BS 7273-4: releasing locked doors when the fire alarm sounds, explained
Summary written and checked by the SPS Technical team · Last checked 1 November 2026
Quick answer
BS 7273-4 is the British Standard for how a fire alarm should release doors that are locked by access control or held open by magnetic devices. It sorts doors into categories A, B and C by how critical they are to escape, and sets how reliable the link between the fire alarm and the door must be. The current edition is BS 7273-4:2015+A2:2023.
What it means for you
- Any access-controlled door on an escape route should release automatically when the fire alarm operates.
- Ask your fire risk assessor which category each controlled door falls into.
- Test the door release as part of the fire alarm service, not just the access control service.
- Keep a green break-glass or other manual release at controlled exit doors where required.
Who it applies to
Any building where doors are locked by access control, held open by door holders or controlled by automatic door systems, and the fire alarm needs to release them.
What changed from BS 7273-4:2015+A1:2021
Amendment 2 was published in May 2023. It replaces BS 7273-4:2015+A1:2021, which BSI now lists as withdrawn. It clarifies the critical signal path between the fire alarm and the door release. It adds detail on acoustic and radio-operated release devices and which door categories they suit. It gives fuller guidance on when to use Category A (critical), B (standard) or C (indirect) actuation.
Common questions
Do access-controlled doors have to open in a fire?
Doors on escape routes must let people out. BS 7273-4 sets out how the fire alarm should release them and how dependable that connection needs to be.
What are categories A, B and C?
They grade how critical the door is to safe escape. Category A is the most critical and needs the most reliable link to the fire alarm; categories B and C allow simpler arrangements.
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Official sources
This page is a plain-English summary, not a copy of the standard. British Standards are copyright of BSI.
Page updates
- 1 November 2026: Edition corrected to BS 7273-4:2015+A2:2023 (published May 2023). BSI lists BS 7273-4:2015+A1:2021 as withdrawn. Official link changed to the BSI product page.
- 12 October 2026: Edition confirmed as BS 7273-4:2015+A1:2021.
Reviewed by the SPS Technical team · Last updated October 2026