Pipe manifold design with opening both sides

[KevinNZ]

Hi

We are designing a pipe manifold with reinforced openings on both sides of the main (like a cross). Is there a code rule (B31.1 or B31.3) that does not allow this or requires special design?

We have designed the reinforcing pads and checked the that the reinforcement zones do not overlap. The branches are DN600 and the main DN750.

We can see there are rules for spacing the branch openings but does this apply when the openings are on the opposite sides of the main?

This issue has come here up before

http://www.eng-tips.com/viewthread.cfm?qid=379970

but no consensus.

Thanks in advance.

 

[gerhardl]

I see that this in earlier thread started a long discussion and as you stated with no consensus. Why not turn the question around: could you adapt, construct or find a solution that undoubtly lies within existing rules and regulations, or a standard commercial component?

Please also be reminded that in such a vessel flow, turbulence, draining and correct placing, orientation and support, plus selection and placing of valves could be a design issue in addition to mechanical strength.

 

[racookpe1978]

What is your design pressure, temperature, fluid, and service?

 

[KevinNZ]

Racookpe - Code B31.1, saturated steam and water @ 6 bar.
Gerhardl - We are very much suck with a custom design that meets the flow path requirements of the manifold.

 

[KevinNZ]

FYI. We have carried out FEA on our manifold and found that the stress in the pipe, away from the reinforcing pads, is notably higher when there is a reinforced tee on both sides of the main, compared to a tee on only one side.

I would recommend large opposite branch connection are treated a special design and not use piping code calculations.