ESD Systems - Questions And Answers

What is the difference in the RTG reading on conductive tile when normal adhesive were used instead of conductive adhesive? Our production floor is covered with static dissipative flooring. The RTG reading is 10⁸ - 10⁹ ohm, and it able to discharge the charge of kV to ground within 0.5 sec. The adhesive used was not conductive and no copper strip was used. How does the charge dissipate to ground? What are the consequences of not using copper strip when lying conductive tile and what are the RTG reading difference with and without copper strip? When I measured the RTG reading on the conductive floor with normal adhesive, the readings were within the specification and it was able to decay the charge within 0.5 sec. - Anonymous, Prai Penang, Malaysia

The RTG will be into the upper ranges of dissipative but more important you would have to assure that each tile had continuity to the next to make contact to ground. There is a chance that, depending on the type of tiles (manufacturer) that electrical contact is made mechanically by direct contact of adjacent tiles, but a conductive substrate would ensure continuous electrical contact with the floor system. Need to know the type of flooring. A poured floor would be dissipative as would a linoleum type of flooring. If dissipative tiling was used then there might be a problem of electrical consistency, again, depending on the manufacturer of the tile. The charge dissipation to ground is attained by several ways: (1) by having over 100 square feet of dissipative floor surface, the floor becomes a natural ground (like a HUGE capacitor) and will dissipate the charge imbalance throughout the whole floor surface, yielding a minimum (almost zero volt) potential (2) the floor may come into contact with water pipes, metal grounded desk/workbench legs, electrical conduit, metal posts or columns tied as in infrastructure to the building and consequently ground, etc. The strip assures a positive ground. Copper can oxidize so we suggest a non-woven conductive strip or tinned copper tape. Depending on the floor’s other non-obvious paths to ground and connection to the building’s substructure, the RTG may by the same or higher than with a positive grounded floor. Again, if the floor was one piece you could get the readings you report.

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