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British and European Intruder Alarm Standards

Code of Practice for installation and configuration of intruder alarm systems designed to generate confirmed alarm conditions.

BS 8473:2006
Code of Practice for Intruder and hold-up alarm systems – Management of false alarms

BS EN 50131 Series
European Standards on Intruder Alarms
(Originally due to commence October 2005)

Guideline for the implementation of BS EN 50131-1:2004


To help ensure that alarms are designed, installed and maintained reliably, suppliers and installers make reference to a series of British Standards and Codes of Practice. Some of these have been withdrawn and replaced by the ‘European Standards for Intruder and Hold Up Alarm Systems’ – usually referred to as the Euro Standards.
The Euro Standards only apply to new systems.  Existing systems remain subject to the British Standards and Codes of Practice applying at the time of their installation; but exceptionally may need to comply with the new Euro Standards if they require such extensive re-design/equipment replacement that they effectively become a ‘new system’.

Means of Introduction

Because some of the Euro Standards relating to components are not yet published, and the Euro Standards do not cover some issues that alarms may be required to meet in the UK to satisfy the police or insurers, an enabling ‘standard’ has been prepared.  This outlines retained/additional UK requirements that apply alongside the Euro Standards and was published in August 2004 titled ‘PD6662:2004 – Scheme for the application of European Standards for Intruder and Hold up Alarm Systems’.

Timescale for Introduction of PD6662

A transition period operated until 1st December 2005, during which new alarms could be installed to previous British Standards or the PD6662 scheme.  Now PD6662 must be used.

Overview of EN 50131

The major differences between EN 50131 and the old BS 4737 are:

  1. Structured standards
  2. Grading of systems
  3. Classification of equipment
  4. Risk based

This provides a structured approach to:

  1. Assessment of risk
  2. Technical survey
  3. System design
  4. Installation of the system in accordance with agreed specification
  5. Installation of equipment in accordance with manufacturers’ recommendations.

A significant advantage for insurers and surveyors applying European Standards to systems is the specification of grades appropriate to the associated Risk. One of the major differences in the European Standards is the grading of systems, which is not a feature of BS 4737.

Security Grading

Under BS EN 50131-1:2004, intruder alarm systems will need to be Security Graded according to the kind of intruder considered likely to try to defeat the system.

Insurers are understood to support the Grading approach and it is expected that they will, in due course, recommend particular Grades of system in relation to particular premises risks.  Where this turns out to be the case, installers and customers may take the lead given by insurers, as regards the minimum Grade of system they require, and discuss whether to go for a higher Grade of system.


The grading of a system based on a structured risk analysis will determine the:

  1. Extent of the system
  2. Signalling
  3. Tamper security

Within the new European Standards there are four security grades:

  1. Grade 1 – low risk
  2. Grade 2 – low to medium risk
  3. Grade 3 – medium to high risk
  4. Grade 4 – high risk

Who Decides the Grade of Alarm?


Installers are required to carry out a formal assessment of the theft risk to determine a suitable Grade of alarm.

To do so they will consider the items at risk, existing security arrangements and any previous thefts, etc.  Before they proceed they will seek the customer’s formal approval, and may also suggest that any interested insurer be consulted.


Depending on the risk exposure, insurers may require an intruder alarm before providing certain insurance covers, eg theft.  As the Grade of an alarm cannot be readily changed after installation, it makes sense to check a proposed alarm with any interested insurer before proceeding.
Insurers may respond to a request to approve an alarm by visiting the premises, making a decision based on information already held by them, or by agreeing the outcome of the installer’s risk assessment.
Insurers will make their own decisions, but as a general guide the following is likely:

Detection and Control System

Grade 2 – Lower risk premises.
Grade 3 – Normal risk premises, ie all except those suitable for Grade 2 or 4
Grade 4 – Very high risk premises, eg cash handling centres, banks, museums.

A further inclusion in the European Standards is the classification of components that are used for the intruder alarm system installations. These will be classified, which in turn will determine where they are installed.

Detection and Control System – Grading

Apart from increasing control panel event memories and levels of recommended detection; the key difference between Grades 2, 3 and 4 is that movement sensors at Grade 3 must be able to detect ‘masking’, ie something has been placed over the sensor lens and at Grade 4 ‘range reduction’, ie something has blocked part of the detectors’ field of view.

Key Action Steps

When having a new alarm installed:

  • Use a reputable installer, eg one inspected by the NSI (NACOSS) or SSAIB.
  • Co-operate with the installer’s risk assessment procedures.
  • Check any interested insurer agrees with the proposed alarm Grade, Detection, Signalling and Response.
  • Where police response necessitates a ‘Confirmation System’ check that the installer designs a system that has:
  • Dual Path Signalling
  • Confirmation from each ‘at risk’ area
  • A ‘Means of Unsetting’ that does not prevent the police being called should an intruder force open the designated alarm entry/exit door.