Fabricated 4way cross section

[Mechh007]

Dear Engineers,
We are using a fabricated Cross 6” x 6”,Sch 80 on the inlet and outlet side of the manifold,Working pressure is 1440 psi.Can you please tell me how to check(calculation) if this design is passing? MOC A234 WPB. Pic is attached for your ref

 

[XL83NL]

Haha, thats a good one (its actually Potok, but who cares )

 

[BigInch]

I've worked for several companies that prohibited fabrications with outlet diameters > D/2

 

[Biggun]

This raises something I've always wondered about: could you split 2 tees down the centerline of the run, then bevel the two pieces and make a cross by welding together the 2 pieces with the branches? Same question with 2 - 45's to make a symmetrical Y?

 

[amos4]

A forged cross is preferred. If you have to use the fabricated cross, you have to make sure the material does not get too brittle for your service. Check HAZ and make sure proper stress release was employed during fabrication.

 

[BigInch]

Then there may be implications due to flow within. Crosses are not good for equalizing flow to the outlets, as far too much of the flow wants to continue in a straight trajectory. There may be erosion issues. There may even be cavitation. On the other hand, impinging flow problems would seem to be eliminated.

 

[XL83NL]

Biggun, thats an interesting Idea. In terms of Code requirements, thats probably not allowed without detailed calcs per 304.7.2, since youd have unlisted components.

 

[BigInch]

CFR Title 49 Part 192 § .153 Components fabricated by welding.
(a) Except for branch connections and assemblies of standard pipe and fittings joined by circumferential welds, the design pressure of each component fabricated by welding, whose strength cannot be determined, must be established in accordance with paragraph UG-101 of the ASME Boiler and Pressure Vessel Code (BPVC) (Section VIII, Division 1) (incorporated by reference, see§ 192.7).
(b) Each prefabricated unit that uses plate and longitudinal seams must be designed, constructed, and tested in accordance with section 1 of the ASME BPVC (Section VIII, Division 1 or Section VIII, Division 2) (incorporated by reference, see§ 192.7), except for the following:
* * * * *
(d) Except for flat closures designed in accordance with the ASME BPVC (Section VIII, Division 1 or 2), flat closures and fish tails may not be used on pipe that either operates at 100 p.s.i. (689 kPa) gage or more, or is more than 3 inches in (76 millimeters) nominal diameter.

 

[LittleInch]

But thus thing is two branch connections which just happento be opposite each other. A cross is also a standard fitting.

The thing pictured needs some reinforcement but is simply a branch connection x 2.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[BigInch]

Yes and it also looks a lot like a component fabricated by welding.