The intrusion alarm systems are designed and used to signal danger situations in facilities under protection, particularly in the case of an intrusion or theft, and can also operate as an indicator of other dangers, such as: personal alarm in case of health problems or robbery, fire detection, gas leakage, flood and other events.

How it works

An intrusion detection system is composed of peripheral devices placed in strategic locations to ensure the protection of specific areas depending on the desired security level.

These systems can be complemented with telephone alarm devices that can communicate alarms or other detailed information to a central station or to previously programmed phone numbers.

Protection types

• Indoor – For this type of protection motion sensors can be installed to cover the area to be protected, usually dual technology or PIR detectors and magnetic contacts placed on doors and windows of access to the building/house.

• Perimeter – For this type of protection are usually installed detectors in the outside for protection of the facilities perimeter; in this case there are several technologies from which we highlight the active infrared beam barriers, the fence detector, the buried cable or, directly installed in the building, the magnetic contacts on the doors and windows and, still, the active infrared beam barriers “recessed” in the doors and/or windows or scanning the facades of the buildings.

• Objects (specific) – Protection of especially important and worthy objects, widely used in museums and art galleries and that may combine several detection and protection technologies.
• Anti-theft – Widely used in commercial spaces by installing magnetic barriers at the exits. In the most valuable products are usually placed tiny sensors that, when passing through the operating range of the barriers, trigger an alarm. There are several types of sensors: stickers, pins, cords etc.
• Technical Alarms – Protection against fire, flood, gas leakage and other perils.

Types of peripheral devices

The security systems peripheral devices are generally divided into three types:

• Detectors
• Command Devices
• Alert Devices

DETECTORS

A detector is a device that detects a certain type of violation and that communicates it to the control panel. There is a wide range of sensors for each type of situation that you want to protect from; ranging from anti-intrusion devices up to technical alarms; in this last case we emphasize the Flood, Gas and Fire detectors.

DETECTORS FOR INTRUSION AND PANIC ALARMS

• Passive Infrared Motion Detector – uses the principle of passive detection of the amount of infrared radiation emitted by a body.
• Active Infrared Detectors – used in the barriers for perimeter protection, the alarm triggers if there is an interruption of the infrared beam established between the emitter and receiver cells housed in columns installed facing each other.

• Dual Technology Motion Detector – detector that uses the combination of two technologies: normally the infrared and microwave technologies. When the PIR sensor is triggered, it activates the microwave sensor, if the latter also make detection, the alarm is triggered. The fact that the alarm triggers only when both sensors are activated reduces the false alarm rate.

• Glass Break Acoustic Detector – used to detect breakage of a glass at a specific location.

• Magnetic Contact – is a common way to protect doors and windows; when it is open the alarm triggers.

• Panic Button – used to require for help, there are two basic types: the fixed button placed at a suitable location, in which the transmission to the control unit is made by wire or radio, and the handheld panic button in that transmission to the control unit is made exclusively via radio, which may be a remote control or even a bracelet placed on the user wrist, the latter often used in cases of bedridden patients.

DETECTORS FOR TECHNICAL ALARMS

• Flood Detector – is used to detect the presence of liquids. Should be placed wherever it is probable the presence of fluids containing water as a result of an infiltration or flooding.
• Gas Detector – is a device that detects the presence of various gases within an area, usually as part of a security system.This type of equipment is used for detecting a gas leakage and to communicate it to a control unit system, thus allowing for an automatic cutting process of the gas supply. It may also sound an alarm.The gas detector can be used to detect combustibles, combustion and toxic gases and oxygen depletion. They may detect various toxic or flammable gases, or a combination of both types.
• Fire Detector – for notification of the presence of fire, there are optical models for smoke detection and thermal models which detect the rapid temperature increase in a particular area.

ANTI-THEFT DETECTORS

• Magnetic field barriers – widely used at the exits of commercial spaces, they detect the proximity of active sensors (stickers, pins, cords etc.) that are placed on the most valuable products.

  The barriers generate a permanent magnetic field between them, when some active sensor comes within range of the magnetic field it is excited allowing the identification of its presence and the system sends an audible alarm, allowing the Security of the establishment to intercept the presupposed thief.

  The sensors affixed on the merchandise, depending on the type of sensor, are disabled or removed from it, by suitable devices when they pass through the cash registers, thus preventing these to activate alarms when passing through the magnetic field of the barriers.

COMMAND DEVICES

These devices have as their main function the command and operation of the security systems, operating keyboards and remote controls are devices that allow the user to interact with the system.

• Keyboards – allow the introduction of codes, program and interaction with the security system.
• Remote controls – allow arm/disarm the system and activating systems’ programmable outputs, which may in turn make to operate various devices, such as lights on/off, open/close gates, etc.
• Phone communicator – despite being an alert device can also, simultaneously, be considered a control device, since it allows the user to access to the remote control panel and perform all the control operations as if using a keyboard.

ALERT DEVICES

These devices allow the security system to send the alert on the occasion of a given event; the alert may be audible in the case of sirens or through communication in the case of a phone communicator.

• Sirens – acoustic and luminous (flash) warning device.
• Phone communicator – a modem that can communicate alarms or other detailed information to a central station, or to previously programmed phone numbers, via telephone lines or GSM.