ASME B16.5 CL600 Flange Rating

[pmover]

The three of us got stumped yesterday on this matter and we've been investigating when we can. i was not successful with search in this forum even though i believe it has been asked before.

Essential criteria:
Piping Code, ASME B31.8
ASME B16.5 12-inch, RFWN Std Flange, A105 Material
30° - 200°F Temp Range
Piping MAOP = 1050-psig
Pipe Material, 12-inch, X52, 0.375wt

ASME B16.5 Group 1.1 lists this flange rating at 1480-psi. Although the flange thickness at weld does not meet the P=2StFET/D in B31.8 for an Class 4 location (compressor station). So, we think a higher strength flange material is needed per MSS SP-44.

ASME B16.5, paragraph 2.7 (I think as i do not have reference with me) states something about Bmax. Please clarify where/when this applies.
Can this flange be utilized and comply with applicable codes? I'm requesting clarification/direction with references in B16.5, MSS SP-44, or otherwise.

thanks!
-pmover

 

[BigInch]

It would need to be 1/2 inch wall for DF 0.4 and that would need a transition piece to weld to the std wall pipe. I would use a higher strength flange; Y52; same as the pipe, as a high strength flange as it would probably be made with at least 52 ksi material anyway and that also allows a wall thicknesses match up w/o any further troubles.

What would you be doing, if you knew that you could not fail?

 

[StevenHPerry]

I don't have B31.8 in front of me, but both B31.1 and B31.3 allow for "listed components with ratings" or something like that. For valves and flanges to B16.5 or B16.34, that's enough for me.

B31.3-302.2.1 and 303

- Steve Perry

http://www.linkedin.com/in/stevenhperry

This post is designed to provide accurate and authoritative information in regard to the subject matter covered. It is offered with the understanding that the author is not engaged in rendering engineering or other professional service. If you need help, get help, and PAY FOR IT.

 

[BigInch]

Steven, the above flange is rated at 1480 psig at normal temperatures based on a design factor of 0.72 Therefore it would be perfectly fine to use it at 1480 pressure in ASME B31.4 service and with B31.8 service in Class 1 location; also a DF 0.72, but NOT class 4, as that class location uses a DF of 0.4 NOT OK!

What would you be doing, if you knew that you could not fail?

 

[pmover]

Does the p=2StFET/D apply to flange rating or is the b16.5 flange rating sufficient? If b16.5 flange rating complys, then a transition piece is not needed (?). FYI, a higher class material for flange was purchased, so no problem. But we found previously installed a105 std flanges on x52 pipe. Hence, the ? & investigation.

-pmover