HM 44. Guidelines for the development of uncertainty estimates for pipe prover calibrations (formerly PMP No. 12)

Overview:

This publication was reapproved in 2022.

All high accuracy flow meters require calibration to establish their optimum operating parameters and, in some cases, to take account of specific process conditions or measurement requirements. The uncertainty of any flow meter can only ever be as good as its last calibration, after which the performance of the meter may be affected by wear, damage or changes in process conditions.

This publication is a basic guide to the principles of traceability and uncertainty of prover calibration, suitable for operators in the field. It is designed to augment the procedures and experience of the established calibration companies and to add the estimation of uncertainty to the established certificates in a metrologically sound manner.

Guidance is provided for each of the calibration methods in common use in the oil industry. This is to augment the existing standards. Block diagrams are used to demonstrate suggested traceability for each method. The guidance for method, traceability and uncertainty outlines what the operator, calibration company and regulator should expect from prover calibration operations.