IP 341 : 1982

Provides method for calibrating, validating and checking process viscosity analysers which measure the viscosity of a liquid petroleum oil by measuring the pressure difference produced across a capillary tube by a constant flow rate of the liquid. The methods cover: calibration, which used reference samples to set up the analyser zero and span; validation, which is an accurate spot check in normal service on the process stream; supervisory checking, which is a routine procedure using either reference samples or the process stream and control charts, to monitor analyser performance. The methods are not intended to cover automatic or semi automatic instruments used mainly in laboratories to analyse discrete samples, though some of the principles and techniques described may apply to such instruments.