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1.5 HOW TO DESIGN AN ANTI - THEFT SYSTEM
An anti-
theft system’s objective is to avoid evil-minded people accessing the areas to be protected without
detection of their presence. Consequently, t
he first thing to be done is to create “perimeter protection”, which
means to position detectors to signal any attempt of intrusion from any external access to the house or office, such
as doors and windows. Perimeter protection must always be part of an anti-theft system and it represents the
simplest solution to obtain the set objective. Doors can be protected using magnetic contacts; for the windows it is
possible to use, depending of the situation, rope contacts for shutters, or glass breaking detectors and volume
detectors with curtain coverage.
The security level can be increased by analysing the possible compulsory trajectories of the intruder and by
positioning more internal detector
s, usually volume ones, which create “trap” protections. One example of this is
the infrared detector positioned in a corridor. Even if the intruder manages to enter in a room, to access the other
rooms he would have to cross the corridor causing the alarm to be set off.
A good anti-theft system must anticipate its deactivation, which means that it must be possible to activate the
detectors only in some areas if necessary. The reason for this is to increase security and comfort. These are some
examples:
In a house equipped with perimeter and trap protections it might be possible to avoid access when sleeping (in
this case only the perimeter protection is activated, whilst the trap protections are kept deactivated).
The same anti-theft protection must be applied to the house and to the office or shop or to an outbuilding (in this
case it is sufficient that the detectors positioned in the different areas are able to connect to the control panel).
In these cases it often occurs that when the house is used, the working place is empty, and vice versa.
In a production or commercial activity it might be necessary to guarantee that some areas keep being protected
by the system even during working hours. For example, the warehouse might have to be protected nearly all the
time (the alarm is only temporarily deactivated when it is necessary).The same case can applied to the garage/
house.
The division into sectors must be carried out according to specific needs, but it is advisable to dedicate at least one
sector exclusively to perimeter protection.
The control panel
’s proper positioning is very important. Besides the obvious fact that it must be placed in a safe
position - which means that it must not be accessible to anyone, it must be far from passages and from doors and
windows - if it contains a communicator it must also be placed in a position which can be reached by the telephone
cable or can be reached by a suitable level of GSM signal (if mobile phone technology is used).
An anti - theft system must always be equipped with at least an acoustic - optical signaller (siren + warning light)
and this must be placed in an external and easily visible position in a frequented area. To avoid damage it must not
be easily accessible, for example it must be placed high enough to require steps to reach it. If the intrusion
attempts are also to be remotely signalled, it is necessary to set up a PSTN or GSM communicator.
To activate and deactivate the system handy remote controls are available. Nevertheless it is advisable to install a
keyboard (sometimes even more than one). This is because of the following reasons:
It enables access to the house or office even if the remote control has been lost (for security reasons it is
advisable to keep keys and remote controls in different places - just as is done for cash point cards and relating
access codes).
It is possible to give the keys only to house maids or to employees.
In order to be able to partially activate/deactivate the systems from the access points of a single sector.
Sector 1
(perimeter)
Sector 2
Sector 3
Sector 4
