Welding to Section VIII Div 1. Butt welds only?

[Gavin_UK]

Can some one help me with understanding what welds are permitted in a pressure vessel to Section VIII, Div 1. (I am looking at 2023 version)
UW-9 a Seems to pretty clear state only Butt welds can be used for retaining pressure....
"Only butt-type joints may be used with the permitted welding processes in UW-27 that include the application of pressure"
But then later, in UW-13.1 it shows fillet welds being used to attach Heads to shells.
If these fillet welds are retaining pressure what is?

Any help appreciated.

Gavin

 

[IdanPV]

Some type of small fittings are allowed to be attached using fillet weld from one side only, see UW-16(f)

 

[David3399]

There are rules for both in certain circumstances. Nozzles may be attached by fillet welds only following Code rules.

 

[Shaikh Mohammed Ammar]

Can some one help me with understanding what welds are permitted in a pressure vessel to Section VIII, Div 1. (I am looking at 2023 version)
UW-9 a Seems to pretty clear state only Butt welds can be used for retaining pressure....
"Only butt-type joints may be used with the permitted welding processes in UW-27 that include the application of pressure"
But then later, in UW-13.1 it shows fillet welds being used to attach Heads to shells.
If these fillet welds are retaining pressure what is?

Any help appreciated.

Gavin

For common attachments you may refer to UW-13 figures
For nozzles you may refer to UW-16 figures
For tube to tubesheet joints you may refer UW-20 figures

Kindly note is your job is U-Stamp you have to draw figures and mention the appropriate figure numbers in your drawings