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System Design

Protecting the perimeter

The criminal landscape has changed in the past few years, driven by a number of factors. Recession, a rapidly advancing but more secure consumer market and a rise in the cost of core elements has served to make raw materials and machinery more attractive to thieves than televisions or other household goods. The result has been an increase in demand for electronic perimeter protection.

Electronic perimeter security was – until very recently – considered to be the exclusive preserve of high-risk large and open sites. Military bases, airports and ports, petrochemical plants and the like were the specialist environments that were targeted for this type of system. Other lower risk applications such as construction sites, vehicle depots, industrial estates, farms and other mainstream businesses opted for the lower technology solution of a physical barrier. Crime trends, however, are forcing a change to such thinking.

Some 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. Whilst physical devices do have a role to play, they also have one major flaw; 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.

The traditional approach to perimeter protection in most mainstream applications has been the construction of some form of barrier, but such elements are not exactly a proactive tool. In simple terms, a high fence might put off the opportunist intruder, but if someone is prepared to climb it, cut through it or tunnel underneath it, then it will be defeated.

This isn’t to say that physical elements at the perimeter do not have a role to play. They do, in that they define a boundary, prevent accidental and innocent intrusion, deter opportunist intruders and control access to the site.

More importantly, the 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 an integral part of many electronic perimeter solutions, because they allow the generation of exceptions. This subsequently allows the introduction of smart technologies, because the solution starts with a premise that nothing should occur in the sterile zone.

It’s worth considering the reasons for establishing an electronic perimeter system before considering the available technologies. In truth, it’s quite a simple answer. Most end users want to be informed of an intrusion as quickly as possible. This is a key consideration. Rather than be able to hand over video footage of someone making off with their assets, end users would rather take action and stop any event as swiftly as possible. Once breached, physical elements of a perimeter cannot do anything to help. However, electronic systems can allow a response to be made.

A growing number of end users are well aware that the likelihood of a timely police response is reduced nowadays, and many of the assets attractive to thieves are hard to trace once stolen. As a result they want systems that empower them to act immediately, rather than systems that only signal to the police when the intruder is inside a building. Whilst internal intruder detection is still an important element of any security system, criminals are aware that assets outside of physical structures can be less risky targets. Because of this, a level of intelligent detection at the perimeter is what most users wish to add to their solutions. They need a first layer of protection, and increasingly are demanding this.

Offering More

The use of technology-based perimeter protection systems is nothing new, but in recent years the technology used 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. Even sites with small grounds or limited surrounding areas can benefit.

An old security adage is that site security should be like an onion; as you peel away one layer, you come up against the next. Such an approach allows a level of integration across a number of systems, all of which can interoperate to enhance total site security.

Traditional electronic perimeter protection systems used to be divided into three basic types; space detection systems, fence-mounted systems and buried cable systems. Nowadays the list should also include thermal imaging, remotely monitored video and video analytics.

Space detection for external sites has come on in leaps and bounds. Not only does it allow detection over wider areas, but it can also be used as a trigger for other systems. As a result, event-driven video surveillance is increasingly seen as one of the leading mainstream perimeter protection options. In fact, since the publication of BS8418, video surveillance has become a prominent tool in the protection of perimeters, due to the fact that compliant systems can attract a police response!

On larger sites, video surveillance can also be supplemented with thermal imaging systems. Whilst such devices are costly, the effectiveness of these devices covering perimeters is impressive. Where sites have extensive perimeters, the units start to become quite cost-effective in relation to other solutions.

Another element that brings together the use of detection systems and video surveillance is the increased use of video analytics. With analytics, it is possible to identify specific behavioural traits to assess whether people at the perimeter are innocent visitors or intruders. They can be tracked and elements such as speed, direction, size, etc., can be considered. The benefit for many sites is that surveillance solutions might already be present, and so the only required addition might be the analysis element.

Active infrared beam detectors have come on in leaps and bounds, and are now simple to set up and install. Not only are these devices very reliable in the field, but they are excellent for use in perimeter applications. Multiple units will usually be required on large perimeters (ranges vary from 20 metres up to 200 metres).

The installation of beam sensors used to be a slow process, and often two people and specialist equipment were required to align units. However, this is no longer the case, and many products feature alignment tools that allow a single engineer to quickly and easily carry out the task!

Where a physical boundary is in place, the fabric of it can be protected by a sensing system. There are a number of technologies available, and recent advances ensure that these are more secure (and simpler to install and maintain) then ever. Most fence-mounted systems are cable-based and sense vibrations, shocks and other events. One of the traditional problems with a fence-based cable was that if it broke or was cut, the system failed until a repair could be carried out. However, this is no longer the case, and many systems can now continue to protect the perimeter, even if the cable has been cut.

The most important issue with regard to fence-mounted systems is that the fence itself must be correctly installed and be in good condition. This places a great importance on fence maintenance!

External Space Detection

External detection is undergoing something of a renaissance, and this is, in part, due to the increase in crimes against sites such as construction, agriculture, storage and transportation locations. With a wide range of commodities attracting the wrong kind of attention, a range of users are looking for a simple solution to protect their assets.

Wireless detection has also become of greater interest to these sites, as it can be used in areas where cabling and power cannot be installed. Also, wireless beam-based detectors are being used to protect perimeters that simply cannot be fenced for reasons of cost.

Benchmark has tested a number of external detection devices, including units from GJD, Optex, Takex and Texecom, all of which achieved Recommended Status.

GJD’s DTect3 is predominantly aimed at the CCTV sector, but where space detection is required, the unit performs very well. The addition of EOL resistors is a bonus for installers, and the sensor is easy to program and configure.

The VX402 from Optex uses a simple design to deliver effective protection. The directional detection feature is a bonus, and for many applications it can add something extra, which is also simple to configure.

Takex’s MS12FE offers four sensors with AND/OR detection. The AND mode requires all elements to trigger to generate an alarm, which might seem like overkill, but the test team felt that the additional level of protection was worthwhile. In OR mode, one unit can offer 180° coverage.

Finally, the Prestige External TD from Texecom is a detector that combines high performance with ease of installation. Its configuration delivers a high degree of flexibility, and time spent setting it up correctly is rewarded with stability and effectiveness.

Video Triggers

The introduction of BS8418 paved the way for event-triggered video surveillance applications to qualify for a police first response, when connected to an approved RVRC (remote video receiving centre).

Trigger devices are typically long range external detectors with a field of view that matches that of camera views.

There once was an opinion that stability wasn’t too important, as verification of any event was carried out by an operator. The fact that RVRCs refused to work with problematic systems soon focused the minds of those selecting trigger devices, and today’s options are very reliable and stable.

Benchmark has tested video surveillance trigger devices from Luminite, GJD and Optex, with all receiving Recommended Status.

Thermal Imaging

Thermal imaging is a valuable tool when securing perimeters, or where sites are typically open, and cover large areas. Because of the nature of assets at such sites, criminals often rely on the theft of large amounts of material, and as a result vehicular access to locations is often required.

Thermal imaging can either be employed alone, and manufacturers that supply thermal imaging sensors include Axis Communications, Bosch, Samsung, Videotec and Flir. The devices can often be connected to traditional video surveillance solutions, or can be networked.

There are also a number of suppliers that combine thermal imaging sensors with traditional video surveillance. This allows the thermal element to detect the presence of a human, and the video element can then take over for positive identification.

In summary

As with many security technologies, perimeter protection is a vast and complex sector. However, continual developments have seen systems become more affordable and more reliable! Despite this, too many still view electronic perimeter solutions as specialist systems. Demand for secure perimeters is growing at a rapid pace, and such thinking is now very out-dated!


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