Pipe to Pipe connection 2

[cjabhijit]

Hi All,

Pls help me to know the step by step procedure to calculate Pipe to Pipe branch connection.

The question is to understand the logic behind developing branch table in Piping Material Specification.

Can somebody advice how to go about it?


Thanks & Regards,
Abhijit

 

[racookpe1978]

What service? (Oil and gas? Stick with the approved fittings.)

 

[cjabhijit]

Let me come to this very precisely.

Actually it is allowed to take 12" x 8" pipe branch as pipe to pipe however what is happening is I need to take these for Fire Water Hydrant where these 8" taps are coming at the same axis like a plus (+) sign. Whether this will be allowed to make? Pipe to pipe 12 x 8 on the same axis 180 deg apart.

I don't think so.

Thanks & Regards,
Abhijit

 

[racookpe1978]

Sure.
Use a 12x8 cross, flanged or socket welded or butt welded as required by your spec.
Alt: 12x12 cross, with 12x8 reducers on each cross-head.
Alt: 12 inch pipe, with 8 pipes scribed, cut and fitted, and the 8 inch pipes also scribed cut and fitted precisely for all joints to be fitted and welded at the full intersections, NDE'd, and accepted. You pay 4x as much for all of the field welding and cutting and fitting and re-fitting, then you STILL have all of the field joints to connect the "cross" with the 12 inch and 8 inch pipe runs.

 

[ahmadsalah]

The rule is basically stress analysis. When you cut a pipe you weaken it, when you weld back something to the cut you strengthen it an extend. depending on the thickness of the pipe, were it is supported and the pressure, temperature etc. you can figure this out. Basically racookpe1978 summarized your options or you can add to that using weldolet with a weldolet reinforcement saddle. you can use a Tee and a reducer on one side and then cut through the Tee with a weldolet on the other side. Good luck

 

[pennpiper]

The important part of the OP's original question was:
"The question is to understand the logic behind developing branch table in Piping Material Specification."

When developing a Branch Table, have the table address the 99.9% of the standard branches you know you will have on the project. The odd branches (that last .o1%, if they happen at all) should be handled as a Special situation on the Isometric/Stress Sketch when you find it. And, do not revise the chart for that odd situation.

Sometimes its possible to do all the right things and still get bad results

 

[LittleInch]

Follow the design code.

Is this metal or PE?

Once you get > 50% of the header, normally much easier and quicker to use a forged (metal) or fabricated (PE) component.

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

 

[cjabhijit]

Thanks for all the responses...I am proposing to have a cross (standard fitting) which is not yet available in the specification.

Thanks & Regards,
Abhijit