Multiple Branch Connections

[Zapster]

Hello,

Is there any guidelines regarding multiple branch connections in B31.3? I need to weld 3 each, ½” thread-o-lets, 120 deg apart, on 3” run. Any comments would be helpful.

Thanks

 

[DLANDISSR]

Zapster:

B31.3 states that branch connections made with standard fittings (like tees, crosses threadolets, weldolets or sockolets) having adequate pressure stregth do not need to be calculated. There is no restriction on the number of connections around the perimeter of the main pipe.

The fittting used must provide enough material to reinforce the pipe sufficiently because the hole cut for the branch or branches reduces the pipe strength.

Suitable fittings are listed in Table 326.1

A threaded or socket weld 2000# (or greater) coupling or half coupling may be used if the branch is not greater than 1/4 of the main size.

It appears from B31.3 that what you propose is acceptable.

What is your pressure and temperature? What schedule pipe is the main pipe?

 

[MJCronin]

zap, et al...

For you information, there are some older guidelines that exist regarding piping fabrication and the spacing of nozzles. This was an important issue when multiple nozzles were "hot worked" into high pressure piping systems ( a process Known as "swaging&quot

The standards are published by an ancient organization called the "Piping Fabrication Institute" (PFI) (see

http://www.pfi-institute.org)

the standard you need is ES-7

Hope that this helps....


MJC

 

[JohnBreen]

Also,

Do not have branch connections so close that their "zones of reinforcement" are overlapping.

Poking holes in a pipe for branch connections really causes a significant weakening of the pipe. Remember there is a reason why the checks in your check book have perforations - makes them easy to tear off. Do not group branch connections any closer than they absolutely have to be.

Regards, John.

 

[Zapster]

Thanks for the info. John’s comments put my concerns into perspective. I too could not find a ASME code reason not to install the thread-o-lets in the same plane. Limited space is the main issue. I may be able to get by with a reducing cross and one T. Are sch XS 3” X 1” reducing crosses readily available for API-5L-B pipe? I looked on the web and could not find a BW X SW cross. Where/what is the best resource for identifying fittings that are readily available?

Thanks for all the help
Zapster

 

[LSThill]

HI

You may find what you are looking for at WFI.

http://www.wfi-intl.com/

Leonard@thill.biz

http://www.thill.biz