Enhancing the performance of fences: effects and evaluation

Perimeter fences can be used to contain an inmate in a prison or detention centre or they may be used to protect a facility against intrusion. The purpose of a fence is to deter a would-be intruder and delay him long enough to permit a response force to apprehend him. A fence can act as a convenient fixture on which to mount Perimeter Intrusion Detection Systems. Simple, inexpensive fences cannot provide more than a minimal delay to an attacker, functioning mainly as a boundary marker. A valuable or vulnerable facility requires the perimeter fence to be a more sophisticated structure. An alternative to replacing fences is to enhance them. This can include the addition of cladding, toppings, barbed tape coils or further fencing panels and materials. As any enhancements will alter the characteristics of the fence, the preferred attack style may change as the weakest feature alters. This paper will describe some of the work that the Home Office Police Scientific Development Branch has carried out on fences at its Langhurst test site. It will define the desirable features needed in a fence. It will detail some evaluations of fences and describe some enhancements that have been tested on fences designed primarily for use in prisons. It will also explore the effect of those enhancements on delay times and on the chances of a successful escape.