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Intruder Alarms - Guidelines for Purchasers [Hardfacts]


The presence of an intruder alarm can deter unauthorised access and crime; but to be truly effective someone needs to be alerted to alarm activations, via local or remote signalling (Notification), in order that they can take appropriate action.  

There are many types of intruder alarm; but whatever their type it is important that they are reliable, resilient against interference, have adequate detection in all ‘at risk areas’, i.e. areas attractive to criminals, and suitable Notification.

This ‘Hardfacts’ outlines some general matters to consider when purchasing a new intruder alarm system.

What Types of Alarm System are available?
Intruder alarm systems are typically installed in one of four configurations:

  • 1     A mains powered battery backed up control panel; with hardwired or wire free links to its detectors and local site Notification (by siren) to alert neighbours  or site personnel. These systems are commonly called ‘Audible Only’ systems.
  • 2     A system as per 1 above; but with remote Notification to nominated persons (keyholders) via a telephone &/or text messaging device - commonly called a Speech or Voice Dialler. Basic diallers connect to the PSTN (telephone landline) network, but those that use the GSM (mobile telephone) network are preferable as they are not vulnerable to telephone line cuts.
  • 3     A system as per 1 above; but with Notification provided by coded signals sent, via a telephone &/or radio based Alarm Transmission System (ATS) to a 24/7 manned Alarm Receiving Centre (ARC), who in turn will contact the keyholders. Often referred to as a (remotely) ‘Monitored Alarm’.
  • 4     A system as per 3 above; but where the ARC can also request a police response to 'Qualifying Activations'.

Note. Systems 1- 3 may sometimes be deployed using only battery power, e.g. to protect garden sheds/outbuildings or temporarily unoccupied properties.

What Type of Alarm System is required?
As a matter of good practice, but otherwise as may be required by a relevant Standard (see section on What Alarm Standards Apply?) this should be determined by an alarm company after a thorough risk assessment, which also (ideally) considers the requirements of any interested insurer. For example:

  • If values at risk are low, and an opportunistic or brief ‘smash and grab’ theft is felt most likely, a system such as 1 or 2 above might suffice by way of general deterrent.
  • If values at risk are moderate, or there is a risk of general intrusion/premises damage, a system such as 3 above may be more appropriate.
  • Where there are high value goods/premises, a risk of prolonged intrusion/premises damage or safety risks to staff/keyholders, a system such as 4 above should always be chosen.

Who Can Install Alarm Systems?
Legally anyone can, but it is wise to only use reputable and competent installers.

The best indicator of competence is to use companies with National Security Inspectorate (NSI) or Security Systems & Alarms Inspection Board (SSAIB) approval; as they are fully audited against British/European Standards for system design, installation, maintenance and monitoring; plus those relating to staff security vetting, training and record keeping.
(Note. NSI or SSAIB accreditation is a pre-requisite for a police response alarm.)

Who Should Respond to an Alarm?
A reliable and trustworthy person holding keys to the alarmed premises (keyholder) needs to attend and investigate all reported alarm activations/faults.

Keyholders will typically be an alarm owner or their staff, tenants, friends or neighbours. These can be regarded as ‘in house’  or ‘non-commercial’ keyholders

For 'Audible Only' systems, a keyholder should ideally be living/working on site or adjacent to it. For 'Monitored Alarms' systems the ARC will need to hold keyholder telephone contact details.

In any event, keyholder attendance in pairs is advisable to reduce safety risks.

Where response involves commercial companies or the police, either instead of or in conjunction with ‘in house’ keyholders, the following matters need consideration:

Commercial Response
When selecting a response company choose one whose staff hold appropriate Security Industry Authority (SIA) licences, which adheres to recognised training and operating procedures, e.g. BS 7984 - Code of Practice for Keyholding and Response Services, is suitably insured and subject to third party (external) inspection of their activities.

Suitable adherence with the foregoing advice may be demonstrated by companies enrolled in the SIA Approved Contractor Scheme (ACS), but the simplest indicator of full compliance is NSI or SSAIB listing.  

Note. Some response companies claim to offer a quicker response to site by storing keys/alarm operating devices in a site key box. This is an undesirable practice and should always be referred to any interested insurer before use.
Police Response
High numbers of false alarms have caused the police to progressively tighten up their criteria for responding to alarm signals, whether received from ARC’s or reported by the public.

Routine response is now only available to systems that have a police Unique Reference Number (URN). To obtain a URN, systems must be installed, maintained and monitored by an NSI or SSAIB approved alarm company/ARC.

Police response will usually also be conditional on the provision of a ‘Confirmed Activation’, i.e. obtaining two alarm signals/pieces of alarm information within a pre-set time period. Such systems need very careful design if police response is to be obtained reliably, and early on, during any break in.

What Alarm Standards Apply?
In the UK various alarm standards exist, which NSI and SSAIB approved companies must observe:

British Standards

  •  BS 4737- Former UK standard for intruder alarms in buildings. Largely withdrawn in 2004 and replaced by European Standards, known as the ‘Euro Standards’.
  • PD 6662: 2010 - Scheme for UK implementation of the Euro Standards.
  • DD 263: 2010 - UK standard for system maintenance requirements.
  • BS 8243: 2010 - UK standard for systems designed to provide Confirmed Activations - used only if a (police response) confirmation system is required.

Note. SSAIB have a code of practice specifically for temporary alarm systems - SS 2004

European Standards (as reflected in PD 6662)

  • EN 50131 - General Requirements
  • EN 50136 - Signalling Systems

A key feature of the Euro Standards is that four ‘Grades’ of alarm are described from 1-4 (4 being the highest),  together with Notification Options of varying type and performance (often also referred to as a signalling ‘grade’).

Alarm companies are required to conduct a formal security risk assessment to determine the Grade of alarm system, and (ideally) a separate ‘grade’ of Notification, i.e. to help design a system felt most appropriate to each customer’s risk exposure.

What Maintenance is Required?

Routine maintenance requirements typically involve one check per annum for Audible Only systems, and two checks per annum for ARC monitored systems, one of which can be a remote check - subject to equipment compatibility.

What Might Your Insurer Want?

Insurers’ requirements will reflect individual circumstances, but in general they look for:

  •  Use of NSI or SSAIB approved companies.
  •  A Grade of system suited to the risk, typically:
    - Typically Grade 2X for 'Audible Only' alarms
    - For monitored alarms, Grade 2 for domestic premises, Grade 3 for commercial ones.
  • Suitable detection in all ‘at risk areas’.
  • A reliable response - e.g. keyholders and the police notified of alarms via an ARC.
  • An ATS that is frequently checked and with faults promptly reported (‘grade’ 4 = within 3 minutes) to the ARC.
  • Confirmation systems that have:
    - Enough detection to provide a ‘confirmed activation’ early on during any break in.
    - A ‘means of unsetting’ that, should a break in occur via an alarm entry/exit door, doesn’t prevent or unduly delay the ARC in calling the police.
    - A ‘grade’ 4 Dual Path (Two signalling routes to the ARC) ATS.

Key Action Steps
When considering a new intruder alarm:

  • Use a NSI or SSAIB listed alarm company.
  • Co-operate fully with an installer’s Grade related risk assessment procedures, noting that it may be necessary to check the proposed Grade of alarm system and related ATS with your insurer, see ‘Hardfacts’ 3012: Intruder Alarms – European Standards for more information.
  • Ensure you have adequate arrangements in place for a suitable and timely alarm response.
  • Where commercial response is required ensure you use a reputable and suitably regulated/licensed provider, e.g. an NSI or SSAIB company.
  • Where police response is required, ensure you understand their requirements, see ‘Hardfacts’ 3008: Police Response to Security Systems for further information.
  • Where a confirmation system is required, ensure you have an adequately designed system, see ‘Hardfacts’ 3022: Intruder Alarms - Confirmation Systems, for further information.
  • Seek insurer advice beforehand, but otherwise check that they agree with the proposals of your alarm company.
    Note. Sending a copy of the installers’ plan of the premises will greatly assist in this
  • Check any property insurance policy for ongoing requirements (conditions) relating to alarm protection and then ensure you comply, as failure to do so may jeopardise your insurance cover.

Sources of Further Information

Other Hardfacts in the Property Protection - Security Series, which are available in our ‘Knowledge Store' at

Your alarm company

National Security Inspectorate (NSI). Tel 0845 006 3003 or see

The Security Systems and Alarms Inspection Board (SSAIB). Tel 0191 296 3242 or see

The British Security Industry Association (BSIA). Tel 0845 389 3889 or see

The RISCAuthority (the UK insurers' technical advice body) see

In particular, see guides to intruder alarms:-




The Security Industry Authority -

The British Insurance Brokers Association (BIBA) -

In particular see their general guide to intruder alarms:-

Next Steps:

  • Source discounted products, available to Aviva insured customers and brokers only, via our Specialist Partners - click here to find out more about the savings you could make
  • View our Tools and Templates
  • Call our Risk Helpline on 0345 366 66 66
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Please Note
This document contains general information and guidance and is not and should not be relied on as specific advice. The document may not cover every risk, exposure or hazard that may arise and Aviva recommend that you obtain specific advice relevant to the circumstances. AVIVA accepts no responsibility or liability towards any person who may rely upon this document.

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