IP 71: Section 1: Petroleum products - Transparent and opaque liquids - Determination of kinematic viscosity and calculation of dynamic viscosity

This document specifies Procedure A, using manual glass viscometers, and Procedure B, using glass capillary viscometers in an automated assembly, for the determination of the kinematic viscosity n of both transparent and opaque products. The scope includes liquid petroleum products, fatty acid methyl ester FAME, paraffinic diesel, hydrotreated vegetable oil HVO, gas to liquid GTL and biofuel diesel mixtures up to 50 percent FAME. The kinematic viscosity is determined by measuring the time for a volume of liquid to flow under gravity through a calibrated glass capillary viscometer. The dynamic viscosity h is obtained by multiplying the measured kinematic viscosity by the density r of the liquid. The range of kinematic viscosities covered in this test method is from 0.2 mm²/s to 300000 mm²/s over the temperature range minus 20 °C to plus 150 °C.

NOTE The result obtained from this document is dependent upon the behaviour of the sample and is intended for application to liquids for which primarily the shear stress and shear rates are proportional Newtonian flow behaviour. If, however, the viscosity varies significantly with the rate of shear, different results can be obtained from viscometers of different capillary diameters. The procedure and precision values for residual fuel oils, which under some conditions exhibit non Newtonian behaviour, have been included.