ISO/FDIS 25549:2026

This document specifies a method for evaluating the shear viscosity of fine bubble dispersions. Three measurement methods are adopted, namely parallel-plate rotational shear, cone-plate rotational shear and coaxial-cylinder rotational shear. The average effective shear viscosity of the fine bubble dispersion is calculated from the measured stress (or strain rate) and the strain rate (or stress) applied to the sample. These measurement methods are readily accessible in commercially available instruments.