Questions And Answers

Per ANSI/ESD S20.20 the required limit for ESD Floor is < 1 x 10E9 ohms, however for Flooring-Footwear System the required limit is < 3.5 x 10E7 ohms. The Flooring-Footwear System’s resistance is resistance in series that is adding the resistance of the components: person, grounding tab, current limiting resistor, footwear material, and floor.  Although one could use a dissipative floor in the 10E6 to low 10E7 ohm range being dissipative, we recommend a conductive floor for grounding a person via ESD footwear.

“Conductive Flooring Material: A floor material that has a resistance to ground of less then 1.0 x 10^6 ohms.” [ESD STM7.1-2005 Definitions]

Per ANSI/ESD S20.20 Flooring - Footwear System as primary grounding method, the required limited is <3.5 x 10^7ohms tested per ESD STM 97.1 Floor Materials and Footwear-Resistance in Combination with a Person.

“ESD protective flooring, used with approved footwear, may be used as an alternative to the wrist strap system for standing operations.” [ANSI/ESD S20.20 section 6.2.2.2 Personnel Grounding Guidance

“The use of floor materials to control personnel or equipment generated static has a number of benefits. Floor materials tend to be passive. Employees who work in areas protected with floor materials simply need to wear and test the appropriate footwear. They do not need to implement any additional actions themselves to assure that the floor material is functioning properly.” [ESD Handbook TR20.20 section 5.3.4.4]