This was first posted in IET Magazine November 2025.
Main Changes Covered
1. False Alarm Reduction
- The standard now explicitly highlights the user’s responsibility to investigate and respond to false alarms every time they occur — those commissioning or handing over systems must inform users of this duty.
2. Commissioning and Handover Improvements
- Before handover, the client or their representative must verify that manual call points have the correct replaceable parts and tools.
- A cause-and-effect matrix (or equivalent text) explaining how system inputs affect outputs must be provided.
3. Maintenance Changes
- Routine servicing intervals remain every six months but now allow flexibility of 5–7 months without losing compliance.
- Control and indicating equipment clocks must be checked/adjusted to ensure accurate event logs.
- In England & Wales, zone plans must be verified annually to reflect building changes.
- New cybersecurity clauses require appropriate security measures and authentication to protect systems.
4. Extensions & Modifications
- A new dedicated section covers how to extend or modify existing fire alarm systems.
- Extensions must comply with the current standard, even if the original system does not.
- Redundant devices (e.g., obsolete call points) should be removed or clearly labelled to avoid confusion during emergencies.
5. User Responsibilities
- If the installation deviates from the standard (e.g., due to compromises in device placement), these variations must now be documented in the logbook, with provided model formats.
Relationship Between BS 5839-1:2025 and BS 7671
The article also clarifies how this fire alarm standard interacts with the UK electrical wiring rules:
- BS 7671 (IET Wiring Regulations) often references BS 5839 for fire alarm systems under certain regulations.
- Where differences occur between the two standards regarding fire alarm systems, BS 5839-1:2025 takes precedence.
- The guidelines emphasise the need for safe isolation — BS 5839 no longer mandates a double-pole isolator, but safe isolation per UK electrical safety regulations remains essential.
Inspection & Testing Notes
- Although functional testing of fire alarm systems should follow BS 5839-1:2025, electrical inspection and testing (e.g., for certification purposes) remains under BS 7671.
- Inspectors must clearly agree with clients on what parts of the fire alarm system are included in any electrical inspection report to avoid misunderstandings about coverage.
Overall Message
Staying current with standard changes helps professionals and building duty holders manage fire safety, meet legal obligations, and reduce risk. Specialists should clearly communicate responsibilities, documentation, and limitations of inspections.
Further details – https://electrical.theiet.org/wiring-matters/years/2025/108-november-2025/key-changes-to-bs-5839-12025-part-2/