I have an an arcane subject today for my commercial floor buyers. If static electricity is an issue at your company or manufacturing facility, then electro-static dissipative flooring may be the answer.
First, why bother? It’s only a little shock. Really?
The human body can generate up to 30 000 Volts in static electricity depending on the type of clothing we wear, the type of upholstery we sit on or floor coverings we walk on. The resulting discharge from the electron imbalance when we touch a grounding source is often felt as a static shock when touching another object. This energy discharge is problematic when working with flammable gasses or sensitive electronic equipment, and the static charge needs to be dissipated via ESD floor coverings or other ESD products, in a controlled manner in order to avoid damage to equipment or people. There are two types of these floors. ESD flooring is an excellent form of facilitating a uniform flow of static electricity directly to a ground point. Most types of vinyl flooring claim to be anti-static. This means that they do not contribute towards the build-up of static electricity in the human body. They also do not drain the static charge already built up. High levels of static are generated in dry areas, and conditions are much worse inland away from the coast.
This means the static electricity is still there to leap onto your project and possibly arc and destroy your sensitive electronics. (Think computer assembly) These floors come in sheet vinyl, vinyl squares, carpet tile, rubber tile and epoxy floors.
Electrostatic conductive (EC) floor coverings contain carbon and discharge static electricity more quickly and can be used in less controlled environments. In controlled environments they would be used in sensitive electrical and assembly areas as well as explosive manufacturing areas.
Static dissipative (SD) floor coverings are chemically treated to discharge static electricity and must be used in a controlled environment with a relative humidity of above 40%. Typical areas of use would be operating theatres, computer areas and instrument control rooms.
They do similar things but are very differently made but installation should be by a qualified installer. Like, well, me. Electrostatic conductive and dissipative floor coverings are usually laid on a cement subfloor. Concrete is a poor conductor of electricity, so this type of floor covering needs to be laid using a conductive adhesive and earthed in order to drain the discharge. Aluminum or copper tape is laid in the adhesive under the floor covering and taken to anearth point. Two earth points are used in case one fails. For larger areas one earth point is allowed for every 20 m2. Earth points are basically copper strips imbedded in the setting material and grounded to a pipe or electrical box. As a rule, electrostatic dissipative floor coverings are never sealed, as this would create a barrier between the floor covering and the human body and so prevent discharge. Conductive sealers are available if required.
