Questions And Answers

If the relative humidity was controlled to a high enough level, it might be possible that an ESD protected area could use a regular sealed concrete floor as an ESD Floor reliably measuring < 1 x 10E9 ohms.  Concrete is hygroscopic (readily absorbing moisture), and it would be the moisture, not the concrete that would be providing the resistance path.  This certainly would not be a best practice.

If the relative humidity was not controlled, the concrete floor would predictably measure high during dry periods, and therefore is not an acceptable ESD control practice.

The ESD Handbook ESD TR20.20 Table 1 lists concrete as a problem not a solution under section 2.4 “Sources of Static Electricity”. Table 1-Typical Static Electricity Sources includes “Floors – Sealed Concrete”.

A solution is noted at ESD Handbook TR20.20 section 3.4.7.10 Paints and Coatings

“Paints and epoxy coatings are applied to concrete floors in thin coats. The primary advantages of these materials are their ease of application and coverage over a wide area. They have a longer usable life than do floor finishes, but less than permanent floor materials. Paints and coatings tend to wear off in time and must be reapplied on a continuing basis.”