BS 5839-1:2025: What the New Fire Alarm Standard Means for Your Building

Key Takeaways
- BS 5839-1:2025 replaced BS 5839-1:2017 on 30 April 2025
- Visual Alarm Devices (VADs) are now strongly recommended for buildings with hearing-impaired occupants
- All fire alarm wiring must use fire-resistant cable, including the mains supply
- Existing systems don't need retrospective upgrading, but maintenance must follow the 2025 code

What Is BS 5839-1:2025?

BS 5839-1:2025 is the updated British Standard for fire detection and alarm systems in non-domestic buildings. It replaced BS 5839-1:2017 on 30 April 2025 and is now the code of practice that governs how fire alarm systems are designed, installed, commissioned, and maintained across the UK. Any new fire alarm installation or significant modification must comply with this standard.

What Are the Key Changes?

The 2025 revision introduces several important changes that affect how fire alarm systems are specified and installed:

Visual Alarm Devices (VADs): The standard now places greater emphasis on ensuring alarms effectively alert all occupants, including those with hearing impairments. VADs — such as flashing strobe lights — are strongly recommended in buildings where hearing-impaired people may be present.

Fire-Resistant Cable: All fire alarm wiring must now use fire-resistant (FR) cable. This includes the mains supply to the fire alarm panel, which was not previously required to be FR cable. Non-FR cable is no longer compliant for any part of a fire alarm circuit.

Red Mains Cable: Mains fire alarm cables must be red to ensure clear identification and prevent accidental disconnection during maintenance or building works.

Manual Call Points: Guidance for manual call point placement has been refined. Call points should be in areas that are normally occupied, where occupants are most likely to see and use them. Installation in rarely used spaces is discouraged.

Commissioning Documentation: Handover expectations are significantly higher. Commissioning documentation must include accurate fire alarm zone drawings, cause-and-effect matrices, and full test certification. All deviations from the standard must be documented in the site's fire alarm logbook.

CPD Requirement: Anyone working on fire alarm systems must now demonstrate ongoing Continuing Professional Development (CPD).

Monitoring in Care Settings: Residential care premises must have systems that automatically notify a monitoring centre when triggered.

Does This Affect Existing Fire Alarm Systems?

The changes are not retrospective for installed systems — you do not need to immediately upgrade a system that was compliant when it was installed. However, there are two important caveats.

First, maintenance procedures must now comply with the 2025 code of practice. This means your maintenance contractor should be following the updated testing and documentation requirements.

Second, any modifications to an existing system must be assessed against BS 5839-1:2025, not the standard that was in place when the original system was installed. If you're adding detectors, extending zones, or replacing panels, the new standard applies.

What Should Facilities Managers Do Now?

If you manage a commercial building in London, Hertfordshire, or Essex, here's your action plan:

1. Audit your current system — Confirm what standard your fire alarm was installed to and when it was last serviced
2. Review documentation — Check that your fire alarm logbook, zone drawings, and test certificates are complete and current
3. Check installer credentials — Confirm your maintenance contractor can demonstrate CPD compliance under the 2025 standard
4. Plan upgrades — If your building has hearing-impaired occupants, discuss VAD installation during your next scheduled maintenance visit
5. Budget for refurbishment — If a major refurbishment is planned, the entire fire alarm system will need to meet BS 5839-1:2025

How Wire Now Can Help

Wire Now is an NICEIC-approved contractor that designs, installs, and maintains fire alarm systems to BS 5839-1:2025 across London, Hertfordshire, and Essex. Our engineers hold current CPD certifications and we provide full commissioning documentation including zone drawings and cause-and-effect matrices.

Whether you need a new installation, a system upgrade, or ongoing maintenance, we can help you stay compliant.

View our Fire Alarm services →

Part of our [Commercial Compliance Guide](/blog/commercial-fire-electrical-compliance-guide-2026) series.