Fence Talk
There are many types and styles of fences available on the market today, and chain link fencing is by far the most common. With origins in Norwich of the United Kingdom, chain link became commercially available in the mid 1800’s in Europe and soon thereafter in the United States during the 1890’s by Anchor Fence. Chain link, also referred to as wire-mesh or diamond-mesh fencing, is an easily produced wire woven type fence wherein vertical coils are looped together into a flattened zig-zag pattern with each individual loop threaded onto the adjacent loops of both parallel coils, thus forming a continuous blanket of wire mesh. To keep the coils from separating, the tips of each pair of vertical coils are twisted or pinched together at the ends to prevent the coils from unwinding.
Wire mesh fencing is typically produced and sold in continuous rolls of varying lengths and heights and is easily installed by simply attaching the flexible mesh to posts and stretching it tightly from one post to the next. It serves its purposes well in many applications, providing inexpensive boundary and demarcation lines for safety and low security fencing needs. Mesh fencing is made from galvanized steel wire, typically hot-dip coated with zinc or aluminum for protection against rust and other corrosive elements, and is cheap when compared to other solutions. Chain link can also be easily applied to custom enclosures and built into various shapes and sizes.
Categorically, there are many more types of fences besides chain link; understanding that a fence is a structure that is freestanding with the purpose of preventing movement across a boundary line. Fences differ from walls by being less permanent in construction and purpose, and in most cases a fence allows for a partial view beyond the demarcation and serves to channel rather than conceal. The most common fence types are stockade, palisade, wrought iron, hollow-tube, split-rail, post mounted or rail mounted, or post-and-rail, balustrade railing, picket, wire mesh, welded wire, woven wire, steel grate mesh, perforated mesh, expanded mesh, and louvered sheet metal mesh. It’s quite the list, so buyers should do some research to ensure the selected fence type serves its intended function and appropriately counters the anticipated threat.
Fences can be made of wood, vinyl, metal and other nontraditional or recycled materials, and can be designed to fit any function. Additionally, fences can be electrified and bestow a shock of up to 10,000 volts when touched, depending on distances and purpose. Some fences can be invisible using technology to alert the presence of a trespasser while allowing for unrestricted and open ingress. Alternatives to regular fencing systems include cement, block and rock walls, natural and manmade berms, ditches and trenches, moats, thorny plants, hedgerows, grasses, bamboo, and even certain densely planted trees. There are as many purposes for fences as there are types, but generally fences are used for residential, commercial, agricultural, industrial and prison applications with the specific intent of achieving a certain visual deterrent along with the more utilitarian purposes of either privacy, channeling and way-finding, delayed entry, and lastly, providing a fortified defense system that could even incorporate such features as crash cabling, anti-ballistic and blast resistance panels and modified meshes designed to resist cutting and climbing.
Fence systems used for high-security purposes are intended to encircle a property primarily to either keep someone from entering or keep someone from getting out; the focus here is on controlling the movement of adversaries rather than just the general public, random passersby, or stray animals. Again, chain link fences are commonly used as security fences due to cost, more so in the United States than in other countries. But because of its economic value, chain link dominates the fence market as the most popular fencing solution and has been used extensively as an inexpensive security fence; however, there are some drawbacks to using chain link products. It has been proven that without significant modifications, standard wire mesh type fencing can be easily breached in a matter of seconds by either pulling up on the mesh and passing beneath it or snipping and unwinding one of the coils and passing through the impending opening, thus significantly diminishing its capability as a security fence solution. One significant modification to standard wire mesh was the mini-mesh, a tighter coiled version of standard wire mesh wherein the coils are smaller and more tightly wound together, thus making the coils much harder to snip and unwind. Another supplement to standard wire mesh fencing is the addition of strands of barbed wire and coils of concertina wire (and razor wire) to the tops, bottoms or sides to increase the fence’s delay-of-entry time.
Photo A. Courtesy of BetafenceUSA
Barbed wire was perhaps the earliest application of “aggressive-defensive” fencing, making it very painful to cross. Originally designed in France by Leonce Eugene Grassin-Baledans in 1860, barbed wire (the use of sharp barbs attached to a strand of wire) came to be, and was soon patented in 1865 by another Frenchman named Louis François Janin. Janin’s version of barbed wire was the original duel-twisted wires with diamond-shaped metal wire barbs. An American version of barbed wire appeared on the market two years later in 1867 and was patented by Lucien Smith of Ohio. Most notably, though, were the subsequent versions and design patents by Leo Leander Bekaert of Zwevegem, Belgium, who was also the founder of Bekaert wire works in 1880. Leo Leander’s version of barbed wire incorporated “star-shaped ‘crowns’ with six sharp points … woven into the wire.” Today, the Bekaert company is the world leader in wire products, and along with its derivative company Betafence, boasts a rich 135 year history of wire and fence production and is perhaps the oldest fence manufacturer in the world. With eight factories in operation, Betafence produces enough fencing each year to circle the world, twice!
Since it is obvious that most high-security facilities require some sort of physical barrier to control ingress or lengthen the delay time required for forced entry, many organizations have moved away from wire mesh products and are now using welded wire meshes, expanded metals and louvered panels offering longer delay times and requiring more sophisticated means of forced entry. The different types of high-security meshes are presented (see Photo A, above). As fences became more advanced and made with stronger steel and thicker gauges, the support posts and structural foundations also became studier and better engineered to withstand the additional weight with respect to high wind loads and less-than-ideal soil conditions. Thus, the most discerning buyers actually do their homework and ask for quality control reports and test results to ensure the product they are purchasing conforms to the desired standards. Wire mesh products should be tested for tensile strengths whether used in chain link or woven meshes, along with strength tests of the welds used in welded wire mesh panels (see Photos B and C, below).
Photo B. Testing of wire tensile strength during production.
Photo C. Testing of individual welds during quality control.
Interestingly, not all critical infrastructure perimeter protection systems meet the same set of high-security standards as the federal government, prisons or our defense organizations, especially in the private sector and for-profit industrial manufacturing sectors. Only until recently, has the federal government intervened heavily with directives requiring additional rigorous physical security standards, more specifically for the protection of our national bulk power supply system (electrical grid substations) following a brazen attack of a key substation in San Jose, California in 2013. The directives issued by the Federal Energy Regulatory Commission to the North American Electric Reliability Corporation (NERC, a group that manages the overall bulk energy supply as the official electric reliability organization) marked a progressive era for the mandated usage of physical security standards and called for more measures to meet tougher performance-based security standards, specifically citing protective barriers and perimeter systems. While high-security fencing systems are just one of many apparent solutions for the protection of perimeters, the NERC and other regulatory agencies must strike a balance between the risks involved, the capabilities and resources of the respective businesses and organizations, and the overall safety and security of our nation’s critical infrastructure, especially our bulk electric supply.
On a final note, the objective of perimeter fencing is to provide a primary line of demarcation offering an appropriate measure of safety, security and defense, followed by layers of protective resistance, and to give confirmation of attempted or real intrusions that prompt an appropriate and curative response.
Clint Hilbert is the Chief Security Officer at Betafence and he specializes in security and perimeter protection solutions and serves as a member of the American Board for Certification in Dignitary and Executive Protection. Betafence, a global perimeter protection company, has more than 135 years of manufacturing and operating experience in the high-security fencing and perimeter protection industry.
Safety Security Consultant, Church Security Institute, Public Safety Chaplain, Portsmouth Police Safety Town Public Relations
7yVery good history and different types of fencing, to get the job done.
Senior Director, Global Public Safety, and Global Crisis Management
9yClint, our organization facilitates training in the area of Threat, Risk, and Vulnerability. This is the best article on Chain Link Fencing that I have read. Do you mind if I share this with our classes and communications. Of course I will credit you. Thanks, Ken