Quick Help: Trenching Polyethylene out to Barn...

[barnfield]

Quick question:

This week I am planning to run black poly water line out to barn and pastures from the house.

Will be starting from a 3/4" copper line from the pressure tank in the basement (& installing a shutoff valve), then go through the basement wall, and then trenched 3 ft deep all the way out to the barn.

Longest run is a good 550 ft. or so.

QUESTION: What diameter of polyethylene to use? 3/4"? 1"?

Fyi, there's 1" black poly from the well to the pressure tank in the basement of the house, then from the pressure tank to the spot where I can tee off from is 3/4 copper. The hydrants themselves are 3/4" diameter inlet.

Is there ANY benefit trenching 1" poly over 3/4" if both the source and the destination are essentially 3/4"???

Will my water troughs fill up any faster?

Thanks!

 

[Gary Slusser]

Change the 3/4" copper to 1" sch 40 PVC, or 1" PE, or 1" copper from the pressure tank tee to where you want to tee off to the barn.

And then run 1" the 550' and tee 3/4" off it to each hydrant. Otherwise the friction loss will reduce flow. And you may have to increase the pressure switch settings (and air pressure in the tank) on the well pump; especially if the 550' goes up hill.

You want a 1" shut off valve and then a 1" check valve on the line to the barn.

 

[Sponsor]

 

[Gary Swart]

Gary Slusser certainly knows more about this than I, but I would be concerned than even with 1" pipe from the pump to the barn there will be quite a bit of friction loss. If the outlet from the pump gives you a choice of a larger that 1" pipe, that would be something I would consider. 550 feet is a pretty long run.

 

[Jadnashua]

It somewhat depends on what you want to be running simultaneously. More is better, though.

 

[Gary Slusser]

PE pipe has the lowest pressure loss of any material. Plus there this line should only have two fittings, one on each end. 1" is used for 500+ wells all the time. A larger ID line fed by his 1" line from the well is not going to benefit his flow much if at all but if money was available, he could go 1.25" if he needed a lot of water like in a milk room etc.. He may want to set his switch and tank to higher pressures though.

 

[barnfield]

Thanks all, the water is to serve 3 frost-free hydrants, to be used for filling water troughs, etc. Not a whole lot of demand, but still.

Also, we were only able to get 300' rolls of poly locally, so there will be one poly-to-poly couple connection.

 

[Gary Slusser]

Then you must not have gone to a pump or plumbing supply house for it but, a 500' coil would have required a coupler too.

You should use 160 psi rated and a SS coupler and two opposed SS hose clamps on each end that are properly torqued. You can get the tee handle torque wrench at a supply house. The primary cause of leaks is over tightening the clamps.

 

[barnfield]

OK! So just ordered the 200# poly in their 300 ft rolls, the hydrants (Woodford brand), and tracer wire.

It's a wholesaler shop that apparently sells primarily to utilities and municipalities for waterworks and that's all they sell. Kinda surprised they didn't have longer rolls, too, but oh well. I'm not sure I would even WANT to try manhandling some big 1000' roll of poly, even if it existed!

Gave the guy a schematic of my plan, and he's compiling all the needed connectors for me, so I'll check when I pick everything up what he's put together. (Pretty sure he said SS, but will verify.)

We plan to hook everything up and test out all the hydrants before backfilling with the tractor. Just in case

 

[Herk]

Good job getting the 200 PSI. It's what I would have recommended.

If you use SS clamps, use two per joint and reverse one of them so the clamp screws point in opposite directions. I'd use brass fittings because the galvanized will rot. Plastic will break.

And I don't know where you live or what your climate is, so I can't give much advice on freeze protection. For cold northern climes, I'd bury the thing five feet deep. If there is a spot where you drive equipment over the top of the line, like a drive where you move tractors or trucks back and forth, I'd go deeper. That sort of thing can drive frost 18' into the ground. And once plastic is frozen, you aren't going to get it thawed until late in the year.

If you're in a mild climate, ignore the above advice.