Page 20 - Valve Selection Handbook

Fundamentals

Figure 2-1. Proposed Zero Gas Leakage Criterion. (Courtesy of Jet Propulsion
Laboratory, California Institute of Technology. Reproduced from JPL Technical Report
No. 32-926.)

2 4
down to 1 X 10" or 1 X 10" sees (standard cubic centimeters per sec-
3
ond), depending on the skill of the operator.
Lower leakage rates in the atom class may be detected by using a
search gas in conjunction with a search-gas detector.
Specifications for proving leakage tightness may be found in valve
standards or in the separate standards listed in Appendix C. A description
of leakage testing methods for the atom class may be found in BS 3636.