Science Fair Project Encyclopedia
Barbed tape or razor wire is a mesh of metal strips with sharp edges whose purpose it is to prevent passage by human beings. Although it is sharper than the barbs of barbed wire, it is not actually razor sharp; the name "razor wire" is a slang term derived from a manufacturer's brand name. The sharp edges of the wire can cause serious cuts in any person attempting to pass through quickly. In high security applications, barbed tape supplanted barbed wire which could be circumvented relatively quickly by humans without tools. Getting past barbed tape without tools is considerably slower, giving security forces much more time in which to respond. (There is little difference in the breaching time for a well equipped opponent.)
Starting in the late 1960s, barbed tape was typically found in prisons and long term mental hospitals, where the increased breaching time for a poorly equipped potential escapee was a definite advantage. Until the development of reinforced barbed tape in the early 1980s, it was rarely used for military purposes or genuine high security facilities because it was actually easier to breach with the correct tools. Since then, however, some military forces have also replaced barbed wire with barbed tape for many applications, mainly because it is slightly lighter for the same effective coverage.
More recently, barbed tape has been seen in more commercial and residential security applications. This is often primarily a visual deterrent since a well-prepared burglar can breach barbed wire and barbed tape barriers in similar amounts of time. Residential usage of barbed tape has been criticised by some as the aggressive appearance of the barbs is thought to detract from the appearance of a neighbourhood.
Barbed tape has a central strand of high tensile strength wire, and a steel tape punched into a shape with barbs. The steel tape is then cold-crimped tightly to the wire everywhere except for the barbs.
Like barbed wire, barbed tape is available as either straight wire or concertina wire. Unlike barbed wire, which usually is available only as plain steel or galvanised, barbed tape is also manufactured in stainless steel, to prevent the points from rusting to bluntness. Typically the core wire is galvanised and the tape is stainless, although fully stainless barbed tape is used for expensive permanent installations or underwater usage.
Barbed tape is also characterised by the shape of the barbs. 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 certainly provide a stronger psychological deterrent.
Barbed tape was first manufactured by Germany during World War I, as an expedient measure during a shortage of wire. Since it was simply punched out of a rolled ribbon of steel tape, it could also be manufactured much faster. This early barbed tape had triangular barbs, and no reinforcing wire. Consequently, although it was harder to cut with ordinary wire cutters , it was easier to cut with shears, and generally weaker.
Commencing in the early 1970s, unreinforced barbed tape started to be commonly used in perimeter barriers in US prisons. Several manufacturers of barbed wire and barbed tape began to offer barbed tape with a reinforcing wire in the early 1980s. The first to be manufactured was probably around 1981, although this has been subject to a patent dispute. Early brand names of reinforced barbed tape included "Man Barrier" and "Razor Ribbon"; the latter probably lent its name to the modern slang term.
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