water supply pipe sizing, 400 feet long

[herm0016]

@skyking @Greenman

i am trenching about 400 feet from the house to the pole barn, any suggestions on cost effective pipe and pipe size for that run? my well only runs about 30psi. volume is pretty meh also.

would like to keep it one piece in the ground, going to go about 4 foot deep. in a cold winter it could freeze. ill have a shutoff in my crawlspace and frost free hydrants near the barn. one hydrant will feed water into the pole barn and ill do it to self drain with the hydrant off. a couple others for the future greenhouse and garden area that will be feeding drip irrigation. only good thing is about 6 foot drop in elevation between house and barn.

 

[Greenman]

It all depends on how much volume you want at the end of the run. My off the cuff guess is that 1" would do the job for normal use.

 

[herm0016]

It all depends on how much volume you want at the end of the run. My off the cuff guess is that 1" would do the job for normal use.

More the better. Like to stay 5 or more gpm. But need a minimum of about 25 psi to run the irrigation system.

Sent from my Pixel 6 using Tapatalk

 

[skyking]

No need to go bigger than that, 3/4" will also work.

 

[Greenman]

No need to go bigger than that, 3/4" will also work.

I agree, but the price difference isn't enough to give up a little volume that might help down the road.

 

[herm0016]

thanks. i may be more worried about it than i should be according to your comments.

 

[drnickriviera]

Don't think 3/4" will do it. Pressure loss table i'm looking at for pex says 3/4" will have 5psi drop per 100' @ 5gpm. 1" shows 1.58psi which would still be marginal once you add fittings into the mix.

PEX tubing technical specifications and general installation practices

Dimensional data, pressure ratings, pressure drop table, typical circuit lengths and other technical specifications of PEX tubing used in system sizing and calculations.

www.pexuniverse.com

http://snowcrest.net/thriftysupply/pdf/Uponor-PressureLossTables.pdf

 

[Greenman]

Don't think 3/4" will do it. Pressure loss table i'm looking at for pex says 3/4" will have 5psi drop per 100' @ 5gpm. 1" shows 1.58psi which would still be marginal once you add fittings into the mix.

PEX tubing technical specifications and general installation practices

Dimensional data, pressure ratings, pressure drop table, typical circuit lengths and other technical specifications of PEX tubing used in system sizing and calculations.

www.pexuniverse.com

http://snowcrest.net/thriftysupply/pdf/Uponor-PressureLossTables.pdf

3/4" pex fittings reduce the ID to 1/2". Use PVC for better flow. 1" will do the job.
1" PVC will drop .66 psi per hundred feet at 5 gpm.

 

[BoomerD]

3/4" pex fittings reduce the ID to 1/2". Use PVC for better flow. 1" will do the job.
1" PVC will drop .66 psi per hundred feet at 5 gpm.

But...in the OP's area, pex would be more resistant to cracking/breaking in freezing weather.

 

[drnickriviera]

That is true. I guess I automatically went pex due to his desire for a continuous run. I think i'd try to boost pressure 10psi

 

[herm0016]

yes, because i dont want to rent a utility scale trencher to go 7 feet down, ill need something freeze resistant.

i could try to adjust pressure, but the well has a flowing pitless because it is artesian some of the year because of the giant reservoir a few hundred feet above and just a mile down the road. so... adjusting things on the well is more complicated than most. anyhow... things get complicated at our altitude sometimes.

 

[bbhaag]

HDPE pipe is probably your best bet as the most economical type to use. As far as sizing goes that is a tough one. 30 psi at the well pump makes it a hard call but I'm gonna say 1.5" will probably do the trick. This leaves you with some head room when you finally decide to upgrade that god awful well pump.

 

[Greenman]

yes, because i dont want to rent a utility scale trencher to go 7 feet down, ill need something freeze resistant.

i could try to adjust pressure, but the well has a flowing pitless because it is artesian some of the year because of the giant reservoir a few hundred feet above and just a mile down the road. so... adjusting things on the well is more complicated than most. anyhow... things get complicated at our altitude sometimes.

The ground freezes 7' deep? Maybe it's time to consider moving from the south pole to the north pole?
Just in case no one ever told you, there are places where water is liquid all year. It's pretty convenient.

 

[BoomerD]

yes, because i dont want to rent a utility scale trencher to go 7 feet down, ill need something freeze resistant.

i could try to adjust pressure, but the well has a flowing pitless because it is artesian some of the year because of the giant reservoir a few hundred feet above and just a mile down the road. so... adjusting things on the well is more complicated than most. anyhow... things get complicated at our altitude sometimes.

Pex will still freeze...unless you heat tape it, but it's much more resistant to breaking/cracking when the water inside freezes and expands.
You still work in the oil biz? Get some heat trace tape. That shit works GOOD for heat tape. I used some from one of our pipeline contractors when we were in Wyoming, wrapped the copper tubing with the ceramic wool they used when they heat-stressed the pipe welds...water came out of the faucet hotter first thing in the morning than it ever did out of the water heater.

I had to re-do my heat tape...

 

[herm0016]

Pex will still freeze...unless you heat tape it, but it's much more resistant to breaking/cracking when the water inside freezes and expands.
You still work in the oil biz? Get some heat trace tape. That shit works GOOD for heat tape. I used some from one of our pipeline contractors when we were in Wyoming, wrapped the copper tubing with the ceramic wool they used when they heat-stressed the pipe welds...water came out of the faucet hotter first thing in the morning than it ever did out of the water heater.

I had to re-do my heat tape...

haha. yes, that would work. im not that concerned about it though. municipal water lines are put in at 6 feet here. yes, that is what i meant by freeze resistant, that the material will survive freezing with water in it. pvc will not, pex will, black poly will.

i joined an electrical contracting company and am in night school for my journeyman. quit the oil gig about 3 months ago.