I'm not seeing anything that directly addresses this joint (two flanges bolted together with a gasket). There is a list of prohibited joints which this doesn't seem to fit into:
5.1.10.10 Prohibited Joints. The following joints shall be
prohibited throughout medical gas and vacuum distribution
pipeline systems:
(1) Flared and compression-type connections, including
connections to station outlets and inlets, alarm devices,
and other components
(2) Other straight-threaded connections, including unions
(3) Pipe-crimping tools used to permanently stop the flow of
medical gas and vacuum piping
(4) Removable and nonremovable push-fit fittings that
employ a quick assembly push fit connector
Then there is a statement about special fittings:
5.1.10.9 Special Fittings.
5.1.10.9.1 Listed or approved metallic gas tube fittings that,
when made up, provide a permanent joint having the mechanical,
thermal, and sealing integrity of a brazed joint shall be
permitted to be used.
It doesn't really meet that because it isn't permanent.
Here is my question, since this is vacuum why didn't they just put a butterfly valve in between those two flanges and save the cost of the ball valve on the other end?
