Circumferential fillet on top of circumferential butt weld? 1

[viper3982]

We have a project that we were about to encounter a problem with. Thankfully it resolved itself without going this direction but I still have the question in my mind of: is it possible?

-We have a pressure vessel; Section VIII Div 1. Head welded to a shell using a single sided butt weld.

Due to some geometry/design issues we were needing an attachment (think similar to an insulation skirt) welded around the shell. A 3" wide 1/2" thick ring.
We normally do this on the body with seal-welded fillets.

Due to some odd circumstances, we were going to be forced to move the skirt up to directly where the head-shell weld is.
*See below*

The question is: Does ASME disallow this weld joint/attachment? What would this be considered? I tried scouring through the UG and UW sections and can't find anything similar or close to it.

 

[SnTMan]

viper3982, I don't believe Div 1 prohibits as such; see UG-82(c). But very poor practice. As a buyer I would not permit it. Impossible to inspect the round seam down the road.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[robyengIT]

I am not an expert but I would have done in a similar way

 

[DekDee]

Neither of the sketches provided are " sound practice".
AS SnTMan has noted - how do you have access to a major weld joint for inspection at a later stage ?
Most codes (not sure about ASME VIII) require a weep-hole so if a weld is covered any leak from the covered weld can be identified.
How do you propose to do that ?

 

[robyengIT]

if the problem is the inspection of the butt weld, what about this ?

 

[SnTMan]

robyengIT, it appears to be a bolted detail. If so:

It does permit exposing the weld seam. I'd want confirmation that it provides proper access either side of the weld for a given NDE technique from a qualfied person.

The single fillet welds can be a problem. They can permit "rust runs" on carbon steel from between the faying surfaces. Looks like h3ll on the paint of a new vessel. Fully seal welded would be better.

Then there is the added cost.

Having said all that there are no doubt some classes of work where future inspection is unimportant. Still...


The problem with sloppy work is that the supply FAR EXCEEDS the demand