Understanding BS 5839-1:2025 – The Updated UK Fire Alarm Standard
On 30th April 2025, the British Standards Institution released BS 5839-1:2025, an updated version of the 2017 standard. This revision establishes the latest guidelines for designing, installing, commissioning, and maintaining fire alarm systems in non-domestic properties throughout the UK.
What Is BS 5839-1?
BS 5839-1 is the UK’s key standard for fire alarm systems in commercial and other non-residential buildings. Referenced in the Building Regulations’ Approved Document B, it specifies system classifications, component placement, performance requirements, and maintenance procedures to ensure safety and legal compliance.
Notable Changes in the 2025 Update
- Preferred Detectors in Sleeping Areas
Smoke detectors are now recommended instead of heat detectors in sleeping accommodations such as hotels, care homes, and student housing to provide quicker alerts. - Expanded System Categories
Lift shafts must be included in L4 systems. Detection in certain low-risk lobby areas is now required depending on system classification. - Refined Manual Call Point Placement
Manual call points should be installed in locations that occupants frequent to improve accessibility and reduce false alarms. - Lockdown Alert Tone Option
Fire alarm control panels can now include a lockdown tone, which must be clearly distinct from fire alarm signals. - Addressing Physical Obstructions
Installers need to consider ceiling beams or ductwork that may obstruct detectors to avoid coverage gaps. - Improved Response Times
Systems must signal activations within 90 seconds and report faults within three minutes to speed emergency response. - Battery and Cable Updates
Red mains cables are now required for easy identification, and the battery backup sizing calculations have been updated—existing systems should be reassessed. - Enhanced Visual Alarm Devices
More focus is placed on visual alarms to support those with hearing impairments. - Mandatory Zone Plans for Multi-Zone Buildings
Clear zone plans must be displayed near control panels in multi-zone sites to assist quick fire identification. - Additional Requirements for Residential Care
Alarms in residential care premises must automatically notify central monitoring stations for immediate response. - Flexible Servicing Intervals and Maintenance Standards
The service window is now 5 to 7 months, allowing more flexibility than the previous strict 6-month interval. Maintenance should cover clock checks, log updates, removal of obsolete devices, and accessible controls. Technicians are expected to maintain Continuing Professional Development (CPD). - Updated Documentation and Certification
All relevant certificates, logs, and documents have been revised. Any modifications to systems require formal Modification Certificates, and deviations must be fully documented.
Why These Updates Matter
The 2025 BS 5839-1 revision strengthens fire safety by:
- Enhancing detection speed in critical areas like sleeping quarters
- Allowing more flexible and clearer maintenance requirements
- Supporting accessibility with improved visual alarm standards
- Raising professional and documentation standards
For those responsible for fire safety in non-domestic buildings, staying up-to-date with BS 5839-1:2025 is vital to ensure compliance and occupant safety.
