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Discussion Starter #1
No, they wont admit it and keep blaming the dog, but I'm plumb out of answers.

The wife came into the house telling me that we have a flood going on from the irrigation hoop, and it's washing out the field road, and flooding the barn.
Sure enough, I get down there and shut off the ball valve to the filter hoop and Maezi injector, and it's coming out of the ground at a full 50gpm or better.
SOMETHING cut loose.

So half an hour and 3.5' of sand dug out later, I find this.
2.5" sched. 40 PVC pressure pipe. Collapsed like a cheap soda straw without breaking, cracking, or seperating from the 90 degree elbow that is just under the sand in the pic. Further down on the other side of the elbow, the PVC collapsed as well, and blew out a 1/2" sliver about 4" long..which is the leak.









Now here's the rub.
The night before, I filled the sprayer from the same line several times, and there was no issue with flow rate, and both spigots on the Chemical barn had the normal pressure.

I have never seen PVC pipe simply collapse without breaking or shattering first.

What is interesting, is the elbow glue joint held nicely. Another reason to love Christys Blue all in one PVC glue.:good2:

Anybody else ever see this sort of thing?

3.5' down in sand, so it's not getting vehicle weight, and the lines were drained for winter...Ice just shatters the PVC anyhow.

Tomorrow is all about digging, to find where the collapsing ends along the line, and deciding wether or not I'm renting a trencher and dropping 30K on installing new trunk lines. Anyone wanna buy a farm? :lol:
 

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That's crazy! It kind of looks like it was collapsed in by a vacuum, but I can't imagine what would cause a vacuum powerful enough to do that damage. You might be on to something with the alien theory.


Edit to clarify: I "Like" the effort and images you included with the post, not the damage to your irrigation system. Also, I might be interested in your farm, but not until you alleviate that alien infestation. :rocket:
 

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56FordGuy may be interested in your farm. He likes to be punished by his property.:mocking: He has a long standing hate relationship with the plumbing at his current place.
 

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I have seen this in higher temp situations. I do not recall finding it in irrigation lines. I will ask one of our plumbers about this tomorrow.
 

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Discussion Starter #6
That is strange Dingeryote. Have to wonder if it was a manufacturing fault.

Edit: Diamond Plastics - PVC Pipe For The 21st Century :dunno:
I have been wondering the same thing.

The outfit that did the install went under about three years ago. Owner was old, and was slipping mentally, and things just got away from him.
They had been in business forever locally though, and were famous regionally for innovations on Orchard irrigation, as well as fruit processing equipment.

The irrigation was installed right after Katrina when PVC was tough to source, so I wonder if the guys didn't get a batch of the chinese junk that was coming in. They wouldn't have used it if they knew, seeing as how they would have to come back and fix things at thier cost, and the crew is all local boys in good standing.

Gonna find out now that it quit raining. Back to the idiot stick this afternoon, and more digging.

At least I got the skeeters dosed yesterday..they were tearing me up something horrible.
I'll post pics of the section when I get it all out.
 

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Discussion Starter #7
I have seen this in higher temp situations. I do not recall finding it in irrigation lines. I will ask one of our plumbers about this tomorrow.
Ultra,

Thanks!

The collapse is about 1.5'-3.5' down, in sand, surrounded by trees.
The water table here is at about 4' in dry years. Definately cool ground, that never approaches the 70 degree point where PVC starts going soft.
No blistering, or other signs of heat deformation, and the organic matter(Roots from nearby Oak) near the pipe shows no sign of heat damage.

Now here's the real head scratcher.
It's a constant pressure system.:unknown:

There's a pressure tank and sensor that keeps the line charged at 50psi.
When a zone valve in the field opens, the sensor triggers the well pump on pressure drop, and 47-50psi is maintained even with an open 2.5" header line in the field, or 5A worth of drip lines opened for purge.

A vaccum would have to exceed neg 276psi AND the 50gal pump tank that is a constant 50psi.
That kind of vaccum would require moving a crapload of water somewhere near the speed of sound...and would be kind of an obvious event LOL!

I'm flummoxed, but not surprised.
If I do all the prep for the known and obvious, only the weird stuff bites me in the keester.
This is just one more strange bite scar.:lol:
 

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Discussion Starter #8
56FordGuy may be interested in your farm. He likes to be punished by his property.:mocking: He has a long standing hate relationship with the plumbing at his current place.
The plumbing here is normally sane and solid. Not many problems except for freeze damage exploding pipe now and then.

Ask him how he feels about bottomless mud, flooding, and pumping excess water.:laugh:
 

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Ultra,

Thanks!

The collapse is about 1.5'-3.5' down, in sand, surrounded by trees.
The water table here is at about 4' in dry years. Definately cool ground, that never approaches the 70 degree point where PVC starts going soft.
No blistering, or other signs of heat deformation, and the organic matter(Roots from nearby Oak) near the pipe shows no sign of heat damage.

Now here's the real head scratcher.
It's a constant pressure system.:unknown:

There's a pressure tank and sensor that keeps the line charged at 50psi.
When a zone valve in the field opens, the sensor triggers the well pump on pressure drop, and 47-50psi is maintained even with an open 2.5" header line in the field, or 5A worth of drip lines opened for purge.

A vaccum would have to exceed neg 276psi AND the 50gal pump tank that is a constant 50psi.
That kind of vaccum would require moving a crapload of water somewhere near the speed of sound...and would be kind of an obvious event LOL!

I'm flummoxed, but not surprised.
If I do all the prep for the known and obvious, only the weird stuff bites me in the keester.
This is just one more strange bite scar.:lol:
I have a few questions:
1) Do you have a booster pump down stream of this collapsed line?
2) Are you absolutely positive it is Sch.40 PVC?
3) Were there tree roots in contact of the pipe near the collapsed line?
 

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The aliens used a tractor beam to beam up several thousand gallons of water.
Wrap the new lines in aluminum foil.

Sorry for the less than helpful post.
 

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Discussion Starter #11
I have a few questions:
1) Do you have a booster pump down stream of this collapsed line?
2) Are you absolutely positive it is Sch.40 PVC?
3) Were there tree roots in contact of the pipe near the collapsed line?
Thanks again Ultra.

#1 No booster pumps. Don't need one, as the line emitters only need 15psi. Not much of any grade change either. 1-2' here and there, but the lines were trenched in with one of those new fangled lasers to avoid issues..unless the guys screwed up.

#2 I'm going to take a caliper to it in the morning. If it's not sch.40, it's pressure rated irrigation pipe, because that is all the company handled. Even if it's 200 pipe, it still takes a crapload of vacuum to collapse. I PAID for sch.40 though..

#3 No tree roots in contact. Several smaller roots, 1/2" dia. of no significance, a half foot or so around it.
 

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Discussion Starter #12 (Edited)
OK, Jed (The Dog the Aliens are blaming) and I dug things the rest of the way out, and lopped off 4' past the elbow, and a couple feet past the obvious collapse.

Then I stuck a light in the pipe looking for further weirdness, and found a couple dimples another foot down, so Jed and I did some more digging, and lopped off another 1.5', and looked again.
I could only see about 5-6' down the length, but it looked clear of Alien mutations and am assuming(Insert witty cliche' here)...I found the end of the extraterrestrial damage.




Another goofy.
I did install a Vacuum breaker to protect the pressure tank, and didn't remember until this thread.
It's the funny Copper thing, to the left of the controller sensor and hose bib. I checked it, and it's working freely with very little spring pressure to overcome. Less than 20' from the collapse. More weirdness.




Got things all glued up, and supported for the night, and will pressure test in the morning, and then get back to killing weeds and fighting the drip line leaks.



Thanks for the ideas guys!!
 

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Thanks for the ideas guys!!
My initial thought was heat damage; but I don't see how that could be the case.

It's tough to tell in a picture; but that cut end in the middle looks more like SCH 5 or SCH 10 than SCH 40. The O.D. will be the same regardless of schedule number; but the I.D. will change.

At my previous 'burb house; the turd who did the irrigation system used some SCH 5 or SCH 10 PVC, and the walls on that stuff are quite thin. Damned if I know where he bought it as it's not real common, and it can't be that much cheaper than SCH 40.
 

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mjncad, I didn't know SCH 5 or SCH 10 PVC pipe was even made? :dunno:
 

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My initial thought was heat damage; but I don't see how that could be the case.

It's tough to tell in a picture; but that cut end in the middle looks more like SCH 5 or SCH 10 than SCH 40. The O.D. will be the same regardless of schedule number; but the I.D. will change.

At my previous 'burb house; the turd who did the irrigation system used some SCH 5 or SCH 10 PVC, and the walls on that stuff are quite thin. Damned if I know where he bought it as it's not real common, and it can't be that much cheaper than SCH 40.
My Master Plumber has not run into this with SCH 40 PVC. I agree with Mjncad, on the pictures the pipe sure looks like a much thinner wall than SCH 40. There should be markings on the pipe to let you know the schedule of the pipe.

When the system was drained and then the valves sealed closed at both ends in warm weather, the air in the pipe will contract as the weather cools and the ground cools and can make a strong vacuum. Thinned walled PVC could be compromised by this. This is especially true on a long run of pipe. I am wondering if this may be the case here. The line could be vented to avoid this.

Other than that, possibly a bad run of PVC with thin areas in the pipe walls. Find out if it is truly SCH 40 and if it is cut the line on a collapsed are to see if the wall thickness varies.

Let us know what you find out. You have my curiosity up now.
 

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That looks to be very thin wall pipe. Are you injecting chemicals through the pipe?

When you drain the line next time, I would install a ball valve at each end to keep a vacuum from forming.
 

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4" Sched 40 pipe should have a wall thickness about 0.25"

Schedule 40 & 80 Pipe Dimensions

If it is Chinese pipe - I wouldn't trust the labelling on the pipe at all to determine what you have.
 

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An open to air valve anywhere along the run should vent it.
 

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Another question:

Did the ground freeze around the pipe and crush it while it was drained possibly?

I am not sure how deep the freezes up north hit you. I know it was a cold winter. The frost could expand the soil and add external pressure to the line while the inside of the line could have had a vacuum with negative pressure. Possibly that gets you into the psi difference to crush the line. I am just throwing guesses out there since I live in the Great State of Texas (the southern part of Texas even) and do not often deal with deep frost line issues. :lol:
 

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According to reports - the frost line went down almost 4.5 feet this year here in MI. Coldest winter in 130+ years.
 
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