ISO 5263-2:2004 specifies an apparatus and the procedures for the laboratory-wet disintegration of mechanical pulps that do not exhibit latency or pulps where latency has already been removed. This apparatus and procedure are required for preparation of the test portion in a number of other International Standards dealing with pulps.In principle, this method is applicable to all kind of mechanical pulps (i.e. mechanical, semi-chemical and chemo-mechanical pulps) that do not exhibit latency, including recovered fibres from mechanical pulps. It is not suitable for mechanical pulps exhibiting latency for which the disintegration procedure described in ISO 5263-3 shall be used.The procedure specified by ISO 5263-2:2004 should also be used to disintegrate all mechanical pulps to be measured for brightness.