Pipe In Pipe 1

[Stu1Clark]

I have a client who wants to install a 3" PE force main inside an unused 8" DI main. The run will be about 9000 lf and change of elevation around 130 ft. My thoughts are than this new main will "dance" inside the 8" causing abrasion and eventual failure. Has any one out there tried this?

 

[LittleInch]

Why would it "dance"?

Inserts are common place and PE has very good abrasion resistance.

The key will be any interference in the DI pipe and whther you have enough axial strenght to pull it in one go. If you can part fill the DI pipe during pulling would help a lot.... Then empty it.

Or is that what you mean? i.e. the DI pipe is also full or partly full of water?

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

 

[Stu1Clark]

By "dancing" I am thinking as the pump cycles on/off the unsupported PE pipe will move in the 8" DI. Especially in any bends. I do not believe the pipe has any water in it.

 

[bimr]

Slip-lining is perhaps the oldest of all trenchless techniques. It involves the insertion of a new HDPE liner pipe of standard diameter and SDR into an existing pipe. Under the right conditions, slip lining is also the simplest trenchless technique. A new pipe with an outside dimension smaller than the inside dimension of the host pipe is either pulled or pushed into the host pipe. The ideal host pipes for slip lining are straight with no deformities, no or modest bends, no severe protrusions into the pipe, and only modest offset joints.

Connect with a supplier/contractor that can take you through the installation details.

Link

 

[gbam]

Chiming in here, first off when I read the initial post I jumped to Carrier and sleeve/casing not slip lining. There are standard spacers that are used to cradle the interior pipe to mitigate against water hammer and "dancing". Any way, Many agencies (Water and Sewer) have standard details for the spacers. I will say that 3" is smaller than I am used to seeing and 9000 feet is very long; but, I think the carrier pipe should be anchored in some manner. I suggest a simple google search to see if there are any products that can handle the situation.

 

[mk3223]

Hope it helps with the video of a pipe insertion inside the old pipe

[link ]

http://plcsusa.com/main-renewal-live-main-insertion.html

[/url]

 

[ACtrafficengr]

You might be able to fill the space between the pipes with cellular concrete.

My glass has a v/c ratio of 0.5

Maybe the tyranny of Murphy is the penalty for hubris. -

http://xkcd.com/319/

 

[dcornelius]

Are you going to pull in the entire 9,000 feet in one pull? Has anyone TVed the 8 inch line?

 

[nackra]

I would suspect that there are fittings in 9,000-LF of 8-inch pipe. Pulling a 3-inch PE pipe (IPS: 3.5-inch OD) might be difficult while meeting allowable bending radius.

https://www.jmeagle.com/sites/default/files/jme_PEWaterandSewer.pdf