ANSI/ESD STM97.1-2025 evaluates the resistance of a person wearing footwear on a proposed flooring system before installation (section 6.1). The evaluation combines representative flooring samples, intended footwear, controlled conditioning, floor-resistance baseline measurements and person-system measurements.
The sections below explain how those stages fit together and direct you to the supporting requirements. For scheduling, responsibilities and documentation arrangements, start with the pre-installation qualification planning guide.
Select the applicable procedure
Section 6.1 applies before installation
Use section 6.1 to evaluate the flooring system before it is installed. The samples must represent the proposed assembly, and the standard recommends using footwear intended for the completed floor.
Evaluating new footwear on an existing floor or evaluating a previously unqualified installed floor involves different procedures. The STM97.1 procedure-selection guide explains when sections 6.1, 6.2 and 6.3 apply.
Prepare the flooring samples and footwear
Represent the proposed installation
Section 6.1.1 requires at least three flooring samples and three pairs of footwear, with the pairs labeled 1 to 3. The samples, referred to as specimens in STM97.1, must include the flooring-system components as they will be used in the installation.
Prepare and mount the assemblies according to the manufacturer’s instructions, including applicable curing, adhesive application and grounding requirements. The flooring sample and footwear requirements cover dimensions, seams, groundable points and footwear selection.
Clean and condition before measuring
Allow for the specified environment and duration
Cleaning follows the material-specific procedures in section 6.1.3. After cleaning, the footwear and flooring samples require at least 72 hours of preconditioning at 12% ± 3% relative humidity and 23 °C ± 3 °C. They remain in that environment until testing is complete.
Moisture introduced during cleaning can affect resistance, and some hygroscopic materials may take longer to equilibrate. The moisture and conditioning guidance explains the distinction between the required conditioning period and the informative Annex B observations.
Confirm the equipment and measurement setup
Meter capability and setup verification
The meter must meet STM97.1’s resistance-range and test-voltage requirements. The resistance-meter requirements identify those specifications and distinguish them from other flooring test methods.
STM97.1 recommends using a calibrated meter and verifying the complete measurement setup before testing. The meter, electrode and lead verification procedures explain the Annex A checks.
Electrodes, support materials and other apparatus must also meet the applicable requirements in section 5. The standard separately recommends evaluating the footwear/person system under Annex C.
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.
Complete the two measurement stages
Establish the floor-resistance baseline
Before measuring the person-system resistance, measure the flooring sample’s resistance to each groundable point. Use the incorporated STM7.1 procedure and the five electrode locations prescribed in STM97.1 Figure 1.
Record the five baseline readings to each groundable point on every flooring sample. A floor mat with only one groundable point is measured to that point only. Consult the standard’s prescribed figure for electrode placement.
Measure the person, footwear and flooring together
The person wears the test footwear on both feet for at least 10 minutes before measurement. The footwear wear-in explanation describes the moisture-equilibrium purpose stated by STM97.1.
The person-system sequence measures resistance with:
- Both feet contacting the flooring sample.
- Only the left foot contacting the sample.
- Only the right foot contacting the sample.
Complete the prescribed sequence for the required groundable points, flooring samples and footwear pairs.
Apply the person-system voltage and reading rules
Section 6.1.4 starts each person-system measurement at 10 volts.
| Initial resistance indication | Required action |
|---|---|
| Below 1.0 × 10⁶ ohms | Record the resistance after 5 seconds. |
| At or above 1.0 × 10⁶ ohms | De-energize the equipment, re-energize at 100 volts, and record after the instrument’s known electrification period or a maximum of 15 seconds. |
If switching to 100 volts produces a reading below 1.0 × 10⁶ ohms, retain the 100-volt reading. Follow the complete connection and repetition sequence in section 6.1.4.
Assemble the qualification report
Identify the tested system and preserve the measurements
Section 6.1.5 requires the report to include:
- The test method, testing organization and completion date.
- The flooring-system components and footwear identification.
- The measurement equipment manufacturers and model numbers.
- Test temperature, relative humidity and conditioning duration.
- The measured person-system data and specified minimum and maximum resistance summaries.
- The five floor-resistance baseline values to each groundable point on every tested flooring sample.
The full two-groundable-point procedure produces 54 person-system data points. Where the permitted one-groundable-point mat exception applies, report the readings actually taken for that configuration.
The standard also recommends recording setup-verification data, sock composition, measurement voltage and equipment calibration due date.
Apply the governing qualification criteria
STM97.1’s intended system-resistance range is below 1.0 × 10⁹ ohms. That scope statement does not itself establish that the facility’s qualification requirements have been satisfied.
The S20.20 footwear/flooring qualification requirements explain the separate system-resistance and body-voltage criteria and how they apply to the footwear/flooring combination.
Frequently Asked Questions
No. Section 6.1.4 calls for floor-resistance measurements to the sample’s groundable points before the person-system measurements. The report retains both sets of results.
Retain the 100-volt reading. STM97.1-2025 section 6.1.4 explicitly addresses this result; it does not direct the operator to substitute the earlier 10-volt reading.
No second-point readings are produced when the permitted exception applies. The 54-data-point count describes the full two-groundable-point procedure. Report the measurements actually taken for the tested configuration.