Reinforcing pad for large opening

[farzam]

Dear All,

our client asked us to apply a reinforcing pad for a 16"nozzle.Actually this nozzle is attached at the 16"vessel, and regarding thickness reduction they want to apply a pad.Actually I do no see pad for nozzle with same diameter of vessel, I believe they should increase the vessel thickness partially. let me know your idea.

Thanks in Advance

 

[gr2vessels]

farzam,
your post is confusing, to the extent of mentioning 16" nozzle associzted with 16" dia vessel. Is the nozzle the same size with the vessel? However, it is common practice to use reiforcing pad added to the shell thickness as local nozzle reinforcement, without increasing the whole shell thickness. Another common practice is the insertion of a thicker shell strake where the nozzle is, to provide a better reinforcement and nozzle stability. Obviously, it is subject of particular design and geometry or Code restrictions. The deciding factor is usually the depth of your pocket (or the Client's acceptance). Please also clarify the meaning of partial increase of shell thickness.
cheers,
gr2vessels

 

[DG72]

Can you use a 16" t-fitting in the shell? Obviously, each end would make up part of the vessel course, the perpendicular opening serving as the nozzle neck. Reinforcement calculations would not be required since you are not cutting any holes.

 

[farzam]

Dear gr2vessels,
Thanks for your post,
Regarding wrc calculation stress ratio is high at location that nozzle attached to shell since shell section corroded.If I put required pad, it will cover whole of shell and some welds.

Thank you

 

[vesselfab]

well, what's wrong with that?

grind welds flush and fully radiograph, then apply pad over existing nozzle and do NBIC repair

Or you can take your clients vessel out of service and cut shell, replace shell section, replace nozzle, do nde and test and put vessel back in service after NBIC alteration is completed