Plastic pipe for underground?

[California]

I read Ultrarunner's recent thread on plastic pipe but I can't draw any conclusions from all the diverse opinions I read.

My location is similar to his (North Bay in this case) and the application similar:

The galvanized pipe from pumphouse to barn is rusted through and leaking, and another line beyond the barn sprung leaks in three places so I capped that one temporarily. One of these lines was installed in 1978 and the other a few years previous. Other lines here are open-air and were originally fed from a windmill and overhead water tank, so these might a hundred years old. We've replaced rusted out sections of the open-air pipes at several points where they sprung leaks. Its time to replace everything.

The water tests with acidity greater than is allowed for a municipal system and it has so much iron that galvanized pipe is choked with rust when I open one up. In some cases, plugged up in less than ten years. The soil also makes rust on tools and implements etc much faster than it should.

What should I use to replace these water lines? I assume some type of plastic pipe. And maybe a different type of pipe for the above-ground portions, at the pumphouse and for the outdoor sink etc. Freezing here is occasional, mild, rare - the open-air windmill tank lines never were damaged.

Something like PEX that can tolerate a mild freeze (with the water turned off) might work - except for its sun exposure aspect.

Any advice?

 

[boggen]

black plastic rolled pipe, heck if i know what the specific name is. i just goto local hardware store, normally menards, and you can get any thing form 1/2" up to a 2 inches. without special order normally. in 100 plus foot rolls. you can get up to 1000 feet plus rolls if special order. some pipe clamps and barb fittings and away i go. though i will place some silicon on the "nut area" of the pipe clamps after i tighten things up.

personally prefer something in 1" to 1.5" inside diameter. vs a smaller diameter. so i can get much more GPM (gallons per minute) and pressure at the faucet locations. if you ever had to deal with long runs of smaller size piping, you will have most likely notice initially you might get good water pressure and volume of water but after a couple minutes if that, it all slows down. this is due to friction loss within the pipe / hoses. bigger inside diameter = less friction.

by code for your area, you may need to bring water up out of the ground via a metal pipe. or a "metal cover" around the pipe. if this is the case, reduce pipe / hose size in the ground. and come up out of the ground with 1/2" or 3/4" size. for my own use, i just use "frost hydrants" or rather "yard hydrants" for everything not in a heated building / area. that way i know if i need to shut things off to keep from freezing, i know the water gets shut off down below frost line, and the water automatically drains out of the hydrant pipe that comes up out of the ground. granted i do get nasty cold 0 or below F temps here in winter.

pex is good and all, but can be rather expensive more so in the fittings and crimping tools. the stuff works. but for major runs say between pump pits and shed and/or house, prefer using large size pipe on them longer runs / main lines. and then down sizing when i get to a faucet or like. a word of warning not all pex and like pex system pipe/hoses are the same. some are not ment to be buried under ground.

normally all plastic pipes and plastic hoses need to be protected from the sun, or risk failure in the pipe/hose within a handful of years or less.

==========
when ya dig the trenches, you may or may not need good clean fill dirt to place around the hose / pipe. it might be worth having some nice clean fill dirt on hand. before digging trench. so you can get everything done in one go. without letting trench setting open for a couple days and letting rain destroy your trench.

 

[powerpace]

Iron pipe in the ground where I live will not last more than a few years. PVC pipe will last a long time if laid properly. The Ranch my Dad managed had two miles of two inch rolled plastic and white plastic pipe. Coming from a redwood tank fed by a spring. Drop was about four hundred feet. That line had been installed about twenty years previous. Trenched about two feet. Over the years some sections had been exposed but no problems.

I have over fifteen hundred feet of rolled plastic pipe 3/4" to 2" including down the well. All buried at least two feet. Galvanized and PVC where it enters a building.

 

[Carl_NH]

As Ryan stated poly pipe - 1" or 1 1/4" depending on if this is gravity fed or pump fed. If pump, 1" should be fine unless you have high volume requirements.

Don't go with the 100 or 160 PSI, go with 200PSI rated it has double the wall thickness and I would bury it 6 inches or so underground. You can do a trencher on the back of the tractor, or rent a pipe layer, or have a local irrigation co trench it in for you if a long run. Use brass connections, two clamps each side and have a small propane torch for warming the pipe up before making a connection.

If you are doing gravity feed, then you may want to increase the size of the pipe.

 

[California]

Good points. I hadn't considered high volume needs. The existing 1.5" water main was sized to gravity-feed from the windmill tower tank down to a big orchard spray rig.

The size needed now should simply flow the full output of the well pump. Anybody know the gpm rating for a well pump fused at 30amp x 220v?

My heaviest use will be filling my 300 gallon watering trailer parked at the well. Then household and garden lines out 100~150 ft. So maybe 1.5" to the manifold outside the pumphouse and its jumbo hose bib for the watering trailer, then separate 1.25" lines to the house, barn, vegetable garden. Ok, I'm one step farther along planning the layout.

200psi poly pipe sounds like a good idea. And stainless steel clamps. Brass or plastic barb fittings? Are there different quality grades or different fittings requirements depending on brand?

I'll consider Code for planning the project properly but I don't need inspection.

 

[hawkeye08]

when using poly pipe (black rolls), take into consideration that the connectors are installed inside the pipe and size up accordingly. Galvanized pipe or PVC has connectors that are on the outside of the pipe...

 

[boggen]

gray color sch80 pvc plastic fittings. is what i normally use. but i don't have a clue if to code. it just what has been used on this farm for years. and they last.

when using rolled up pipe. lay it out. err un roll it, let the pipe "weave" kinda like a snake in the trench. you don't want the pipe as straight as possible. but weaving. the weaving allows the pipe to flex some during any sort of ground movement and compaction of the ground over time. without causing the pipe damage.

run 1.5 all the way to everything, and then reduce right before going up to the garden hydrants. KISS (keep it simply stupid) vs trying to have a half dozen different pipe sizes and a variety of fittings.
i don't remember the numbers off hand any more. but 100 to 150 feet. and then the fittings do add up big time. in friction loss. more so at higher volumn flow rates. could mean a lawn sprinkler only shoot 10 feet away from it vs 15 feet away from it. being able to flush a toliet, while someone is in the shower (well i still don't recommend that) but... you might not get as bad as a sudden hot or cold shower. pending on your lines.

if you can afford the little extra cash for the large size fittigns and pipe. and for them longer runs go with a bigger size pipe. because once it is in, it is in, and no easy way to change your mind later.
1" bare min, 2" max suggested. 1.25" to 1.5" more likely good enough.

contact a wholesale electrical place near you to pick up some "trace wire" to toss into trench when ya do your piping. cheap insurance for years to come and finding the hose.

pototoe plow 3pt hitch, can work as a trencher, renting a mini ex (excavator) can make work good as well for trenching. call around if ya renting a mini ex. even if it is 30 mins to 1 hour away. if ya got the time. it may save you 100 plus bucks or more. prices range all over the place.

my personal preference is get below the frost line for any given area. but at bare min get below 2 feet. running heavy tractors and equipment (loaded down truck to semi truck and trailers) over pipe that is barely in the ground = smashed busted pipe. and trying to dig up 100 feet of pipe to find out were the problem is = putting in a new pipe most likely.

 

[California]

gray color sch80 pvc plastic fittings. ... has been used on this farm for years. and they last.

Aboveground included? - is Sch80 suitable at the pumphouse for the aboveground tees to the various circuits' shutoffs, and maybe even for the hose bib risers out in the garden? That would sure make installation easier.

I don't need to worry about frosty ground. Worst cold spell here will have daylight temps above freezing and maybe once in ten years a string of 22 degree nights. I can cover the aboveground stuff and drain most circuits when that rare chill arrives. Hmmm ... maybe I should shelter these tees inside the pumphouse.


Lots of good points in your post, and the ones above. The project is beginning to come into focus.

 

[boggen]

sch80 above below ground does not matter were ya use it BUT....
all plastic should be protected above ground. "end of story"

if ya use plastic above ground, put it into something, build something over it. "do something" over on www.koiphen.com they build a lot of liner koi / goldfish ponds. and alot of the plumbing for filters and like is above ground. some folks have spray painted there pipe, (pipe may need to be roughened up) certain types of paint work better than others and will not flake off as easily.

as far as garden stuff and like. were you will need to weed eat around, "protect" those pipes with metal outter casing or come up through the ground with metal. galavenized for example. plastic hose and pipe is way to easy to break. if you run plastic above ground. it needs to be supported. so the plastic own weight with water in it, will not break the plastic. plastic can get hard and brittle when above ground and more so in direct contact with sunlight.

build a small little "dog house" or "doll house" were the roof opens up like a hinged box, if need be, and toss your manifold (tees and valves) inside. or get a large cheap plastic tote from walmart or like when there on sale and toss over everything and toss a concrete block ontop of that to keep wind and animals from tipping it over.

if you have a pump house already toss all the stuff inside of it.

remember its not also the cold and or sun rays, but all the little bloody varmints, mice, squirrels, raccoons, or what ever pests you have, while they may not like plastic, they will and do chew into the plastic in rare occasions.

====================
never run pipe up and then back down (upside down U), or you will create an "air lock" that your pump or gravity feeding will not over come. if you have to run pipe up and then back down. install a "bleeder valve" in highest spot. to bleed out the air. while you may never really need to let air out once things are up and going. you will grumble and complain and carry on. once everything is hooked up. and your not getting the water flow or any water at all. till ya bleed out the air, if you run pipe / hoses up and then back down.

 

[oosik]

I have 1.25 inch black plastic roll pipe from my well to the house - about 125 feet. Installed the pipe in 1982 and its still as good as the day I installed it. Took the old pressure tank out of the well pit and put a new tank in the basement; summer of 2013. When we cut the plastic pipe the plumber & I noted that there was ZERO buildup of anything on the inside of the pipe.
Can't ask for anything better than that.