Advantages and disadvantages of perimeter protection system
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Perimeter Protection
Perimeter protection is the first line in the defense to detect an intruder. The most common points equipped with sensing devices for premise perimeter protection are doors, windows, vents, skylights, or any opening to a business or home. Since over 80% of all break-ins occur through these openings, most alarm systems provide this type of protection. The major advantage of perimeter protection is its simple design. The major disadvantage is that it protects only the openings. If the burglar bursts through a wall, comes through the ventilation system, or stays behind after closing, perimeter protection is useless.
1.
Door switches. These are installed on a door or window in such a way that opening the door or window causes a magnet to move away a contact switch, which activates the alarm. They can be surface mounted or recessed into the door and frame. A variety of types of switches are manufactured for all types of doors and windows. The switches are both wide gap type and magnetic standard type.
2.
Glass break detectors. These detectors are attached to the glass and sense the breakage of the glass by shock or sound. Glass breakage sensors use microphone transducers to detect the glass breakage. A ceiling sensor over a window covers a 30-degree radius.
3.
Wooden screens. These devices are made of wooden dowel sticks assembled in a cage-like fashion no more than 4 inches from each other. A very fine, brittle wire runs in the wooden dowels and frame. The burglar must break the doweling to gain entry and thus break the low-voltage electrical circuit, causing the alarm. These devices are used primarily in commercial applications.
4.
Window screens. These devices are similar to regular wire window screens in a home except that a fine, coated wire is a part of the screen. When the burglar cuts the screen to gain entry, the flow of low-voltage electricity is interrupted and causes the alarm. These devices are used primarily in residential applications.
5.
Lace and panels. The surfaces of door panels and safes are protected against entry by installing a close lace-like pattern of metallic foil or a fine brittle wire on the surface. Entry cannot be made without first breaking the foil or wire, thus activating the alarm. A panel of wood is placed over the lacing to protect it.
6.
Interior sensors. They come in many shapes and sizes depending upon the application, for example, interior motion detector units and proximity and boundary penetration.