ANSI/ESD STM97.1-2025 provides a procedure for evaluating a new footwear type with an existing flooring system (section 6.2). Three pairs of the new footwear are tested at ambient temperature and humidity. Each pair is measured with both feet contacting the floor, then with only the left foot and only the right foot.
The evaluation produces nine resistance readings for the tested person-footwear-floor combinations.
Select the footwear and test area
An area of the existing static-control floor
Choose an area of the existing floor for testing the footwear. STM97.1 recommends a high-traffic area; it does not make that location mandatory.
If the situation involves pre-installation evaluation or a previously unqualified floor, consult the STM97.1 procedure-selection guide before selecting the procedure.
Prepare the measurement equipment
Meter and hand-held electrode
Use a resistance meter meeting STM97.1-2025 section 5.1 and a hand-held electrode meeting section 5.2. The resistance-meter requirements explain the required measurement range and voltage capabilities.
Recommended checks before measurement
STM97.1 recommends using a calibrated meter and verifying the meter and test leads under Annex A.1 before taking these measurements. It also recommends evaluating the footwear/person system under Annex C.
The equipment-verification guide explains the Annex A checks and their distinction from calibration.
Personnel safety
The person-contact procedure requires attention to electrical safety. Follow the equipment’s grounding instructions and applicable personnel-safety requirements. STM97.1 section 4.0 also calls for electrical hazard reduction practices and consideration of ground fault circuit interrupters or other protection where personnel may contact electrical sources.
Resistance results from this method must not be used to determine the relative safety of personnel exposed to high AC or DC voltages.
Clean the floor, footwear and electrode
Material-specific preparation
Section 6.2.2 specifies the following cleaning procedures.
| Item | Preparation |
|---|---|
| Flooring, mats and other hard surfaces | Follow the manufacturer’s recommendations, or clean with an isopropanol-water solution such as 70% IPA made with deionized, distilled or purified water, using a clean, low-linting cloth. |
| Textile and other floor coverings | Follow the manufacturer’s recommendations. In their absence, use standard hot-water extraction procedures such as ANSI/IICRC S100, AATCC TM171 or AATCC TM138. |
| Floor finishes | Remove surface contamination with a clean, dry, low-linting cloth. |
| Footwear and foot grounders | Wipe the bottom and inner soles of footwear, and the part of a foot grounder that contacts the floor, with a dry, low-linting cloth to remove dust. |
| Hand-held electrode | Clean with the specified isopropanol-water solution and a clean, low-linting cloth, then allow it to air dry. |
Ambient temperature and humidity
Section 6.2.2.6 requires all tests at ambient temperature and humidity. Moisture introduced during cleaning can nevertheless affect the results; the moisture and conditioning guidance explains the Annex B qualifications.
Measure each footwear pair
Follow the section 6.2.3 sequence
- Wear the test footwear on both feet for at least 10 minutes to establish moisture equilibrium.
- Connect the meter’s negative lead to ground as defined in ANSI/ESD S6.1. Connect the positive lead to the hand-held electrode.
- Set the voltage to 10 volts DC.
- Stand on the flooring with both feet and grasp the hand-held electrode.
- Energize the measurement equipment.
- If resistance is below 1.0 × 10⁶ ohms, record the value after 5 seconds and proceed to step 9.
- If resistance is 1.0 × 10⁶ ohms or greater, de-energize the equipment. Some integrated instruments automatically sense resistance and adjust the applied voltage.
- Energize the equipment at 100 volts and record after the instrument’s known electrification period or a maximum of 15 seconds. Retain the 100-volt reading even if it falls below 1.0 × 10⁶ ohms.
- Repeat steps 1 through 8 with only the left foot contacting the flooring. Hold the other foot in the air or place it on an insulating surface.
- Repeat steps 1 through 8 with only the right foot contacting the flooring, keeping the other foot out of contact.
- Repeat steps 1 through 10 for the remaining two footwear pairs.
Report the results
Required records
Section 6.2.4 requires the report to include:
- The standard test method used.
- The footwear manufacturer and style or identification number.
- Identification of the flooring system.
- The organization completing the testing.
- The manufacturer and model number of all measurement equipment.
- The test completion date.
- Temperature and relative humidity during testing.
- All nine resistance values in ohms: three readings each for both feet, the right foot and the left foot.
Recommended supporting information
The standard also recommends reporting setup-verification data, sock composition, measurement voltage and the equipment calibration due date.
These resistance readings do not complete footwear/flooring qualification by themselves. The S20.20 qualification requirements explain the separate resistance, body-voltage and conditioning requirements.
Frequently Asked Questions
STM97.1-2025 section 6.2 requires three pairs of the new footwear. Test each pair with both feet, the left foot alone and the right foot alone, and report all nine resistance values.
No. Section 6.2 requires selecting an area of the existing static-control floor. A high-traffic area is recommended.
Retain the 100-volt reading. Under section 6.2.3, the switch follows an initial 10-volt reading at or above the threshold. Record the 100-volt result after the instrument’s known electrification period or a maximum of 15 seconds.