Fencing, gates, and crash-rated vehicle barriers as the deter/delay/detect spectrum, fiber-optic, microwave, and buried-cable perimeter detection technologies, and CPTED — Crime Prevention Through Environmental Design — as a real, structured design framework.
The perimeter is the outermost layer of defense-in-depth, not a substitute for it — a single strong fence is a single point of failure, and this module treats the fence line the way it should be treated in practice: as one layer among several, deliberately paired with detection technology and, further in, with the interior sensors covered in Module 5. It works through fencing and vehicle barrier specification (including ASTM F2656 crash ratings), the three major perimeter intrusion detection technologies, and the false-alarm engineering every one of them demands once deployed outdoors.
By the end of this module you should be able to explain why CPTED's four strategies — natural surveillance, natural access control, territorial reinforcement, and maintenance — are a legitimate, ASIS-recognized engineering framework and not a soft add-on to hardware, and why a fiber-optic sensor mounted behind unmaintained shrubs is protecting a line no one can actually see.