FIELD DAYS 2011
Introduction to Razor Wire By Paul Fitzsimmons Razor wire was first manufactured by Germany during World War I, due to a shortage of wire. Because it was punched out of a rolled ribbon of steel tape, it could be manufactured much quicker. It had triangular barbs and no reinforcing wire, so was easy to cut with shears, but not with ordinary wire cutters. In the early 1980s, manufacturers began offering razor wire with an embedded reinforcing wire, which improved the structural integrity, and made it more difficult to cut. It is manufactured in a three stage process, the first stage being the barbs punched into a flat steel tape. A groove is then cold forged into the tape and the tape has a high tensile wire pressed into the groove. Finally the razor wire is clipped into its finished configuration. The barbs themselves are not actually razor sharp along the edges, however the points of the barbs are extremely sharp, and it is not uncommon for
installation staff who do not use the necessary PPE or handling techniques to suffer injury while handling and installing the product. There are three different configurations predominant in New Zealand – flat rings (loops), single coil, and concertina. All three can be manufactured in short barb, medium barb or long barb configuration, from galvanized or stainless steel material. Medium barb is uncommon in New Zealand. Although there are no formal definitions, typically short barb barbed tape has barbs from 10 mm to 15 mm long, medium barb tape has barbs 20 mm to 25 mm long, and long barb tape has barbs from 60 to 66 mm long. There does not seem to be much available research to indicate whether longer barbs are actually more effective in resisting penetration, but they provide a stronger psychological deterrent.
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Short barb single coil attached to chain link
Razor wire is generally installed attached to horizontal supporting wires (either barbed or plain) although it can be fitted by attaching to a surface using metal clips or ties. Concertina is particularly suitable for this method of installation, as it is basically self supporting when attached along the bottom. Rings should be overlapped approximately 25% for maximum effect. Razor wire should be installed at a minimum of 2m above ground level, and warning signs should also be installed on the fence at 7.5m intervals. PPE for installation includes safety glasses, and heavy leather gloves. Welding golves are a good option, as they tend to be heavily constructed, and protect the wrists as well as the hands. Generally, two people are required for installation, and they must have a good understanding, as sudden movements at the wrong moment could result in serious injury.
600mm diameter long barb rings attached to two strands of barbed wire