Intercomparison of the effective areas of a pneumatic piston gauge determined by different techniques

A variety of primary measurement techniques is available for the measurement of pressure to 1 MPa and above. To ascertain the systematic uncertainty, it is best to perform direct intercomparisons of primary instruments. When direct intercomparison is not possible, one can use a highly stable, reproducible transfer artifact such as a simple piston gauge. Such intercomparisons are described, utilizing a piston gauge calibrated by a mercury manometer (with 0.1 MPa full-scale pressure), four large diameter 'dimensional' piston gauges from two different manufacturers (all with 1 MPa full-scale pressure), and a controlled clearance piston gauge (with 7 MPa full-scale pressure).