Question has been raised again about N2 purge panel for silane not being able to deliver high pressure to test pigtail after bottle changes. I provided the client my take on CGA that calls for purge panel in Section 8, to be used for providing inert gas source and that it no where references this as the panel pressure test source. However, they are asking how the pigtail connection is tested after bottle swaps.
There are two common practices for testing the cylinder connection after the cylinder change and it really depends on the purge gas being used.
Critical Systems Inc process is to use a 10%Helium/Balance Argon for purge gas and performed an outboard leak check on the cylinder fitting after the bottle change using a handheld detector specifically targeting Helium(0-3PPM range). We also used a handheld Hydride Analyzer (0-5PPM range for SIH4) to leak test the cylinder connection after the cylinder was turned on.
We have been to a few other facilities that use a Nitrogen, typically they will perform an inboard helium leak test after the cylinder change.
Air Products Standard Operating Procedures require an Inboard Helium leak test after Cylinder Change and a Gas Specific test on the Cylinder Valve after the cylinder is turned on for all Category 3 gases.