London Fire Brigade

Fire alarms

False fire alarms

Automatic fire alarm systems help to keep premises and their occupant's safe by providing an early warning of a possible fire and enabling people inside the building to evacuate. However, did you know that the vast majority of  signals from automatic fire alarms are not actual fires?  Fire alarm and detection systems react to an increase in heat or the presence of smoke. Unfortunately, they can also react to things such as steam, cigarette smoke, aerosol sprays, and light smoke from cooking.

When a fire alarm goes off, as a result of anything other than a real fire, this is considered to be a false alarm. False alarms have local consequences that could include disruption and expense. Reputable alarm system maintainers will be able to provide useful advice in how to reduce and manage false alarms. 

If Fire & Rescue Services are asked to attend a false alarm, this is considered to be an Unwanted Fire Signal. We encourage the use of automatic fire alarm systems, due to their value as a fire warning mechanism. However, we expect owners of these systems to implement safe working practices to reasonably prevent the Fire & Rescue Service from being asked to attend false alarms, particularly where false alarms are a regular occurrence.


What are the consequences of unwanted fire signals?

  • It ties up our fire engines when they could be going to real emergencies or our firefighters could be carrying out vital training;
  • Frequent false alarms in a building cause staff to become complacent and less willing to act quickly when the alarm activates,
  • • When we have to travel at high speed to attend ‘emergency’ calls, the public and our crews may be subject to unnecessary risk.

How to avoid

 To help avoid Unwanted Fire Signals, please ensure that:

  • The fire risk assessment for your premises is up to date and reflects the conditions in your premises. 
  • Your fire alarm and detection system has been properly designed, installed, and commissioned and that it is properly managed and maintained.
  • You have people designated to take responsibility for the management and maintenance of your fire alarm system.
  • False alarm causes are investigated with appropriate curative action taken to prevent unnecessary recurrence and ensure effective system operation. 
  • In the event of your fire alarm operating, the premises is evacuated, where this forms part of the fire strategy for your premises. 
  • Your fire alarm procedures include the designation of specific staff to check whether or not there are any signs of a fire, when the fire alarm sounds. 
  • If any signs of fire are found, ensure that there is a designated member of staff to call the Brigade using the 999/112 system. 
  • Any false alarms are properly recorded in the fire alarm log book, including remedial actions taken to prevent a recurrence.

For further information please contact your local fire safety office.