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Perimeter Protection: Detection

by Benchmark

The perimeter of any site is the ideal place for security to be implemented. It represents the first point of intrusion, and detection at the earliest time allows a greater window for threats to be nullified. The perimeter also allows a site to define private areas and to ensure that those who stray beyond the boundaries have done so intentionally. Despite this, emphasis on perimeter protection remains low in many applications despite increasingly efficient technologies being available to counter any threats.

The perimeter represents a very important element in any security plan. It is often the first point at which a demarkation between public and private land is made, and represents the earliest opportunity for a site to define when a target – whether welcome or not – has entered its space.

Whether a perimeter is designed to prevent ingress or simply to identify that the status of the area has changed, it is important that installers and integrators, and in turn end users, are aware of the need to have an identifiable and obvious perimeter. Whether this is a six foot fence festooned with razor wire or a simple low height wall which can be stepped over will be dependent upon the needs of each individual site. What is more important is that anyone entering a protected area is aware that they have done so.

By creating an obvious barrier, it can then be considered that persons within the protected area have made a conscious decision to be there. However, it makes sense to also consider whether a perimeter can be adapted to enhance the security of the location. Due to the fact that it’s best practice to create an obvious perimeter, it makes sense to also use it for the first layer of a system.

For some, the term ‘perimeter protection’ summons up images of physical barriers. There is nothing wrong with a physical approach to perimeter protection, but such elements will not offer complete protection. One thing to consider when selecting a physical security solution is that these types of products simply work by making it too difficult or too time-consuming for criminals to effect an entry or to damage property. The hope is that they’ll give up and move on a softer target.

To be more effective, physical measures will need to be used in conjunction with other systems. For example, a high will be able to be scaled by a determined criminal, and once this has been achieved, the site is obviously vulnerable unless the violation is reported by a monitoring system.

Given the depth of options with regard to technology-based perimeter protection systems, it makes sense to implement these, either as part of a layered approach or linked with other systems to create a more holistic approach to site security.

Adding systems

Electronic perimeter security systems have often been considered to be the exclusive preserve of high-risk large and open sites. Lower risk applications are generally viewed as typical users of physical options. However, the evolution of various technologies coupled with increased economies of scale have resulted in the reduction of equipment costs. Additionally, the use of wireless connectivity options has made installation and remote connectivity a realistic option for even the smallest and lowest risk applications.

Despite these advances, some still believe that the way to make a perimeter more secure is to have longer, higher, more robust physical elements. This is tied very much to a siege-mentality that seems to pervade thinking when it comes to perimeter security.

As already highlighted, if a criminal is prepared to put in the necessary effort, they will be defeated. Technological solutions are far more credible, and as interest from end users rises, the argument for electronic perimeter-based security becomes ever more compelling.

While the construction of some form of barrier does appeal to a wide range of users, such elements are not exactly proactive. This isn’t to say that physical elements at the perimeter do not have a role to play when looking at technology-based options. They can act to create a sterile zone – an area where the boundary is established, and beyond which any intrusion can be deemed to be an event that requires some form of action.

Sterile zones are a common element of many electronic perimeter solutions, because they simplify the generation of exceptions. If a sterile zone exists and all activity within it is prohibited, then any exceptions are clearly violations. This subsequently enhances the use of smarter technologies, because the solution starts with a simple premise that nothing should occur in the sterile zone.

It’s worth considering the end users’ goals when establishing which technologies to deploy in an electronic perimeter system. In truth, this is usually a simple task. Most end users want to be informed of an intrusion as quickly as possible. This is a key consideration in perimeter protection design. Rather than delay intruders with obstacles that can be defeated in time, or capture video footage to be reviewed after the event, end users would rather take action and stop any intrusion as swiftly as possible.

Once breached, physical elements of a perimeter cannot do anything to help. However, if they are supplemented by technology-based systems, this can allow an immediate response to be made.

A proactive design

There have always been detection technologies designed to create an early warning of intrusion. Detecting the presence of people before they can reach a protected area makes a lot of sense. However, in the past security industry standards relating to police response shifted the emphasis onto internal detection because of the increased stability such an approach offers.

Of course, due to budgetary constraints and a lack of resources, police response to alarms has become somewhat hit and miss. The number of high profile cases where police simply did not respond, or where policies prevented a timely intervention, have made it increasingly important for many end users that the earliest warning is achieved. The best way to achieve this is by detecting activity at the perimeter.

This can require solutions which deliver longer range detection, especially for applications on isolated industrial sites or in rural locations.

When it comes to detection over longer distances, there are a variety of options. Often the choice will come down to what the site requirements are and the physical characteristics of the protected area.
Choices can include passive detectors, active detectors, fence-mounted and other dedicated PIDS (perimeter intruder detection systems), video surveillance with analytics and thermal imaging with analytics.

Many manufacturers offer wireless versions of external detectors, and these can simplify installation where cabling to a perimeter might be costly.

Passive detection predominantly makes use of PIRs. There are also a number of dual tech and tri tech units with a variety of coverage patterns and ranges. While these devices use advanced signal processing to filter out sources of nuisance alarms, there will inevitably be a degree of risk to stability in some external locations.

Increasingly, installers and integrators are using passive detection devices in double-knock configurations. This often involves the detection device coupled with other detectors or video devices. This ensures that if an event occurs, it is only signalled as an alarm if both elements simultaneously signal.

Benchmark has tested a number of external passive detection devices, and for longer range applications they do offer a cost-effective solution. There are many passive detection options with very clever dual sensor designs, but these are predominantly aimed at shorter detection distances although some can be used over extended ranges.

Photoelectric beams are active detection devices, and do enhance the level of reliability on offer thanks to ongoing research and development by the leading manufacturers. These work by protecting a straight line between points, usually following a perimeter. Unlike space detection devices they don’t cover open areas.

Over the years the operation of photoelectric beams has – on the surface – remained the same, but significant advances have been made with regard to processing and stability. The days of wind-borne rubbish or small animals and birds triggering the units are over, and tamper and sabotage attempts have also been largely eliminated.

As with passive detectors, ranges do tend to vary, with distances into the hundreds of metres being achieveable. In Benchmark tests, many active infrared beams have actually exceeded their quoted ranges without any detriment to performance. Whilst we wouldn’t recommend doing this, it does indicate that the best units are very capable of achieving the specified performance in a range of conditions.

As is the case with passive detectors, infrared beam units can be linked with other technologies, or indeed with other detection devices, to create a double knock scenario. For example, a site with infrared beams at the perimeter could link these with space detection covering open areas. Alternatively, the beams could be linked with analytics using either video or thermography for a more complete solution.

Laser-based detection devices are another option, and the choice of available devices is growing. One benefit of laser-based sensors is that there are units which can deliver exact positioning information.

While many detectors identify the area which is in alarm via zoning, laser sensors can pinpoint targets using X-Y coordinates. With appropriate software, this information can be used by the overall system to track targets around a site, adding to the useful data supplied in the case of an early warning system.

Fence-mounted systems are another technology which has not only developed to offer greater levels of performance, but have also become more installer-friendly thanks to on-going advances by the leading manufacturers. Whilst such solutions fall short of being ‘plug-and-play’, the configuration, operation and integration of such solutions have advanced significantly. Economies of scale have also ensured that prices are competitive, making such solutions ideal for a wider range of applications.

In summary

In recent years the technology used for perimeter protection has evolved, making such systems easier to install. Additionally, the costs have fallen. Because of this, an increasing number of sites could benefit from such solutions including those with small grounds or limited surrounding areas.

Traditional perimeter protection systems used to be divided into space and active beam detection, fence-mounted and buried systems. Nowadays the list also includes laser-based detection.

The various technologies have come on in leaps and bounds. Not only do they allow perimeter protection but they can also be used as a trigger for other systems.

Continual developments continue to deliver systems that are increasingly more affordable and more reliable! Despite this, too many still view electronic perimeter solutions as a specialist option. Demand for secure perimeters is growing at a rapid pace, and such thinking is now very out-dated!

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