A calibrated resistance meter does not, by itself, establish that the complete test setup can make the required measurements. The electrodes and test leads also affect the measurement. Verifying them together helps identify equipment problems before the results are used to evaluate the flooring or footwear/flooring system.
Before testing, Craftsman Concrete checks the resistance meter against known resistors and verifies the assembled meter, electrodes and leads using the procedure applicable to the project. These checks help identify equipment problems before readings are used to assess flooring installed by Craftsman or another contractor. Equipment that fails verification is addressed before project testing proceeds.
ANSI/ESD STM97.1-2025 describes checks of the meter and the complete setup in Annex A. ESD TR53-01-22 provides a separate apparatus-verification procedure in Annex G. Their reference-resistor tolerances and procedures differ, so the requirements should be applied within the relevant method.
What needs to be verified?
The meter, electrodes and leads together
ANSI/ESD STM97.1-2025 recommends verifying the entire measurement setup before measurements are taken, including the meter, resistance measurement electrodes and test leads. Its product qualification procedure refers this verification to Annex A (section 6.1).
The standard separately recommends using a calibrated meter (section 5.1). Calibration addresses the meter; the complete-setup checks also include the electrodes and leads.
STM97.1-2025 Annex A: verifying the meter and complete setup
Recommendations and required pass limits
Annex A is normative. The annex says its verification steps should be performed. The pass limits within A.2 and A.3 are written as requirements. Test leads must remain uncoiled during verification.
A.1: check the meter against known resistors
- Select at least two known resistors. At a minimum, use one between 1.0 × 10³ Ω and 1.0 × 10⁵ Ω and another between 1.0 × 10⁷ Ω and 1.0 × 10¹⁰ Ω, each with a tolerance of ±5%.
- Connect the meter to the resistor, or to a resistor decade box, using an appropriate connection method. Keep the leads uncoiled.
- Set the test voltage to 10 V for a resistor below 1.0 × 10⁶ Ω and to 100 V for a resistor above 1.0 × 10⁶ Ω.
- Apply the voltage and record the resistance after the measurement stabilizes, or after 5 seconds for a resistor below 1.0 × 10⁶ Ω or 15 seconds for a resistor at or above 1.0 × 10⁶ Ω.
- If the measured resistance differs from the expected nominal value by more than 10%, send the meter for calibration or repair.
Surfaces used for the complete-setup checks
The lower- and upper-limit checks use two different surfaces defined in the standard:
- Metal plate: a flat metal surface, such as stainless steel, thick enough to support the specimen’s weight without becoming distorted (section 5.4).
- Specimen support surface: a flat surface with surface resistivity greater than 1.0 × 10¹¹ Ω/square under ASTM D257, or surface resistance greater than 1.0 × 10¹⁰ Ω under ANSI/ESD STM11.11 (section 5.5).
The specimen support surface must be measured under the same humidity conditions in which the material will be tested.
A.2 and A.3: check the complete setup at its lower and upper limits
| Check | A.2: lower limit | A.3: upper limit |
|---|---|---|
| Test surface | Metal plate defined in section 5.4 | Specimen support surface defined in section 5.5 |
| Electrode placement | Both electrodes on the plate, without touching each other | Both electrodes on the support surface, without touching each other |
| Connections | One meter lead connected to each electrode | One meter lead connected to each electrode |
| Test voltage | 10 V | 100 V |
| When to record | After stabilization or after 5 seconds | After stabilization or after 15 seconds |
| Pass limit | Below 1.0 × 10³ Ω | Above 1.0 × 10¹⁰ Ω |
What to check when a limit test fails
If the A.2 reading is above 1.0 × 10³ Ω:
- Clean the resistance measurement electrodes.
- Verify continuity of both measurement leads.
- Verify that the meter can measure 1.0 × 10³ Ω or less.
If the A.3 reading is below 1.0 × 10¹⁰ Ω:
- Verify that the electrodes and leads are not touching each other.
- Verify that the meter can measure 1.0 × 10¹⁰ Ω or more.
If the problem persists, repair or replace the measurement equipment.
Readings exactly at the limits
Neither pass limit includes equality. A reading of exactly 1.0 × 10³ Ω does not pass A.2, and a reading of exactly 1.0 × 10¹⁰ Ω does not pass A.3.
The printed corrective steps address readings above the A.2 limit and below the A.3 limit. The standard does not provide a separate corrective step for a reading exactly at either boundary.
Craftsman Concrete recommends resolving any failed setup check before using the equipment for project testing, including a result exactly at either limit.
How the lower-limit result affects subsequent measurements
STM97.1-2025 notes that measurements may be limited in accuracy below 1.0 × 10³ Ω. It also states that the lowest measurement value is limited to the value obtained in Annex A.2 (section 1.2). See the measurement uncertainty guide for calculations and reporting.
TR53-01-22 Annex G: checking the apparatus against known resistors
Select reference values for the required range
The informative Annex G of ESD TR53-01-22 describes verification of the apparatus over a range extending at least one order of magnitude below the lowest required value and one order of magnitude above the highest required value.
The known resistance values are selected by the user according to the control items being verified. TR53 gives 1.0 × 10⁵ Ω to 1.0 × 10¹⁰ Ω as an example range, with reference-resistor tolerance no greater than ±10%.
That range is an example, not a universal requirement. The reference tolerance also differs from the ±5% specified in STM97.1-2025 Annex A.1.
Perform the Annex G resistor check
- Select a known resistance value from the user-defined set.
- Connect the apparatus’s negative terminal to one resistor lead and its positive terminal to the other.
- For a resistance below 1.0 × 10⁶ Ω, apply 10 V and wait 5 seconds or until the apparatus stabilizes, then observe the result.
- For a resistance at or above 1.0 × 10⁶ Ω, apply 100 V and wait 15 seconds or until the apparatus stabilizes, then observe the result.
- The apparatus passes when the reading is within 10% of the known resistance value.
Troubleshooting footwear/flooring measurements under TR53
Check leads, contacts and measurement capability
The footwear/flooring troubleshooting procedure in ESD TR53-01-22 follows four steps (section 7.2.3.3):
- Confirm that the test leads are not loose, broken or disconnected.
- Examine the electrodes for contamination. Clean them according to the manufacturer’s recommendations and allow adequate drying time before retesting.
- Using the appropriate leads, verify that the apparatus can measure resistance values above and below the expected measurement range.
- Using the apparatus and appropriate leads, verify that the electrodes can measure resistance values above and below the expected range.
Frequently Asked Questions
Craftsman checks the meter against known resistors and verifies the assembled meter, electrodes and leads using the procedure applicable to the project. Equipment that fails verification is addressed before testing proceeds. These checks apply to testing flooring installed by Craftsman or other contractors.
No. ANSI/ESD STM97.1-2025 recommends both a calibrated meter and verification of the complete setup before measurements. The Annex A checks include the electrodes and leads as well as the meter.
No. STM97.1-2025 requires an A.2 result below 1.0 × 10³ Ω and an A.3 result above 1.0 × 10¹⁰ Ω. A result equal to either boundary does not pass. Craftsman recommends resolving the failed check before using the setup for project testing.
No. ANSI/ESD STM97.1-2025 Annex A.1 specifies reference resistors with ±5% tolerance. ESD TR53-01-22 Annex G uses user-defined known resistance values with tolerance no greater than ±10%.
The apparatus should be checked at least one order of magnitude below the lowest required value and one order of magnitude above the highest required value. The selected values depend on the control items being verified. Under the Annex G procedure, the reading must be within 10% of the known resistance value to pass.