ISO 23581:2020

This document specifies a procedure for the determination of kinematic viscosity (ν) at 40 °C in the range from 2 mm2/s to 6 mm2/s by calculation from dynamic viscosity (η) and density (ρ) of middle distillate fuels, fatty acid methyl ester fuels (FAME) and mixtures of these using the Stabinger type viscometer.
The result obtained using the procedure described in this document depends on the rheological behaviour of the sample. This document is predominantly applicable to liquids whose shear stress and shear rate are proportional (Newtonian flow behaviour). However, if the viscosity changes significantly with the shear rate, comparison with other measuring methods is only permissible at similar shear rates.