Intruder alarm
Intruder alarms detect attempted intrusion or unauthorised entry into a building, room, site or secure installation and trigger a response. Well-fitted and maintained intruder alarms can make organisations and individuals less likely to become victims of burglary, vandalism and other forms of attack.
There are many different types of intruder alarms, with selection depending on personal preference, location, building size, level of protection required, monitoring, method of response and so on.
Intruder alarms can be wired or wireless. Generally wireless alarms are easier to install. Installing wired alarms can be disruptive and even domestic installations will generally need to be fitted by a professional.
Intruder alarms can be 'bells only', 'speech-dialler' or monitored alarms.
Bells-only alarms, also known as 'audible alarms' make a loud noise when they are triggered. This is intended to alert nearby people to a potential intruder and to scare off the intruder. Unlike monitored or speech dialler alarms, there is no guarantee that any form of assistance will come, and in urban environments, alarms are often ignored.
A speech dialler or 'text alert' system will call or text nominated phone numbers. Contacted 'keyholders' may then take action, either investigating themselves, or notifying another respondent. They then may be able to remotely access CCTV cameras or microphones within the premises to monitor the situation and determine what sort of response is required.
Alarms may be monitored commercially, sometimes as part of a wider contract for installation and maintenance. The alarm connects to an alarm receiving centre (ARC) when triggered. The receiving centre will generally first ring the building and ask any respondents for their password identification. If this is incorrect or if there is no answer, they may inform the nominated keyholder(s) or respond themselves, or may notify the police.
Because of the number of false alarms, the police will only respond to alarms with a police unique reference number (URN). To be given a URN, alarm systems must be installed, maintained and monitored by a company listed with the National Security Inspectorate (NSI), or Security Systems & Alarms Inspection Board (SSAIB).
The police accept 3 types of new installation:
- Sequential: The first alarm notifies a keyholder. A second, different alarm in a designated period will notify the police.
- Audio: The alarm activates microphones allowing the alarm receiving centre to listen for any criminal activity.
- Visual: The alarm activates CCTV cameras allowing the alarm receiving centre to look for any criminal activity.
Response may be withdrawn following three false calls in 12 months and will only be restored if the system complies with the police policy on reinstatement.
The required type of alarm, security grade, type of signalling and response an be determined by undertaking a risk assessment. The risk assessment process should involve consultation with the insurer of the premises. Certain types of cover offered by insurers may be conditional upon the level of protection given by the intruder alarm system. This may for example require remote signalling to an alarm receiving centre, keyholder response, and police response.
The British Insurance Broker's Association (BIBA) define grades of alarm as:
- Grade 1: Not adequate for insurance purposes.
- Grade 2X: Suitable for lower-risk homes.
- Grade 2: Higher-risk homes and some lower-risk commercial premises.
- Grade 3: Commercial and high-risk homes.
- Grade 4: High-risk premises.
Ideally there should be at least two keyholders available at all times responsible for responding to alarms, preferably in pairs. They must be highly-trustworthy individuals who should be able to attend within 20 minutes, should be contactable by telephone and have their own transport.
To avoid noise nuisance alarms should cut out after 20 minutes. Failure to do so can result in prosecution.
[edit] Related articles on Designing Buildings Wiki
- Access control.
- Carbon monoxide detector.
- CCTV.
- CDM.
- Commercial security systems.
- Construction phase plan.
- Entry control.
- Fire and rescue service.
- Fire dampers.
- Fire detection and alarm systems.
- Glass break detector.
- Health and safety.
- Heat alarm.
- Insurance.
- Joint fire code.
- Noise nuisance.
- Perimeter security.
- Security and the built environment.
- Smoke detector.
[edit] External references
- Association of Chief Police Officers, Commercially Monitored Remote Signalling Intruder Alarms for Police Response.
Featured articles and news
What it is and how to use it.
Investors in People: CIOB achieves gold
Reflecting a commitment to employees and members.
Scratching beneath the surface; a guide to selection.
ECA 2024 Apprentice of the Year Award
Entries open for submission until May 31.
UK gov apprenticeship funding from April 2024
Brief summary the policy paper updated in March.
For the World Autism Awareness Month of April.
70+ experts appointed to public sector fire safety framework
The Fire Safety (FS2) Framework from LHC Procurement.
Project and programme management codes of practice
CIOB publications for built environment professionals.
The ECA Industry Awards 2024 now open !
Recognising the best in the electrotechnical industry.
Sustainable development concepts decade by decade.
The regenerative structural engineer
A call for design that will repair the natural world.
Buildings that mimic the restorative aspects found in nature.
CIAT publishes Principal Designer Competency Framework
For those considering applying for registration as a PD.
BSRIA Building Reg's guidance: The second staircase
An overview focusing on aspects which most affect the building services industry.
Design codes and pattern books
Harmonious proportions and golden sections.
Introducing or next Guest Editor Arun Baybars
Practising architect and design panel review member.