copper water services corroding 1

[skillz]

I've had a contractor friend contact our company about a project that his company completed 18 months ago that has had some problems arise recently.

They completed a water main project and installed all water services. The Village has called him regarding leaks with these services, although they didn't know the reason why.

The contractor went out and dug up the locations of the leaks and found that the copper water services have corroded and are leaking already. Keep in mind this has only been 18 months since project completion.

We're baffled. Does anybody have any ideas what is going on here?

The location is a north suburb in Chicago.

 

[CarlB]

You'll have better response posting this in the Corrosion Engineering forum.

 

[skillz]

Thanks Carl!

 

[cub3bead]

What is the pH of the water and the LSI? You need those to determine if it is a water chemistry problem.

Since this problem has come up so soon after installation is it a galvanic or stray current problem? You didn't indicate whether the problem was above ground or below ground but have you checked the soils report for corrosivity?

 

[bimr]

cub3bead is on the right track. pH of the water and the LSI are required.

I will add that there is a well known corrosion problem in the collar communities around the Chicago suburbs that are served by well water. The corrosion is primarily due to low water pH. The low pH water will corrode copper.

However, this would be considered as a chronic long term problem and leaks should not occur in just 18 months. You may be dealing with two issues; firstly poor installation workmanship and secondly corrosion.

 

[dicksewerrat]

You should also check the Ph of the soil around the pipes. Some people are building on old dump sites and ash is very corrosive.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[cvg]

you might also assume that the installed piping (as manufactured) was defective - although this may be difficult to prove...

 

[skillz]

This is Lake Michigan water. The corrosion appears to start right at the flare of the nut that screws into the shutoff valve. It looks like a typical 1" of 1 1/2" copper water house service.

I do have pictures, but do not know how to post them here, and I do not have a website where I can put them up on. Does anyone know how to post them, or give me an address to send them to for more advice?

I have also posted this in the corrosion engineering forum as recommended, but it is getting views here as well.

 

[skillz]

this was just posted at corrosion eng. as well, but thought some might like to see this:

I uploaded the pictures at

http://www.tinypic.com

Search for images CopperCorrosion1 and CopperCorrosion2 and you'll see what I'm talking about in this case.

http://tinypic.com/tags/?tag=CopperCorrosion1

http://tinypic.com/tags/?tag=CopperCorrosion2

Metengr is right, this is Lake Michigan water and should not have any problems with pH. I could see it in some far NW or SW outlying suburbs that have well water, but not in this particular community.

 

[LHA]

Chlorine corrodes copper. From the pix, it looks like very localized attack. Is the corroded area near a chlorine injector? If so, I would reduce the cl2 concetration, by either diluting the cl2 prior to injection, or adding multiple injection sites.

Remember, amateurs built the ark...professionals built the Titanic. -Steve

 

[skillz]

Here are some more pictures, you can see what's going on a little better here. Any feedback you all can provide would be great. Thanks

http://i1.tinypic.com/s18cpz.jpg

http://i1.tinypic.com/s18dh4.jpg

http://i1.tinypic.com/s18dnq.jpg

http://i1.tinypic.com/s18dtw.jpg

 

[bimr]

You have not mentioned any complaints by users of blue water or green staining of porcelain plumbing fixtures, improperly. Also, the pictures do not show blue green corrosion either. Blue water or green staining would indicate corrosion due to the water.

cub3bead suggested getting the pH of the water as well as the LSI. The corrosion looks severe enough that so you probably should get a complete water analysis.

However, knowing the water quality of Lake Michigan, it is unlikely that you are experiencing corrosion from the water.

It is more likely that you are experiencing corrosion on the outside of the pipe as shown in your 4th picture.

You can use the information from Cast Iron Soil Pipe Institute to determine if the soil is corrosive. The information contained in American National Standard A21.5, American Society of Testing and Materials A674, A74 and A888, and American Water Works Association Specification C 105 provide installation instructions and an appendix that details a 10 point scale to determine whether the soils are potentially corrosive to cast iron. Information on this Standard is available by emailing the Cast Iron Soil Pipe Institute and its member companies.

Here is a good discussion of copper pipe corrosion:

http://www.wssc.dst.md.us/copperpipe/copperpipewp.cfm

Other than that, you need to provice more information. Everything else is speculation.

 

[hydrae]

For corrosion that fast I would suspect stray current
The fact that it is most evident at the corp also leads me in that direction.
Check the electrical grounding of the houses (if you can), did the electricians skimp on the ground rods and are just using the copper water pipe as ground and or worse the neutral?
You can check the current through the service line by using a clamp-on ammeter around service line

A broken heater element inside the hot water heater can also cause a lot of stray current through the water line, in that case the current would not be continuous.
Hydrae

 

[rconner]

I have no experience with corrosion of copper pipe but believe cub3bead, hydrae, and others have probably given you some very good suggestions (the keys to such diagnoses being the very "localized" nature and apparently very rapid attack, perhaps electrical in accordance with Michael Faraday's law). If a stray current survey (current could be from virtually any source or direction, but leaving the pipe at that specific point of attack?) does not reveal the presence of any current, and/or if there is no significantly corrosive environment, about the only other thing I can think of would be if there were any high velocity water leaks at the flared locations. High velocity water, in little whirlwinds or vortexes picking up abrasive sandy soil particles from the backfill?, could perhaps blast through even metal rather rapidly, and leave a smooth polished surface on some exterior surfaces as may be eveident in some pictures.

 

[thewellguy]

I would also look into stray voltage/current. I install many waterline in the Chicago area and have never had a problem like that. Also could it be electrolises. What it the end of the copper pipe hooked to

 

[Pump2005]

Is this a brand new development? What was buried there? A check of the soil would be the first thing. I have seen soil corrode copper but not in that fast of time. Over years. I would also look at the services being made of bad or damaged copper tubing. Damage to a pipe prior to being installed will definitely turn into a problem down the road.

 

[bimr]

Maybe this article will help:

http://www.copper.org/resources/properties/protection/underground.html

"It is also known that improperly prepared or installed flared tube joints on underground service lines, caused by the presence of residual burrs on the seating surface, can result in localized erosion and corrosion. When this occurs, the problem is readily recognized by the U-shaped pits on the affected areas, which are essentially free of residual corrosion products (figure below). "

 

[ddnaomi]

Is the main line ductile iron or PVC. If it's PVC then the connection is very close to the end of the copper line. As an experiment try inserting a length of CTS polyethylene tubing between a replaced copper connection and the house. If there is a stray current from an electrical ground the corrosion will occur at the connection to the CTS poly tube because the poly tube will act as an insullator. I would think there is a stray current at these locations. Several questions do need to be answered though

1) Is this happening at ALL the connections?

2) Has anybody exposed a connetion that was not leaking to check it's condition?

3) If the connections that are not leaking in good condition then is there a stray current at the connections that are leaking?

4) Why are they installing copper pipe when Polyethylene tubing is available? That's all I ever spec and haven't had a problem in years.

5) Obviously they have other service connections on other parts of the system and they don't appear to be having problems. Are there any significant differences in the new installations vs. the old ones?

 

[JustinJones]

no anodes were installed on any of the services?

 

[rconner]

In the area of the ANSI/AWWA C600 installation etc. standard where it talks about mains encased in polyethylene, this standard also contains the requirement, "Service lines of dissimilar metals also shall be wrapped with polyethylene or a suitable dielectric tape for a minimum clear distance of three feet (0.9 m) away from the gray-iron or ductile iron main."