The USNWG works to promote, encourage, and participate in the establishment of a comprehensive set of legal metrology standards for commercial measurement of hydrogen for vehicle and other refueling applications including (1) device design, accuracy, installation, and use requirements; (2) method of sale requirements; (3) test procedures; and (4) fuel quality standards. The ultimate goal is that these standards will ensure the accuracy of measurements, enhance consumer protection, foster fair competition, and facilitate economic growth and trade.
The USNWG works through in-person meetings, conference calls, and email. The USNWG is currently accomplishing its goals through two subcommittees; one will work to simultaneously develop equipment standards and test procedures and a second will develop fuel specification requirements.
The 101st National Conference on Weights and Measures (NCWM) Annual Meeting met July 23-28, 2016 in Denver, CO. Two proposals to modify NIST Handbook 44 Section 3.39 Hydrogen Gas-Measuring Devices-Tentative Code on the NCWM Specifications and Tolerances (S&T) Committee agenda were adopted. The hydrogen gas devices code will be modified to recognize that required information on sealable metrological parameters may also be made available in an electronic format on Category 3 devices. A modified version of S&T Item 339-2 widens the current hydrogen code accuracy tolerances of 1.5 % acceptance to 5.0 % and the current maintenance tolerance of 2.0 % to 7.0 %. The code will have only one accuracy class designated as Accuracy Class 7.0. The adopted changes to the hydrogen code will appear in the 2017 edition of NIST Handbook 44.