BS 5839-1:2025 is the current British Standard code of practice for fire detection and fire alarm systems in non-domestic buildings. It was published on 30 April 2025 and replaced BS 5839-1:2017. The revision does not mean existing systems automatically need replacing, but it does change how new systems are designed, how extensions and modifications are carried out, how systems are serviced and what records building owners should keep.
For building owners, facilities managers and responsible persons, the practical question is not “what does the standard say?” but “what do I need to do differently?” This guide answers that. It explains who BS 5839-1 applies to, which changes matter operationally, when an existing system should be reviewed, and what documentation you should keep on file.
If you want a professional view of where your current system stands, our fire alarm services cover design, installation, servicing and system reviews against BS 5839-1:2025.
Key takeaways
- Published: BS 5839-1:2025 was published on 30 April 2025 and replaced the 2017 edition.
- Not retrospective: existing systems installed to an earlier edition do not automatically become non-compliant or need replacing.
- New work: new systems, extensions and modifications should follow the 2025 edition.
- Servicing: the six month servicing cycle remains, with a new tolerance of one month either side.
- Documentation: cause and effect information, zone plans and recorded variations now carry more weight.
- Key design changes: smoke detection in main stairways, no heat detectors in sleeping rooms, and new expectations for alarm receiving centre signalling and cyber security.
- Action: use your next service, refurbishment or fire risk assessment review as the point to check your system against the new edition.
What is BS 5839-1?
BS 5839-1 is a code of practice published by the British Standards Institution. It gives recommendations for the planning, design, installation, commissioning and maintenance of fire detection and fire alarm systems in non-domestic premises.
It is not a law in itself. However, fire safety law in the UK requires the responsible person to provide appropriate fire detection and warning and to keep it maintained. BS 5839-1 is the recognised benchmark that fire and rescue services, insurers, fire risk assessors and third-party certification bodies use to judge whether a system is suitable and properly maintained. In practice, following it is the clearest way to show you have met your duties.
Who does BS 5839-1 apply to?
BS 5839-1 applies to fire detection and fire alarm systems in non-domestic premises. That includes:
- Offices and business parks
- Factories, warehouses and industrial units
- Shops, retail parks and shopping centres
- Schools, colleges and universities
- Care homes, supported housing and hospitals
- Hotels, hostels and student accommodation
- Leisure, hospitality and public buildings
- Common areas of mixed use buildings
Fire alarm systems in homes, including many individual flats and houses, are covered by BS 5839-6 instead. Some buildings, such as blocks of flats with commercial units or HMOs with communal systems, may involve both parts. Your fire risk assessment and your fire alarm provider should confirm which applies.
Who needs to pay attention to the 2025 changes?
- Responsible persons and duty holders, who carry the legal duty for fire safety
- Building owners and landlords, particularly those with multiple sites or tenants
- Facilities and estates managers, who manage maintenance contracts and records
- Care home, school and hotel operators, where sleeping risk and vulnerable occupants bring stricter requirements
- Anyone planning a refurbishment, fit out or extension, as new work should meet the 2025 edition
Does BS 5839-1:2025 mean my existing fire alarm needs replacing?
No, not automatically. BS 5839-1:2025 is not retrospective. A system that was designed and installed correctly to BS 5839-1:2017 or an earlier edition does not become non-compliant overnight just because a new edition has been published.
What changes is how the system is treated from here:
- Servicing should now be carried out in line with the maintenance recommendations of the 2025 edition.
- Extensions and modifications should meet the 2025 edition. The new standard makes clear that new work in an extended system should conform to the current version.
- Your fire risk assessment may identify that the system no longer suits the building, its occupants or its evacuation strategy. If that happens, upgrades may be needed regardless of which edition the system was installed to.
In other words, you do not need to replace a working, suitable system. But you should expect your engineer to point out where the system falls short of current guidance, and you should plan for those gaps to be addressed when you next extend, refurbish or upgrade. A fire alarm system review is the simplest way to understand where those gaps are.
The changes that matter most to building owners
BS 5839-1:2025 is a large document and many changes are technical. Below are the changes most likely to affect the people responsible for running and paying for a building’s fire alarm.
1. A clearer focus on the evacuation strategy
The 2025 edition places the building’s fire evacuation strategy at the centre of system design. The fire alarm is expected to support how people will actually leave the building, whether that is simultaneous evacuation, phased evacuation or a stay put approach in certain areas.
What this means for you: your fire alarm design and your evacuation strategy should match. If your evacuation strategy has changed since the system was installed, the system may need reviewing.
2. Earlier consultation and clearer responsibilities
The standard now expects consultation between the relevant parties before design begins, not during it. These parties can include the user or purchaser, the designer, consultants, the fire authority and the insurer. It also sets out more clearly who is responsible for each stage, including handover and the production of zone plans.
What this means for you: if you are commissioning a new system or a major extension, expect to be involved earlier and to sign off key decisions, such as the system category and the use of visual alarm devices, before equipment is ordered.
3. Smoke detection in main stairways
Main stairways should now be protected by smoke detection, multi sensor detectors or suitable combustion gas detection, rather than heat detection. Automatic detection is also expected in stairway lobbies.
What this means for you: stairways are escape routes. If your existing system uses heat detection in a main stairway, raise it at your next service or review.
4. No heat detectors in sleeping rooms
Heat detectors should no longer be used in rooms where people sleep. Smoke detection is expected instead, because it gives earlier warning to people who are asleep.
What this means for you: this is especially relevant to care homes, hotels, hostels and student accommodation. If you operate premises with sleeping risk, ask your provider to check the detection type in bedrooms.
5. Stronger requirements for premises with sleeping risk
The 2025 edition tightens recommendations where people sleep, particularly where some occupants may need help to evacuate. For example, it introduces addressability requirements for premises where ten or more people who need assistance to evacuate may be sleeping, and it no longer accepts the absence of alarm receiving centre signalling in residential care premises and supported housing as an agreed variation.
What this means for you: care home and supported housing operators should treat a system review as a priority, as these changes directly affect how quickly a fire is identified and responded to.
6. Alarm receiving centre signalling and transmission times
The standard introduces new expectations for how quickly alarm signals should reach an alarm receiving centre, with different requirements for life protection and property protection systems. It also sets minimum signalling grades and requires control panels connected to an alarm receiving centre to be labelled, including the centre’s contact details.
What this means for you: if your system is monitored, check that your signalling route meets current expectations. This is particularly important if your monitoring still relies on analogue phone lines affected by the PSTN switch-off.
7. Cyber security for connected systems
Fire alarm systems are increasingly connected to networks and remote access tools. BS 5839-1:2025 introduces cyber security recommendations, including suitable authentication and protection for remote connections and network cabling.
What this means for you: if your fire alarm can be accessed remotely by your provider or linked to a building management system, ask how that access is secured and who controls it.
8. Fewer false alarms, and a duty to investigate them
The section on limiting false alarms has been restructured. Users should be told at handover that every false alarm should be investigated and, where appropriate, action taken. Labelling to reduce accidental activation is also addressed.
What this means for you: false alarms should be recorded and investigated, not just reset. With many fire and rescue services no longer attending automatic alarms at commercial premises without a confirmed fire, a reliable system and a clear investigation procedure matter more than ever.
9. Evacuation tones only for evacuation
Fire alarm sounders should be used only for fire evacuation. Other situations, such as lockdown alerts, should use clearly different signals.
What this means for you: schools and other sites that use their fire alarm sounders for lockdown or other alerts should review this with their provider.
What changed for servicing and maintenance
For most businesses, the maintenance changes will be the first they notice, because they show up at the next service visit.
- Servicing interval: the six month servicing cycle remains. The 2025 edition now accepts a tolerance of one month either side, so a visit five to seven months after the last one is not treated as non-compliant.
- Panel clock: the engineer should check and correct the control panel clock so event logs are accurate.
- Zone plans: zone plans and device location information should be checked for accuracy over a twelve month period.
- Alarm receiving centre testing: for monitored systems, each type of alarm signal should be tested to confirm it is received.
- Remote access: servicing should take account of the new cyber security recommendations.
Our fire alarm servicing and maintenance is carried out in line with these updated recommendations, with clear service reports after every visit.
What changed for extensions and modifications
The 2025 edition has a new section dedicated to extensions and modifications. This matters for any business that adds devices during a fit out, changes a layout or connects new equipment.
- New work in an extended system should conform to the current edition of the standard.
- A new model certificate is provided for extensions and modifications.
- Redundant equipment should be removed or clearly labelled as not in use.
- Firmware updates should be treated and certified as modifications.
What this means for you: every alteration to your system should come with proper certification. If contractors have added or moved devices without paperwork, that is worth addressing.
What should be reviewed during maintenance or refurbishment?
The best time to check your system against BS 5839-1:2025 is when you are already working on it. Use your next service visit, refurbishment or fire risk assessment review to check the following.
At your next service visit
- Is the system still serviced at least every six months?
- Is the panel clock accurate?
- Is the zone plan accurate and displayed next to the panel?
- Are all alarm receiving centre signals being tested and received?
- Are there recurring false alarms that have not been investigated?
- Is remote access to the system secure?
- Are all recorded variations still valid?
Before or during a refurbishment
- Will the new layout affect detector coverage or sounder audibility?
- Does the evacuation strategy still match the system?
- Are stairways and stairway lobbies protected by suitable automatic detection?
- Are sleeping rooms protected by smoke detection rather than heat detection?
- Will new ceilings, partitions or raised floors need additional devices?
- Will any redundant devices be removed or labelled?
- Will the extension be certified to the 2025 edition?
When your fire risk assessment is reviewed
- Is the system category still appropriate for the building’s use?
- Has occupancy, use or sleeping risk changed?
- Does the risk assessor recommend any improvements to detection or warning?
If any of these questions raise doubts, a BS 5839-1:2025 system review will give you a clear, prioritised list of what needs attention.
What documentation should businesses keep?
Documentation is one of the clearest themes of the 2025 edition. If a fire and rescue service officer, insurer or auditor asks how your system is designed and maintained, these records are your evidence.
Keep the following on file, and make sure they are easy to find:
- Design certificate: confirms the system was designed to BS 5839-1
- Installation certificate: confirms the system was installed to the design
- Commissioning certificate: confirms the system was tested and works as designed
- Acceptance certificate: confirms the system was handed over to the user
- Verification certificate: where third-party verification was carried out
- Cause and effect matrix or description: explains what the system does when each device operates, such as which sounders activate, which doors release and which plant shuts down
- Zone plan: shows the building layout and detection zones, displayed next to the control panel
- As fitted drawings: show where every device is installed
- Logbook: weekly tests, service visits, faults, false alarms, repairs and all agreed variations from the standard. Logbooks can be kept in paper or digital form.
- Servicing certificates: issued after every service visit
- Modification certificates: for every extension, alteration or firmware update
- Record of variations: any agreed departures from the standard, with the reasons and who agreed them
- Battery calculations: confirm the standby power is sufficient
- Alarm receiving centre details: contact information and signalling arrangements, where monitored
If you have taken over a building and these documents are missing, that is a common trigger for a full system review. Our team can help rebuild the records as part of our fire alarm services.
What should building owners do now?
- Find your records. Locate your certificates, logbook, zone plan and cause and effect information.
- Check your service interval. Make sure your system is serviced at least every six months.
- Ask your engineer about the 2025 edition. At your next visit, ask where the system falls short of current guidance.
- Plan ahead for refurbishments. Build fire alarm changes into any fit out or extension from the start.
- Review sleeping risk areas first. Care homes, hotels and supported housing should prioritise a review.
- Check your monitoring. Confirm your alarm receiving centre connection and signalling route are current.
- Record everything. Make sure variations, false alarms and modifications are logged.
Frequently asked questions
When was BS 5839-1:2025 published?
BS 5839-1:2025 was published by the British Standards Institution on 30 April 2025. It replaced BS 5839-1:2017.
Is BS 5839-1:2025 a legal requirement?
BS 5839-1 is a code of practice, not a law. However, UK fire safety law requires suitable fire detection and warning to be provided and maintained, and BS 5839-1 is the recognised benchmark used to judge whether that duty has been met.
Is BS 5839-1:2025 retrospective?
No. Existing systems designed and installed to an earlier edition do not automatically need to be upgraded. New systems, extensions and modifications should follow the 2025 edition.
Do I need to replace my fire alarm because of BS 5839-1:2025?
Not simply because a new edition has been published. You may need upgrades if your fire risk assessment identifies that the system is no longer suitable, or when you extend or modify the system.
What are the main changes in BS 5839-1:2025?
The main changes include a stronger focus on the evacuation strategy, earlier consultation at design stage, smoke detection in main stairways, no heat detectors in sleeping rooms, new alarm receiving centre signalling expectations, cyber security recommendations, a new section on extensions and modifications, a servicing tolerance of one month either side of six months, and stronger documentation requirements.
How often should fire alarms be serviced under BS 5839-1:2025?
At least every six months. The 2025 edition allows a tolerance of one month either side, so a service between five and seven months after the previous one is acceptable.
Does BS 5839-1:2025 apply to homes?
No. BS 5839-1 covers non-domestic premises. Fire alarm systems in homes are covered by BS 5839-6.
What is a cause and effect matrix?
It is a document that shows what happens when each device or zone activates, for example which sounders operate, which doors release and whether a signal is sent to an alarm receiving centre. The 2025 edition expects this to be provided at handover.
What is a variation in BS 5839-1?
A variation is an agreed departure from the recommendations of the standard. Variations should be agreed by the relevant parties, justified and recorded in the system logbook. The 2025 edition also lists certain variations that are no longer acceptable.
Can heat detectors still be used under BS 5839-1:2025?
Yes, in suitable areas such as kitchens, plant rooms or other places where smoke detection would cause false alarms. They should not be used in sleeping rooms, and main stairways should be protected by smoke detection or other suitable detection.
What happens if my fire alarm does not meet BS 5839-1:2025?
If it was installed correctly to an earlier edition and remains suitable for the building, it does not automatically need changing. If your fire risk assessment or engineer identifies it as unsuitable, the responsible person should plan improvements to meet their legal duty.
Who can check my system against BS 5839-1:2025?
A competent fire alarm provider. Look for third-party certification, such as BAFE SP203-1 or NSI, as evidence of competence.
Book a BS 5839-1:2025 fire alarm review
Whether you manage a single site or a portfolio of buildings, understanding where your fire alarm stands against BS 5839-1:2025 puts you in control of upgrades, budgets and compliance, rather than reacting to an inspection or incident.
Full Circuit Fire & Security can review your existing system, check your documentation, and give you a clear, prioritised plan. Explore our fire alarm services or book a fire alarm review with our team today.