There may be some confusion with the terms "conductive" and "dissipative". If the material has a surface resistance of 1x10^4 ohms or greater but less than 1x10^11 ohms then it is dissipative. Dissipative materials do conduct, just at a slower rate then conductive materials. If a material is too conductive (< 1x10^4 ohms) there is a chance that a charged conductor touching this material may experience an ESD event. Dissipative materials are better choices for controlling ESD events for work surfaces, packaging, etc. Refer to our white paper on ESD Discharge Times

The recommended electrical resistance for Flooring from ANSI ESD S 7.1 and ANSI/ESD-S20.20 is <1x10^9 ohm RTT which starts from the upper dissipative range but can include the conductive range. The conductive range is less than 1x10^4 ohms (so 9x10^3 ohms is conductive). Over 1x10^4 ohms (to 9x10^10) is considered dissipative.

The standard is flexible so the end user's ESD control program can be written to specify the floor material to satisfy their specific internal requirements.

However in general, floor materials in the upper conductive range or low dissipative range work well for ESD control floor coverings. Since dirt and other contaminant are typically insulators, the flooring will measure less than 10^9 ohms throughout the maintenance cycle. All of ESD Systems.com's Floor mat materials, as well as Statproof® Dissipative Floor Finish meet the electrical requirements for ANSI/ESD-S20.20. Conductive floors will provide a somewhat more rapid charge decay, but ESD safe floors with Statproof® Dissipative Floor Finish properly applied will limited tribocharging to under 50 volt charge generation.

• "ESD Basics" by Lou DeChiaro, Lucent Technologies
• "ESD Audits" by Larry Fromm of Hewlett Packard
•  Panel Discussion on "ESD Common Myths"