Protektive Pak - Questions And Answers

What is the difference between a static dissipative and static conductive floor? I have read that dissipative implies resistance greater than 10E5 ohms/sq. ft. When choosing a floor, are there any electrical safety issues that will be compromised by a conductive rather that dissipative floor material, for example? - Anonymous, Arrow International, Inc., Reading, PA

Good questions. You are correct in the definition of conductive versus dissipative bordering on 1.0x10^5 ohms/sq or 1.0x10^4 ohms. The safety of the individual always comes before any program. The largest safety worry about a very conductive floor is for the path to ground resistance being to low. This may lead to the magnitude of current traveling through a human to go over 1 mA AC or 4 mA DC causing a “surprise” reaction and endangering the person. UL recognizes this fact and gives safety approval to our foot grounders that have at least a 1 megohm resistor in series with the ground path and exposed to less than 250 VAC. The minimum current a person could receive with a 1 megohm resistor to ground is 0.25 mA, well below the 1 mA requirement from the MIL-STD-454. The ESD Association (ESDA), Standards ANSI/ESD S7.1-1994 and ESD DS20.20-1998 states that an ESD Floor should be under 1.0x10^9 ohms. Most companies go with a low dissipative floor with the thought that dirt, time, and wear will cause the resistance to increase a few magnitudes.

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