About security systems
A security alarm is a system designed to detect intrusion – unauthorized entry – into a building or area. Security alarms are used in residential, commercial, industrial, and military properties for protection against burglary (theft) or property damage, as well as personal protection against intruders
Some alarm systems serve a single purpose of burglary protection; combination systems provide both fire and intrusion protection. Intrusion alarm systems may also be combined with closed-circuit television surveillance systems to automatically record the activities of intruders, and may interface to access control systems for electrically locked doors. Systems range from small, self-contained noisemakers, to complicated, multi-area systems with computer monitoring and control..
The most basic alarm consists of one or more sensors to detect intruders, and an alerting device to indicate the intrusion. However, a typical premises security alarm employs the following components:
- Premises control unit(PCU), Alarm Control Panel (ACP), or simply panel: The “brain” of the system, it reads sensor inputs, tracks arm/disarm status, and signals intrusions. In modern systems, this is typically one or more computer circuit boards inside a metal enclosure, along with a power supply.
- Sensors: Devices which detect intrusions. Sensors may be placed at the perimeter of the protected area, within it, or both. Sensors can detect intruders by a variety of methods, such as monitoring doors and windows for opening, or by monitoring unoccupied interiors for motions, sound, vibration, or other disturbances.
- Alerting devices: These indicate an alarm condition. Most commonly, these are bells, sirens, and/or flashing lights. Alerting devices serve the dual purposes of warning occupants of intrusion, and potentially scaring off burglars. These devices may also be used to warn occupants of a fire or smoke condition.
- Keypads: Small devices, typically wall-mounted, which function as the human-machine interfaceto the system. In addition to buttons, keypads typically feature indicator lights, a small multi-character display, or both.
- Interconnections between components. This may consist of direct wiring to the control unit, or wireless links with local power supplies.
- Security devices: Devices to detect thieves such as spotlights, cameras & lasers.
In addition to the system itself, security alarms are often coupled with a monitoring service. In the event of an alarm, the premises control unit contacts a central monitoring station. Operators at the station see the signal and take appropriate action, such as contacting property owners, notifying police, or dispatching private security forces. Such signals may be transmitted via dedicated alarm circuits, telephone lines, or Internet.
Security system grades
Systems classified, as Grade 1 would be most at risk from “Opportunist” thieves. Intruders would have little knowledge of Intruder Alarm Systems, and would be restricted to a limited range of easily available hand tools, such as hammers, chisels, screwdrivers, pliers etc. This Grade would typically be used for most domestic ‘Bells Only’ Systems. This grade is a lower standard than BS 4737.
Systems classified as Grade 2 are likely to be targeted by criminals who will have prepared themselves prior to a crime and will know something about the contents of a building. Intruders would have limited knowledge of Intruder Alarm Systems, and would have the use of a general range of tools and portable instruments such as multimeters, bolt cutters, battery drills etc. This grade would normally account for large residential and small commercial Systems such as Florists, Bakers, Salons and Carpet Retailers.. An option has also been created for lower risk Grade 2 systems, which are not monitored. These are classified as Grade 2X.
Systems classified as Grade 3 are likely to be required where a buildings contents are perceived to be high value, and criminals are likely to spend time planning an intrusion. Intruders would be conversant with Intruder Alarm Systems and have a comprehensive range of tools and portable electronic equipment, such as oscilloscopes, laptops, security screwdrivers etc. Typically this grade would account for most commercial systems such as bonded warehouses, motor garages, computer distributors, mobile phone shops, sports shops etc.
Systems classified as Grade 4 will apply where security takes precedence over all other factors. Intruders are expected to have the ability or resource to plan an intrusion in detail and have access to a full range of tools and equipment. This would include the means to substitute vital components in the Intruder Alarm System. Typically this grade accounts for security systems that could be applied to military installations, bullion and cash centres, government research establishments etc. In these circumstances there is a high risk of organised crime or terrorism.
Most applications would fall in the category of Grade 2, if you are not sure you should seek advice from your insurance company.
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