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Reviewing PIDS

Having traversed the farmlands of the Free State for many years, I learned a lot about perimeter intrusion detection systems (PIDS) from there.

I knew that I was nearing the expiry of my right of passage from one farmland to the next when I came across either tall trees in a row, thorny bushes or a three-string perimeter wire fence. I had to avoid getting too close to homesteads otherwise I would be met by a pack of vicious dogs and if I continued further towards homesteads I could expect to stare at a barrel of a gun in some cases.

Though technology has greatly improved and is available in South Africa, the principles of perimeter security are still more or less the same. Perimeter security calls for a total solution approach that 'deters, detects, delays and denies intruders access'.¹ If perimeter security does not incorporate these concepts, it is not a complete solution.

Deterrence

Some, if not most, perimeter security fences give the impression that they are there to deter any intruder. Petty thieves get intimidated by the looks of a fence and will easily skip a formidable barrier to an easy one elsewhere. On the South African security landscape I have seen lots of fences with deterrence as the primary objective. I have seen high wall fences and palisade fencing with or without razor wire. I have also seen electric fencing gaining popularity in places. The problem is that the skilled professionals still get through such security systems. Users need to think beyond deterrence.

Detection

Adding the detection concept to that of deterrence can enhance perimeter security. This can be done by adding a detection mechanism to the perimeter fencing. If one could know in advance when an intruder was advancing towards the fence or was actually crossing over, the property owner would be better prepared before the intruder came to the home or facility. Better still, a reaction unit could have a good head start in response to a breach in security. Waiting for a thief to break in for the home or a facility alarm system to go off is leaving oneself too vulnerable. Choosing an intruder detection system needs careful consideration. Things such as the probability of detection (Pd), false alarm rate (FAR) and costs needs to come into the criteria to choose such a system. Please note that cost is last on the list.

Delay

Once a property owner or reaction response unit is able to receive advance warning that an intruder has breached the perimeter security, there is need to delay the intruder as much as possible to buy time for the reaction unit to arrive at the scene. The delay concept to perimeter security is key to successfully securing assets and lives. This is the purpose of razor wire on top of perimeter fencing and sometimes rolled razor wire after the perimeter fencing, ditches, etc. All such mechanisms are delaying systems meant to buy time. This technique is a good add-on to standard perimeter fencing. A word of caution here, it is imperative that all delaying systems in place have the capability to detect the intruder's advance and communicate under one system and in sync with the rest of the systems in place. There are many software applications that allow for this integration. Delaying the intruder easy access to the perimeter long enough to deny him access to the home or facility is the primary objective.

Denial

Finally, denying the intruder the opportunity to get close to the protected home or facility is of critical importance. In today's world that has become terrorist infested, a mean intruder too close to a property can still cause serious damage by using explosives. This is why the fourth and final concept to perimeter fencing is essential and should never be left out of the equation in considering a perimeter security solution.

Here are some interesting examples from the many perimeter intrusion detection systems (PIDS) options available:

Multidirectional vibration fence sensor cable provides super sensitivity and accurate response to vibration caused by any intruder through 360° in three axes.

Magnetic concealed/buried sensor is designed to detect and locate intruders, over outdoor walls or pavement. Based on the Magnetic Anomaly Detection principle of operation, it detects any intruder who crosses the system carrying ferromagnetic objects as small as a pocket-knife or wearing metal buckles. Atmospheric conditions or wild animals do not affect the magnetic field.

Sensor barbed tape combines perimeter physical barrier protection with realtime electronic location identification.

Geo-seismic anti-intrusion perimeter system which is propagated underground, creates an invisible band around the site to be protected through special patented geo-seismic sensors that detect the pressure waves generated by a subject walking on any surface. The geo-seismic sensors are piezoceramic transducers, which produce a weak electric signal when subjected to stress.

Keith Muloongo is the Africa Business Development Director for Biomotic SA.

1. Robert Gruber, PSP Master Halco Security Solutions Group http://psi.praeger.com/pdfs/whitepapers/PerimeterSecurityandtheFourDs.pdfhttp://psi.praeger.com/pdfs/whitepapers/PerimeterSecurityandtheFourDs.pdf

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