This Standard specifies a method for determining the viscosity number and K-value of a PVC-resin derived from a pipe, fitting or compound. In this standard, only the method for isolation of the PVC-resin is detailed, while for the determination of viscosity number reference is made to ISO 174. An equation for the calculation of K-value (according to Fikentscher) from viscosity data is given (K-values corresponding to a series of viscosity numbers for PVC resin are given for information in annex A). The presence of other polymers may invalidate the method (see clause 3).