NIST Evaluating Master Meters

Several years ago, the NPGA’s Technology, Standards and Safety Committee (TS&S) developed a proposal to change to the requirements in Handbook 44 Specifications and Tolerances for Weighing and Measuring Devices. Handbook 44 contains the requirements that are adopted and used throughout the U.S. to verify the accuracy of meters and scales used in the propane industry.

The TS&S Committee proposed that a “master meter” be used as an alternative to the volumetric proving device that is used to verify the accuracy of propane meters. The use of a master meter would provide more flexibility and the potential to more efficiently and cost effectively certify meters in use in the propane industry.

Although the concept was viewed favorably, the National Conference on Weights and Measures would not approve the proposal until adequate verification of the performance of master meters in the field was provided. Efforts to undertake field trials are now underway and NPGA is participating with a group of weights and measures officials and others to get the field trial program up and running.

One of the hurdles that must be cleared is the need to develop a computational model of the metering process in order to develop a standardized procedure for use in the field. This can be a complex problem because propane may tend to vaporize as it moves through the pumping system and meter due to pressure drops that can occur in the system. To this end, NIST has requested assistance in developing this model and NPGA has volunteered to request assistance from its manufacturing members who may have already addressed this computational fluid dynamics modeling problem. Please contact Bruce Swiecicki if you are willing to assist in developing this model.