Pressure vessel, ASME VIII-1, UW-16, Nozzle attachment

[valenak]

Hello everyone!
I have a nozzle which is welded through shell and jacket plates. We are having a trouble making a fillet weld on the outside surface of a shell, because there is practically no access.
Is there any type of weld that allows making only full penetration groove weld without making a fillet weld on the backside?

 

[SnTMan]

valenak, in my opinion your proposed detail would be acceptable. UW-16 does not specifically require the fillet.

Is it an option to project the nozzle inside the vessel?

Regards,

Mike

 

[valenak]

Thank you Mike!
Yes, the nozzle is projected inside the vessel. Pressure vessel of rectangular cross section externally reinforced by u-beams. U-Beams form a jacket around an inner vessel.
As I understand, if there is no fillet weld on the nozzle then it is not in accordance with sketches in figure UW-16.1. Should then strength calculation for the groove weld be performed UW-15? Or there any other rule in a Code, which allows making only inside full penetration groove weld ?
Thanks!
Sorry my bad English

 

[SnTMan]

As a full penetration weld I do not believe weld strength calculations are required. Note that details shown in Fig UW-16 are not the only acceptable details.

If the nozzle is projected inside the vessel (your sketch does not show it as such) why not add the fillet to the inside?

Regards,

Mike

 

[valenak]

Thank you Mike!
Sorry for misleading you. The nozzle does not protrudes inside the vessel. It is flushed with the
vessel ID as it described on a attached sketch.
So, if fillet weld is not required, should then the dimension tw (Fig. UW-16.1 sketches (t) and (u)) of a weld be not less than tn nor less than 0.25 in as it reads in UW-16(e)(2) ?

 

[SnTMan]

valenak, I would say yes if partial penetration detail is used. Note these details are limited to NPS 6.

If full penetration, I would say the applicable sketch is (d), omitting the fillet.

Regards,

Mike