Forged Flange Modification

[jproj]

Hi All,

I have a question relating to a 900# RFLWN "Type V2" FVC forged flange (SA-182 F22 CL3 material) that is currently on a vessel in hydrogen & sour service (similar to the one pictured on page 11 here:

http://www.forgedvesselconn.com/catalog030199_2.pdf

). Is it possible (perhaps feasible is a better word) to remove the flange and buttweld the connecting pipe directly onto the nozzle neck? Aside from PWHT and any other NDE requirements, are there any other things that need to be considered for this type of modification?

Thanks in advance for everyone's help!

jproj

 

[SnTMan]

jproj, assuming it works dimensionally, I don't know why you couldn't.

Regards,

Mike

 

[Fizza453]

JPROJ

After cutting the flange, you need to perform Appendix-2 calculations for the flange, because it is no longer manufaturer's standard pressure part and neither it is ASME Standard pressure part. You cannot accept this flange under the provisions of UG-11.

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[gr2vessels]

jproj, you meant page 23?! Fizza, after removal the flange will be paper weight in the office, no need for Appx 2 calculation.
Most of the specifications in hydrogen service recommend direct piping welded connection to the vessel nozzle, even past the ESD valve. Feasible, I don't know how much will cost the rework, but you'll sleep a lot better without leaking flanges. Your idea is a common technical solution, but you need some piping checks, perhaps a solid pipe anchor near the new weld.
Cheers,
gr2vessels