Welding Nozzles 1

[Richard1977]

Hello, I need to design a horizontal pressure vessel on saddles. It must contain 3500 gallons of ethyl mercaptan at 30 psi. A manhole and nozzle connections must be provided. As a beginner on pressure vessel calculation I have a basic question. Which is the criteria to choose a weld with a partial penetration or full penetration at nozzle?.
Thanks.

 

[gr2vessels]

Obviously, full penetration since the ethyl mercaptan is corrosive. Also, you have to review the ASME Section Viii Division 1 for the approved nozzle neck welding type (Clause UW-15 and UW-16).
cheers,
gr2vessels

 

[MJCronin]

Richard,

I suggest that you specify an ASME Section VIII vessel and leave the welding details to the fabricator. Full penn welds are required by the ASME code.

You can get a good quality vessel by:

- getting a good datasheet filled out
- providing a sketch
- Specify MAWP, materials, nozzle sizes, manway size ,coatings, support points etc.

Call up a fabricator and begin talking

-MJC

 

[stanweld]

Full penetration nozzle to shell welds are not mandated by ASME VIII, Div.1. Refer to FIG. UW-16.1 (i), ((j), (k), (l), (m), , (o),(p)... to name a few.

 

[gr2vessels]

Obviously, full penetration since the ethyl mercaptan is corrosive.
gr2vessels

 

[MikeMet]

I agree with those above that full penetration is best, but the decision on whether nozzle welds are full penetration is up to the purchaser. If the purchaser does not specify then the fabricator can choose the style of weld or question the purchaser as to what style of weld they want. Our company specification state that all nozzle welds shall be full penetration.

 

[GenB]

in ASME work, for the press and temp you may not need
full penetration but just abutting fillets. considering the material hauling you specify, you shall make the vessel to hold for longevity.
I would use a true groove design, it's better to be safe than sorry.