Controlling static electricity on concrete
Q: Why can’t bare or sealed concrete be used as a method for controlling static electricity in a electronics manufacturing environment verse utilizing a Conductive or Static Dissipative covering and/or coating?
A: I’ve done some studies on ESD resistive characteristics of the several different floor surfaces. In light of the following question, I just snapped some photos of ESD readings on the following surfaces:
Bare concrete (dry). Results- barely conductive, very humidity dependant; in the insulative range(1E09-1E12)
Asphalt. Results- unacceptable; above insulative.
Dirt. Results- pretty good, acually comes in at barely dissipative; Upside, cheap; Downside, hard to clean.
ESD Carpet (Ground Zero Information). Results- ESD conductive(2.5e4-1.0E6).
ESD Tile (Ground Zero Information). Results – ESD dissipative(1.0E6-1.0E8).
Sealed Concrete. Results-unacceptable; a sealed concrete is necessary for heavy foot traffic, but the very thing that would make the concrete conductive is sealed out- moisture. This floor could be made dissipative very easily with an ESD chemical (Ground Zero Information).
Particle board. See asphalt