An Uncertainty Analysis of a NIST Hydrocarbon Liquid Flow Calibration Facility Available to Purchase

This paper presents the uncertainty characterization of NIST’s new hydrocarbon liquid flow calibrator (HLFC). This facility uses a passive piston prover technique where fluid is driven by pumps while the measuring piston is passively stroked through the calibration interval. This facility is typically operated using MIL-C-7024C fluid (also known as Stoddard solvent – a surrogate liquid for JP-4 and JP-5 jet fuels), but using a variety of other fluids offers a wider range of measurements. The range of flows for this facility is 0.19 to 5.7 liters per minute – lpm (0.05 to 1.5 gallons per minute – gpm). Over this range, the expanded uncertainty claim for this facility is ±0.01%, at 95% confidence level. The uncertainty of a dual-turbine meter tested in the system is also reported. In addition, NIST is working to incorporate additional piston provers so that the flow for hydrocarbon liquids calibration service will reach 760 lpm (200 gpm).