BS 5839 fire detection and alarm systems for buildings; how the 2025 revision improves fire safety
BS 5839-1:2025 is the best practice guidance in the UK for professionals who design, install, commission, and maintain fire detection and alarm systems. Revision to the code of practice was based on extensive consultation and incorporates lessons learned from fire incidents, including a fatal fire at a London care home.
The 2025 revision supersedes BS 5839-1:2017’s code of practice for the design, installation, commissioning and maintenance of fire detection and alarm systems in non-domestic premises. Application of the revised code across new building works including extensions and alterations will thereby enhance fire protection, reduce risk, and underpin the continued safety of buildings and their occupants.
What are the key changes involved?
- Annex updates: revised annexes provide clearer guidance, especially on visual alarms
- Clear zone plans: multi-zone buildings, including areas where people sleep, must have zone plans for faster emergency response
- Automatic fire alerts: in residential care environments, fire alarms must send automatic alerts to monitoring stations for quicker action
- Smoke detectors in sleeping areas: automatic smoke detectors are now preferred for use in rooms where people sleep
- Simplified call point placement: manual call points should be placed only in occupied areas
- Guidelines for modifications: clearer rules for modifying existing systems to stay compliant
- Updated terminology: ‘care homes’ are now ‘residential care premises’, and ‘fire service’ is ‘fire and rescue service’
- Visual alarm devices: greater focus on visual alarm signalling, especially for those with hearing impairments
- Routine servicing clarification: routine servicing is no longer considered a system re-design.
The 2025 revision was conducted ahead of schedule by FSH/12/1 to improve safety measures. FSH/12/1 is the British Standards Institution (BSI) committee responsible for developing and maintaining British Standards related to installation and servicing of fire detection and fire alarm systems. Their work directly influences the way fire alarm systems are designed, installed, and maintained across the UK.
Application of the 2025 revision
Changes deriving from BS5839 are not retrospective, except for maintenance procedures. The way in which planned fire maintenance is carried out must now comply with the 2025 code of practice.
However, whilst maintenance providers may note recommendations for improvement based on the 2025 standard, retrospective upgrading of fire systems to BS 5839:2025 is not mandatory, as the 2025 code of practice was not a legal requirement for fire systems installed before that time.
Recommendations to uplift existing fire systems may be made where reasonable and when the safety of the building occupants is compromised. However, the client retains the right to refuse these works if the recommendation is non-retrospective.
Residential care providers do not need to re-inspect their properties and Fire Risk Assessments (FRA) should continue to be carried out periodically as part of standard operating procedures.
The 2025 code of practice applies to additional or new works carried out. For example, where a new wing is planned for a care home, the existing fire alarm system would need to be modified and extended to cover the new area. While a new extension/modification to the fire alarm system must comply to BS 5839:2025, pre-existing elements of the fire alarm system do not need to be uplifted to match BS 5839:2025 as long as the pre-existing system complies with previous standards.
Compliance with BS 5839:2025 applies to any extension or modification to an existing fire alarm system, no matter how small. For example, installation of one additional smoke detector or manual call point would need to comply to BS 5839:2025.
The UK’s Fire Industry Association (FIA) is providing continuing professional development on BS 5839:2025 during the summer of 2025 for fire safety compliance providers, enabling competent providers to evidence that their knowledge is up to date.
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