Other Types of Fencing

Other types of fencing materials are used for higher security installations, such as prisons. Such materials are highly resistant to common attacks. They are costly and require careful installation and maintenance.

When possible, fences should be far enough from a facility to allow security responders to reach attackers before they can breach the fence. Security responders are most likely to succeed when the fence has alarm sensors.

The area inside the fence (the secure side) should be completely clear of foliage and other materials that would provide cover for someone who breached the fence. An attacker who successfully breaches the fence should face a very wide open space before reaching the facility.

The area outside the fence (the insecure side) also needs to be carefully prepared. Foliage and natural barriers such as rocks should be used to keep anyone from driving a vehicle close to the fence where the vehicle could be used as a ladder to climb the fence. These same barriers may discourage someone from trying to crash through the fence. Foliage and other natural barriers need to be far enough from the fence fabric that attackers could not use them to help climb the fence.

If your high-security facility uses fencing as an outer perimeter barrier, any utility openings an attacker could use to crawl through the fence must be secured. Such openings include drainage ditches, culverts, vents, ducts, and other openings with a cross-sectional area larger than 96 square inches with the smallest dimension larger than 6 inches. These openings need to be protected by securely fastened welded bar grilles. As an alternative, drainage structures may be constructed of multiple pipes, with each pipe having a diameter of 10 inches or less. Several pipes of this diameter may be placed and secured at the inflow end of a drainage culvert to prevent intrusion. Let engineers know before you add grilles or pipes to culverts or other drainage structures. They will need to compensate for the culverts’ diminished flow capacity and consider additional maintenance for them.