Applicability of ASME B31.9 to compressed air

[nbmcrae]

I am working on a compressed air system for a manufacturing plant. It is to operate at 110psi (relief at 137 psi), 120F max, and piping size up to 4". This seems to all fall very nicely within the B31.9 standard for building services piping. I am intending to use TransAir aluminum piping and connectors (ASME B31.1 and B31.3 certified).

The question I have is related to connecting B31.9 piping to pressure vessels. This system will have a desiccant dryer and receiving vessel also operating at 110psi and up to 120F. Is it acceptable to connect B31.9 piping to a pressure vessel? Or do I have to use B31.3 because it connects to a pressure vessel?

Thanks.

 

[JohnGP]

As I understand it, ASME B31.9 doesn't have any limitations with regard to connection of compressed air piping to pressure vessels.
Cheers,
John

 

[gr2vessels]

nbmcrae,
The pressure vessel code jurisdiction ends at the nozzle flange face;- what are you connecting to it is your responsibility and is not regulated by the pressure vessel code. You may connect any ASME B31 including B31.9 pipe to the vessel, provided the system maximum operating pressure/temperature (relief set at 137 psi at 120 deg F) does not exceed the pressure vessel limitations.
Also, on your selection you have to stick to the limitations of B31.9 and you seem to do well in that department. Perhaps a bit of attention to the aluminium tubing connections, they're nice and cool, but hot on price and repair if needed. Surely, the competiton will turn green seeing your grin...
Cheers,
gr2vessels

 

[nbmcrae]

Thanks for the responses. That was my understanding of the codes, but our pressure vessel authority in Saskatchewan does not like the B31.9 code and they are trying to tell me that I have to design to B31.3 for any piping system connected to a pressure vessel. I will continue to discuss this with them.

 

[XL83NL]

Have you checked w/ NBIC NB-370 for jurisdictional requirements?

 

[MJCronin]

I have designed and specified many compressed air systems for industrial applications.

They have all been in accordance with ASME B31.3.

I suggest that you review the information in the first part of B31.3 that refers to applicability.

MJCronin
Sr. Process Engineer

 

[curtis2004]

nbmcrae,

Did Saskatchewan vessel authority give you specific reason why your piping designed to B31.9 not good enough? "Does not like" is not good reason.

Another alternative: What would be a different if you design your compressed air system to B31.1 instead of B31.9?

Curtis