Just replaced 500′ of sched 40 1″ PVC water line that had been in 25 years. I had put in 20′ sticks and had four leaks since Jan 1 in the old pipe. All the failures occured in the bell end as the curve was transitioning down to it’s long thickness. Pipe was buried 12″ to 18″ deep, in sand. Material was brittle when removed. Had green lettering on the outside. Pressure is between 60-80 PSI for years. This is central Texas, with temp extremes of 15 degrees to over 100. Any ideas?
Thanks
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bump
I'm no expert, but it sounds to me like someone used Sch 40 electrical conduit for water line. Belled pipe is not a common product for pressure situations. Frankly, I'm surprised it lasted this long. If you think about it, the process of belling the end of PVC likely makes the material thinner at that point.
I see belled pipe installed pretty much all the time for water pressure. Get it delivered straight from the plumbing supply. My bet is it wasn't conduit.
Did any of the failures look like abrasion?
No abrasion, and it wasn't conduit. The pipe we replaced it with was belled also. The fractures occured in the reverse curve of the bell. each about 1/2" long and running perpendicular to the length of the pipe.
perpindicular? hmmm... gradual radius for the trench and nothing too sharp for the pipe?
These were on straight runs. All PI's had fittings. No bends.
Was there any place for expansion?
With 500 ft it is going to move a bit.
And why didn't you go back with PE? You can get that in 250 and maybe 500 ft spools.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I'm no plumber, and have always used PVC. Never even occured to me. That's what I pay the frickin' plumber for...
Black poly pipe has been the standard in the NE for years.
Could the pipe have been exposed to sunlight (UV rays) longer than it should have been.
I cringe everytime I go by this one particular landscape irrigation outfit that has racks of PVC sitting outside uncovered. Not a good thing long term.
Don't know how he stored it. It was 25 years ago. If I hadn't have made as-builts I wouldn't even remember where the damn runs were, except for the bib risers.
Anyway, DW and I finished up cleaning up and leveling before the rain hits this weekend. After it gets some rain on it I can roll it better. Then I got to put the 8X8 cinder blocks in with concrete on the bib risers.
After the rain, oughta be some hand-axes and points show up...
There was something wrong with the pipe from the get go. I have installed 1/2 " up to 12" with glued bell end. Never seen a problem. Have dug up old pvc and the joints are as strong as new. The bell end is swaged during manufacturing and perhaps that was wrong or the chemical makeup was off. More than likely all of the pipe was from the same shift and batch of pvc so they will all show this defect.
Well, it's history now. Thanks for the input.
One possibility not yet mentioned is turbulence.
If you had high flows in the pipe the pipe would have been best installed with the bell end toward the supply end to minimize high Reynolds number at the joints. If hihg flow and turbulence was the cause of faiure I'd guess that the bell ends faced the house.
Super high flow rates can destroy PVC bell joints (or at not fully mated coupling joints) in a few years, low flow rates and it wil last almost forever underground.
It was just residental type flow rates. It was in-ground 25 years. The bells were joined with the flow direction, like the first stick from the meter had the bell on the other end.
It's really no big deal. I've replaced the line, but just wondered what the life would be. Hopefully, I'll be taking the dirt bath before I have to do this shid again.
Thanks for the input.
I have seen some bell ends that were severely softened due to excessive primer or glue. As you know, the primer and glue are both PVC solvents and if they put too much in the pipe, it could have softened the joint, the bell end being the most vulnerable location.
Bruce
I was thinking that too. But would it take 25 years to show up? We need a PVC archeologist. I got samples too. A lot of the pipe was real brittle, and some was normal. I bandsawed the joints apart, and the fracture went al the way through beyond the end of the mating piece. Just about 1/8" from the end of the stopping point of the mating end. Didn't see any erosion, just a hairline crack.