Full Description ADOPTED_FROM:EN ISO 1628-1:2021 This document defines the general conditions for the determination of the reduced viscosity, intrinsic viscosity and K‑value of organic polymers in dilute solution. It defines the standard parameters that are applied to viscosity measurement. This document is used to develop standards for measuring the viscosities in solution of individual types of polymer. It is also used to measure and report the viscosities of polymers in solution for which no separate standards exist.