This standard primarily specifies a method for determining the drainage performance of pulp suspensions using specific instruments. The core of the standard involves the use of a 200-mm diameter sheet former or a standard sheet-making device to simulate and measure the drainage process of pulp. Among the methods, the "drainage time method" refers to evaluating drainage performance by measuring the time required for the suspension to complete filtration under standardized conditions. This method is particularly suitable for various types of pulp, especially for measuring the water suspensions of mechanical pulp. In related fields, specialized instruments for assessing pulp drainage performance also include dynamic drainage analyzers that simulate the dynamic conditions of paper machines and pulp freeness testers (Schopper type) used to determine the degree of beating.