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Standards and Compliance4 min read

BS 5839-1:2025 Servicing: Intervals, Tolerance and What Each Visit Should Cover

What BS 5839-1:2025 changed for fire alarm servicing: the six-month interval with a five to seven month tolerance, ARC signal checks, remote service and cyber security.

By Incognito Fire & Security · September 26, 2026

Technical review pendingVersion 1medium confidence

Last updated September 26, 2026.

Sources used

1

Review sources and evidence basis

Source labels describe the evidence basis; current manufacturer documents and licensed standards remain authoritative. Professional disclaimer

Source note. This article is based on the Fire Industry Association's published summary of the changes, Guide to the changes in BS 5839-1:2025 (Version 1, June 2025). It has not been checked line by line against the text of BS 5839-1:2025 itself, which is the authoritative document. Check clause wording in the standard before relying on it in a contract, certificate or dispute. The standard applies to the UK; other countries use different codes.

The interval

The FIA guide quotes subclause 43.2.1 of the 2025 edition: a competent person should carry out successive inspection and servicing visits at intervals of approximately six months. Two notes accompany it:

  • One inspection, test and service may be carried out any time between five and seven months after the previous one.
  • The date of acceptance is the datum for these periods.

The 2017 edition said the period between visits should not exceed six months, and that if it did, the system should be considered no longer compliant with that part of BS 5839. The FIA describes the change as clarifying customary practice: servicing within the month before or after it falls due.

Note that quarterly servicing is a contractual choice, not something this guidance requires. Where a contract specifies more frequent visits, the six-month schedule of full inspection still applies as a minimum recommendation.

Actions the FIA highlights at service visits

  • Time clock. Check and adjust the control panel time clock at every visit. It matters most where the system uses day and night settings.
  • ARC signals. Where the system signals automatically to an alarm receiving centre, check the signals sent at every visit. If more than one type can be sent, such as fire and fault, confirm each is transmitted correctly.
  • Disablement. When servicing needs protection disabled in significant parts of the system, keep it to a practicable minimum, and tell premises management which areas are affected. This includes disabling sounders and visual alarms.
  • Duct smoke detectors. Functional testing of smoke detectors in ventilation ducts is now on the list of actions at the 12-monthly visit.
  • Zone identification. At the 12-monthly visit, verify that the zone reported on the control panel is the zone that was tested and that it matches the zone plan.
  • Text descriptors. Checking the text descriptors on an addressable system is not specifically recommended as a routine service action. The FIA says premises management is responsible for telling the servicing organisation about changes, and suggests it may be prudent to confirm descriptors periodically, for example every five years.

Remote service and cyber security

With IP-connected panels, the FIA reports a new clause 43.4 covering:

  • physical measures, such as locking the comms cabinet or fitting anti-tamper plugs to patch leads
  • a method of authentication before remote access is accepted, in the panel or gateway software
  • a risk assessment before any remote service, particularly read, control or write functions
  • making sure the system is fully operational when the remote service ends, if there is any risk it might have been compromised

Faults that cannot be repaired

Where a fault has been reported and the service organisation cannot complete an effective repair, the FIA says fault indications should not be concealed, for example by suppressing them.

What to do with your own schedule

If your service contracts, checklists or software reminders assume a fixed calendar interval, check what tolerance they allow. A five to seven month window suits the guidance, but always record the date of acceptance and each visit date so the datum is clear.

See also the fire alarm maintenance schedule and annual inspection under BS 5839-1.

Test what you have learned with the free daily fire alarm fault challenge, which includes questions on this topic with the source shown for every answer.

Scope

This article covers BS 5839-1 as used in the UK. Servicing requirements in Ireland, the United States, Canada, Australia and New Zealand are set by different standards and local authorities, and are not covered here.

Frequently asked questions

How often should a fire alarm be serviced under BS 5839-1:2025?

The FIA's summary of subclause 43.2.1 says successive inspection and servicing visits should be at intervals of approximately six months. A visit any time from five to seven months after the previous one is acceptable, with the date of acceptance as the datum for those periods.

What happens if a service visit is a few weeks late?

Under the 2017 edition the guidance was that if the period between visits exceeded six months, the system should be considered no longer compliant with that part of the standard. The FIA reports the 2025 wording brings the standard into line with common practice: a visit within one month either side of each six-month point is acceptable.

Does the 2025 standard say anything about remote servicing?

Yes. The FIA reports a new clause 43.4 on remote services and cyber security, including preventing unauthorised access by physical means such as locking the comms cabinet, authentication of a request to accept a remote connection, and a risk assessment before remote read, control or write functions.

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