For STM7.1-2020 laboratory qualification, conditioning means holding flooring samples at the specified temperature and humidity before testing. Samples are conditioned for at least 72 hours at low humidity and tested there, then conditioned for at least 72 hours at moderate humidity and tested again. Both resistance-to-groundable-point and point-to-point measurements are required at each stage.
ANSI/ESD STM7.1-2020 is an ESD Association standard test method (STM) for electrostatic discharge (ESD) flooring, approved by the American National Standards Institute (ANSI).
Conditioning environments
Section 6.1.1.1 specifies the low-humidity stage, and Section 6.1.1.2 specifies the moderate-humidity stage.
| Stage | Relative humidity | Temperature | Minimum conditioning |
|---|---|---|---|
| Low humidity, first | 12% ± 3% | 23°C ± 3°C | 72 hours |
| Moderate humidity, second | 50% ± 5% | 23°C ± 3°C | 72 hours |
Order of the qualification stages
Section 6.1.5 of STM7.1-2020 prescribes the sequence.
Low humidity first
After cleaning, the flooring samples are placed in the low-humidity environment for at least 72 hours. Both qualification resistance tests, resistance to groundable point (Section 6.1.6) and point-to-point (Section 6.1.7), are then performed in the conditioning environment.
Moderate humidity second
Once the low-humidity testing is complete, the flooring samples are placed in the moderate-humidity environment for at least 72 hours. Both tests are then repeated in the conditioning environment.
Frequently Asked Questions
ANSI/ESD STM7.1-2020 uses low humidity of 12% ± 3% relative humidity and moderate humidity of 50% ± 5% relative humidity, both at 23°C ± 3°C. Flooring samples are preconditioned for at least 72 hours in each environment.
After cleaning, flooring samples are conditioned for at least 72 hours at low humidity and both qualification tests are performed there. Only after low-humidity testing is complete are the samples conditioned for at least 72 hours at moderate humidity and both tests repeated there.
Yes. The resistance-to-groundable-point test in Section 6.1.6 and the point-to-point test in Section 6.1.7 are performed inside the low-humidity conditioning environment and repeated inside the moderate-humidity conditioning environment after the prescribed conditioning.