Perimeter protection such as barriers, walls or electric fences function as a first-line deterrent in preventing or discouraging intruders from illegally entering your property. Unfortunately this often leads to a false sense of security as the owner is usually unaware of illegal perimeter breaches. This is the reason most property owners choose to combine their barriers with perimeter intrusion detection systems (PIDS).
If you have installed a perimeter intrusion detection system around your property, you have taken the first step in protecting your most valuable asset. Whether you have installed PIDS to guarantee the safety of your home and family, workplace, equipment or possessions, it is important to guard against false alarms. Multiple false alarms lead to complacency and you need to be certain that when you receive a PIDS alarm, it is a real event.
Most PIDS rely on vibration in order to ascertain whether there is an intruder or not. Furthermore, well known, internationally recognised PIDS use a sequence of events and movements to pinpoint the exact type of intrusion, such as cutting or climbing, and the location of the intrusion. While this provides extremely accurate detection, no system is infallible and anything causing vibrations around the perimeter may trigger a false alarm. To avoid this, you should minimise vibrations caused by non-hostile events.
The main culprits for false perimeter alarms and how to prevent them are listed below.
Poor fence condition
This is without a doubt the most common trigger of false alarms. Loose or unsecured fence panels can cause significant vibrations, mainly due to wind. When this happens, vibrations pass into the fence post and automatically trigger a warning. You should ensure that your fence is in the best possible condition and that all fence panels are securely attached. Regularly inspect the perimeter fence after a spell of particularly windy weather and be certain to fix any loose panels you may find.
Overgrown fences
It is very difficult for your PIDS to determine the difference between a person climbing a fence and a tree branch bumping into the fence in the wind. While advanced PIDS use intelligent algorithms to detect the different types of vibrations, you should be sure that there are no overhanging trees or plants within striking distance of the fence and cut back any offending branches. You may also want to use weed matting to ensure that nothing can grow too close to your perimeter.
Gates with chain locks
Most people will try and gain access to your property at perimeter doorways or gates, and particular attention should be paid to this area. Often gates and doors are secured with a chain lock. These look far more secure than they actually are and have the added disadvantage of bumping against the door or gate frame. Once again, the PIDS will issue a false alarm, believing that someone is attempting to force entry.
Old fence signs
Similarly to the chain locks, a ‘no-entry’ or ‘trespassers will be prosecuted’ sign can be a double-edged sword. It may dissuade people from accidentally trespassing, but can vibrate against the fence in high winds. If you are going to use a sign, use steel cable ties to secure it in place.
Loose razor coil
In high-security applications, barbed wire is a very popular means for protection against intruders who would climb a fence or scale a wall. However, ageing razor coil tends to generate unwanted alarms when bumping into the fence. As a result, razor coil should be regularly checked and maintained if necessary.
PIDS solutions
Another way of decreasing your false alarm rate without compromising accuracy is installing an internationally recognised and certified PID solution.
The VibraTek solution supplied by Samian Technologies (a subsidiary of Solution House Holdings) has been independently evaluated by the UK government’s Centre for the Protection of the National Infrastructure (CPNI) agency. Part of the responsibilities of the CPNI is to advise high-security sites within the UK which perimeter detection system will provide the best value for money in terms of system performance and cost. More than 500 km of VibraTek sensors effectively secure hundreds of sites worldwide. The system is sophisticated yet easy to install.
PIDS are an invaluable part of the overall security infrastructure and technology. False alarms can be very distracting and lead to complacency, but if you take these preventive measures you can ensure that the only alarm you hear is the one you need to.
For more information contact Tiaan Janse van Rensburg, Solution House Holdings, tiaan@solutionhouse.co.za, www.smartperimeter.co.za
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