The TAPPI T 254 standard specifies a method for determining the dispersion viscosity of pulp copper ethylenediamine (CED) by falling ball method. This method evaluates the coalescence and cellulose properties of pulp by dissolving pulp in copper ethylenediamine solution and using a falling ball viscometer to measure the viscosity of the solution. Copper ethylenediamine solution is a commonly used cellulosic solvent, which can reflect the chemical structure and processing performance of pulp. This standard is suitable for bleached chemical pulp and Miscellaneous pulp soluble in copper ethylenediamine solution. It is widely used in the paper industry and provides an important basis for pulp quality control and process optimization.