The ISO 5351:2010 standard specifies a method for determining the limit viscosity value of pulps in a copper-ethylenediamine (CED) solution. This method is mainly applicable to bleached chemical pulps, but also to pulps that are completely dissolved in a CED solution by Miscellaneous. The standard estimates the degree of coalescence and degradation of their cellulose by measuring the viscosity of the pulp at a specific shear rate. It is important to note that the results measured by this method can be used to assess cellulose degradation during pulping or bleaching, but the technical validity of the results may be limited for pulps with higher lignin content. This standard provides an important tool for pulp quality control and performance evaluation.