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Intruder Alarm Systems - ACPO Policy Changes 2006

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Intruder Alarm Systems - EN50131

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Intruder & Burglar Alarms

Since our company was formed in 1986 we have always advised people to keep their house alarm as simple and easy to use as possible.

That way you always use it (there are extensive technical standards we have to keep to eg for the survey, Risk Assessment, the equipment and the installation, they are explained in the later paragraphs).

Which rooms to cover/protect depends upon the risk to the contents of those rooms (and if they are an easy route to get to any valuables you keep, (eg in rooms upstairs).

We would always recommend that you have all doors to outside alarmed with door contacts.

Depending upon the layout of the rooms downstairs, we would also always recommend that you have ‘PIR’s’ – Passive Infra Red Detectors, (also known sometimes as ‘Beam’s). to protect any valuables in those rooms, normally one ‘PIR Detector’ in a corner just below the ceiling covers even a large room (the ‘beams’ come out in a fan shape and this means they cover up, down and across the room.)

You do not necessarily have to cover every room with PIR detectors, this can be expensive and unnecessary. For instance if the kitchen door to outside is alarmed and the front door is alarmed a burglar would not normally try to remove a washing machine (for instance) through an alarmed door, (due to the weight of the washing machine and the risk to them of being caught)

However they would consider breaking through a window (or door) to easily carry away a valuable TV, Digital Video Recorder or expensive figurines/china etc, (which is where PIR detectors are so useful as they should activate immediately, at least one exterior door requires a delay for entry and exit to the house).

PIR Detectors and Door Contacts are connected to a Control Panel, (normally this is a blank box and goes into a cupboard.) You then have a small keypad (like a telephone keypad and usually smaller than two light switches) which would be close to the door you normally come into the house through (this keeps the delay you need before the alarm would activate to the minimum).

Alarm Sounders (Bell Boxes): 2 Bell Boxes are normally used, one to the front of the house and one to the rear. They look identical, but only one contains the sounder, two strobe lights and a cut off timer (for noise pollution laws the sounders must cut off after 20minutes). We also have an additional “cut off timer” in the Control Panel (so that if one should somehow fail (very rare) then the other one will silence the alarm system. However even though the alarm sounder switches off after 20minutes, should a PIR detector again detect movement the alarm will then sound again for 20minutes as this indicates that someone (or something) continues to move about in the house. An additional sounder is usually fitted in the hall, so that if you are asleep you can still hear the sounder.

Vibration Sensors: In certain situations a Vibration Sensor fitted to a window may be more appropriate e.g. a very large dog or a cat that likes to climb onto window sills!

Break Glass Detectors: Break Glass Detectors are very similar to Vibration Sensors and as they say, detect the sound of breaking glass, however Vibration Sensors can be better as not all intruders break a window to get in! (It’s unusually far easier to prise the frame or double glazing panel out and less dangerous to the intruder than dealing with broken glass).

Pets: Pet (PIR Detectors) Sensors are a great deal more reliable now, and providing they are carefully installed they can be used even with for instance, a Labrador. However, as they won’t detect a dog the size of a Labrador, they similarly won’t detect a child/person of that size (which again is where the risk to the house needs to be considered). If any pets can be kept in kitchens, or areas where there are not any valuables, then an alarm system combined with normal PIR Detectors, Pet Sensor PIR Detectors, door contacts and maybe vibration sensors on windows could give you more protection. PIR Detectors (and Pet Sensors) all work on the basis that the closer you are to the beams the larger you appear to the beams, (which is where unfortunately a fly landing on the sensor can set off the ‘beams’/detector, however again this is rare)

Similarly a cat that likes to sit on window sills, jump up onto cupboards etc will be seen as a much larger object the closer it gets to the detector. Therefore, PIR Sensors are not normally recommended if you have very larger dogs or very active cats!

Panic Attack Buttons: These again are what they say and may be fitted in a bedroom for instance, they are ‘live’ 24 hours a day, so even if you have not switched your alarm system on (e.g. during the day) if you press the button the alarm will go off. However, again you need to be careful where you install panic attack buttons as if children are able to reach up to the button – they will of course press it out of curiosity! You can only stop your alarm sounding by going to your keypad and putting your code in. (This is a safety feature and part of the standards)

Wireless (or Radio) Alarm Systems: Again are (mostly) as the name implies, with the following exceptions eg the Control Panel does still have to be cabled into the mains electricity and we (at CDS Security) always cable the exterior bell box back to the Control Panel (although you can get Radio/Wireless Bell Boxes but our engineers personal opinion is that a wired alarm Bell Box gives greater security.) Wireless Alarm Systems are installed more easily on the whole but the equipment is more expensive than a conventional “wired” system. Each Detector/Keypad (again you can have PIR Detectors, Door Contacts and Vibration Sensors etc) all have their own individual batteries (but these need to be changed every 2 years.) The technology has advanced considerably in recent years and radio alarm systems are not now prone to false alarms, however we would still not recommend installing Radio Alarm Systems close to a busy taxi rank for instance, due to the possibility of radio interference.

In the Event of a Power Failure: The Control Panel is wired into the mains electricity but also has a re-chargeable battery, for the standards this battery must still have enough power to keep your alarm system running for at least 12hours (even if the battery is 4-5 years old) Therefore the battery has to be replaced when it reaches this age In the majority of houses we find that the batteries usually last at least 24-36 hours if there is an extensive power cut. However the more equipment you have in the alarm system the less “stand-by” time you get from the battery, no matter how large your alarm system the batteries have to be able to keep your alarm system “live” for a minimum of 12 hours (as above).

If the Alarm is set off accidentally: It’s easy to forget sometimes to switch the alarm off when you come downstairs on a morning, or have children etc. however if you quickly put your code into the Keypad (this is a 4 number code that you choose and can change as you wish/want to yourself) then the alarm will be silenced before your neighbour even realises you have accidentally set it off

Audible Alarm Systems: e.g. if the Alarm goes off the Bell Boxes and your internal sounder will go off and the strobe light’s on the bell box will flash.

Signalled or Communicated Alarm System: If the alarm is activated a signal is sent to our Alarm Receiving Centre, who depending upon the type of activation/signal can phone the police, your house and/or a key holder that you have nominated. This type of Alarm System has to comply with even more stringent standards than an Audible Alarm System in order to have (and keep) police response.

Auto-Dialler: An auto-dialler can be fitted to most alarm systems, and will dial a number of telephone numbers (we and you can programme the telephone numbers in quite easily). If the alarm goes off, it will ring these numbers in sequence and play a recorded message of your choosing (to summon assistance for you from a friend or relative).

Safety Features: The following are all requirements of the British / European Standards that all Intruder Alarm Systems are supposed to be installed to.

Cables: All cables are to be tamper proof e.g. if a cable is cut the Alarm should activate.

All Detectors: (including PIR Detectors/Vibration Sensors/Door Contacts etc.) again should be tamper proof, if they are disconnected, the lid removed etc. the alarm should activate.

Keypad and Control Panel: again as above – tamper proof.

Bell Boxes/Sounders: - again tamper proof.

Other Safety Items Carbon Monoxide detectors, smoke and heat sensors, intercoms, nurse call systems, flood detection systems etc can all be incorporated into your alarm system.


 A number of insurance companies give discounts (e,g, 5-10% or more) if you have an alarm system installed and maintained by an approved / accredited installation company. CDS Security & Fire is accredited to Gold Standard by NSI (National Security Inspectorate).

Technical Standards The following are the standards to which Intruder Alarm Systems are to be installed to, to comply with British / European Standards, police and insurance requirements

Intruder Alarm Systems – EN50131

From 1st October 2005 New European Standards for Intruder Alarms replaced British Standard 4737. These apply to all Intruder Alarm Systems to be installed to Domestic and Commercial premises alike.


The System Design Proposal (Previously Specification) is to be based on a Risk Assessment One of the fundamental differences between the current British Standards and the new EN standards is the way in which systems are to be designed.

EN standards require system designs to be based on RISK.

To aid this, intruder alarm systems installed in buildings are graded. The grade of system (please refer to next section) will take into account the:

5. Risk level of the premises/house

6. Risk level to the occupants (or householders)

7. Contents value

8. Typical knowledge intruders might be expected to have

The risk assessment is a fundamental part of the survey, this will form the basis of the System Design ‘Proposal’.

It is therefore essential that all the risks are considered and that the system as designed is therefore suitable and adequate to protect the particular risks.

Grading of Systems and Grading of Equipment

System grades (1-4) are categorised within the EN standard as:

Grade 1 - Low risk system where intruders are expected to have little knowledge of intruder alarm systems and be restricted to a limited range of easily available tools. (This standard is less than the previous BS4737 and it is expected that grade 1 will not be acceptable to most Insurance Companies. E.g. certain devices are not required to be ‘tamper proof’)

Grade 2 - Low to medium risk system where intruders are expected to have a limited knowledge of intruder alarm systems and the use of a general range of tools and portable instruments.

Grade 3 - Medium to high-risk system where intruders are expected to be conversant with intruder alarm systems and have a comprehensive range of tools and portable electronic equipment.

Grade 4 - High-risk system where security takes precedence over all other factors. Intruders are expected to have the ability or recourse to plan an intrusion in detail and have a full range of equipment, including means of substitution and vital components in the intruder alarm system.

Additional Items

The equipment is now graded according to the level of protection built into the device, with grade 1 being the lowest (least secure) security grade. 12 hours of standby battery power is now mandatory (BS4737 was 8 hours). Control Panels are to have considerably more ‘reporting information’ e.g. for greater event recording and memory

Environmental Classification of Equipment:

As well as the 4 security grades, the equipment now has to conform to one of 4 environmental classes:

Class 1 – Indoor (Even temperature) (e.g. office / living room)

Class 2 – Indoor General (e.g. Garage)

Class 3 – Outdoor Sheltered

Class 4 – Outdoor General (Open to the elements etc)  


Intruder Alarm Systems – ACPO Policy Changes 2006


ACPO (Association of Chief Police Officers) tightened national police response to Remotely Monitored Security Systems in April 2006.

The ACPO policy states “after the 1st of April 2006 we will allow 3 Policed false intruder activations and 2 Policed false personal attack activations, when these thresholds have been reached for either element a level three letter will be generated”. (Prior to 01/04/06 the level was 5 Policed false intruder alarm activations).

The changes are likely to mean that a significant number of Alarm Systems will need to be upgraded to incorporate Confirmation Technology in order to minimise the risk of having police response withdrawn. A Confirmed Activation is one which results from the activation of 2 or more independent detectors within a fixed period e.g. incorporates confirmation technology.

Systems capable of generating confirmed activations

(Generally those installed after September 2001) e.g. incorporating confirmation technology. Will only qualify for re-instatement of police response by demonstrating they have been false alarm free for a period of 3 consecutive months.

Systems which are NOT capable of generating confirmed activations (Generally those installed before September 2001)

Will NOT be allowed the 3 months alarm free period and must be upgraded to incorporate confirmation technology before qualifying for reinstatement of police response.

All systems that have Police Response withdrawn

Must regain response within 6 months, if not the Police URN will be withdrawn.

An application for a Police URN (after it has been withdrawn)

Would be subject to any charges made by the police under the ACPO Policy, and the system would have to be upgraded to full European Standards, the costs could be significant to upgrade your alarm system to European Standards, e.g. the Control and Detection equipment etc may require replacing.

Systems without Confirmation Technology are at greater risk of exceeding the Policed false alarm level and we would strongly advise that you have your system upgraded in order to minimise the risk of having Police Response withdrawn.


For advice, assistance or a free quotation, please Contact Us on 0191 384 0079.   

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