BS5839-1:2025 Effective from: APRIL 29th 2025

Overview

Introduction

The British Standard BS 5839-1 defines best practices for the design, installation, commissioning, and maintenance of fire detection and fire alarm systems in non-domestic premises.
The 2025 revision brings significant updates, effective from 29 April 2025, which reflect lessons learned from incidents, technological advances, and changes in fire safety risk management.

Full compliance is not optional – it is a legal, moral, and commercial obligation.

Legal Compliance

  • Fire Safety (England) Regulations 2022, Regulatory Reform (Fire Safety) Order 2005, and associated laws require that buildings have adequate fire precautions.
  • BS 5839-1 is considered best practice guidance under these laws.
  • In the event of a fire-related incident, failure to follow updated standards could be used in court as evidence of negligence or breach of duty.
  • Insurers increasingly require compliance with the latest standards as a condition of coverage.

Key Risk: Non-compliance could lead to enforcement action, financial penalties, criminal prosecution, or loss of insurance cover.

Protecting Life and Property

  • Changes such as mandatory zone plans, better alarm signalling to Alarm Receiving Centres (ARCs), and prioritising faster-detecting sensors in sleeping areas directly enhance occupant safety.
  • Ensuring that alarm systems are tested and maintained properly, especially multi-sensor detectors, reduces the risk of fire deaths and damage.
  • Rapid and reliable detection is critical to safe evacuation, especially in vulnerable occupancies such as care homes, hotels, and sleeping accommodation.

Key Principle: Updated standards reflect real-world experience and improve early warning and system reliability.

Maintaining Professional Reputation

  • Certification bodies such as SSAIB and NSI expect certified companies to maintain compliance with the latest standards.
  • Failure to align with BS 5839-1:2025 could lead to non-conformances during audits and even suspension or withdrawal of certification.
  • Clients expect their service providers to demonstrate up-to-date knowledge and professional excellence.

Key Impact: Non-compliance damages company credibility, risks losing certifications, contracts, and competitive advantage.

Risk Management and Insurance

  • Many insurers now specify that fire alarm systems must comply with the latest BS 5839-1 revisions as a condition of commercial property insurance.
  • Non-compliant systems may invalidate claims or increase premiums.
  • Updated maintenance requirements help reduce false alarms, which can result in fines or withdrawal of emergency service response.

Key Advantage: Adhering to the standard strengthens insurability and reduces liability exposure.

Continuous Improvement and Innovation

  • Standards like BS 5839-1 evolve based on technological improvements (e.g., multi-sensor devices, new remote signalling options).
  • Adopting the latest best practices ensures systems are more efficient, resilient, and future-proof.
  • Early compliance demonstrates an organisational culture of continuous improvement.

Key Outlook: Staying ahead protects the business and its clients from emerging risks.

Conclusion

Compliance with BS 5839-1:2025 is not merely a box-ticking exercise—it is a critical investment in:

  • Life safety
  • Legal protection
  • Company reputation
  • Client satisfaction
  • Competitive positioning

Every stakeholder, from system designers and engineers to building owners and facilities managers, must take responsibility for ensuring that systems meet the latest standards

KEY Changes Overview

Maintenance Items:

    • The time on the control panel must be adjusted during every maintenance visit.
    • Service intervals remain at 6 months but now have flexibility to be 5 or 7 months (previously, exceeding 6 months was non-compliant).
    • The zone plan must be verified during service (device text is not included).
    • All redundant systems (old detection, call points, etc.) must be removed.
    • All interfaces must be accessible for service (they cannot be hidden within other control panels, such as lift controls).
    • All ‘variations’ from BS must be justified and recorded in the fire alarm logbook.
    • Competent persons (engineers) must now undertake continual professional development (CPD).
    • You can now write the battery fitted date directly on the battery with a sharpie-which was previously not allowed.
    • Network signalling to be checked (new clause 43.3.22).
    • All detector LEDs/Remote LEDs to be checked as part of the service procedure (new clause 43.3.4).
    • Annex F provide new formula to assist in calculating false alarm rates.
    • Faults are not allowed to be concealed (new clause 44.2.4) e.g. EOLs in panels/links across loop terminals.
    • Extensions and Modifications are covered under a new section (section 7) and must now be carried out to the new standard irrespective of the standard of the existing part of the system.

Design/Installation Items

  • Mains cables to fire alarm systems must be red; this requirement has been clarified.
  • L4 systems now include detection at the top of lift shafts and other flue like shafts (e.g. openrisers) but NOT within 1.5m of the shaft.
  • L2 design now includes sleeping risk in addition to specifically risk-assessed additional rooms.
  • All low-risk lobbies (e.g., toilet lobbies and other small lobbies) must now have detection (depending on L system specified).
  • Lock-down alarms can now be integrated into the fire alarm system, provided they have a distinctive tone (previously not allowed).
  • The formula for battery calculations has been changed to clarify it.
  • Clarifications have been made regarding ceiling obstructions, including ductwork and closely spaced beams.
  • Monitoring requirements on category L systems have been clarified: 90 seconds for fire signal and 3 minutes for failure of transmission equipment.
  • Monitoring requirements on category P systems have also been clarified: 120 seconds for fire signal and 31 minutes for failure of transmission equipment.
  • ARCs should have more information on the premises e.g. sleeping risk etc
  • Where practicable the type of device that triggered the alarm and whether more than one device (coincidence) triggered should be transmitted to the ARC.
  • Additional clauses added for cybersecurity (remote logging in).
  • Table E1 (detector selection) is now Table D1.
  • There is now a list of items prohibited from being listed as a variation: including zone charts and monitoring in care homes
  • A new sticker must be placed on the front of the panel: “FALSE ALARM NOTICE – This fire alarm has an active connection to fire and rescue service…
  • Functional Earth (screen) sleeving must be pink as per BS7671 Table 51.
  • Reference to 25m and 16m travel distance to MCP removed.
  • MCP mounting height tolerance +200mm / -300mm (i.e. an MCP can no longer be fitted at 1.7 metres).
  • Certification and Documentation

All certification based on the model certificates within BS5839 must now be updated as the entire document now uses different paragraph numbering compared to the old standard, meaning even unchanged paragraphs have new Clause numbering associated to them.