The thickness of the galvanized tape must lie within 0.5 to 0.55 mm. Initially, a thinner tape affects the security barrier very little, but it will make its lifetime several times shorter over a long time. The core wire must be high-carbon and galvanized, lying in the diameter ranging from 2.4 mm to 2.5 mm. With ungalvanized wire, you will soon lose your fence. Clips must also be made from galvanized metal; otherwise, corrosion at the conjunctions will compromise the structure functionally and aesthetically.
Galvanized zinc layer thickness is the main quality criteria, and it decides the galvanized razor fence corrosion resistance. When the zinc coating is thicker, the corrosion resistance is better.
High mechanical properties of materials (strength, hardness, elasticity) make it virtually impossible to slice without any special tools, and a protective layer of zinc on the material gives a high resistance to corrosion and long service life of at least 25 years.
Number of Loops in Coil
The loops number may vary from 31 to 61. The less the number of loops, the lighter the coil and the more convenient it is to be installed. This leads, however, to a greater number of junctions, which are potentially vulnerable. A ruse of some dishonest sellers is to declare a lower price per coil, while the latter consists of fewer loops and ends up to be overstretched when installed.
Number of Clips
Sometimes, the seller, taking advantage of the customer’s incompetence, does not specify the number of clips (3 or 5) and sells the cheaper 3-clip spiral at the price of the more expensive 5-clip one. It should be borne in mind that a 3-clip fastening is permissible only with small-diameter spirals (500-600 mm) — at the expense of degradation of the barrier efficiency (its rigidity and resistance to cutting) — while with large-diameter spirals (900 mm) it is totally unacceptable, for the fence becomes virtually useless.
You should thoroughly examine the tape folding. The tape has to be tightly pressed around the core-wire. It must not bear any signs of damage (deformation of) to the galvanized surface, which often happens when rundown equipment is used (worn-out punches) or there are faults in the manufacturing procedure. The same factors define barb sharpness.
Coil Extension Length (the length of the secured territory)
The coil extension length declared in price quite often differs from the actual one. The principal requirement here is that the interval between the loops should not exceed 390 mm. Overstretching results in a greater loop interval, degradation of spiral rigidity and, correspondingly, compromises the whole highly-efficient-security-barrier concept.