BS 5839-1:2025 Explained: Your Guide to Fire Alarm System Standards

Fire safety regulations are always evolving to reflect new technologies and achieve higher standards for protecting life and property. One of the most important updates within recent years is the release of BS 5839-1.2025. 

Whether you’re a business owner, fire safety professional or manager of a non-domestic building (i.e. commercial, public, industrial buildings), then understanding this revision is essential. 

In this blog, we break down what BS 5839 is and what key changes the 2025 revision brought in for compliance.

 

What Is BS 5839‑1?

BS 5839‑1 is the British Standard for fire safety. It sets out the code of practice that must be followed for: design, installation, commissioning, and maintenance of fire detection and fire alarm systems. This is specifically in UK non-domestic buildings. The guidance is designed to achieve reliable fire detection to safeguard life, property and continue operations. 

It is widely recognised by fire authorities, building professionals and insurers that benchmark for compliance and good practice. 

“BS 5839‑1 is a British Standard that governs the design, installation, commissioning and maintenance of fire detection and alarm systems in non‑domestic premises.” – BSI.knowledge

 

What Is BS 5839‑1:2025?

As of 30 April 2025, 5839-1:2025 replaced BS 5839-1:2017 after that was officially withdrawn. The 2025 update introduces revised requirements and clarifies responsibilities to ensure systems are not only fit for purpose but also aligned with the latest safety expectations and legal obligations.

Here are all the changes you should know about.

 

BS 5839 2025 Guidance Note

• Sleeping zone detector types – in sleeping areas, smoke or multisensor detectors are now preferred, rather than heat-only detectors
• Timing criteria – Ensure fire alarm signals to an ARC (Alarm Receiving Centre) reach within 90 seconds, fault signals must be detected under 3 minutes

• Cable installation – The mains cables for fire system wiring must be red and fire-resistant
• Zone plans – in multi-zone systems, a floor plan showing detection zones must be present and up-to-date
• Updating / expanding current systems – changes or extensions must be documented and comply with the new BS 5839-1:2025 standards
• “False alarm notice” – it is mandatory to display a “false alarm notice” on connected panels
• Qualifications – ensure all contractors maintain evidence of Continuing Professional Development (CPD) and records are up-to-date
• Interfaces – Interfaces must be accessible, identifiable and testable
• Visual alarms – The standard emphasises the use of VADs (Visual Alarm Devices) for occupants with hearing impairment

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How To Comply With the 2025 Update

If you have responsibility for a fire alarm system, here’s the next steps to respond and comply with the new standard:

1. Audit your current system against the new standard
2. Ensure your fire alarm provider is a specialist and is familiar with BS 5839‑1:2025, CPD accredited and uses correct documentation
3. Use up-to-date certification forms, documentation and maintain the logbook
4. Always review changes and extensions carefully ensuring they always follow the standard
5. Ensure regular maintenance continues and it includes additional checks
6. Make sure staff understand procedures and signage is in place

Overall, BS 5839-1:2025 contributes towards a significant step forward in fire safety. The 2025 version offers much clearer guidance, stricter compliance and improved protection than its 2017 predecessor.

If you’re unsure whether your current system complies with BS 5839-1:2025, or if you need help navigating the new changes, our expert team is here to help. Get in touch today for professional advice or to schedule a fire alarm inspection.

Key Takeaways

• BS 5839-1:2025 is the updated fire alarm standard for non-domestic buildings, replacing the 2017 version as of 30 April 2025, with stricter compliance and clearer guidance.
• Key changes include stricter rules on detector types in sleeping areas, faster signalling times, mandatory zone plans, and fire-resistant red cabling.
• All system upgrades or modifications must follow the new standard, with full documentation and proper commissioning.
• Building owners and responsible persons must ensure systems are audited, maintained, and managed by qualified professionals with up-to-date training and certification.