Static discharge, also Stained Concrete Designs College Station as electrostatic discharge or ESD, is caused by the discharge of electrons from a static charge that can build up on an insulating body. Numerous modern electronic devices are very sensitive to ESD because of their very thin layer of insulating glass that can get damaged when exposed to as little as 40V of discharge or less. Electrostatic discharge has been documented as a significant contributor to serious problems ranging from computer freeze-ups and dropped phone calls to failures of semiconductors and shutdowns of mission critical operations.
The need to manufacture integrated components that use less power and improve circuit design and operation will continue to generate significant challenges for designers to reanalyze conventional building materials, and design static free environments and stringent static control procedures so static discharge cannot become a problem in the first place.
ESD floors make an effective method of controlling static discharge that can result in significant damage, injury and financial loss, as well as providing conformance to the latest recommendations of EOS / ESD 2020-2007. Electrostatic dissipative floors are recommended for use in electronic assembly and test areas, flammable storage and processing, and munitions areas. There are a number of terms which are sometimes used incorrectly by sellers to describe static control flooring. Conductive flooring is not the same thing as static dissipative flooring. Conductive flooring is a floor that has low BVG (body voltage generation) readings, offering high levels of protection for your products whereas static dissipative flooring products are engineered for use where static discharge control is required, but the resistance level of the flooring does not need to be as low as that provided by conductive flooring. Similarly, the term “antistatic flooring” is different as it helps eliminate static electricity by providing a controlled low resistance. An antistatic floor dissipates charges from components you’re working on as you lay them on the floor. If conductive flooring also exhibits antistatic properties, it will usually meet or exceed any static control requirement for body voltage generation.
In the case of ESD flooring, the two most important ESD standards for flooring are ESD STM 97.1-1999 Floor Materials and Footwear and ESD STM 97.2-1999 Floor Materials and Footwear. ESD STM 97.1-1999 Floor Materials and Footwear standard recommends a flooring footwear total system resistance of no greater than 35 megohms. ESD STM 97.2-1999 Floor Materials and Footwear states that no ESD floor should allow the generation of more than 100 volts when tested in conjunction with a person wearing conductive footwear.
The majority of ESD flooring failures that occur, are due to elevated moisture and alkalinity levels in the substrate. Moisture levels should be no higher than 3 lb per 1000 square feet per 24 hours. Moisture problems can be detected easily by pulling samples and performing ASTM moisture tests. ASTM-F-1869 – Standard Test Method for Measuring Moisture Vapor Rate of Concrete Subfloor Using Anhydrous Calcium Chloride (the maximum allowed transmission rate is 3 pounds per 1000 square feet) and ASTM F-2170 – Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in Sutu Probes (the maximum relative humidity should be below 80%) can be used to measure moisture vapor rate and relative humidity of a concrete subfloor respectively. Moisture and alkalinity problems can be avoided by filling the cracks before installation, leveling and patching the sub-floor, and installing vapor barriers.
The cost to repair and maintain an ESD floor should also be taken into account. Vinyl static dissipative flooring is the costliest and most difficult to maintain flooring because of its high buffing costs. Broadloom Carpet ESD flooring requires regular vacuuming and yearly wet extraction because of its vulnerability to stains. Rubber ESD flooring will also need periodic scrubbing with a single disc machine to maintain a shine on the surface of the floor. Epoxy ESD flooring needs to be cleaned regularly. If it has a polyurethane topcoat, it may be re-applied every 10 years or so, to keep the floor looking brand new.