BS 5839‑1:2025 – The New Benchmark for Fire Alarm Systems in the UK
On 30 April 2025, the British Standards Institution released BS 5839‑1:2025, updating its 2017 predecessor. This revision sets the gold standard for fire detection and alarm system design, installation, commissioning, and maintenance in non-domestic premises across the UK
What Is BS 5839‑1?
BS 5839‑1 is the British Standard for fire alarm systems in non-domestic buildings, referenced in Approved Document B of Building Regulations. It outlines system categories, components, siting, performance and maintenance procedures, ensuring life safety and regulatory compliance
✨ Key Updates in the 2025 Edition
1. Detector Preference in Sleeping Areas
Smoke detectors are now recommended over heat detectors in sleeping accommodations (e.g., hotels, care homes, student accommodation) to ensure faster alerts
2. Category Enhancements
- Lift shafts must now be included under L4 systems.
- Detection is also required in low-risk lobbies depending on the chosen category
3. Manual Call Point Placement
Enhanced guidance ensures call points are installed in regularly occupied areas, improving accessibility and reducing false activations
4. Lockdown Tone Integration
Fire alarm panels can now include distinct lockdown alert tones—but they must remain clearly distinguishable from fire signals
5. Addressing Ceiling Obstructions
Installers must account for beams or ductwork that could shadow detector coverage, ensuring no blind spots
6. Improved Monitoring Times
Automatic systems must signal activations within 90 seconds and faults within 3 minutes—reducing detection delays
7. Battery & Cable Rules
- Red mains cabling is now compulsory for identification.
- The battery-backup sizing formula has been updated—existing systems should be re-calculated
8. Visual Alarms & Inclusivity
Greater emphasis is placed on Visual Alarm Devices (VADs) to support deaf or hard-of-hearing individuals
9. Zone Plans in Multi-Zone Sites
Mandatory, clearly-displayed zone plans are required near control panels in multi-zoned buildings, aiding fast response
10. Residential Care Enhancements
In residential care premises, fire alarms must now trigger automatic alerts to a central monitoring station for immediate response
11. Servicing Clarity
- A 5–7 month window is now permitted between professional servicing—a change from the strict 6-month rule.
- Maintenance must include clock checks, log updates, removal of redundant devices, and accessible interfaces. Technicians must maintain Continuing Professional Development (CPD)
12. Document & Certificate Updates
- All certificates, logs, and documentation templates have been revised.
- A formal Modification Certificate is required for any system changes.
- Any deviations (variations) must be documented and logged
Why This Matters
These updates aren’t just paper changes—they’re life-saving enhancements:
- Faster detection in key areas, especially sleeping zones.
- Improved reliability via new maintenance flexibilities and clearer service criteria.
- Inclusive safety, ensuring accessibility for disabled persons through VADs.
- Documentation & competency, raising the bar on professional standards
