Examples of Use

Examples of use and requirements for the raised flooring field

On the preceding pages we explained the meaning of the word electrostatic, and showed its various measurements. What else does one have to bear in mind in the raised flooring field, and what requirements are useful? The electric resistance of the various areas add up, which in actual practice means: The resistance to ground R2 must never be lower than the highest resistance of the individual elements in the series: floor covering / adhesive / raised flooring panels / sound-insulating bearing plate / pedestals.

The floor systems have to meet the following requirements:

1. Offices with terminals, sales and display rooms, etc. In these areas, a floor covering is sufficient that is antistatic according to DIN 54 345 = < 2 kV as its voltage charge. 2. Rooms with electronic equipment, such as computer centers, offices with special equipment, resistance to earth R2 = < 1 x 109 Ohms or voltage of charging U maximum of 2 kV. 3. Unprotected electronic components or components with requirements for protecting people, such as testing shops in the electronics manufacturing field, resistance to ground R2 < 1 x 108 Ohm, contact resistance of the location acc. to VDE 0100, RST > 5 x 104 Ohm or RST > 1 x 105 Ohms (the amount of rated voltage is decisive). 4. Unprotected electronic components or components, such as manufacturing or laboratory rooms for making, repairing or testing electronic equipment, subassemblies or components, resistance to ground R2 < 1 x 108 Ohms. 5. Explosive atmospheres in general, such in potentially explosive laboratories, gas pressure control facilities, battery storage rooms, resistance to ground R2 < 108 Ohms. 6. In medical rooms, newly installed, R2 < 107 Ohm, in four years R2 < 108 Ohm; HF-surgery R2 > 5 x 104 Ohms. 7. Potentially explosive substances, such as in manufacturing and storage rooms of explosives, munitions or pyrotechnical articles, resistance to ground R2 < 106 Ohms.

Summary:

For most areas of application of access flooring systems, a floor covering is usually sufficient which does not exceed the 2 kV limits to charging. Requirements on the resistance to ground in the overall construction are not advisable; according to the listing above, requirements on the resistance to ground are only necessary in some areas, such as central computer rooms. Due to the varied tests and requirements, seen as a whole, the field of electrostatics is a difficult subject to understand. This is perhaps the reason why, in the past, overly stringent requirements were made on resistance to ground. Manufacturers of raised flooring can only fulfill resistance to conductance as low as < 108 Ohms by using highly conductive coverings, panel materials and adhesives. Bearing the building costs in mind, exaggerated requirements which are not practical or necessary should be avoided. Further, it should be mentioned that appropriate clothing by the user (conductive shoes) is crucial. Even a floor construction that is technically perfect in terms of its electrostatics will be ineffective with insulating shoes. ESD damage is inevitable in such case.