Water pipe replacement materials?

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Rich Feldman
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Water pipe replacement materials?

Post by Rich Feldman »

This is off-topic except that it involves fluid leaks and conductance. So it's here in the section reserved for ephemeral things (and neutron claims).

It's time to replace the 60-year-old buried water pipe that runs from meter to my house. It's nominal 3/4" galvanized steel, and developed an expensive leak very close to the house end.
snip493.JPG
After that discovery, house water supply was switched to a garden hose connection from a gracious neighbor. Then back to my own water meter, through a kluge connection to old pipe upstream of the break.
snip563.JPG
I've been talking with plumbing contractors about digging up and replacing the whole 82-foot (25 m) run, which is about 18 inches deep in soil that never freezes. Directly-buried copper pipe is common around here, and that's what most of my shockingly-high bids are for. Most of my friends and family recommend PVC pipe to save money. Both are permitted by the 2016 California Plumbing Code and by my city (the AHJ = Authority Having Jurisdiction).

One contractor says he uses Schedule 80 (extra thick) PVC in new-house jobs all the time, and that it's better than copper. Last week I'd decided to go with Type K copper pipe, the thickest standard (0.065" wall). There are parts of the USA where Type K is mandatory for buried copper in domestic water service. But my local hardware stores and big-box stores carry only Types L and M (0.040" and 0.025" wall), in fact their helpers didn't even know that copper pipe came with lettering colors other than blue and red. There are 90 feet of 3/4" Type K waiting for me at Grainger in San Jose, at about $4.35 per foot, but the most recent contractor tells me it's a waste of money. He would upsize to nominal 1" type L, which he surely has tons of. I looked up tables of dynamic pressure drop, and he has a good point if I'll be using outdoor sprinklers for irrigation.

Comments and stories welcome, if offered within the next couple days.

Oh & by the way, copper pipe joints embedded or covered in concrete "shall be brazed using a filler alloy melting at not less than 1100° F."
All models are wrong; some models are useful. -- George Box
John Futter
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Re: Water pipe replacement materials?

Post by John Futter »

Rich
here in nz, land of earthquakes we used galv steel pipe until it did what yours has done
we now use HDPE colored blue for water yellow color for gas
This stuff is not cheap but very effective
a cheaper option is black HDPE that is used on farms to supply stock water same quality and dimensions as the blue
fittings from hansenproducts .com
guess what color pipe I use, it comes 100 yds down the hill from my header tank -its been there 35 years
Jerry Biehler
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Re: Water pipe replacement materials?

Post by Jerry Biehler »

The solder for copper above 1100F is called SilPhos. I hate the stuff.

You cant use PEX?
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Rich Feldman
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Re: Water pipe replacement materials?

Post by Rich Feldman »

I opted to spend a little extra for copper, 'cause of its long and successful history. At my wife's request I also had the contractor pull a building permit, so the job was registered & inspected by someone from the City. Might have saved a couple hundred dollars by using flexible HDPE, such as in John's comment above. It's uncommon in my neighborhood. One plumber said it was hardly worth the trouble for my relatively short run, esp. with a tee in the middle for existing hose bib and automatic irrigation.

Buried PEX is conditionally approved in California Plumbing Code 2016. "2. When PEX tubing is placed in soil and is used in potable water systems intended to supply drinking water to fixtures or appliances, the tubing shall be sleeved with a material approved for potable water use in soil or other material that is impermeable to solvents or petroleum products."

Yesterday my sister signed a contract to pre-emptively replace a buried polybutylene water supply line, installed in about 1990. Funny about that stuff. Polyethylene and polypropylene continue to be popular in all manner of things plastic.

It made me sad that my plumbing crew appeared to habitually:
* Leave the outside of soldered joint areas all greasy with surplus flux.
* Leave pipe supported by random high points on the undisturbed trench bottom soil. No rock-free bedding under, beside, or immediately over the pipe.
* Backfill 18-inch-deep trench with damp, clay-ey native soil up to full depth, before any effort to compact it. So what if they had a gas-powered jumping jack! Ever hear of filling in progressive "lifts"? Surface cracks are already apparent in places where the fill has settled from rain plus gravity.

On account of weather etc., the new pipe (in service) lay exposed for 11 days before inspection and 14 days before backfilling. I removed flux myself after watching a special patina develop around the joints.
patina.JPG
Well ahead of the backfilling guys, I got my pipe generally surrounded with sifted dirt (3/4" mesh). It's supposed to be trouble-free for the next 100 years! Better not be touching any sharp rocks, or differential concentration cells, eh?
corr2.JPG
Lots more detail at source: https://www.copper.org/resources/proper ... round.html
If someone were to point out that soil chemistry here is about as benign as anywhere, I would grudgingly have to agree. :-)
All models are wrong; some models are useful. -- George Box
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