Welded Branch Reinforcement

[magusinp]

I am calculating a branch connection of 2" pipe into 2-1/2" using ASME B31.3. The criteria for determining the amount of reinforcemnet area is directly related to the amount of material removed from the header. The amount of material removed from the header pipe is usually the same diameter as the branch pipe. However, if the flow rate does not require so large a diameter, could you not make the hole in the header pipe small and thus limit the amount of reinforcement required?

In other words, why can't you cut a 1/2" diameter hole in the header and weld the 2" pipe directly to the 2-1/2" pipe as a stub-on?

 

[codeeng]

I see no reason why you can't do this, however you'll need to account for double corrosion allowance.

 

[StoneCold]

Magusinp
Mainly because you are making a mess for the next guy who comes along. It is like putting screens inside a Tee fitting. It might work but when the next guy comes along and tries to trouble shoot the system He will cuss you for a long time.
Just use a "Weld-O-Let" to get the reinforcement that you need and go with that. Don't try something tricky that only you know about.
My two cents.

StoneCold

 

[jte]

magnusinp-

I agree with both codeeng (it's code legal) and with StoneCold (no matter how well you document it in 5 years nobody will remember). I considered doing something similar once on a hillside level instrument nozzle on a vessel. At least that unusual design would be immediately visible to anyone entering the vessel regardless of paper trail. Once the paper trail and institutional memory are lost, the only way your proposed design would be recognized is when they RT the connection and try to figure out what the heck they are looking at.

Another issue to consider is mechanical (non-pressure) piping loads which will be better handled by an 'olet type fitting.

jt

 

[StressGuy]

And that area replacement makes no accounting for the strength of the connection with regard to external piping loads.

Just say no to stub-ins, make you stress engineer happy

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.

 

[PEHasan]

The best option is to use Weldolet.

The second option is to use 2.5" x 2" Reducing Tee (B16.9), if possible.

 

[unclesyd]

I have to agree with all the above saying don't do it use the WeldOlet or at least make the penetration in the run close to the branch size.

My first big idea when I started my career was choked. no pun intended, off by an internal undersized branch connection. A 4" that was actually a 2". I was going to save a lot on money but failed. It was probably ten years later that I found the answer to why the flow was lacking. From that day I never assumed anything was anything until I checked.