Success message
Error message
The publication of BS 5839-1:2025 brings a number of important changes to the design, installation, commissioning, and maintenance of fire detection and fire alarm systems for non-domestic premises. For designers, installers, and building operators, understanding these changes is critical to ensuring both compliance and safety.
In this article, we’ll highlight the most significant updates and show how a recent project we delivered in North London (2023) already aligns with the new requirements.
Under the 2025 edition, rooms where people sleep are now defined as high-risk rooms. Automatic protection is required in these rooms. Importantly, heat detectors are no longer permitted in sleeping rooms. Instead, smoke-sensitive detection must be used to provide early warning.
Stairway lobbies, previously considered low-risk and therefore often excluded, are now designated as areas requiring automatic fire detection. This change reflects the critical role lobbies play in escape routes and containment.
Greater emphasis is now placed on the selection and application of detectors. For systems incorporating multi-sensor detectors, designers must clearly record: 1. The chosen operating mode(s). 2. The reasoning behind the configuration. This information must be made available to the commissioning technician and included in the operating and maintenance manual.
In 2023, we designed and installed a fire alarm system for a four-storey house in North London, converted into an HMO (House in Multiple Occupation). The property provides supported housing for ex-offenders, with staff on-site 24/7 and strict security protocols.
One of the major issues was tenants smoking in their rooms, despite repeated management interventions. This created a significant challenge in managing the false alarm rate, as recommended by BS 5839-1, whilst also ensuring the reliability of the automatic fire detection system. False alarm management (avoiding unnecessary evacuations). Life safety (ensuring reliable detection in sleeping areas).
After careful analysis, we implemented the following: 1. Installed Discovery Multi-sensor (Heat/Optical) detectors connected to an Advanced fire panel. 2. Configured so that optical smoke activation triggers a pre-alarm instead of a full building evacuation. 3. Pre-alarm alerts on-site staff, who can investigate quickly (the building is compact enough for a rapid response). 4. If the pre-alarm proves to be a false activation (e.g. due to smoking), staff instruct tenants to ventilate the room, reset the panel, and log the incident. 5. If a genuine fire is detected, staff activate the nearest call point and follow fire safety protocols. 6. Should smoke spread into communal areas, communal detectors escalate the system to a full alarm automatically.
Sleeping rooms: Protected by detectors capable of smoke response, meeting the BS5839-1:2025 requirement that heat detectors are not acceptable. Detector selection: The choice of multi-sensor detectors and their configuration was carefully documented, consistent with Annex D of BS 5839-1:2025. Practical resilience: Balances the need for early warning with the reduction of nuisance alarms, essential in a high-risk residential environment.
This North London project highlights the benefits of: Forward-looking system design: Even though the installation pre-dated the 2025 standard, the approach taken already aligns with the updated recommendations. Multi-sensor technology: Offers flexibility and reliability in challenging environments such as HMOs and supported housing. Documentation discipline: Recording detector configurations and decisions is now a compliance requirement, not just best practice.
The updates in BS 5839-1:2025 underline the growing focus on: 1. Protecting sleeping occupants. 2. Ensuring escape routes (stairway lobbies) are properly monitored. 3. Holding designers accountable for detector selection and configuration. Our North London HMO project serves as a strong example of how careful system design, multi-sensor detectors, and well-documented configurations can deliver both compliance and effective protection in line with the new Code of Practice.
At LFS, we don’t just understand the Code of Practice – we live it. We know exactly what you and your employer need to succeed in the fire and security industry.
That’s why we offer the EAL Level 3 Diploma in Providing Electronic Fire and Security Systems – the perfect next step if you want to:
Gain industry-recognised qualifications.
Learn directly from professionals who know the fire industry inside out.
Equip yourself with the knowledge and practical skills employers are looking for. 👉 Start your journey with LFS today – and join the next generation of skilled fire and security professionals.