Hello,
Please,
ANSI/ESD S20.20-2021
Table 2 Footwear/Flooring System
Required Limit = Peak Voltage <100 Volts
IEC EN 61340-5-1
Table 2 - Person/Footwear/Flooring system Required Limit
Rg < 1,0 × 109 Ω and body voltage < 100 V (average of 5 highest peaks)
Q: which of the two test methods is preferable? And even more reliable?
Many thanks
Regards Gabriele
Hello Gabriele,
Good question. There are always slight differences in the requirements, but they are always trying to achieve the same goal. In this case, the system resistance of less than 1x10*9 ohms is the same. In ANSI/ESD S20.20 it is quoted by ANSI/ESD STM 97.1. The difference is in the requirement of peak voltage. In this case ANSI/ESD S20.20 is slightly more restrictive as only one value exceeding 100 volts will cause the system to fail.
But in all practical situations, flooring/footwear systems don’t usually fail just with one peak greater than 100 volts. If you follow a pattern and not try to “fool” the test most of the time, either method will pass or fail.
One thing to keep in mind, you can create a walking pattern that would pass either of these tests. The walking test must truly be representative of a real walking steps.
Hello John,
Many thanks.
I have a (portable) walking tester and I use it to definitively evaluate a flooring / footwear system after measuring the system resistance of less than 1x10 * 9 ohms ( some time even a bit higher)
My instrument prints me the average of 5 highest peaks ( as for 61340-5-1 request).
Normally I do not follow the pattern indicated by IEC 61340-4-5 but I use to ground the instrument with a wire of 10 sometimes 15 meters and the other pole of the instrument connected to the sensor held by the person. In this way I can travel/walk over a large area. Indeed, when the system is at the limit of 100V body voltage, there is never a single peak, but several.
When, on the other hand, the system is perfect we should not have peaks of 100V, but sometimes it happens to identify that the floor is not perfectly clean, or a fragment of insulating material has attached itself under the sole of the shoe, then yes the average of the 5 peaks that exceed i 100V.
Almost to laugh, but sometimes I even identified that the person had pain in the knee and therefore with that leg did not press the shoe sufficiently on the floor giving rise to peaks> 100V.
However, I find it very useful to use the (portable) W-Tester to evaluate the footwear / flooring system of a large EPA area where people work standing. The indications given by the W-T are much more reliable than just measuring only the resistance to ground of the footwear / flooring system.
Best Regards…Gabriele