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Uncertainty Budget for the NIST Hybrid Humidity Generator



Christopher W. Meyer, W Wyatt Miller, Dean C. Ripple, Gregory E. Scace


We provide here a detailed uncertainty budget for the new Hybrid Humidity Generator (HHG) that has been constructed at the National Institute of Standards and Technology (NIST). The HHG generates frost/dew points from –70 °C to +85 °C using calibration gas flows up to 150 L/min. For frost/dew points above –15 °C, the two-pressure method is employed, and for frost points at or below –15 °C, the divided-flow method is used (hence the name “hybrid”). The total expanded (k=2) uncertainty is estimated for HHG generation of the following quantities: frost/dew point, mole fraction, and relative humidity. The total uncertainty is estimated separately for the two-pressure and divided-flow methods.
International Journal of Thermophysics


humidity, generator, standards, saturator, calibration, hygrometer, uncertainty, water vapor
Created December 1, 2012, Updated November 10, 2018