ANSI/ESD STM97.1-2025 provides a procedure for evaluating a newly installed floor that was not evaluated before installation, or an existing static-control floor whose history or manufacturer is unknown (section 6.3).
The evaluation measures resistance through a person wearing footwear intended for that floor. Testing takes place at ambient temperature and humidity, with both-feet, left-foot and right-foot measurements repeated at the required floor locations.
Determine whether section 6.3 applies
The STM97.1 procedure-selection guide distinguishes this evaluation from pre-installation testing and testing new footwear on an existing floor.
Footwear intended for the flooring system
Section 6.3 requires using footwear intended for the flooring system. After that initial footwear set has been evaluated, additional footwear types can be evaluated using the section 6.2 procedure for new footwear.
Establish the test locations
Minimum tests by contiguous floor area
Section 6.3.1 specifies:
| Contiguous flooring-system area | Minimum testing |
|---|---|
| Less than 500 square meters | Five tests in different locations |
| Greater than 500 square meters | Five tests in different locations on every 500 square meters |
The wording does not explicitly assign an area of exactly 500 square meters or explain how to count a partial additional block. Document how those cases will be handled in the project’s test plan rather than presenting an assumed rounding rule as a requirement of the standard.
The floor-testing location and sampling comparison explains why counts from different methods should not be treated as interchangeable.
Prepare the equipment and floor
Meter capability and recommended verification
Use a meter meeting STM97.1-2025 section 5.1 and a hand-held electrode meeting section 5.2. The resistance-meter requirements explain the specified range and voltage capabilities.
STM97.1 recommends using a calibrated meter, verifying the meter and test leads under Annex A.1, and evaluating the footwear/person system under Annex C before these measurements. The equipment-verification guide explains the Annex A checks.
Cleaning before evaluation
Sections 6.3.2.1 through 6.3.2.5 specify the 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. |
The cleaning-before-testing guide explains why cleaning instructions differ between qualification, acceptance and routine verification.
Ambient conditions and cleaning moisture
Section 6.3.2.6 requires testing at ambient temperature and humidity. Moisture introduced by cleaning can still affect the results; the moisture and conditioning guidance explains the informative Annex B qualifications.
Personnel safety
Follow the equipment’s grounding instructions and applicable personnel-safety requirements. STM97.1 section 4.0 calls for electrical hazard reduction practices and consideration of ground fault circuit interrupters or other protection where personnel may contact electrical sources.
Resistance results must not be used to determine the relative safety of personnel exposed to high AC or DC voltages. The shock- and ignition-safety explanation distinguishes ESD-performance measurements from safety determinations.
Take the measurements
Prepare the person and connections
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 and the positive lead to the hand-held electrode. The grounding-reference guide explains the distinction between test connections and grounding verification.
Set the voltage to 10 volts DC.
Measure with both feet contacting the floor
Section 6.3.3 prescribes the reading sequence:
- 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.
- If resistance is 1.0 × 10⁶ ohms or greater, de-energize the equipment, re-energize 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 for each foot and test location
Repeat the setup and reading sequence with only the left foot contacting the floor, then with only the right foot contacting it. Hold the other foot in the air or place it on an insulating surface.
Repeat the complete both-feet, left-foot and right-foot sequence at every additional location required by section 6.3.1.
Report the results
Required records
Section 6.3.4 requires:
- The standard test method used.
- The manufacturer and description of the flooring evaluated, including its components. For an existing system, report as much about it as is known.
- The footwear manufacturer and style or identification number.
- 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 measured data points.
- Minimum and maximum resistance values per 500 square meters, reported separately 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
Yes. STM97.1-2025 section 6.3 applies to an existing static-control floor whose history or manufacturer is unknown. The report records as much about the flooring system as is known.
No. Section 6.3 requires both-feet, left-foot and right-foot measurements. Repeat the setup and reading sequence for each, then repeat the complete sequence at the required additional locations.
No. Section 6.3.1 states cases below and above 500 square meters without explicitly assigning equality or a partial-block rule. Address those cases in the project’s test plan without presenting the planning decision as quoted standard language.
Retain the 100-volt reading. Section 6.3.3 directs the operator to use that result even when it falls below the threshold that triggered the voltage change.