design of branch connection

[Lahane]

I have to design a 3" branch connection (OD 95 mm & 9.5 mm WT) on header of 24"OD & 12.7 mm WT.

The branch connection is at 90 degree & 4.5" offset from longitudinal axis of header.

The design code is ASME B 31.3. can any body suggest how to perform the design calc mathematically as mathematical expression in para 304.3.3 of ASME B 31.3 are for branch connection at top of the Header.

 

[DSB123]

Lahane,
Before doing any calcs you need to be sure you are complying with the Code requirements initially. Are Tangential/hillside branches allowed by B31.3?

 

[StevenHPerry]

There's no problem with adapting the area replacement method to fit your needs and I'm not aware of hillside stub-ins being explicitly disallowed, but you won't be qualifying this branch in B31.3 according to 304.3.

Turn the page to 304.7.2 and good luck!

- Steve Perry

http://www.linkedin.com/in/stevenhperry

 

[C2it]

The B31.3 area replacement method explicitly requires that the axes of the run and branch interesect, thus ruling out hillside nozzles.

If you can get access to FE-Pipe, it will do an excellent FE job by adapting a standard mesh template for a hillside nozzle.

 

[StevenHPerry]

C2it...

Just to be clear, the area replacement method says you can't qualify a hillside nozzle by that method, but it doesn't say a hillside nozzle shall not be used. Right?

That was my interpretation.

- Steve Perry

http://www.linkedin.com/in/stevenhperry

 

[C2it]

Steve,

I was quoting thisfrom 304.3 of B31.3 2008:

(b) The rules in paras. 304.3.2 through 304.3.4 are minimum
requirements, valid only for branch connections in which (using the nomenclature of Fig. 304.3.3)

bla bla bla

(4) the axis of the branch intersects the axis of
the run.

Hillside nozzles by definition will not have intersecting axes, so are out of play in my view.

 

[StevenHPerry]

Paraphrasing... the 304.3 rules are only valid if the axes intersect.

It does not say 'thou shalt not use hillside nozzles.' You just can't qualify them to 304.3.

Why wouldn't a 304.7 hillside nozzle be in play?

- Steve Perry

http://www.linkedin.com/in/stevenhperry

 

[MJCronin]

Let me ask the obvious.....

What possible process reason requires the branch to be a "hillside" ?

I hope that the answer is NOT "to match an existing piping system"...

 

[Lahane]

actually two branch connections are there on either side of axis of header as it will have ultrasonic sensors in it.

 

[DSB123]

SteveParry,
I thought the axes had to intersect in order to use area replacement method which is basically what the question related to. I not so rash as to exclude the use of hillside/tangential nozzles but pointed out that Code compliance needed to be maintained whereas you suggest the area replacement method could be used.Can it?