Security alarm system is a set of jointly operating technical means for detection of intrusion (attempted intrusion) on the protected object. It provides collection, processing, transmission and presentation of service information and information on intrusion (attempted intrusion) in specified form.
Conditionally, security alarm systems can be divided into two types:
Autonomous security alarm system.
It provides control of the situation at the site and in case of detectors actuation includes a siren, strobe-flashes and other devices to attract the attention of people around.
Security alarm system with connection to a central monitoring station (CMS).
In this case when alarm events occur at the guarded object the information is transmitted via different communication channels to the remote units of non-departmental security service for prompt response.
Object security is based on a multi-border scheme, when two or more security alarm loops are created, each of them using technical means, based on different operating principles.
Boundary 1 (perimeter) – external, the earliest point of detection. This boundary blocks windows, doors, hatches, ventilation ducts, heat entrances, non-capital walls and other elements accessible to unauthorized entry.
Boundary 2 (Volume). The second boundary is designed to protect the interior volumes of the premises. The requirements for the second line of protection are mainly reduced to the correct selection of the detectors, their adjustment and tuning. In critical facilities (bank vaults, storerooms of valuables, weapons storage rooms, etc.), several detectors, different in their physical principle of operation, are used to protect individual rooms. The peculiarity of this point is the multiplicity of separate rooms, common corridors and the need to specify the exact room where the alarm occurred.
Milestone 3 (Point). The point is understood as a local object, the material values protected by the alarm system. Safes, metal cabinets or directly objects and exhibits are blocked by the third boundary.
Selection of sensors and detectors used for all guarding borders is performed taking into account many factors: climatic conditions, design features of the guarded object, probable penetration ways, guarding regime and tactics.
In general case security alarm system consists of: receiving devices (devices), intrusion detectors, light and sound devices, communication lines, sources and power circuits.
Intrusion detector is a device for generating alarms, intrusion attempts, or for triggering alarms. One of the main characteristics of detectors is the detection zone. This is the zone in which the detector gives an alarm signal (intrusion) when a standard target (person) moves at a constant distance from the detector.
Detectors come in:
- passive opto-electronic infrared
- active optronic detectors
- radio wave
- ultrasonic
- capacitive (inductive)
- magnetic contact
- microphone
- security pressure detectors
- piezoelectric
- shock-contact
- electric contact
- handheld intrusion detectors
Intrusion alarm receivers (devices) are used to:
- reception of notices from intrusion detectors (security alarm loops or other receiving and control devices,
- Signal conversion, notification output for direct perception by person,
- further transfer notices,
- activation of sirens,
- in some cases for power supply of intrusion detectors.