The term ‘perimeter security’ is widely used in cybersecurity in reference to measures that protect computer networks from hackers and unwelcome intruders. But the need for perimeter security isn’t a new phenomenon. One of the earliest known instances of perimeter security is Hadrian’s Wall, built by the Romans in around 122 AD, allegedly to defend the Roman empire. But it's likely that prehistoric humans would have used various perimeter defences to protect them from being attacked by wild animals and possibly other tribes.
What is Perimeter Security?
Perimeter security refers to the measures taken to protect the boundaries of a property. In this context we are primarily thinking about physical perimeter security techniques.
Medieval castles were designed and built to be highly defensive and safe. Their designs included a number of practical and effective perimeter security measures. They were often surrounded by a strong, outer curtain wall that formed the primary defensive layer around the castle. These walls were often extremely thick (in excess of 2m) with a core made from stone and rubble and outer skin made from gigantic, smooth stones laid like bricks. This wall design helped to withstand battering ram attacks and made it very difficult to climb.
In around the 14th century castle design evolved to used concentric walls, one layer of curtain wall inside the outer layer. Ditches were also used and when these were filled with water they became moats which provided another effective layer of perimeter security. Its worth noting that the water in these moats was extremely foul and smelly which acted as a further element in castle perimeter defences.
Moats prevented attackers from even getting close to the outer castle curtain wall and therefore stopped them from using battering rams. Moats also made it very difficult for attackers to tunnel under the castle walls.
Turrets, towers and lookout points provided further perimeter security by enabling watchkeepers to spot attackers as they approached. Overhanging holes and platforms called machicolations were used by defenders to fire arrows and hurl everything from dung to dead animals at those who were attempting to gain access to the castle.
Types of Perimeter Security
While concentric layers of curtain walls along with moats filled with foul water provided effective perimeter security for castles these aren’t practical tactics for most modern situations. Here are some of the primary forms of perimeter security used today.
Physical Barriers and Anti Climb Protection
Physical barriers such as walls, fences, hedges and gates are all important elements in an effective perimeter security strategy. Much like the curtain walls used around medieval castles, perimeter walls and fences often provide the first layer of property protection.
The best and most appropriate physical security barrier very much depends on the specific situation. For example, a farm might use ditches or build up earth banks to prevent vehicles from accessing fields and areas of the property. And high security establishments will typically use high perimeter walls or fences, possibly topped with anti climb protection.
Perimeter security may also includes various forms of automated barriers such as bollards or rise and fall barriers.
Access Control Systems
Access control systems are another important and effective perimeter security technique. Systems include intercoms that require visitors to announce their presence to enable barriers or gates to be opened, or key code entry systems. Gates manned by security staff are another highly effective but expensive form of access control.
Security Lighting and CCTV
Security lighting that illuminates property perimeters, possibly switching on in response to detected movement, is a highly effective form of perimeter security. When coupled with CCTV, security lighting helps ensure any intrusion attempt is captured on film to provide valuable evidence.
CCTV and security lighting also provide highly effective anti-intruder deterrence.
Windows and Doors
Windows and doors are the primary entrance points used by burglars. And for many properties their windows and doors, along with the building walls, form the property perimeter.
This makes it essential that doors and windows are as secure as possible and all vulnerabilities, such as weak locks or hinges, are identified and fixed.
Why You Need Perimeter Security
With crime rates increasing due to the cost of living crisis perimeter security is an essential consideration for all properties. Offices, factories, schools, colleges and hospitals along with private homes and other locations, all need to pay attention to perimeter security.