ASME B31.3 Branch Connection through weld

[TheYoungOne]

We are getting ready to install some o-lets on a piping run per customers drawing. One of the o-lets is located in the center of a circumferential butt-weld. The butt weld has been 100% radiographed prior to the o-let installation. A co-worked asked if this was allowed by B31.3? I've looked through the book multiple times and cant find anything that discussed it.

I've told the specific PM to contact Customer Inspector for clarification. Even doing so, I would still like to know where to find clarification in the book to make sure we are ok. I don't think its a good idea if everyone built stuff per customers recommendations, I am a firm believer in Manufactures responsibility as well. I want to agree/disagree with their clarification based on the code. Thanks in advance!

 

[XL83NL]

Allowed by B31.3? B31.3 (most probably) does not specifically prohibit this circumstance. B31.3 sets out minimum requirements for piping system to ensure a safe operation. It is up to the Designer to design the piping system to the extent necessary for safe operation. Do you deem this to be a problem?

Some information on material of construction, line size, wall thickness, service etc. can be helpful to users here assist in this query.

 

[TheYoungOne]

Pipe is SA312-TP316L, Line size is 6" Sch. 40, Branch is 1" Thread-o-let A182-F316L 3M. Service I am not to sure of as this is another PM's project. We didn't design the system, customer had a third party engineering service.

Personally no, I wouldn't see this as a problem but my strength is Section VIII as I deal mostly in Pressure Vessels. The joint has been radiographed and holds a joint efficiency of 1.0 so to me its just like were installing a coupling on the piece of pipe.

The question was posed to me and I'm cautious at times giving a direct answer without finding any reference in the code book. I would say its good practice to try and avoid doing so but when its necessary and the joint has been radiographed it is ok.

I didn't want to give them the go ahead and then somebody find in the book where its prohibited, wanted to make sure I wasn't missing something. In all instances I always suggest sharing the question/solutions with the customer to assure they concur, and our AI when applicable.

 

[moltenmetal]

I'm not aware of a B31.3 prohibition of this practice. We avoid it because it looks bad. We also avoid, but do not control, branch welds which intersect the long seam weld line of a welded seam pipe.

 

[uaepiping]

I have seen client specs stating clearly that no new welds on any weld previously done on the pipes.
Try to avoid it. Seek some other location for olet.