Grounding: Key Rules and Regulations for ESD Footwear and Flooring Systems
Grounding: Key Rules and Regulations for ESD Footwear and Flooring Systems
ESD footwear — heel grounders, toe grounders, and ESD-safe shoes — works in tandem with ESD flooring to provide a continuous path-to-ground for standing operators, safely dissipating static charge before it can discharge into a sensitive component. The system only functions when both elements are compliant: ESD footwear on non-ESD flooring provides no ground path, and ESD flooring without grounded footwear leaves the operator’s body charge uncontrolled. ANSI/ESD STM97.1 requires that the total resistance from footwear combined with the wearer be less than 1.0 × 10⁹ ohms; ANSI/ESD STM97.2 requires peak body voltage below 100 volts; and ANSI/ESD TR20.20-2016 requires footwear to be worn on both feet and tested daily before entering any EPA. For a complete ESD program guide, visit our ESD Program Essentials hub.
ESD Footwear & Flooring Compliance Requirements
| Requirement | Standard | Specification | Notes |
|---|---|---|---|
| Total system resistance (footwear + wearer) | ANSI/ESD STM97.1 | < 1.0 × 10⁹ Ω | Measured person-to-ground with footwear worn on ESD-compliant flooring |
| Peak body voltage | ANSI/ESD STM97.2 | < 100 volts | Measured with body voltage meter during normal walking on ESD flooring with ESD footwear |
| Footwear worn on both feet | ANSI/ESD TR20.20-2016, §12.2.1 | Required — both feet | Single-foot grounding is not compliant; charge can accumulate on the ungrounded foot |
| Daily verification before EPA entry | ANSI/ESD TR20.20-2016, §12.4 | Test at start of each shift | Use a person-to-ground resistance tester or combo tester; document results |
| Flooring surface resistance | ANSI/ESD S20.20 / ANSI/ESD STM97.1 | Verified per ESD control plan | Flooring must be tested before relying on footwear grounders as primary grounding method |
ESD Test Equipment for Footwear & Flooring Compliance
| Equipment | Product | Measures | Standards |
|---|---|---|---|
| Surface Resistance Meter | Desco 19290 Digital Surface Resistance Meter Kit | Point-to-point (Rtt) and resistance-to-ground (Rtg) of flooring, worksurfaces, garments, and packaging | ESD TR53, ANSI/ESD S4.1, ANSI/ESD S7.1, ANSI/ESD STM97.1 |
| Body Voltage Meter | Desco 19431 Body Voltage Meter | Human Body Voltage (HBV) on a person in combination with ESD footwear and flooring | IEC 61340-4-5, ANSI/ESD STM97.2 |
| Combo Tester (Wrist Strap + Footwear) | Desco 19270 Combo Tester X3 with Dual Foot Plate | Person-to-ground resistance of wrist straps and footwear grounders simultaneously; dual foot plate for both-feet verification | ANSI/ESD TR20.20-2016 §12.4 |
Frequently Asked Questions
Why must ESD footwear be worn on both feet?
ANSI/ESD TR20.20-2016 Section 12.2.1 requires footwear on both feet because a single grounded foot does not reliably control charge on the entire body. When only one foot is grounded, the ungrounded foot can accumulate charge through contact with the floor, and charge can redistribute between feet during walking. The ground path through a single foot may also be intermittent depending on gait and floor contact. Wearing grounders on both feet ensures a continuous, redundant ground path regardless of which foot is in contact with the floor at any moment.
What is the difference between testing flooring with a surface resistance meter vs. testing the operator with a combo tester?
A surface resistance meter measures the electrical resistance of the flooring material itself — it verifies that the floor meets ESD specifications but does not test the operator’s ground path. A combo tester (like the Desco 19270) measures the complete person-to-ground resistance with the operator standing on the test plate wearing their footwear — this is the correct test for daily shift verification per ANSI/ESD TR20.20-2016. The combo tester verifies the entire ground path including footwear condition, skin contact, and body resistance. Both tests are required: floor resistance is verified periodically; operator footwear is verified daily.
How do I verify ESD flooring performance before relying on heel grounders?
Measure floor surface resistance point-to-point (Rtt) and resistance-to-ground (Rtg) using a surface resistance meter per ANSI/ESD STM97.1. The floor must meet the resistance specification in your ESD control plan before footwear grounders can be used as the primary grounding method. Also measure body voltage per ANSI/ESD STM97.2 with an operator walking normally on the floor wearing the intended footwear — this system-level test confirms the footwear-floor combination achieves the required <100V body voltage limit under actual use conditions.
What ESD Association standards govern footwear and flooring programs?
The primary standards are: ANSI/ESD STM97.1 (measurement of floor materials and footwear resistance), ANSI/ESD STM97.2 (measurement of body voltage in combination with footwear and flooring), ANSI/ESD TR20.20-2016 (ESD control program requirements including footwear testing frequency and both-feet requirement), and IEC 61340-4-5 (international standard for footwear and flooring measurement methods). ESD Association standards, test methods, standard practices, and technical reports provide the complete framework for building and auditing a compliant footwear and flooring program.
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Content developed in partnership with Desco Industries.
