StaticSmart ESD Flooring Library

Figure 8 shows the ordered values for an audit-type run at a major electronic manufacturing facility.

It contains approximately 285 observations made on a vinyl tiled floor. It is worthy of note for two reasons. First, because it contains so much more data than is usually amassed in a single area audit, a valid statistical analysis is possible; and second, because it takes one man with meter and computer in hand only about 30 minutes to do this job.

It should also be noted here that this installation outright failed the user's specification for resistance and yet, with proper footwear easily met the performance requirement of body potentials below 100 volts. The quantitative explanation for this is to be found in the experimental work reported in the next section.
 

Body Voltage Test Results

The following data was generated in two ways. First there is laboratory work under controlled conditions and with limited sample size and second, in the field under normal working conditions. Figure 9 summarizes the laboratory data.

It shows peak voltages on a test individual with footwear and floor resistances defined and measured as described above under two different body /shoe relationships, normal wear and with both feet insulated from the shoes by means of high resistance polyethylene booties.

Figure 9: Flooring/Footwear Body Voltage Test Data  
 

Figure 10: is a chart giving the conversion of resistance data from engineering notation to logarithms.