Anti-Static Flooring Part Four
SPECIFICATION AND STANDARDS
The rate at which electrostatic charge is dispersed within and through the floor finish is controlled by the resistance, measured in the unit Ohms (Ω), usually expressed in thousands (Kilo-ohms or KΩ) or millions (Mega-ohms MΩ) and denoted by units expressed as a figure of ten with indices, i.e.103 for 1KΩ or 106 for 1MΩ. Greater values of resistance suggest a slower passage of electrostatic charge and the decay of voltage measured.
Resistance may be measured in one or more of four ways:
(a) between two points at a pre-defined distance on the surface of the cured resin floor finish
(b) between the surface and the underside of the resin finish (the substrate)
(c) earth leakage of the whole system, between the surface of the resin finish and via the substrate to a point defined as electrical earth
(d) a combined body voltage test where the charge level generated and its decay rate on a person walking the floor is measured using specialist equipment to identify the interaction between floor and specialist footwear.
It is not uncommon for those operating facilities which demand static controlled flooring to be unsure of their exact numerical requirements, when expressed in the terms above.
Anti-Static Flooring Part Three
SELECTION OF FLOORING MATERIAL
Static controlled grades of resin flooring are available in Types 3 to 8 (coatings, self-smoothing and trowel applied screeds). It is important for the specifier to understand that there is a wide range of products and properties available and to select the system that best meets the requirements for the working environment as a whole and to not treat the individual elements in isolation. Colour should be discussed with the flooring manufacturer, as there may be certain colour limitations on static controlled flooring due to the darkening effect of carbon or other conducting additives.
Anti-Static Flooring Part Two
TYPICAL APPLICATIONS FOR STATIC CONTROLLED FLOORING
In certain industrial environments the attraction or adhesion of dust may present a problem. In areas where volatile gases, powders or liquids are processed, stray electric currents are undesirable and potentially dangerous. In areas where sensitive electrical devices are manufactured, electrostatic discharges may damage these components. Each of these areas will have requirements for static controlled floors. Typical examples are: Semi-conductor and electronic assembly, Pyrotechnics, Munitions, , Micromechanics, Miniature bearings, Optical lenses, Photographic film, Lasers, Biotechnology, Pharmaceutical production, Clean rooms, surgical implant manufacture and medical environment, even some Food & Drink production environments.
Anti-Static Flooring Part One
We will all be familiar with the effects of the build up of static electricity. Taking off a sweater made from synthetic fiber will often be accompanied with ‘crackling’ sounds as sparks jump across. On some days we can experience unpleasant shocks from touching car door handles particularly when wearing shoes with synthetic soles. The same effects are responsible for the adhesion of dust on surfaces. Under normal conditions these effects are, at the most, merely unpleasant but not particularly dangerous. However in the industrial environment such electrostatic build-up can cause lasting effects which may inhibit production or at worst endanger life.
Concrete floors are normally sufficiently conductive due to their pore water to dissipate any electrostatic charges on the surface. However floor finishes, often used to provide a more hard wearing or chemically resistant surface, may be an effective natural insulator and should be selected with caution in some circumstances. Where appropriate, a static controlled grade of Resin flooring should be selected. Static controlled grades are generally derived from normal Resin flooring grades by incorporating a proportion of carbon powder or fibers, but other more sophisticated solutions may also be used by the manufacturer.