27/10/2025
The Complete Guide to BS 5839-1:2025 Fire Alarm Regulations for Commercial Buildings
- Sleeping Areas: Smoke detectors are now clearly preferred over heat detectors in bedrooms or sleeping areas such as care homes, hotels and student accommodation to enable earlier fire detection.
- Lift Shafts: Category L4 systems must now include detection at the top of lift shafts to improve response times in vertical escape routes.
- Low-Risk Lobbies: Certain lower-risk areas, such as toilet lobbies, may now require detection depending on the system category and risk profile.
- Manual Call Points: Placement guidance has been strengthened to ensure accessibility and visibility in all occupied zones, with clear exemptions where call points may be located behind security barriers.
- Lockdown Alarms: Systems may now integrate lockdown tones, provided they are distinct from fire alarm signals, an important update for schools and public facilities.
- Ceiling Obstructions: Installers must assess ductwork, beams or lighting tracks that could obstruct detector coverage and adjust spacing accordingly.
- New Category L Monitoring Times: L-category systems must monitor activation signals within 90 seconds and detect faults within 3 minutes.
- Backup Battery Sizing: The standby battery capacity formula has been revised. Panels and larger systems may require upgrades to meet the new calculation method.
- Red Mains Cables: Fire alarm mains cables must now be red and fire-resistant throughout the system for clear identification.
- Panel Labelling: Control panels that automatically connect to the Fire & Rescue Service must now display a visible “False Alarm” label to discourage unnecessary callouts.
Beyond the operational system changes, BS 5839-1:2025 also updates documentation and competency requirements.
- Clarified rules for short-circuit isolators – two simultaneous faults must not disable protection across more than 10,000 m²
- Clearer definition of a “competent person”, requiring demonstrable qualifications, training and experience.
- Fire-resistant cable is now mandatory for all alarm circuits and mains supply cabling.
- Reorganised structure and numbering aligned to the modern BSI format for easier reference.
- Education: Verify coverage in classrooms, dormitories and shared spaces. Keep maintenance and training logs to minimise false alarms.
- Automotive: Car dealerships and workshops must confirm correct detector types in both showrooms and service areas, with compliance to the new cable and labelling requirements.
- Warehouses: Review fault tolerance and circuit isolation arrangements in large open areas; linear heat detection may be suitable under the new guidance.
- Offices: Reassess integration with lifts, access control and ventilation systems. Ensure all records and testing logs reflect the new competency requirements.
- Healthcare: Validate that fire alarms integrate properly with life-safety systems and ensure maintenance teams meet the competency definition.
Failing to comply with BS 5839-1:2025 can lead to enforcement under the Fire Safety Order, invalidate insurance and increase life-safety risk.
Adhering to the new standard provides:
- Improved occupant safety and faster emergency response
- Reduced false alarms and operational disruption
- Clearer documentation for inspections and audits
- Long-term reliability and cost savings through correct maintenance
How Sygma Ensures Compliance
Sygma Fire, Security & Electrical delivers fully compliant fire alarm design, installation and maintenance services in accordance with BS 5839-1:2025. Our engineers are NICEIC-approved and BAFE-registered, providing national coverage for education, automotive, healthcare and commercial sectors.
To arrange a compliance review or discuss an upgrade to BS 5839-1:2025 standards, contact Sygma today.
Many facility managers and duty holders have questions about how the new BS 5839-1:2025 Standard affects their buildings. Below are clear answers to the most searched queries from business owners, property manager and compliance officers.
What is BS 5839-1:2025?
BS 5839-1:2025 is the British Standard for the design, installation, commissioning and maintenance of fire detection and alarm systems in non-domestic premises. It replaces the 2017 version and came into effect on 30 April 2025.
Who must comply with BS 5839-1:2025?
Any duty holder under the Regulatory Reform (Fire Safety) Order 2005 is responsible for ensuring that their fire alarm system meets BS 5839-1:2025. This includes building owners, facility managers, landlords and anyone controlling commercial or public buildings.
What are the main changes in BS 5839-1:2025?
Key updates include smoke detectors now preferred in sleeping areas, mandatory detection at the top of lift shafts, new monitoring and fault-detection time limits, red fire-resistant mains cables, revised backup battery calculations and clearer competency and documentation rules.
Does BS 5839-1:2025 apply to schools, hospitals and car dealerships?
Yes. The standard applies to all non-domestic buildings including education, healthcare, retail and industrial sites. Each environment must meet the relevant system category (L1-L5, P1-P2) based on its fire-risk assessment.
What happens if my fire alarm system still follows BS 5839-1:2017?
Existing systems remain valid but should be reviewed at the next service or upgrade. When modifications are made, the new work must comply with the 2025 edition. Periodic assessments ensure continued compliance and insurance validity.
How often should commercial fire alarms be tested?
Weekly user tests and six-monthly inspections by a competent contractor are recommended under BS 5839-1:2025. Larger or high-risk sites may require quarterly checks.
What is a competent person under BS 5839-1:2025?
A competent person is defined as someone with adequate training, experience and knowledge of fire alarm systems and relevant regulations. Certification from recognised bodies such as NICEIC or BAFE provides suitable evidence.
Where can I get a BS 5939-1:2025 compliant installation?
Sygma Fire, Security & Electrical provides design, installation, maintenance and compliance audits in line with BS 5839-1:2025 across the UK.
- British Standards Institution (BSI) – BS 5839-1:2025 Code of Practice for Fire Detection and Fire Alarm Systems in Non-Domestic Premises
- Fire Industry Association (FIA) – BS 5839-1:2025 Summary of Changes
- Electrical Contractors’ Association (ECA) – Technical Bulletin on Fire Alarm Standards 2025
- Apollo Fire Detectors – Technical Update Briefing, September 2025