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Stopping criminals before they get near - the importance of perimeter security

In South Africa today, security is the watchword, regardless of whether you are a private home-owner or run a large business.

As criminals become more adept at finding their way through security systems, however, so the detection of unwanted intruders even before they enter the premises has rapidly become the preferred route taken by installers of alarm systems today.

A wide range of solutions exists to protect the perimeter of one’s property, which can be implemented either individually or as a combination of various applications to provide an holistic security offering.

According to Rudi Kuhn, sales manager at Elvey Security Technologies, there are numerous security products available that can play a role in an effective solution, including electronic beams, electric fencing, outdoor passive detectors, alarms and CCTV cameras.

“Just one type of system can be used, although a combination of the above is probably better. Cameras do not really protect anything, but they do give an idea of what happened,” he says.

“However, outdoor photoelectric detectors are by far the most reliable and cost-effective means of detection and these can be disguised so as not to alert the criminal to their presence.”

Kuhn says that depending on the level of risk, one may wish to use multistacking, which involves adding more than one set of beams to a line of detection, meaning that one could set up a series of beams broadcast from the same tower, but at different heights, making it impossible for the intruder to crawl under or jump over the beams.

However, since photoelectric detectors are electronic, are they not susceptible to interference from microwave signals?

“You need to understand the difference in technology to answer the question properly, since although both are part of the electromagnetic spectrum, they are very far apart on it,” he says.

“Photoelectric detectors rely on an infrared light source that flashes at a constant frequency and if an object blocks the receiver for even a millisecond, the unit will cause an alarm, whereas microwaves are much higher up on the spectrum to infrared. The problem lies with the radio frequency effect on the internal electronics of the photoelectric detector.”

“So the short answer is that although it is possible for microwaves to interfere with an inferior product, there are products that have been designed to negate such interference.”

Security solutions

Zane Greeff, technical director at Elvey says that when choosing a perimeter security solution, it boils down to the risk that is being faced.

“The risk to a private homeowner is very different to the risk faced by an airport, for example, as a private homeowner has to consider burglars, whereas an airport needs to have security designed to potentially keep out terrorists,” he says.

“However, depending on the risk, we can help clients put together a solution that will offer first-level security – such as an electric fence and a fence alarm system – second-level security (a beam or volumetric detector) and third-level security, which could include electronic burglar alarms system in a home.”

Greeff says that many homeowners are now installing outdoor detectors to provide a level of early warning, but that there are factors to consider, as potential impediments such as plant or animal interference.

“It is therefore vital to talk to security experts, as there are quite a few options available.

“On any outdoor detection device, the user can also choose to incorporate visual element – like a CCTV camera – which can be set up to begin recording, the moment a motion detector is set off.”

According to Kuhn, there are other systems (which would be too pricy for a private homeowner) that can be put in place to provide perimeter security for large installations like airports.

Pros and cons of perimeter security

Kuhn points out that it is still possible to add new security measures to an existing solution.

“The most commonly used basic security offering is motion detection, which has its drawbacks, as for one, the technology here looks at the field of view and uses fancy algorithms to define movement,” he says.

“The problem being that a plastic bag blowing in the wind will constitute movement, so if one is considering an upgrade, by evaluating the installation you can most probably salvage the existing cameras you might need to upgrade the control equipment.”

Kuhn points out that in the current South African climate, there are other issues that need to be taken into account when installing a perimeter security solution, such as power outages.

“These are a concern for all security installations, so one should ensure adequate standby power is calculated as part of the solution, while the issue of camera placement and selection can only be addressed by proper training.”

According to Greeff, there are pros and cons to each and every technology that one could use for security, so it is always important to consult the experts first.

“For example, there may be a solution that works great for industry, and yet it falls flat in a domestic application and visa versa.”

“It is all about having the right products for the right applications. Not every product suits every application, which can make choosing the correct solution difficult,” he concludes.

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