Break-out-Flanges or Break Flanges

[gchegde]

1) Break-out-Flanges or Break Flanges: I am required to check if design considers "Break-out-Flanges or Break Flanges" for hydrotest. Appreciate information on Break-out-Flanges or Break Flanges.
Previous thread Ref:

http://www.eng-tips.com/viewthread.cfm?qid=302062#post

2) Spec break : In your opinion the location of spec break be advised in P&ID?

 

[TD2K]

I'm not sure what is meant by break flanges for hydrotest. If you had a system that was welded with a pressure spec break, I could see installing a set of flanges to allow the high pressure and low pressure systems to be independently hydrotested. In fact, in this case, the high pressure/low pressure spec break would occur at this set of flanges rather than at the outlet of the high pressure valve as is typically done.

Spec breaks be it between piping specifications, insulated and non-insulated systems, heat tracing and non-heat traced systems and perhaps things like stress relieving or PWHT should be shown on the P&ID as the process engineer has to make those decisions when the P&ID are initially created. Without those specification breaks, piping can not start detailed design (those are not decisions IMO piping should be making). PWHT can be handled by spec breaks (SR/non-SR) or by pipe spec breaks where one pipe spec is stress relieved while another pipe spec which is identical to the first except for not being stress relieved. I've seen both done.

 

[Torm]

As a constructor, and often working with engineering in the upfront design, we have directed the placement of the flanged connection in piping systems when it is desireable to test one side of the flange pair at different pressures. I think the system engineer would always then show the flange pair on the P&ID, for routing/modeling by the designer. If the design pressure is different on each side of the flange pair, then this would typically mean either side of the flange pair is under a different spec, thus, a spec break at the flanges.

 

[racookpe1978]

But note that the flange (on the low pressure side of the spec break) might thus be "over-rated" for its service, just to be thick enough to match the higher pressure side (bolt hole size and spacing and RF diameter).