1. Some variations are no longer acceptable
BS 5839-1 is a code of practice, so variations from its recommendations can be agreed between the interested parties, provided they are recorded on the certificate and in the logbook. The 2025 edition keeps that, but states that, in the light of a number of fatal fires, some departures are so harmful to life safety that they should not be treated as acceptable variations at all (clause 6.6). They are:
- No zone plan (or equivalent diagram) where a storey has more than one zone, particularly in premises where people sleep.
- No link to an alarm receiving centre in a residential care home, or in supported housing where that link is needed.
For contractors this changes the conversation at handover and at service visits: these can no longer be written off as agreed variations.
2. A new section on extensions and modifications
Section 7 now covers extending or altering an existing system. The headline points: any new work should meet the current standard, even if the system as a whole does not; someone competent in fire alarm design should take responsibility for the extension; and the extended system should be recommissioned as far as needed to check the new work has not affected the old, for example battery capacity, radio signal strength and cause and effect. An extensions or modifications certificate should then be issued.
The standard also warns that extending an addressable circuit with cable of a different type can cause unreliable communication, so a whole circuit may need rewiring if the original cable is no longer available.
3. Simpler manual call point siting
Clause 19 sets out where call points go. In the 2025 edition:
| Rule | BS 5839-1:2025 |
|---|---|
| Where | On escape routes, at every storey exit and every exit to open air leading to a place of ultimate safety (19.4) |
| Travel distance | No more than 45 m to the nearest call point along the actual route; 30 m straight-line where the final layout is not yet known (19.5) |
| Height | 1.4 m above finished floor to the centre of the operating face, with a tolerance of 0.2 m above and 0.3 m below (19.8) |
| High hazard areas | A call point close by, for example in kitchens or spray areas (19.6) |
| Type and cover | Type A (single action) with a transparent protective cover (19.1, 19.2) |
4. Rooms where people sleep
The 2025 edition recommends giving preference to forms of automatic detection other than heat detectors (or sprinklers acting as heat detectors) in rooms where people sleep. Heat detectors respond too slowly to give a sleeping occupant early warning of a fire in their own room; smoke, multi-sensor or combustion gas detectors are the expected choice. This matters for hotels, care homes, student accommodation and the like, especially in Category L2 designs.
5. Restructuring
The old clause 4 has moved into a new Introduction, and the former clause 33 has been merged with clause 31, the clause on investigating false alarms. If your paperwork or software quotes clause numbers from 2017, check them: several have moved. Periodic inspection and servicing is clause 43, routine testing is clause 42, and the model certificates are in Annex G.
What stayed the same
The service interval is unchanged in substance: an inspection and service about every six months, with any visit from 5 to 7 months after the previous one acceptable (clause 43.2). The weekly test by the premises continues (clause 42.1). See how often a fire alarm should be serviced for the full schedule.
Common questions
When did BS 5839-1:2025 come into effect?
On 30 April 2025. It supersedes BS 5839-1:2017, which is withdrawn.
Do existing systems have to be upgraded to BS 5839-1:2025?
Not automatically. A code of practice is generally applied to new work. When an existing system is extended or modified, the new work should meet the current standard (Section 7), and some shortcomings, such as a missing zone plan where one is needed, can no longer be accepted as a variation (clause 6.6).
Which variations are no longer acceptable under BS 5839-1:2025?
Clause 6.6 lists the absence of a zone plan where a storey has more than one zone (particularly where people sleep), and the absence of alarm receiving centre signalling in residential care homes or in supported housing where it is needed.
What is the height for a manual call point in BS 5839-1:2025?
1.4 m above finished floor level to the centre of the operating face, with a tolerance of 0.2 m above and 0.3 m below (clause 19.8).
Can heat detectors be used in bedrooms under BS 5839-1:2025?
The 2025 edition recommends giving preference to other forms of automatic detection, such as smoke, multi-sensor or combustion gas detectors, in rooms where people sleep, because heat detectors respond too slowly.
FireCompliance Pro schedules every service inside the 5 to 7 month window, issues the certificate the moment the engineer signs off, and gives your client a live portal showing exactly where each building stands.
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