Environmental science and technical association (IEST) announced publication international standardizes technical committee a few days ago (ISO/TC) the first file of 142 work outs " the purifying device of air and other gas " . IEST released the ISO/DIS 21220 that is used at filterability to be able to check -- groovy and ventilated air particle filter.

Detailed description uses this draft international standards to determine the test program of the atomic inhaler function in common and ventilated product and test equipment. This file puts forward method of two kinds of tests, it is to be based on filter respectively initiative efficiency and place place use filter the efficiency of medium: Check filter to be in namely efficient filter of limits " accurate method " and in inferior efficiency limits " rough method " . Additional, this standard included a specification that add a page to filter the selection method of material, press falling computational method and course colander pressure fall.