How to transition from PVC Force main to HDPE force main? 1

[gt5879c]

I have an 8" force main that is PVC that I need to transition to HDPE in order to do a directional drill for a section. How would I transition this pipe from PVC to HDPE and back? What type of coupling or transition collar?

 

[bimr]

Here is one method, fuse a bell onto the hdpe pipe.

http://independentpipeproducts.com/downloads/updates/Bell MJ.pdf

You can also use a mechanical joint or coupling:

http://www.isco-pipe.com/catalog/pdfs/Mechanical.pdf

http://www.isco-pipe.com/catalog/pdfs/FM.pdf

 

[CivEnvEng98]

A MJ adapter would work.

I usually spec out a larger HDPE pipe to meet similar internal diameters. So if I had an 8" pvc line and my HDD was 10" HDPE, my callout would look like this:

STA xx+xx, xxLT/RT, Construct:
(1) 2" Manual ARV
(1) 8" Plug Valve
(1) 8" 11.25-Degree bend
(1) 10" x 8" reducer
(1) 10" MJ HDPE/PVD Adapter

 

[gt5879c]

CivEnvEng98:

What is your 11.25 bend for? Why is the air release valve necessary?

Thanks

 

[CivEnvEng98]

gt5879c,

The bend is to transition to the bore angle, which is typically 10 to 13 degrees downward at each end. A fabricated HDPE fitting is much more expensive than a "off the shelf" DIP fitting and probably quicker to procure. It's your choice.

The arv is to help vent the high points in your line. The bore creates 2 high points, one at each end. Some only put one arv on the upstream side, but I always specify 2 for improved maintenance. I suggest manual ARVs unless the utility specifies the automatic style.

 

[dirt101]

molded flange adapter for the HDPE (the molded flange adapter will also need the heavy duty back up ring, red rubber gasket and 8 bolts)
flange to mj adapter (with PVC megalug gland, transition gasket and red rubber gasket and 8 tblots)

would be what I would use to connect PVC to HDPE, also be sure to check for material homogenialites between the flange adapter and pipe