MP500/4N-8-16 Installation
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3.3.3 How to protect areas and people
The purpose of an intrusion alarm system is to prevent some prowler from accessing the areas to be protected without him noticing the
system. This means monitoring openings and passages, which lead to two different techniques:
The
“perimeter" protection
, where detectors are installed in all the openings (entry doors, windows, skylights, and glass doors)
on the exterior of the areas to be protected. The detectors must cover the entire perimeter: even one single, small, and seemingly
insignificant opening that is not monitored represents a protection shortcoming and makes it a potential point of entry for intruders.
The advantages of this solution are that the alarm is given as soon as someone attempts to enter and that it is possible to arm the
system even if there are people in the rooms; the disadvantage is that if the intruder success in entering without setting off the
alarm, it is no longer possible to detect him and he may act without consequences.
The
“trap” protection
guarantees that the most important rooms and passages (like corridors and stairways, etc.) are surveyed.
The advantage of this solution is that the intruder may not wander about undisturbed, in that sooner or later his presence would be
detected; the disadvantages are that when his presence is detected, he has already entered and it is not possible to arm the alarm
system with people inside the rooms.
Figure 6 - Perimeter and trap protection
The best and most versatile protection is obtained, obviously, by using both technique. In paragraph
this will be
explained. Protecting the same room with more than one type of detector, when technically and economically possible, is a good idea
because it increases the probability of discovering an intruder.
In particular situations, like a building surrounded by a garden, it is even possible to consider a form of "advanced" protec tion, in the
sense that is constitutes a confine of protection in front of and remotely from the actual areas to be protected, seeking to anticipate
potential intrusions as much as possible. A typical example are the detectors installed along the gates or the perimeter walls of a
garden or outdoor courtyard, but they might also be seismic detectors installed along a driveway within the property.
