Perimeter security is the first defence in maintaining a high level of port security, thus choosing the right fence material is paramount. Mini-mesh, expanded metal and welded wire are just some of the options to consider for fencing materials.
It’s simple: the thicker the metal wire or tighter the weave, the more difficult it is to climb and the more time consuming it is to cut. Mini-mesh is a very heavy duty, tightly woven chain-link fence that has no toe holds for climbing, can’t be easily crawled under, and the weave is too small for bolt cutters.
Thicker gauge pipe should be used as end posts, line posts and top rail to support the added weight of mini-mesh or even heavier fence fabrics. The use of razor ribbon, razor tape and razor coils with barbed wire and other deterrents make climbing a fence far more difficult and mentally intimidating. Intrusion and motion sensor technology can also be designed into a fence system to help alert security personnel of a potential breach in secured perimeters.
A variety of heavy-duty vertical picket steel fences are available in the industry using welded wire technology to eliminate toe and hand holds. Typically using a high grade 8 gauge wire on 1/2'' centres, welded wire is available in 7' to 10' wide panels with up to 12' and even 15' vertical pickets. Pickets are welded to horizontal crossbars to create panels that are then hot dip galvanised to cover all the welds and prevent rust and corrosion. For more corrosive and salt-water environments, such as in and around a port or harbour, some manufacturers offer very precise PVC coatings with no pinholes or gaps that cover the galvanised protective layer. Installation often uses a square or I-beam steel post for 6' to 8' panels using a no access bolting system.
The PVC coated products are beautiful and offer far more aesthetic appeal. While there are a lot of colour options, black and green seem to be the standard in the security industry. To penetrate a welded wire panel requires far more than bolt cutters. To cut an opening large enough for a person to get through in a welded wire fence would take an incredibly long time – allowing security personnel or other assets to identify the potential penetration and to dispatch security personnel.
Expanded metal mesh
Expanded metal mesh is available in both medium and high security grades. It is made from special carbon steel, stainless steel or aluminium to increase tensile strength with diamonds small enough that it is virtually impossible to cut, climb or crawl under. The primary purpose of expanded metal mesh is to create a physical perimeter barrier. Basically, expanded metal is a solid sheet of steel that is simultaneously slit and stretched into a rigid, non-ravelling open mesh which takes as many as 72 individual cuts to create a 36'' hole.
Round, square or c-posts can be used with no access fittings andmust be able to support expanded metal mesh weighing as much as 3 or 4 lbs. per square foot. High security fence products must be installed correctly and by certified and approved installers. Expanded metal mesh can be used to retrofit existing chain-link fence by covering the chain-link fabric with the expanded mesh. Depending on wind conditions, the existing framework may be strong enough to support the new mesh although some additional support may be required. Expanded metal mesh is primarily specified as hot dip galvanised finished but it is also available with vinyl or powder coating and in black, green and brown.