This part of ISO 16232 defines methods for determining the size distribution of particulate contaminants extracted from automotive components using techniques described in ISO 16232-3, ISO 16232-4 and ISO 16232-5, using automatic light extinction particle counter instruments (APC). It only applies to the analysis of the whole volume of extraction liquid. The size range of particles that can be measured by this technique is limited to <= 70 μm(c), because of the method of calibration used (ISO 11171). However, the calibration can be extended to other sizes provided that it is agreed and included in the Inspection Document. This technique is only applicable to measuring particles contained in clear, single phase liquids.