BS EN 50131-1: intruder alarm system requirements and grades, explained
Summary written and checked by the SPS Technical team · Last checked 1 November 2026
Quick answer
BS EN 50131-1 sets the core system requirements for intruder and hold-up alarm systems, including the four security grades and the environmental classes that equipment must meet. In the UK it is applied through PD 6662. The current edition is BS EN 50131-1:2006+A3:2020.
What it means for you
- The grade of your alarm system is defined here, from Grade 1 (low risk) to Grade 4 (high risk).
- Detectors, panels and signalling equipment must each meet at least the system grade.
- Equipment must suit where it is fitted, indoors or outdoors, as set out in the environmental classes.
Who it applies to
Designers, installers and owners of intruder and hold-up alarm systems.
Common questions
How does BS EN 50131-1 relate to PD 6662?
BS EN 50131-1 sets the European system requirements. PD 6662 is the UK scheme that says how to apply them, along with UK standards for installation, maintenance and alarm confirmation.
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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.
Reviewed by the SPS Technical team · Last updated October 2026