How Well Is Your ESD Flooring and Footwear System Working?

The ESD flooring and footwear system is an effective way to ground people that need to be on the move in a factory.   The footwear, when worn properly, is designed to drain the voltage from a person to the floor and then to ground.   Periodic testing of both the floor and the footwear is required to verify proper functioning.

Until recently, a System Resistance Test (ANSI/ESD STM97.1) was all that was needed to qualify an ESD control flooring and footwear system.  If the resistance was less than 35 megohms, it was assumed that the person’s voltage would not exceed 100 volts (the upper limit for ANSI/ESD S20.20).    However, this testing is done with the person stationary and having both feet flat on the ground.  What happens when the person starts moving and the entire foot is not making contact with the floor?

The most recent version of ANSI/ESD S20.20 now requires a Walking Voltage Test (ANSI/ESD STM97.2) be performed when qualifying flooring and footwear systems.  The test consists of measuring body voltage generate during a six step pattern used to simulate moving throughout a facility. This test will determine the actual voltage on the person while moving. Research has shown that when tested separately, ESD floors and footwear systems may pass the resistance test, but when used together, can greatly exceed the 100 volt threshold.

Determining the maximum voltage generated by people moving on the factory floor is very valuable information.  By knowing the maximum voltage generated you will know that your flooring and footwear investment is performing as designed.  You may also be pleasantly surprised to find out that the system is working quite well and you are able to handle devices with much lower Human Body Model (HBM) damage thresholds.

Equipment is available to accurately measure and record the walking voltage.  One such instrument is the WT5000.   The WT-5000 walking test kit measures and records the walking voltage while providing a graphical readout.   The instrument connects to a PC using any Windows version for easy data collection.   The WT-5000 identifies the peak voltages per the requirements in the standards.                                                

The two-in-one EFM51WT meter holds the PEAK value of the measured body voltage, as well as the LIVE static voltage measured on the operator’s body. The kit includes the EFM51 static field meter, walking test adapter plate, hand probe and conductive carrying case.  The EFM51 is a fully function field meter that in addition to the Walking Test, measures and detects electrostatic fields, surface potentials and discharge times (with optional charge plate accessory – p/n 7100.EFM51.CPS.SET.)

You have made the investment in an ESD flooring and footwear system so that people can be mobile and still protecting your products from ESD events.   Determining your actual walking voltage generated is critical to knowing that your products are being protected.