Last year, upwards of 25 trillion cubic feet of natural gas were delivered to customers in the United States, and when it changed hands, nearly every cubic foot was measured using gas flowmeters. The accuracy of those meters has enormous commercial importance, and NIST has a long-standing research program to improve flowmeter calibration. The scope of that program has now literally expanded in the form of a newly arrived test bed known informally as the Big Blue Ball.
