Design guidelines for effective perimeter security

Design guidelines for effective perimeter security
Alongside the hype in the media about the border wall, this might be a good time for commercial and industrial companies to take a closer look at their own borders. Threat levels are increasing due to rising crime, civil activism and even cyber threats and it is more important than ever to push the line of defense all the way to the borders.

When addressing perimeter security, it is best to try and design a layered system since there is no single technology or solution that would fit every application. The layers and technology should be selected based on the level of detection and identification that is required; as well as the terrain and environment it will operate in, which is ultimately determined by the value of the information or product that is being protected. It would be an overkill to implement a multi-level intrusion detection system with thermal cameras and a fiber optic intrusion detection system on an anti-cut & climb fence that is protecting a dog run.

When designing a perimeter security application it is important to consider the “5-D” rule, deter, detect, delay, deny and defend. Just like in the example above, the D’s must match the objective and level of threat. Although each layer has a specific goal it is important to have a way of connecting them together to form a unified system that provides situational awareness. Let’s look at each of these elements:


The dictionary definition of deter is to “discourage (someone) from doing something, typically by instilling doubt or fear of the consequences”. This is the area that needs the most attention in my opinion as it differentiates the intruder’s motivation. For the most part theft is a crime of opportunity; the easier it is to reach objects of value the more prone they are to be taken. Have you ever noticed how junk yards have very intimidating fences built from flat steel panels with barbed wire spanning the top and most likely a vicious dog inside the property - this is a very intentional and effective method of deterring opportunistic criminals from attempting to enter the yard; only those with a clear objective and intent would attempt entry.

There is a delicate balance between cost, aesthetics and deterrent capabilities that must be considered when designing a perimeter system. A perimeter with minimal deterrence capability will require a greater investment in the other layers.

Before we get into the technologies, we need to first understand the purpose of a wall or intrusion detection system. The main purpose is to deter entry, however in this modern age of information we would expect it to do more, at bare minimum, it should give us additional situational awareness. After all without knowing how many attempts it thwarted, we might feel that it was a waste of resources and more importantly we may never know how many intruders succeeded.

What elements would be useful in deterrence?

A physical barrier is the basis of a deterrent system. The design and material choices will determine the effectiveness. Understanding the delicate balance between aesthetics and function is what makes these choices very difficult; very few corporate or industrial facilities want to resemble a prison however there are ways of achieving a balance between the look and the perceived/ actual effort it would require to penetrate the perimeter.

Lighting is as important as the physical barrier because it intimidates the intruder especially if it is well designed and strategically placed. Motion activated lighting is also very effective because of the surprise reaction and perceived detection; these can easily be used as an early warning sensor and delay medium.

It has been shown that the strategic placement of warning signs, is a significant psychological deterrent against crimes of opportunity, signs are used very effectively in the residential security market and should not be ignored in the commercial space. The idea behind using signs is to encourage the would-be intruder to reconsider entry by magnifying the possibility of apprehension. Other deterrents include landscaping and plant selections as well as animals and guards.

Even the best deterrent perimeter will require a detection system that is capable of verifying the perimeter’s effectiveness. Just because there was no evidence of breaches, it doesn’t necessarily mean there weren’t any breaches and this is the reason why there should be a routine review of its effectiveness and adjustments made accordingly.


Effective detection systems should do more than just detect intrusion attempts; they should also provide greater insight into the nature of the intent. By designing the system to be able to identify and classify the method, force and agility of the attack; we can better understand the nature of the threat and subsequently prepare a better defense. For example, in a very high security application, there may be an area outside the perimeter fence that is designated as a deterrent zone, discouraging advancement towards the perimeter; by using radar or thermal imaging with analytics, the detection system would then trigger an alert when an intruder entered the deterrent zone and track targets as they advance through the deterrent zone, alarming when they enter the area adjacent to the fence. This early warning of an imminent breach would provide additional time to engage the intruder. With a lower level of security, the requirement would only be to detect the attempt at the fence or just inside the perimeter.

When determining the detection method, a significant amount of consideration must be given to the environmental factors around the detection area like; wildlife, visibility and natural camouflage. These can interfere with detection capabilities or cause nuisance alarms. It is always advisable to build a tiered detection system using at least two different technologies thus reducing the possibility of unconfirmed false alarms. An example of this would be using thermal cameras together with a fence intrusion detection system to determine if the fence alarm was caused by an animal or a real intruder.

Since there is such a vast amount of technologies that can be used to detect or confirm detection of intruders, here is a list of technologies that can be used for perimeter detection:
  • Fiber optic and RF fence mounted cable and sensors
  • Electric fence
  • In ground sensors
  • CCTV – traditional and thermal combined with analytics
  • Ground and thermal radar
  • Seismic acoustics
  • Microwave and infrared sensors
  • Laser sensors


Up to now we have been passive in the process, relying upon the deterrent to do its job, but since the detection system has been triggered, we need to be proactive in preventing intrusion by denying entry. Denial of entry must be done early and with the intention of dissuading further attempts to gain entry. One of the most effective methods beside physical confrontation is through voice commands.

The use of remote loud speakers or long range acoustic hailers is very effective at getting the attention of the intruder as well as bringing attention to the area. By issuing a stern warning that conveys authority and strength of intelligence, the intruder is warned that any advancement will be met with force, both perceived and physical. This is the reason why the scripting of this message is paramount to its success.

In some instances of very high security targets, the denial and delay phases may occur outside the perimeter or inside a DMZ just inside the perimeter.


The denial phase also triggers the delay protocols which would include additional electronic and design tactics that would slow down the advancement towards the target. It is important to design the delay phase with three main goals:
  1. Delay the intruder from reaching the target
  2. Direct the intruder to a safe engagement point for apprehension
  3. Provide sufficient time for a response team to engage

On the physical side an LRAD type system together with high intensity strobes would be very effective at stopping the intruder from further action due to the physiological effects on the human body. Since these systems tend to stretch the budget there are other methods of delaying the advancement of the intruder towards their target.

By designing landscape obstacles in conjunction with lighting, audio and sensors we could force the intruder into a funnel leading to a safe area of interception. Drones are starting to play an increasing role in both delay and identification of intruders. Their entry into the market is slow due to FAA regulations and their investment in more sophisticated autonomous drones.


Should the previous four layers fail to stop the intruder from advancing, they will at least have slowed the advancement enough to allow time to defend the target. Although defense is the least desirable and most dangerous situation; with adequate planning some of the danger can be mitigated because we now understand the full intention and skill level of the intruder even though we may not know the target.

Perimeter intrusion detection is only one part of the total physical security plan; other components include access control, closed circuit tv, video management and storage, analytics, intrusion detection and possibly a physical security information management system. A comprehensive command and control system would also include other building and automation systems like HVAC, lighting, sprinkler and parking systems.

In order to design a comprehensive and effective security plan, it is advisable to adopt a holistic approach that starts with a valid vulnerability survey that examines every aspect of the facility; including utilization, occupancy, physical and human targets as well as all electrical and electronic systems and evaluates their effect on safety and security. One factor that is often ignored is the continued evaluation and adjustment even after the system has been in place for some time. Security is as dynamic as the environment.

Product Adopted:
Share to:
Comments ( 0 ) provides weekly and monthly e-Newsletters which include the latest security industry news, vertical solution case studies and product information.

Please key in code