Targeted response, where immunity to false alarms is critical (industrial workshops or where detection is linked to a suppression system)

The report found that the intelligent devices were more discerning and slower to react to false stimuli such as steam or smoking toast, without compromising the speed of reaction to real fire threats.


The FPA summarised their findings in the report:


“These simple demonstrations show clearly the potential benefits of using intelligent detectors fitted with multiple sensing units. They also illustrate that it is important for the configurations used to be carefully tailored to the environment… to ensure both immunity to false alarms as well as a rapid response to real fire threats…”


The FPA has shared the test results with the British Standards Institute (BSI) and the Building Research Establishment (BRE) to support their work in updating standards that relate to false and unwanted fire alarms.

Picture credit:  Getty Images / Chemistry

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