http://www.diy.com/nav/fix/plumbing/plumbing-supplies/plumbing_fittings/-specificproducttype-pipes/Polypipe-25mm-x-25m-MDPE-Pipe-11478225?icamp=recs

(usual disclaimer)

Usually buried. Wide range of fittings. A pan-UK standard.

Thanks for the link PWS - I will look into this further.

Have you thought of calling or stopping in at your local plumbing supply store?

Even Home Depot and Lowe's usually have people knowledgeable on the subject and codes.

The best answers will come from a professional in your area that understand local codes. What works here is not necessarily applicable to your local.

Yes, have thought about it stopping into a big box.

In the past, information has not always been reliable.

This is why I research myself and ask questions from trusted sources (CR4) and local professionals.

As far as my local codes, being in the middle of no-where, a 30" minimum depth, anti-backflow valve, and local source supply valve (yes, I checked with the AHJ) are all that is required for this type of installation.

Thanks - KJK

If I were in Minnesota, at the "little house" I'd go the the only lumber/hardware store in area and ask Eldon what he sells the most of.

Pex, (crosslinked polyethylene) is probably the most durable. And more expensive.

Properly installed, and bedded, I'd say that PEX would last well over 100 years in the ground as opposed to only about 50-75 for straight PE pipe. (I have some that old on the farm in Ark. installed in the well in 1952)

Rocks have a way of finding underground pipes so, proper protection from sharp rocks is essential.

Whatever you do go 3/4, or larger. Bigger pipe = less internal stress, but 50 PSI isn't much for either.

Not much help really, just go with whichever plastic you prefer.

Hey Lyn,

Thanks. I looked into PE and chose PEX because of what you indicated, "rocks" and in my case tree roots and occasional heavy (20 and up to 50 ton) equipment criss-crossing the route.

I'll backfill with a sand bed and the rest with clear spoils tamped in through several lifts.

A neighbor is lending me his field tile trencher. The trench will be so narrow, I see no need to route the PEX in a conduit.

I can get 300' (the length I need) of PEX from Lowe's for about $130 which will not cut into my beverage fund to badly The fittings will be few and the crimp tool is only about $8.

Just wanted to check in here and ensure I was thinking along the right lines. I have a few buddies here that I knew would have working experience and would not steer me wrong.

Thanks again - KJK

Quote - "and the crimp tool is only about $8." - From Lowes? Are you talking about the tool for the cheap clinch rings? These are no good for underground. You need the proper crimp rings and the tool for these was $49 when I worked as a department manager of plumbing at Lowes

My bad and you are correct - While at Lowe's last night I saw that they are about $50. I was looking at the wrong tool on line.

Thanks - KJK

Hi bigg,

Good point - never though of the importance of NOT running straight and tight.

Thanks for the input. I will leave some "lanyap" when I'm laying it in.

Regards - KJK

I would go 1 1/4" or as large (less pressure losses) as the budget will allow with poly pipe (water pipe not the thin walled garden retic stuff) and the readily available spanner tighten compression fittings where required. It comes in set length rolls or can be ordered to spec.

Hi Doggoneit,

My concern with going with a larger pipe is as follows;

My well water pressure is fair at best. My theory is that if I go with a larger diam, the tube will fill and pressurize when the yard hydrant is off. When the valve is then opened, initially you will have good pressure and flow until until the pressure reduces from use and water delivery decreases.

I base this on 1" tubing I got from a buddy of mine to use for watering. He gave me about 200' and the symptoms above are what I experienced.

The 3/4" garden hose I have been dragging around has worked well with adequate flow and pressure.

Thanks - KJK

It looks like the coefficient of linear thermal expansion for PEX is about 0.2mm/m/deg C. I don't know how much temperature change you get 30" underground. But, this would let you do a quick estimate of how much "lanyap" you need.

Thanks for the info polymerfan!

Given that the bury depth is 36-inches, the ambient earth temperature should remain fairly constant throughout the year at around 52 degrees F, plus or minus.......it's highly dependent of his actual location....

Since I don't know where KJK lives in the US, together with the typical frost penetration depth there, a conservative low value should be used (say for the midwest...corn belt) of -20 F. that should cover all bases unless some more pertinent low temp value is supplied.

http://en.wikipedia.org/wiki/Lagniappe may be helpful to anyone wondering what is meant by lanyap.

Ron - Thanks for the link - KJK

You seem determined to use PEX but you should go larger than the 3/4 you say is adequate. PE will stretch and move and will not be an issue with offsets, rocks, or roots. Use a minimum of UL 100 (100 psi rated) or higher (170 psi is available) rating and at least 1 inch id. That will give you a little leeway with pressure drop over time. The lines will diminish in diameter after extended use due to encrustation. If you are absolutely sure you have what you need, hell you don't need advice.

One other issue with yard hydrants, they are designed to drain water out of the riser stem to the base when they are shut off. Make sure you install some gravel under the hydrant to allow for drainage. The riser stem is designed to flow with gravity and will only flow to the top of the water table. If the water table is high and frost can penetrate most any depth then the water in the riser will also freeze. That will render your hydrant useless in the winter or worse if a riser actually cracks or freezes in an open position. If you cannot overcome the frost problem, then a heat trace will be required from the hydrant handle to the bottom of the hydrant. Other than those little issues they work well.

Kevin,

Some very good points to consider. I was familiar with the French drain style of the hydrant and the needed bedding.

My significant water table is about 42" below grade, I plan on installing the hydrant 36" below grade. Hopefully I will not have a problem with freezing.

Another plus is that I blow my existing irrigation lines (installed by previous owner) out with an air compressor in the fall. So far, no problems with freezing.

The PEX I picked up is rated at 160PSI

Thanks for your input - KJK

Kevin is right, make sure you have a good gravel subbase under those yard hydrants, otherwise you will erode the soil backfill around and under the hydrant when they drain.

If you experience sub-freezing whether during the winter months then make absolutely sure you that can drain the entire water line and each yard hydrant, otherwise any water that is left within the line will freeze, expand, and then bust your expensive PEX line.

Make sure you have sufficient gradient downward from high points (say, at midpoint between hydrants) in the line back to a low point located at the yard hydrant. This is needed to facilitate positive drainage of the line.

Hey there Capt,

Yes, the gravel bedding under and around the French drain is very important.

I will be sure to watch the pitch.

As I stated, I have had good luck with blowing the lines out in the fall.

This line that I am putting in will be buried at 36" min so any trace amount of water left in the line should not freeze or any ground water that seeps back in through the French drain on the hydrant will be below the frost line.

Thanks - KJK

Hey there KJK, those are good practices that you're following. Blowing out lines with compressed air on irrigation/sprinkler lines is essential to prevent freeze/thaw damage. you wouldn't believe how many homeowners and commercial/businesses (not to mention golf courses) around here don't do it, thereby damaging their expensive systems! Stupid peeps do stupid things it seems.....I suppose they believe in propping-up the construction industry and irrigation installers in this neck of the woods, all at the expense of their wallets!!! LOL

Good style my man!

Good luck with your project!!! Post some pics here of the installation, especially during the construction phase!!!!

Thanks for the encouraging words, being a sparky, this is a bit out of my environment.

You read my mind - I will definitely post pictures!

Regards - KJK

Being a "sparky" isn't much different from being a CE.....for you, think of water flow in electrical terms......the higher flow of water in a much restricted pipeline results in high pressure losses due to friction (ie, smaller pipe sizes vs. larger ones) is much akin to pushing higher currents through restricted wire sizes, which in turn results in higher resistance and temps.....the two aren't much different.

Capt,

My experience with PEX has been less than stellar, replaced leaking under slab copper (it was corroding from the inside out) with PEX in the attic which also leaked (possibly due to UV exposure during or before installation, never froze), PEX is supposed to be able to expand to four times its diameter when frozen without bursting, but the fitting can still burst if the freeze is in the fittings.

KJK. you may be better served with a larger line because with a smaller pipe diameter you will experience greater pressure loss due to wall friction.

Some calculation examples using Schedule 40 PVC (losses w/ PEX will be similar):

FLOW PRESSURE LOSSES IN PSI/100 FT. FOR VARIOUS PIPE SIZES

(GPM) 3/4" 1" 1/5"

5.0 2.75 0.835 0.071

10.0 9.99 2.99 0.361

For 300 feet of pipeline, multiply the friction pressure losses listed above by a factor of 3x.

If you have limited system pressure in the house you may want top elect going with at least an 1-inch diameter PEX line instead of a 3/4-inch one, but then again economics do come into play as well and what you can afford.

Thanks for the calcs

Thank you to all for the guidance and suggestions!

The project was a huge success!

The water line was part of a larger project, 450' of drain tile.

Talk about dodging the bullet - 1 mile to the south, it POURED!!!!

Many thanks to the crew!

Well Done!!!!! Thank Heaven for modern tractors and implements. And friends!

Thanks Lyn - Could not have done it without you

KJK, many thanks for the pics! Looks like a very successful DIY project!

I hope you tapped the half keg and served your "help"! BBQ anyone????!!!!! LOL

Hey there Capt,

Oh yes, we ate and drank very well.

The girls cooked up a feast for us!!!!!

Good time had by all!!!!

Nothing more American than a day of hard work with good friends/family followed by brewskis and fantastic food.....sorta like a barn raising for days past!

Glad you had friends and family over to help you realize your project!