Plastic pipe for underground?

[daybreak1998]

Howdy,
You will want to use HDPE (High Density PolyEthylene) plastic water pipe [waterline]. There are some variations... go with the higher pressure 200psi style. Yes, the 160psi is cheaper, but, when you go through the trouble of in the ground, ya never want to go back and fix it. Always use brass connections, use a torch to slightly heat the end and put on the brass barb connection. Use stainless steel bands. The less connections, the less places for leaks. If you need a 200' run get 250' of pipe. The pipe comes in all sizes and lengths. For water spickets.... er, I am in the cold area and use Woodford Iowa freeze-proof yard hydrants. Wherever you purchase the plastic pipe, talk with them about water spickets used in your area. OH, the stuff works in the ground and above ground.

 

[charlz]

A downside to using the higher psi rated black poly is the higher the psi rating the stiffer, sometimes much stiffer, it is than the lower psi rated. Hard to get it unrolled. If you can lay it out on a hot, sunny day that really helps relax the pipe and take the curl out of it. Generally the rule of thumb for poly pipe selection is twice the highest pressure... so if you have this on a well pump/pressure tank that cuts out at 60psi then you could get away with 120psi rated pipe.

Gophers will also eat poly pipe but not pvc so that can be a consideration as well.

 

[8N Ren]

Daybreak hit on the head, that's what mines like but they used the white plastic barbed connectors. Also double clamp your connections, heating it as stated sucks them down nicely when tightened.

 

[California]

Gophers? I hadn't thought of that. They are all over the place here. What do I need to specify for pipe that they won't eat?

Also - thinking ahead - say I want to unscrew a galvanized spigot riser out of its underground 'T'. If this takes extreme force is there a risk of breaking the underground main? (I've had this happen with lawn sprinkler risers).

 

[boggen]

Gophers? I hadn't thought of that. They are all over the place here. What do I need to specify for pipe that they won't eat?

Also - thinking ahead - say I want to unscrew a galvanized spigot riser out of its underground 'T'. If this takes extreme force is there a risk of breaking the underground main? (I've had this happen with lawn sprinkler risers).

*scratches head* huh? why would ya ever need to remove a vertical pipe?

by default if you compacted the pipe in correctly with sand and/or dirt. it can take some force. but if you are unscrewing a pipe up out of the ground. you are how do i say this. SOL, trying to screw something back in. without having to dig down to the fitting in the first place to re-attach something. and digging down, you will have access to fittings to get your tools on them, and busting stuff is more or less a non issue then, or less you really mangle stuff up.

most yard hydrants. you never have to deal with underground stuff, beyond initial install. and if something fails, normally everything unscrews out of the very top. and pulls up and out of it. so you never have to dig down to were the main pipe connects to it.

 

[MH8675309]

Even if you dont have to worry about frost - it is a good idea to bury it deep enough to not get damaged if a machine ever has go over it. boggens 2 foot minimum is a good idea

 

[lostcreekranch]

Try these for laying the poly pipe from rolls;

3 Point Subsoiler-Subsoiler Attachment | Agri Supply #73410

3 Point Pipelayer-Pipe Layer Attachment | Agri Supply #73622

Sent from my iPad using TractorByNet

 

[California]

why would ya ever need to remove a vertical pipe?

Replacing galvanized pipe here is normal maintenance. The water is acidic, beyond the spec allowed for municipal water.

The second picture below was last week's repair to a line that was extended to the garden in the late 70's. Note all its galvanizing was gone. Next morning the area was wet again. I dug it back up and found two more leaks a foot down the line - near another clamp I recall installing about 2003.

Then I discovered wet ground 100 ft away. The main there was replaced in the 60's. I remember digging that one up ... with Dad encouraging me to hurry :hissyfit: so we could get the house water turned back on the same day.

The time has now come to re-engineer everything.

What's better to allow future replacement of galvanized risers - plastic or brass for the T's underground?

View attachment 380639 View attachment 380642

 

[Carl_NH]

For the GPM output of your pump based on a breaker size of 30 AMP/230V a GUESS would be 1.5 to 2 HP pump, then the GPM depends on the HP, and # of pump stages, then static or average depth of water as primary factors.

But, I would suspect you are between 10-15 GPM range.

I would use brass or SST for connectors and if you can afford brass or SST risers too. As you know galvanized will plug up fairy fast.

 

[California]

For the GPM output of your pump based on a breaker size of 30 AMP/230V a GUESS would be ... 10-15 GPM range

Thanks!

I found a chart that relates pipe size/volume:
GPM/GPH Flow based on PVC Pipe Size, ie, How much water can flow through Sch 40 Pvc Pipe Size 1/2" 3/4" 1" 1.5" 2" 2.5" 3" 4" 6"

According to the chart, it looks like given ideal conditions a short 3/4" outlet pipe (rated 36gpm max, 23gpm preferred) would pass the full output of the well pump - whatever that is. Then size up from there considering friction loss due to length and fittings. So I don't need to go back to the 1.5" size that I'm replacing. Maybe 1.25" for the longer runs, so a big Rainbird sprinkler can have good volume out at the end of the line.

The chart linked above also references a chart for length/loss that indicates the Rainbird 100 ft out would receive 10~20 psi less than at the well. This seems acceptable.

I like the idea of trenching with a ripper or potato plow. But where I need to make the first repairs, only my backhoe's boom can fit in there.