ASTM E493/E493M-11(2017)

1.1 This practice2 covers procedures for testing devices that are sealed prior to testing, such as semiconductors, hermetically enclosed relays, pyrotechnic devices, etc., for leakage through the walls of the enclosure. They may be used with various degrees of sensitivity (depending on the internal volume, the strength of the enclosure, the time available for preparation of test, and on the sorption characteristics of the enclosure material for helium). In general practice the sensitivity limits are from 10⁻¹⁰ to 10⁻⁶ Pa m³/s (10⁻⁹ standard cm³/s to 10⁻⁵ standard cm³/s at 0°C) for helium, although these limits may be exceeded by several decades in either direction in some circumstances.