Rerounding HDPE Pipe

[WasteNot]

Has anyone ever rerounded HDPE pipe after a vacuum collapse? I have a 4"/8" dual-contained HDPE force main. The 4" pipe collapsed, apparently after a vacuum release valve failure. I am exploring options to complete replacement of the pipe.

 

[dicksewerrat]

Call your HDPE supplier.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[stanier]

Do a hydrotest and you will find it will re round. It collapsed with an external pressure of 100kpaq and thus to rem round it at the pressure rating will be a piece of cake. PE does not work harden.

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

http://waterhammer.hopout.com.au/

 

[rconner]

This is a somewhat strange-sounding inquiry, particularly if the 4" carrier is solid wall pipe with some meaningful wall thickness.

Are you sure interior pipe is not e.g. instead "necked-down" as with pulling load, or alternatively has leaked and leakage is exerting/has exerted excessive external pressure in the interstice between the casing and carrier, and thus against the outside of the 4" pipe?

 

[WasteNot]

Thanks to you all for your thoughts. Multiple lines of inquiry have pointed to the hydrotest. The wall thickness varies at the different points we have checked. We have also replaced vacuum release valves.