What is Chain Link Fabric?
Fabric comes in a variety of gauges. Gauge is the diameter of the wire; the higher the gauge number, the smaller the wire diameter. Standard mill diameter tolerance is + or - .005". Common gauges and diameters are as follows:
11 ? gauge=.113"
12 ? gauge=.099
Chain link fabric is available in heights of 36", 42", 48", 60", 72", 84", 96", 120", and 144". The fabric is formed by weaving a series of spirals together. How the top and bottom of fence is finished is referred to as the selvage.
Fences less than 72" must knuckle both ends by industry standard (KK). Heights of 72" and higher, are generally twisted or barbed at one end and knuckled (BK) on the other. For high security enclosures, chain link can be obtained with both ends twisted or barbed (BB).
Zinc coatings may also differ. There are two different processes for applying zinc to wire. Galvanized after weaving (G.A.W.) is a process in which wire rod is drawn to the finished gauge, then woven into chain link fabric.
The fabric is then pulled through a pot of molten zinc. This process applies 1.2 ounces of zinc coating per square foot of fabric and conforms to ASTM standards.
The other process for applying zinc coating to chain link is called galvanized before weaving (G.B.W.). In this process the wire rod is drawn to gauge, and the strand wire is then pulled through a pot of molten zinc.
The wire is then woven into chain link fabric. Generally chain link fabric made using this process carries a zinc weight of .8 ounces per square foot or less.
The distance between two parallel wires in the fabric is referred to as the mesh size. The most common mesh sizes are 2" or 2 ?", but smaller mesh of 3/8", 5/8", 1", 1 ?", 1 ?" and 1 ?" are available for projects that require a higher degree of security.
The quality of chain link fence fabric is determined by both the gauge of the wire and the weight of the zinc coating applied to the wire.
The American Society for testing material has established standards for residential and commercial chain link fence fabric under designation A 392-96.
What is Frame Work?
Frame work is the tubular steel frame that chain link fabric is attached to. The frame work is comprised of three components; top rail, line posts, and terminal posts.
Terminal posts are set in concrete and are end, corner, and gate posts. Line posts are smaller in diameter than terminal posts and are the intermediate posts between terminal posts. These should also be set in concrete.
The top rail is attached to the terminal posts and passes through fittings which are attached to line posts. This provides a horizontal frame that supports that fabric.
The chain link fence frame work is also zinc coated to provide protection against corrosion. There are two methods of coating tubular products. In the first method, coils of steel are slit to the proper width, then formed into pipe and the seam is welded.
After the pipe is formed, the pipe is then taken to a pot of molten zinc and submersed. Both the interior and exterior of the pipe are zinc coated. This method is referred to as the hot dip process.
In the second method, the slit to width coil of steel is formed into pipe and then seam welded. The pipe then passes through an in line vat of molten zinc, which coats the exterior with zinc.
A clear organic coating is applied over the zinc, providing additional protection from corrosion. The interior of the tubing is coated with a zinc rich paint. This method is referred to as in line, flow coat galvanizing.
Both methods of manufacturing conform to ASTM F669-92. The quality of tubular products is relative to the thickness of steel, as well as the zinc coating.
What are fittings and how are they used?
To assemble a chain link fence system several types of fittings are required. Fittings can be classified into three types; those used in the line of fence, those used on terminal posts, and those used in conjunction with gates.
All residential fittings are made from a die cast aluminum or steel that has been galvanized. Industrial and commercial fittings are made from galvanized steel, cast iron, or malleable steel.
Fittings are an integral part of the fence, as they secure the components of the fence system. Gate fittings are especially important. The gate is the only part of the fence that moves and that people come into contact with on a regular basis.
It is very important that they fit and do not move on the gate post once installed. This will keep the gate from sagging. For security, barbed wire can be added to all types of commercial projects. Fittings should conform to ASTM F 626-96.