pinholes in copper plumbing pipes

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George Stolz said:
Not exactly. Last time I'd checked in was this thread, it's been awhile. :)

http://terrylove.com/forums/index.php?threads/who-is-joe-tedesco.13681/
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Wow, read through the thread you linked and don't know which side I would team up with.

Seems Terry gave the reins to someone he knew little about in the first place so I give him the majority of blame for what happened. Moderators on sites like this one are only chosen from members that have some history on the site and those in control have some idea of what kind of a person they are putting in those positions.

I submitted a photo to EC&M years ago when Joe was behind the "what's wrong here" segment they have. I was not impressed at all with how he handled that either. His comments on the code violation in the photo were spot on, he changed the entire story behind how I found it and made me and my inspectors look like fools:( I got a message shortly after that was published from the State Electrical Division's director wanting to know which one of his inspector's passed that job, had to explain none of them did, was just something I uncovered and thought I would submit to that publication.
 
I used to post there. I do a lot of work on pumps and got some good info from some of the members so I thought it was fair to offer up some when I could be helpful.

It was a pretty good site until Terry "upgraded" it to support more advertising, now my anti-virus settings kick me out because of spyware issues.

When I did check in Mike Whit moderated the electrical portion and did a good job. I was impressed at how even handed he handled things.
 
Eddy Currents

Eddy Currents

edward said:
How does the process work?
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Prior to electricity, eddy currents referred to small swirls of water that developed along a flowing body of water. These often erode away at the edges of the body of water, the same thing happens in pipes. Any deformity inside the pipe, no matter how slight, will create these eddy currents and they will, given enough time, erode away the pipe wall.
 
Another interesting tidbit is that a fluid flows through pipe in a vortex with the greatest velocity occurring approximately r/3 from the center whereas r= radius.
 
GoldDigger said:
One mechanism is that very turbulent water produces an actual negative pressure region in which a small bubble forms and then collapses, causing a hydraulic shock wave that produces very high surface velocities and forces.
A similar mechanism causes cavitation in poorly designed propellors or ones which are used at too high a speed. Again the symptom (besides inefficiency) is corrosion to the metal surface.
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At the flows typical in a residential setting, not likely. Moon-made-out-of-green-cheese not likely, absent some truly amazingly poor installation practices. A 10 gpm flow in 3/4" "K" tubing is around 8 ft/sec. That's the max velocity recommended by the Copper Development Association for any pipe size. I found a discussion on line regarding propeller tip speeds, and the suggested limit was about 100 ft/sec. So unless something is hideously wrong with the installation cavitation isn't likely. On the other hand, the same reference does discuss pinhole leaks and points to water chemistry as the likely culprit.
 
Have also seen some studies that relate to the sloppy soldering techniques/excessive use of flux that remains in the piping system.
 
Quick close valves cause water hammer in a piping system. Examples of quick close valves are dishwashing machines, flush valves (Sloan valve on a commercial water closet or urinal), and lavatory faucets with auto turn off.

Code requires a hammer arrestor in such applications.
 
My sister had the same problem in the hot water lines at her house about 15 years ago in different areas at different times. She had a circulating pump so they would have hot water instantly. After the second time they disconnected the circulating pump and never had any more problems. Maybe having the pump was just a coincidence, I don't know for sure.

They replaced the copper pipe with some type of flexible tubing (PEX??) and then had trouble with the connectors growing some kind of mold almost instantly. Turns out those connectors were not compatible with the tubing.

I was so proud of her as she finally had to get someone from the water company, water softener rep, and the plumber there at the same time. All the fingers pointed to the plumber. The water softener guy said the incoming water almost did not even need softened.

The plumber agreed to change out the fittings at no cost (imagine that) then promptly failed to change out 4 or 5 in a crawl space. She found them shortly after he left the first time and made him come back to change them too. He wasn't happy about that. As I said, I've never been prouder of her.
 
This has come up before and will not be a grounding issue. We were discussing pipe corrosion today at our monthly meeting and its a very complex subject, but it almost always is a water quality issue that causes corrosion.
To start get a copy of the customers water supplier Consumer Confidence Report, it gives the results of certain required water tests, in particular look for the compliance with the EPA lead and copper rule. Water with a low ph erodes the protective oxide layer on the inside of the pipe, and causes lead corrosion (sound familiar? This is what happened in Flint, MI)
Our water system adds caustic to raise the PH from 7.4 to 8.1
And I have reports from the American Water Works Association that states pipe corrosion is caused by DC current, not AC. very rare to find DC current on water pipes.
 
tom baker said:
And I have reports from the American Water Works Association that states pipe corrosion is caused by DC current, not AC. very rare to find DC current on water pipes.
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Maybe rare to find externally applied DC, but if you have copper, zinc and an electrolyte all in same system you have a battery.
 
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