# CPVC Failure



## Plumberman

About 2 1/2 years ago my company re piped about 200 ft of heating water supply and return underground with 6'' CPVC. We have had nothing but problems out of it. We have made numerous repairs of couplings and 45's It got so bad that we replaced the whole run, again it leaked. The glue joints are breaking. Had it tested by the glue company and by the manufacturer. They both blame each other. I am beginning to believe its something in the ground reacting with the chemical and the glue. Some of the fittings have blown completely off after months of being in service. Needless to say we are at our wits end and no one has any answers. I voted that we tear it all out and go back with steel, which is what they had in the first place. Electrolysis reeked havoc on the steel before. That's why they chose CPVC. Anyone ever ran into this?


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## Plumberman

Think I answerd my own question....

No allowance for expansion- CPVC has a greater thermal coefficient of expansion than other materials a plumber has traditionally used. In other words, it will expand more when used in a hot water application than other materials, such as copper. If this characteristic is not considered in the design and installation, disastrous results can ensue. CPVC expands 4.7 inches per 100 feet for every 100 degree Fahrenheit rise in temperature. In a multi-story building where long runs of piping are common, it is especially important to allow for this expansion. Every straight run of pipe must be provided with a properly sized and supported expansion loop. The expansion loop will absorb the deflection resulting from thermal expansion of the pipe. In the absence of the expansion loop, the expansion of the pipe will stress the fittings to the point of failure.


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## uaplumber

There was a strip mall in Edmonton that the engineer forgot to design expansion joints for. The plumbers did not notice. The water was turned on and the pipe expanded just enough to damage the end walls of the building. It was 2" copper lines.


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## Plumberman

I didnt know that CPVC expanded at 5 in per 100 ft for every 100 degree rise. The run is well over 200 ft. This has to be the problem. They are running their heating water at about 130 to 135 degress. The hottest they run is 140.


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## user4

Regular PVC has similar results, poly vinyl chloride in states like Illinois is a self destructing sytem because of the temperature changes, this was revealed ten years after the product came into general use, but by then it was too late, and companies worked on coming up with ways to compensate for the product defect, like using mechanical expansion joints.


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## Plumberman

What about glycol chemicals, I just read that they dont react too well with the glue.


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## user4

Plumberman said:


> What about glycol chemicals, I just read that they dont react too well with the glue.


The glycol systems I have worked on were done with very heavy schedule CPVC that we threaded and put together just like galvanized steel pipe, but that was many years ago.


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## Plumberman

This is Sch 80 CPVC. Everything I have read up on suggest that expansion loops are a must. And glycol based chemicals reek havoc on the glue joints. There ARE NOT any expansion loops in this system which is underground and they run glycol through their system


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## user4

You might want to compare replacing it with CPVC done correctly with threaded fittings against doing it in stainless steel with victaulic joints and stainless fittings, or even stainless steel with welded fittings.


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## Plumberman

This has been on going for 2 yrs and they finally put me on it, now I have to clean up this mess.


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## user4

Plumberman said:


> This has been on going for 2 yrs and they finally put me on it, now I have to clean up this mess.


Isn't that even more incentive to fix it right on the first try?


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## Plumberman

Killertoiletspider said:


> Isn't that even more incentive to fix it right on the first try?


Yeah it is, I wasent saying it was a bad thing. I just want to make sure that is exactly the problem before I bring my cards to the table. I feel pretty sure that is what is going on.


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## PaulW

As a side note:
Beveling the ends of the pipe are very important also. If your not already doing it. This prevents the sharp edge of the pipe pushing the glue out of the fitting.


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## Protech

I agree with KTS. Tell them to shell out the dough to go stainless. Get soil tested first to see if there is anyhing in it that will attack it.


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## Plumberman

We are installing expansion joints which should have been installed upon burial. This seems like a step forward.


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## Plumberman

Protech said:


> I agree with KTS. Tell them to shell out the dough to go stainless. Get soil tested first to see if there is anyhing in it that will attack it.


They did shell out the dough, a bunch of it. Now its on us....


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## ASUPERTECH

Killertoiletspider said:


> Regular PVC has similar results, poly vinyl chloride in states like Illinois is a self destructing sytem because of the temperature changes, this was revealed ten years after the product came into general use, but by then it was too late, and companies worked on coming up with ways to compensate for the product defect, like using mechanical expansion joints.


 
Hot water is not allowed in or rated for PVC??:blink:


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## Plumberman

It still expands and contracts.... KTS was pointing out that CPVC expands but PVC does as well


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## ASUPERTECH

I've installed expansion joints for all kinds of DHW systems and a few process systems. Used PVC for water services even, but I've never put an exp. jt. in on the PVC. Do I start to sweat this or what. I'm thinking not due to the avg. water temp. of the gnd water hear @ 77 F.


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## Plumberman

ASUPERTECH said:


> I've installed expansion joints for all kinds of DHW systems and a few process systems. Used PVC for water services even, but I've never put an exp. jt. in on the PVC. Do I start to sweat this or what. I'm thinking not due to the avg. water temp. of the gnd water hear @ 77 F.


Down here we don't either, our average is about the same as yours. He was talking about Illinois so I am not sure bout that one


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## masterk

Any piping used for heating, that is buried in the ground is going to give you a problem. There is no room for expansion and contraction with the earth holding it tight in place.
I would try installing the lines in a bigger concrete utility pipe using the utility pipe as protection and with room for movement.
Thats why they make concrete tunnels for steam lines that go under ground, buildings,etc.


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## Scott K

There is a seperate glue company from the manufacturer of the pipe? 

With Ipex for example, I'm pretty sure they make their own glue.

When you talk about expansion joints - are you talking about expansion loops (4 - 90's), or expansion joints like the ones that basically look like a bushing, a coupling, a reducing coupling, another bushing, and then a piece of pipe, and then a coupling types (ones I've used from Ipex on their Corzan CPVC).


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## Plumberman

CPVC Oatey glue is what was used. 

These expansions joints.....


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## SPH

hot water and CPVC is baaaad news. We do ALOT of repairs on this, especially recirc lines. That stuff really should be banned.


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## muck

We went to a class and thier big thing was the right amount of glue on cpvc. if the swab dripped then its to much glue. An excess of glue will make it fail and crack.


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## Cal

SPH said:


> hot water and CPVC is baaaad news. We do ALOT of repairs on this, especially recirc lines. That stuff really should be banned.


 There is a lot being used around here ( Wash. D.c. Area) . To be honest I have seen quite a bit that has been in a while and haven't seen many problems at all .

Still like copper .

Cal


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## Plumberman

Just an update, we went in and installed expansion joints in the lines. Even though I fought for a complete re-pipe. We went with the Metra Gator expansion joints, they run about a grand a piece but for the time being they are doing their job....


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## user4

Plumberman said:


> Just an update, we went in and installed expansion joints in the lines. Even though I fought for a complete re-pipe. We went with the Metra Gator expansion joints, they run about a grand a piece but for the time being they are doing their job....


For now.

All moving parts in a mechanical system are doomed to failure.


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## Plumberman

Killertoiletspider said:


> For now.
> 
> All moving parts in a mechanical system are doomed to failure.


Correct, thats why I mentioned for the time being, I just hope they fail after I retire....


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## Protech

I wouldn't sweat a pvc water service in FL unless you are running several hundred feet. The ground temps don't fluctuate as much as they do up north.


ASUPERTECH said:


> I've installed expansion joints for all kinds of DHW systems and a few process systems. Used PVC for water services even, but I've never put an exp. jt. in on the PVC. Do I start to sweat this or what. I'm thinking not due to the avg. water temp. of the gnd water hear @ 77 F.


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## plumb4fun

This is disheartening news. I recently installed at one of my schools an 80 foot supply and return run of 1-1/2" cpvc heating pipe underground between buildings and all I used was thermocell insullation and some sand backfill. It replaced rusted out steel pipe. I hope I don't have any problems. This was 6 months ago. I bought it from Ferguson and did some research to see if it was up to the application. The sales rep said it would be fine. We shall see.:whistling2:


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## ASUPERTECH

Protech said:


> I wouldn't sweat a pvc water service in FL unless you are running several hundred feet. The ground temps don't fluctuate as much as they do up north.


 Hey bud I was reading the last post and it got me to thinking, with these last 2 cold snaps, I have been doing alot of water service repairs and leak repairs over the last 1.5 months wonder if this is due to the larger and longer cold spells we've been having...
No warrenty calls though...


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## Protech

Are you thinking they are freeze damage?


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## ASUPERTECH

Protech said:


> Are you thinking they are freeze damage?


 Could just be the excessive thermal expansion that there not used to here in Pinellas County?


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## Protech

I wouldn't think thermal expansion would be an issue on the municipal system since many homes have PRVs on the mains and water heaters. Any thermal expansion would be released by the PRVs.


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## ASUPERTECH

Protech said:


> I wouldn't think thermal expansion would be an issue on the municipal system since many homes have PRVs on the mains and water heaters. Any thermal expansion would be released by the PRVs.


 Not many homes here with Pressure reducing valves, by law city cannot exceed 90 psi. For homes equipped sure thermal expansion devices could absorb it, but I think even in the normal operating ranges that are materials here on the pennissula aren't accostomed to. I can't remember having a temp swing in 2 days of 35- 40 since I lived in NY. Maybe it's just a phase but sure seems like alot. Who really cares, I'm working:thumbsup:


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## Plumberman

plumb4fun said:


> This is disheartening news. I recently installed at one of my schools an 80 foot supply and return run of 1-1/2" cpvc heating pipe underground between buildings and all I used was thermocell insullation and some sand backfill. It replaced rusted out steel pipe. I hope I don't have any problems. This was 6 months ago. I bought it from Ferguson and did some research to see if it was up to the application. The sales rep said it would be fine. We shall see.:whistling2:


It probly is, the problem that we were having was both boilers running at the same time in excess of 140 degrees. They also have an outside air sensor, to save on energy costs. When it is warm the boilers dont run as much, and our weather is crazy down here in the winter. It might be 70 for two days the drop to 20 for three. This is where all the expansion and contraction was taking place. It actully pulled the pipe out of the fittings because it moved so much, also the glue that was used wasnt bonding to the pipe as it should....


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## ASUPERTECH

Plumberman said:


> It probly is, the problem that we were having was both boilers running at the same time in excess of 140 degrees. They also have an outside air sensor, to save on energy costs. When it is warm the boilers dont run as much, and our weather is crazy down here in the winter. It might be 70 for two days the drop to 20 for three. This is where all the expansion and contraction was taking place. It actully pulled the pipe out of the fittings because it moved so much, also the glue that was used wasnt bonding to the pipe as it should....


Did you use 1 or 2 step glue/ primer?


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## Plumberman

ASUPERTECH said:


> Did you use 1 or 2 step glue/ primer?


Not sure I follow you on the one or two step. But we primed and glued. It was pre-insulated joints of pipe. The straight runs held becauses there wasnt any insulation on the last 6 ins of pipe. The problem seemed to happen when we had to make cut pieces and strip the insulation off. The coating was hard to remove even after hitting it with a buffing wheel.


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