Each test meter is matched to the facility best suited to provide optimum accuracy. Six loops utilize a primary standard, the gravimetric method wherein water flowing through the primary element is diverted into a tank for a measured time period and weighed. Test methods meet ASME/ANSI MFC-9M-1988 "Measurement of Liquid Flow in Closed Conduits by Weighing Method" and International Organization for Standardization Code ISO 4185-1980 "Measurement of Liquid Flow in Closed Conduits - Weighing Method."
A standard calibration includes 12 test points covering a range of Reynolds number from the maximum attainable to about 10% of the maximum. External specifications may supplement this test program to include additional test points or modify the test range for specific applications. The influence of specific upstream piping on performance may be evaluated by reproducing field upstream piping geometry, including elbows, tees, or flow straighteners.
Virtually all flow meters used in nuclear power propulsion systems for the U.S. Navy have been tested at Alden.