EN50131- what it means for domestic burglar and intruder alarms

Different houses in different locations need different levels of security and the new European Standards (EN50131) are designed to make it clear what a particular system will provide and how it can be expected to perform under different circumstances.  These standards replace BS4737 and use a completely new vocabulary.  A clear understanding is important when commissioning an alarm system but it is important to bear in mind that while the grading system describes the technical capabilities of particular systems and their components, it is the design of the system as whole that determines its effectiveness in the event of criminal activity, and a few comments on design are included at the end of this FAQ.

The new grading system describes two elements in an alarm system:

  • the robustness of the system to being tampered with by potential intruders is shown by a number (1-4)
  • the way in which the alarm system announces that someone is trying to enter the property without authorisation is shown by letter (X,B,C).

 so a grading level would look like Grade 1X, or Grade 2B etc.

As with every system of standards, the full documentation is extremely precise and therefore extensive, but the salient points of the Grading systems are outlined below.

Intruder alarm system robustness  gradings

The robustness of an alarm system is defined by its resilience to being tampered with by intruders trying to disable the alarm system.

Grade 1 intruder alarms

These are the most simple systems and do not include any real tamper proofing.  They are suitable only for the most low level of risk situations and are not normally installed by professional installers and are found mostly in the DIY market.

Grade 2 intruder alarms

This is the level of tamper proofing most commonly found in domestic alarm systems; it is also the minimum level that can be accepted for a Police response system.

With a Grade 2 system, a signal will be triggered if the alarm is tampered with, alerting the key holder of unwanted activity at the location.

Grade 3 intruder alarms

In addition to triggering a signal if the alarm is tampered with or damaged in any way, Grade 3 systems will also activate a signal if they are rendered inactive by, for example, being covered up.  Grade 3 systems are therefore used in higher risk areas and particularly where there is general public access to an area.  Grade 3 systems are therefore rarely needed in domestic alarm systems.

Grade 4 intruder alarms

This is the type of system used for for very high risks eg bank vaults and is very rarely, if ever, used in domestic installations.

Intruder Alarm System response signal grading
Alarm system signalling grade X

With a System X alarm, audible and possibly visible signals are triggered at the location, in other words the alarm will sound a siren or similar and may also flash. The intention is therefore to alert people in the immediate vicinity (and of course inside the property) of unauthorised activity and to deter the potential burglar from entering the property.

Grade X corresponds to an ‘Instant audible only’ system in the old BS grading scheme.

Alarm system signalling Grade B

With this level of signalling, a signal is transmitted from the alarm to an ARC (Alarm Receiving Centre).  via the normal telephone network using a digital communicator.

If the telephone line is cut, this of course reduces a Grade B system immediately back to Grade X.  An upgrade can therefore be arranged to a Grade B system whereby Redcare is used.  With Redcare, the line is constantly monitored so any interference or damage to the line is recognised and this information is then immediately passed to the authorised keyholder.  It is important to be aware however that the Police normally need further corroborating evidence before taking action.

Alarm System Signalling Grade C

Two independent paths are used to connect the alarm system to the ARC (Alarm Receiving Centre) in a Grade C alarm system.  One path is usually the normal telephone network (as in the Grade B system).  The second system may be GSM/GPRS (ie mobile phone network system), or increasingly a broadband connection is used in combination with GPRS.

The advantage of using two independent signal paths to the ARC is that  if one path is taken out by an intruder, the signal from another device within the alarm system can be carried by the remaining path.  This is important as the Police normally require two signals from an alarm system  to confirm an unauthorised entry and before taking action.  Since the equipment generating the signal for the second path is usually located inside the  property (either a mobile phone system or broadband) the intruder inevitably  triggers a second signal, such as a door contact alarm, before being able to enter the property and disable the second path.

How to use the new EN501301 grading system

Grading systems are extremely helpful but they are only half of the equation in determining the level of protection afforded by an intruder or burglar alarm system.  The design of the system is crucial too.

A Grade 2C installation could comprise a Grade 2 door contact alarm fitted to the front door of a house and a Grade 2 Passive Infra-red (PIR) detector fitted in the hall, and coupled via a dual path signalling system to an ARC .  Although this system would qualify for a Police URN (Unique Reference Number), the actual level of protection would of course be minimal and unlikely to provide the necessary two triggers needed for Police action. 

With this scenario, any Insurance Claim could be dismissed on the grounds that the system design was inadequate and the victim of the crime would be limited to trying to recover losses from the installing company, assuming of course they were still in business.

In order to ensure that a domestic alarm system will adequately protect a property and any insurance claim be honoured, it is always advisable to use an installer that has approval from one of the industry’s regulatory bodies, such as the SSAIB.  As the example above shows,  it is essential that the design of the intruder alarm system takes into account the  type of property, its location and the level of risk being protected.  A registered installer will be able to advise on both the system design and its specification and ensure that should a claim ever be made, the alarm system will be deemed suitable and appropriate.

False economies can so often end in disaster but where your home is concerned, it could mean losing both precious and valuable possessions and then losing an insurance claim you believed covered them.