This International Standard specifies an apparatus and a method for the laboratory wet disintegration of pulp. It specifies the disintegration apparatus and in some cases the disintegration procedures required in a number of other International Standards dealing with pulps. In principle, this method is applicable to most kinds of pulp, including recycled fibres. It is not suitable for some very long-fibred pulps such as those from cotton and similar materials; it is not recommended for the removal of latency from mechanical pulps.