Year
1989
Abstract
A revised volume calibration standard, ANSI N15.19-1988, \"Volume Calibration Techniques for Nuclear Materials Control,\" has recently been adopted. The revised standard incorporates a data standardization model that is directly applicable to tanks equipped with differential pressure measurement systems for determining liquid height. When measurements differ because of departures from reference temperature, the model specifies procedures for standardizing both calibration data and in-tank liquid height measurements. The model also provides for the standardization of liquid height measurements that vary because of 1) differences in flow resistance in pneumatic lines, 2) differences in the density of air in the vapor head and the reference pressure lines, and 3) the density of gas in pneumatic lines. The use of diagnostic plots and graphical techniques is emphasized in the standard and a practical method for estimating volume uncertainties when measurement errors are dominated by run-to-run differences is also provided.