Calibration are performed using Thunder Scientific Model Number 2500 Humidity Generator, this self contained system capable of producing atmospheres of known humidities using the fundamental, NIST proven, "two-pressure" principle. This system is capable of continuously supplying accurately known humidity values for instrument calibration, evaluation, and verification, as well as for environmental testing.
Using this device, we are able to generate very precise humidity values from 10% to 95%RH at temperatures from 0 to 70°C, with system uncertainties of 0.70%RH (k=2).
The client’s instrument is subjected to a three (humidity) point calibration at a specified temperature, typically 20, 50 & 80%RH with a minimum “soak”, or equilibration time of two hours at each value, with the sensor(s) exposed to a moving air stream of controlled humidity and temperature at a velocity of 20 liters per minute. These ‘As Found’ indications of the instrument are evaluated for compliance with required tolerances. If needed, and appropriate for the instrument, adjustments are performed to optimize the instrument’s indications and the test is repeated to determine ‘As Left’ indications.
Testing may be varied in accordance with the client’s requirements and fewer or more test points may be selected.