This document analyses the impact of changes to : as regards to the following:
— precleaner efficiency;
— elimination of two secondary element tests (collapse and blocking);
— revisions to the recommended ISO dust injector (Table 1);
— validation of the absolute filter weighing method; and
— inclusion of Annex H, "Penetration sensitivity".
These changes refine the precleaner efficiency calculation, eliminate seldom used tests, which were lengthy or costly, further clarify dust injector use, the validation of the absolute material, and the precision of the efficiency measurement.