New Code in Yellow:
5.1.10.3.1* Positive pressure patient gas systems, medical support gas systems, vacuum systems, and WAGD systems constructed of hard-drawn seamless copper or stainless steel tubing shall have all turns, offsets, and other changes in direction made using fittings or techniques appropriate to any of the following acceptable joining methods:
(1) Brazing, as described in 5.1.10.4
(2) Welding, as described in 5.1.10.5
(3) Memory metal fittings, as described in 5.1.10.6
(4) Axially swaged, elastic preload fittings, as described in 5.1.10.7
(5) Threaded, as described in 5.1.10.8
(6) Flange, as described in 5.1.10.9.3
5.1.10.9.3 Flange Fittings.
Flange fittings that comply with the following shall be permitted only where required:
(1) Suitable for service at 2070 kPa (300 psig) or above and able to withstand temperatures of 538°C (1000°F)
They shall have seals with a not require extensions for brazing
be of brass or copper construction with an appropriate dielectric.
(2) Permitted only for vacuum and wagd systems.
(3) Limited to joining stainless tubing to copper tubing.
Reason for additional code:
Stainless is allowed to be used for Vacuum & WAGD distribution piping, however, no joining method exists that is both permitted by code and also practical. Typically, the stainless pipe sizes involved would be too large to braze it to copper tubing. Flanges are bolted, and therefore not "permanent" as required. Welding stainless to copper tubing isn't possible because same size stainless and copper tubing aren't really the same size.
Perhaps the code should permit flanges.
