Proficiency test for effective area determination of a pneumatic pressure balance in Mexico

A pneumatic pressure proficiency test for effective area determination of a pressure balance was performed among 4 accredited calibration laboratories in Mexico. CENAM provided the reference values (making initial and final calibrations) and was the pilot laboratory. The Mexican Accreditation Entity (ema) collaborated. The participants calibrated, by cross floating, a Wika pressure balance model CPB 5000 with accuracy class 0.015% of the reading in the range 0.7-7 MPa. The calibration pressures were 0.7, 1.4, 2.1 3.5, 4.2, 5.6 and 7.0 MPa. For A0 and Ae, the normalized error equation was used to compare the results of the laboratories with CENAM's reference values. The results obtained were satisfactory (En did not exceed the compatibility limit, −1 ⩽ En ⩽ 1).