copper piping corrosion

[Chip Roberson]

I noted this corrosion on some copper piping in a basement and would like to find out what the possible causes or concerns of this condition are.

Thanks Chip

[Bruce Breedlove]

It could be flux in the solder.

[Jerry Peck]

It could be flux in the solder.

Yep, certainly looks like the flux was not wiped off.

[Scott Dana]

As a newbie inspector I'm still not clear on how best to identify copper pipe corrosion. Do you guys write up any time you see the green oxidation? What are some of the other signs that I should be on the lookout for in addition to what the picture shows. Thanks.

[Rick Hurst]

Scott,

Green oxidation on copper is the same thing as rust is to iron.

It is evidence of a leak. I always write it up.

[Scott Dana]

Is it really evidence that there's a leak or just that there is oxidation that may/can lead to leaking? I would be interested in know how you actually write it up.

[Brian E Kelly]

As I see it all the corrosion (green stuff ) is on the joints and that is the result of a plumber not wiping his joints from the flux. This is not necessarily a leak or a future leak. Try wiping away a small amount next time with a wet rag and the pipe under should be clean.
There could be other issues as the pictures and my eyes are not the best.

[Bob Harper]

Copper Pipe Information from PlumbingWorld.com (http://www.plumbingworld.com/cuno_info_page.html)

Generally, the green crud is from not wiping off the acid flux. FYI, a lot of schools teach techs to wipe the pipes down completely with flux to shine them up! No rinse cycle. I guess you could test the crud with litmus paper or wet it and sprinkle a little baking soda on it and look for a reaction but I don't know that is recommended anywhere.

HTH,
Bob

[Chad Fabry]

I guess you could test the crud with litmus paper or wet it and sprinkle a little baking soda on it and look for a reaction but I don't know that is recommended anywhere.


The acid in the flux is only acidic for a short time. It reacts with everything around it until it reaches the pH level of its surroundings. Testing for pH anytime farther out than few days or week at most won't yield quantifiable results.

Everything on Earth (or universe) wants to be the same temperature, the same pH, and the same level. It's only a matter of time.

[Randy Aldering]

The "green stuff" is oxidation. In these photos, it appears to be due to poor workmanship. Copper tubing, properly installed, will have wiped joints. Several of these appear to be "cold sweat" joints, sweated with water in the tubing, so the solder cools quickly, and appears dull grey instead of silver (unless lead solder was used, which is another thing). I have found pinhole leaks that have developed in as little as 10 years from failing to wipe off the excess flux from sweating copper tubing and fittings. This can be a real pain, particularly inside finished walls. It is always written up as corrosion. Dampness in the basement or crawl space will accelerate the corrosion, as the moisture does react with the flux.

[Bob Harper]

Pinhole Leaks in Copper Pipes - Marc Edwards QA (http://www.wssc.dst.md.us/copperpipe/copperpipewp.cfm)
Another article on the problem.
HTH
Bob

[Dave Rice]

My father-in-law has been a plumber for about 40 years and I asked him to make sure I am right such as the others are. It is more than likely poor flux cleaning when they sweated the pipes together. My father-in-law said if a copper piipe is leaking corrosion will not stop the leak usually and water drips will be present. I think like the others, its poor workmanship on the plumbers part. You will find a lot of that going around. lol.