A resistance meter must meet the requirements of the test method being used. Measuring range, test voltage, voltage tolerance and performance under load can differ between methods. A calibration certificate alone does not establish that the instrument can perform the required test.
Craftsman Concrete performs resistance testing for flooring systems installed by Craftsman and other contractors, using equipment selected for the applicable testing requirements. Reviewing meter capability helps the facility’s ESD program team determine whether existing results need further investigation or additional testing.
The comparisons below distinguish the equipment requirements for floor qualification, installed-floor acceptance, footwear/flooring system testing and routine compliance verification.
Understanding the meter specifications
Measuring range
The measuring range identifies the resistance values the instrument can measure. The required range depends on the applicable method and the purpose of the test.
A meter that displays a resistance value does not necessarily meet the method’s requirements for measuring that value.
Open circuit and under load
An open circuit voltage is the voltage at the instrument’s output without a connected measurement load.
An under-load requirement specifies the voltage the instrument must maintain while supplying current through the resistance being measured. An instrument’s open circuit voltage alone does not establish its voltage under load.
Voltage tolerance and resistance accuracy
Voltage tolerance describes the permitted difference between the specified test voltage and the voltage the instrument supplies. Resistance accuracy describes the instrument’s accuracy when measuring resistance.
These are separate specifications. A voltage tolerance of ±5%, for example, is not a statement that the resistance measurement has ±5% accuracy.
ANSI/ESD STM7.1-2020: product qualification and acceptance testing meters
Product qualification meter
For product qualification, ANSI/ESD STM7.1-2020 requires a meter capable of measuring from 1.0 × 10³ Ω to 1.0 × 10¹⁰ Ω. Its voltage requirements depend on the resistance being measured:
| Resistance being measured | Required test voltage |
|---|---|
| From 1.0 × 10³ Ω to below 1.0 × 10⁴ Ω | 10 V ±5%, open circuit or under load |
| From 1.0 × 10⁴ Ω to below 1.0 × 10⁶ Ω | 10 V ±5%, under load |
| At or above 1.0 × 10⁶ Ω | 100 V ±5%, under load |
These are the product qualification meter requirements in section 5.1.1.
Acceptance testing meter
For acceptance testing, ANSI/ESD STM7.1-2020 specifies an open circuit voltage of:
- 10 V ±5% for measurements below 1.0 × 10⁶ Ω.
- 100 V ±5% for measurements at or above 1.0 × 10⁶ Ω.
Either the product qualification meter specified in section 5.1.1 or the acceptance testing meter specified in section 5.1.2 may be used to measure installed or applied flooring systems for acceptance testing.
Section 5.1.2 specifies the acceptance meter’s test voltages but does not state a separate overall resistance range. If results are disputed, STM7.1-2020 requires a meter meeting the product qualification requirements to resolve the disagreement.
ANSI/ESD STM97.1-2025: person-footwear-floor resistance testing
Measuring range
ANSI/ESD STM97.1-2025 requires a meter with a resistance range extending from 1.0 × 10³ Ω or lower to 1.0 × 10¹⁰ Ω or higher.
Test voltages
The required voltage depends on the resistance being measured:
| Resistance being measured | Required test voltage |
|---|---|
| Below 1.0 × 10⁴ Ω | 10 V ±5%, open circuit or under load |
| From 1.0 × 10⁴ Ω to below 1.0 × 10⁶ Ω | 10 V ±5%, under load |
| At or above 1.0 × 10⁶ Ω | 100 V ±5%, under load |
ESD TR53-01-22: resistance measurement apparatus
Test voltages
ESD TR53-01-22, an ESD Association technical report, specifies:
- 10 V ±5% for measurements or pass/fail indications below 1.0 × 10⁶ Ω.
- 100 V ±5% for measurements at or above 1.0 × 10⁶ Ω.
The specified voltage tolerance applies both when the apparatus is open circuit and when it is under load.
Recommended measuring range
TR53-01-22 recommends apparatus capable of measuring at least one order of magnitude below the lowest required value and one order of magnitude above the highest required value.
This means a range extending to one-tenth of the lowest required value and ten times the highest required value.
ASTM F150-25: resistance accuracy and open circuit voltages
Resistance measurement accuracy
ASTM F150-25 specifies a self-contained resistance meter, such as a megohm meter, or power supplies and current meters configured for resistance measurement with ±10% accuracy.
Open circuit voltages
The apparatus must provide open circuit voltages of:
- 10 VDC ±10%.
- 100 VDC ±10%.
ANSI/ESD S20.20-2021: capability for the compliance verification plan
Match the equipment to the required measurements
ANSI/ESD S20.20-2021 requires the selected test equipment to be capable of making the measurements defined in the facility’s compliance verification plan.
The standard also explains that calibration certificates do not ensure that equipment can perform the required compliance verification measurements. Equipment selection therefore requires checking the applicable measurement requirements as well as the calibration documentation.
Frequently Asked Questions
Yes. Craftsman Concrete performs resistance testing for flooring systems installed by Craftsman and other contractors, using equipment selected for the applicable test method and facility requirements. Craftsman also reviews meter capability and test documentation to help determine whether further investigation or testing may be needed.
No. Open circuit voltage is measured without a connected measurement load. An under-load requirement concerns the voltage supplied while current flows through the resistance being measured. Where the method specifies voltage under load, an open circuit specification alone does not establish compliance.
ANSI/ESD STM97.1-2025 requires 100 V ±5% under load for measurements at or above 1.0 × 10⁶ Ω. The 10 V under-load range ends below that boundary.
Yes. ANSI/ESD STM7.1-2020 permits either its product qualification meter or its acceptance testing meter to measure installed or applied flooring systems for acceptance testing (sections 5.1.1 and 5.1.2). A meter meeting the product qualification requirements is required to resolve disputed results.
No. ANSI/ESD S20.20-2021 requires equipment capable of making the measurements defined in the compliance verification plan. A calibration certificate alone does not establish that the instrument has the required measuring range, test voltages or other capabilities.