NPL has completed the accreditation of its newly developed capability for calibration of dew point hygrometers at above-atmospheric pressures.

(Image courtesy of iStockphoto)

This was added to the NPL UKAS schedule in July 2011. Dew point calibrations at atmospheric pressure are widely available, but NPL is only one of two NMIs worldwide providing these calibrations at elevated pressures, and no commercial or industrial accredited labs have this capability.

Humidity in air at pressures near 1 MPa (10 atm) is important for compressors, air dryers, and air supply systems generally. Applications of humidity measurements in a wider range of gases and pressures include: fuel gas, nuclear and electricity generation and supply, and high purity process gases.

Calibration at the pressure of use is important because humidity sensor performance (thermal and sorptive behaviour) is typically affected by the pressure of the background gas.

Find out more about NPL's work on Temperature & Humidity

Watch: 'Water, water, everywhere, nor any drop to drink' - a whistle-stop lecture on Humidity Measurement

For more information, please contact Stephanie Bell