Razorwire

Barbed tape or razor wire is a mesh of metal strips with sharp edges whose purpose is to prevent passage by humans. The term "razor wire", through long usage, has generally been used to describe barbed tape products. Razor wire is much sharper than the standard barbed wire; it is named after its appearance, but is not razor sharp. The points are very sharp and made to rip and grab onto clothing and flesh.

The multiple blades of a razor wire fence are designed to inflict serious cuts on anyone attempting to climb through and therefore have a strong psychological deterrent effect. Razor wire is used in many high-security applications because, although it can be circumvented relatively quickly by humans with tools, penetrating a razor wire barrier without tools is very slow and difficult, giving security forces more time to respond.

Starting in the late 1960s, barbed tape was typically found in prisons and secure 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 (and especially after the September 11, 2001 attacks), it was rarely used for military purposes or genuine high security facilities because, with the correct tools, it was easier to breach than barbed wire. Since then some military forces have replaced barbed wire with barbed tape for many applications, mainly because it is slightly lighter for the same effective coverage and it takes up very little space compared to barbed wire or reinforced barbed tape when stored on drums.

More recently barbed tape has been used 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, using simple techniques such as cutting the wire or throwing a piece of old carpet over its strands.

Due to its dangerous nature, razor wire/barbed tape and similar fencing/barrier materials is prohibited in some locales. Norway prohibits any barbed wire except in combination with other fencing, in order to protect domesticated animals from exposure.

Razor wire 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. Flat barbed tape is very similar, but has no central reinforcement wire. The process of combining the two is called roll forming.

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Wikipedia