GB/T 1548-2016 "Pulp—Determination of limiting viscosity number in cupriethylenediamine (CED) solution" specifies the method for determining the limiting viscosity number of pulp in cupriethylenediamine (CED) solution. It is identical to ISO 5351:2010 with modifications. By measuring the viscosity ratio of pulp in CED solutions of different concentrations and extrapolating to obtain the limiting viscosity number, this standard reflects the average degree of polymerization and fiber strength of the pulp. It specifies the preparation of reagents, calibration of instruments, sample preparation, and testing procedures. The sample must be tested for oven-dry solids content, and the viscometer must be calibrated. Calculations are performed according to standardized formulas, and the test report must include relevant parameters to ensure the reliability and comparability of results.