HDPE surface installation questions 2

[irrigationguy]

Looking at installing a 24 or 30" Hdpe dr9 4710 line on top of ground. 4200 linear feet, 500' elevation. This will replace a buried steel pipe that has failed to due landslides that has z kinked a 20" steel pipe. Any advice how to anchor or hold the pipe from sliding/snaking too much? Will be pushing water up a hill, open discharge at the top. Also any advice on longevity of line on top of ground? Need this to last 50+ years. Ideas to hold pipe if that ground under it slides? Thanks in advance​

 

[CarlB]

Chapter 8 in this document addresses aboveground installation

https://usfusion.com/wp-content/upl...Pipe-Institute-Handbook-Polyethylene-Pipe.pdf

 

[bimr]

Here is the same book from the original source and it appears to be a better pdf:

PPI

 

[pierreick]

Hi,
Take a look at this document.
Pierre

 

[1503-44]

If you have a large (especially daily) temperature variation, generally you should not lay HDPE on the surface.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

Even UV stabilised PE will be lucky to make 50 years.

The issue also si one of solar gain / temperature derating above 20C.

Even if this line runs continuously, which is not possible to guarantee for 5 years neve mind 50, you could still get solar gain as the pipe is black.

Anything above 20C and you start to de-rate. not sure what SDR9 is good for, but you don't have much spare if you're lifting water up 500 ft / 151m / 15 bar at the base.

PE also expands and contracts like no ones business ( 10 times that of steel) so surface lay needs to allow for that and is often laid as a snaky lay. but you need to avoid it turning into a Z shape.

Best lay it at 90 degrees to the slope.

Landslides are a bitch to deal with so I would avoid trying to fix things which are unfixable and just go out and fix it when it moves / breaks, but it is alit more flexible than steel and will withstand a lot of movement.

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

 

[Snickster]

Attached is photo of above ground HDPE installation at Richmond Power Plant in St. Croix Virgin Islands. I did not design but I had to do a firewater system modification which affected the piping. The pipe was about 300 - 400 feet long, straight, and was supported with clamp type supports as shown and had a rubber expansion joint on each end to absorb thermal expansion. Each end also went into the ground after the expansion joint so it was basically anchored at each end.

 

[Snickster]

The attachement in the previous post was not opening. Here is it again.

 

[Snickster]

Here is clamp support close up. Note that it is realatively loose and allows the pipe to slide.

 

[Snickster]

Here is expanison joint close up.

 

[Snickster]

Here is other side of line from first photo posted.

 

[Snickster]

Here is the above ground piping design guide of the Plastic Pipe Institue (PPI). This can be obtained on their website along with other good reference material.

https://plasticpipe.org/