Guide To ESD Flooring Materials
Developments in flooring technology provide more options and offer flexible approaches
By Dave Long
Many facilities managers agonize unnecessarily while attempting to choose the "right" ESD flooring for their corporate environments. Because most high tech businesses house multiple processes, each with its own individual flooring requirement, satisfying every department can be a daunting, thankless challenge. Further frustrated by conflicting ESD specifications as well as the plethora of propaganda from static control flooring manufacturers, facilities managers sometimes defer to the choice of a selection committee or else they invest countless hours of valuable time trying to find that perfect material. In either case, the result is too often the selection of a single type of surface for every area where ESD mitigation is required or anticipated as a future requirement.
Unfortunately, the "one-size-fits-all" philosophy for static control flooring typically yields compromised results. For example durability might be emphasized at the expense of ergonomics, or a decision might be based on the installed cost of the floor rather than on the total cost of ownership. Or maybe the committee, swayed by one influential person—from shipping and receiving, for instance—decides to install a tough, chemical resistant walking surface throughout the facility, even though 95 percent of the space resembles an office more than a factory.
To solve the problem, a growing number of high tech businesses are selecting different types of esd flooring for different parts of their businesses, often utilizing architects to help them create a functional, attractive and well-integrated environment.
A Bit Of History
In the 1970s and early 1980s, when ESD was slowly creeping into what has become our everyday world of PCs, PDAs and GPSs, flooring manufacturers were generally unaware of the need for ESD mitigation. In 1979, when military subcontractors adopted DOD- 1686, the Mil spec for ESD, flooring manufacturers raced to develop groundable materials for places where ESD sensitive equipment was handled, stored or used. Like any nascent industry, it took a while to perfect the various flooring materials, and some of the early suppliers got it right and some of them didn't, as the following paragraphs illustrate.
Because static control properties were easy to incorporate into the regular compound, vinyl was initially the material of choice for ESD flooring. By introducing veins of conductive material into standard vinyl tile, suppliers could produce a static control floor that was reliable, while also easily and effectively manufactured.
Yet, while ESD vinyl was a start, and a good one, it wasn't the panacea people hoped it would be. Some vinyls were too soft while others were too brittle to handle the heavy loads in areas where large computer equipment is assembled and moved. In wave soldering areas, spills from the solder machines would melt the material. Some vinyls contained plasticizers that could not be used in certain clean-room applications.
Others utilized fire retardants like halogens which, in the event of a small fire, could create corrosive gases causing damage to unmanned spaces like the underground offices of a telephone company.
Early versions of ESD epoxy, while durable and easy to maintain, often failed conductivity tests. During the mixing process, an incomplete dispersion of conductive fibers would produce an ESD floor that was not adequately conductive. To boost conductivity, it was common practice to "shock" epoxy floors with high-voltage power supplies, a process akin to medical defibrillation. Shocking helped bridge the insulative gaps between the suspended conductive fibers. Shocking, however, did not always work, particularly in cases where either an error in the mixing process or poor quality control by the chemical manufacturer produced a compound containing a deficient number of fibers or conductive particles.
Carpet had its own, albeit different, set of problems. The conductive fibers in the early carpets were not robust enough to withstand traffic and the fibers would break down, rendering the static control qualities of the floor ineffective. Also, conductive carpet produced in the 70s and early 80s was almost exclusively a broadloom product similar to the carpet installed in your house. Because repairs to broadloom carpet are both difficult and conspicuous, and because, at the time, electronic manufacturing processes were much dirtier than they are today, facilities managers generally considered carpet unsuitable for manufacturing environments.
Though rubber has always been one of the most stable, durable and resilient flooring materials, early ESD rubber flooring was not attractive. The early rubbers were available only in the carbon-loaded black version of the material, which most people found either ugly or dirty-looking, so were considered unsuitable for large areas or for clean rooms.
Today, Excellent Choices Abound
By the late 1980s, however, several reliable options for ESD flooring had been introduced. Today, there are attractive static control versions of vinyl, epoxy, carpet and rubber, all of which provide effective, long-term ESD mitigation. Each product has its own positive attributes and each also has potential drawbacks that should be understood and possibly addressed.
*This article originally appeared in the November '03 issue of Conformity Magazine.