scope:

This part of ISO 17491 specifies a method for assessing the resistance of a gas-tight suit to outward leakage of air through, for example, essential openings, fastenings, seams, interface areas between items, pores and any imperfections in the materials of construction. This test does not simulate penetration by gases in an inward direction. Although the danger to the wearer arises from leakage in an inward direction, this test method assesses the outward leakage of air after the gastight suit has been inflated so as to stretch the material of construction, thereby enabling the test method to be capable of detecting very small imperfections, e.g. holes, splits or tears.