# Copper pipe pitting - Possible causes?



## gmchiurazzi (3 d ago)

Hello everyone,

I have a client who is experiencing pitting/spalling on the interior of their domestic cold water system. Nothing is chemically treated or softened, and the buildings on both sides of this one aren't having problems. Off the top of my head all I can think of is possibly electrolosis - Any ideas on what else might be causing this?

Many thanks!


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## Tommy plumber (Feb 19, 2010)

What part of the county?

There are different theories.
One that I tend to think is the most plausible is impurities in the copper tubing. The impurities leach out and holes develop. Similar to de-zincification.

But this is a site for professionals only. 

Are you in the trade?


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## Master Mark (Aug 14, 2009)

gmchiurazzi said:


> Hello everyone,
> 
> I have a client who is experiencing pitting/spalling on the interior of their domestic cold water system. Nothing is chemically treated or softened, and the buildings on both sides of this one aren't having problems. Off the top of my head all I can think of is possibly electrolosis - Any ideas on what else might be causing this?
> 
> ...



Its probably an electrical grounding issue...... the electrical box has a ground rod somewhere
and that has become loose or broken off over time.... Then the back up ground on the plumbing system
gets hit with all the surges and sometimes it cannot ground itself properly out the water service so it
eats up the water heaters and thins the copper water lines down to beer can thin... 

we run into this all the time -- you need some new grounds installed and see if that does not help


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## gmchiurazzi (3 d ago)

Tommy plumber said:


> What part of the county?
> 
> There are different theories.
> One that I tend to think is the most plausible is impurities in the copper tubing. The impurities leach out and holes develop. Similar to de-zincification.
> ...


I'm in the southwest (Phoenix AZ). I'm not a licensed plumber, but I've been invloved in plumbing engineering for going on 35 years (hopefully that qualifies). I'm asking here because long ago I learned that the guys in the field know a heck of a lot more than the folks with college degrees...


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## ROCKSTARPLUMBER (Dec 14, 2008)

gmchiurazzi said:


> I'm in the southwest (Phoenix AZ). I'm not a licensed plumber, but I've been invloved in plumbing engineering for going on 35 years (hopefully that qualifies). I'm asking here because long ago I learned that the guys in the field know a heck of a lot more than the folks with college degrees...


thank you for saying that. Ego checked at the door. Not many can or would do that.


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## sparky (Jan 8, 2014)

gmchiurazzi said:


> Hello everyone,
> 
> I have a client who is experiencing pitting/spalling on the interior of their domestic cold water system. Nothing is chemically treated or softened, and the buildings on both sides of this one aren't having problems. Off the top of my head all I can think of is possibly electrolosis - Any ideas on what else might be causing this?
> 
> ...


We don’t know nothing about electricity,this is a plumbing only forum 😜😜😜😜😜😜😜lolololol


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## sparky (Jan 8, 2014)

gmchiurazzi said:


> Hello everyone,
> 
> I have a client who is experiencing pitting/spalling on the interior of their domestic cold water system. Nothing is chemically treated or softened, and the buildings on both sides of this one aren't having problems. Off the top of my head all I can think of is possibly electrolosis - Any ideas on what else might be causing this?
> 
> ...


What type of blding is this and what is it used for???


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## Plumbus (Aug 4, 2008)

There is quite a bit of literature on the subject.
For a start, try googling "corrosion erosion".


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## gmchiurazzi (3 d ago)

ROCKSTARPLUMBER said:


> thank you for saying that. Ego checked at the door. Not many can or would do that.


LOL I'm not a college grad, not an engineer, just a dumb plumbing designer...  I've been told I'm too extroverted to fit in with engineers. I try to tell the kids these days to spend time in the field and keep yer yap shut - just listen and learn. When I was a pup I used to get out and ask the tradesmen what they thought of the drawings (without telling them I designed it). I got my ass kicked a bunch but if you don't understand how the guys in the field think you'll never be any good at it!


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## gmchiurazzi (3 d ago)

Plumbus said:


> There is quite a bit of literature on the subject.
> For a start, try googling "corrosion erosion".


Yea, I have reams of it, but I've never seen this type of deterioration. It's not erosion corrosion, it's not from burrs in the piping, it's almost like the crappy cast iron - the problems are everywhere.


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## gmchiurazzi (3 d ago)

sparky said:


> What type of blding is this and what is it used for???


The building is actually a forensics lab, but the only piping experiencing the problem is the domestic cold water serving the cooling towers. The rest of the building is fine as far as anybody knows. No water treatment, no softeners, water is probably in to 20-30 g/gal hardness range.


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## sparky (Jan 8, 2014)

gmchiurazzi said:


> Hello everyone,
> 
> I have a client who is experiencing pitting/spalling on the interior of their domestic cold water system. Nothing is chemically treated or softened, and the buildings on both sides of this one aren't having problems. Off the top of my head all I can think of is possibly electrolosis - Any ideas on what else might be causing this?
> 
> ...


Is this M or L copper!?????


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## gmchiurazzi (3 d ago)

sparky said:


> Is this M or L copper!?????


I believe it's type L.


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## jim285pro (Sep 3, 2020)

What in tarnation is a plumbing designer?


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## gmchiurazzi (3 d ago)

jim285pro said:


> What in tarnation is a plumbing designer?


We're sorta like the whores of the engineering world. Too cool to be an engineer, too dumb to go to college. We make the engineer of record look good at a fraction of the cost...


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## TerryTotoSucks (5 mo ago)

What professional license do you hold ?


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## gmchiurazzi (3 d ago)

TerryTotoSucks said:


> What professional license do you hold ?





TerryTotoSucks said:


> What professional license do you hold ?


That's the beauty of it... None. I'm a Certified Plumbing Designer (ASPE) and an NITC Certified ASSE 6020 medical gas inspector, but I don't consider those on the same level as a PE.


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## skoronesa (Oct 27, 2015)

gmchiurazzi said:


> The building is actually a forensics lab, but the only piping experiencing the problem is the domestic cold water serving the cooling towers. The rest of the building is fine as far as anybody knows. No water treatment, no softeners, water is probably in to 20-30 g/gal hardness range.


It's likely because the re-circ. pumps run constantly. Fittings/valves introduce turbulence which causes erosion, as @Plumbus mentioned.

This can be mitigated by upsizing piping, slowing pump flow rates, insuring that all piping is properly reamed, and removing any debris from the system.


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## TerryTotoSucks (5 mo ago)

Send your failed piping samples here for testing.








Pipe Failure Analysis


ATS' material, mechanical and metallurgy labs perform pipe failure analysis. Our experts perform inspections in the lab and out in the field.




atslab.com


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## sparky (Jan 8, 2014)

skoronesa said:


> It's likely because the re-circ. pumps run constantly. Fittings/valves introduce turbulence which causes erosion, as @Plumbus mentioned.
> 
> This can be mitigated by upsizing piping, slowing pump flow rates, insuring that all piping is properly reamed, and removing any debris from the system.


I Dont think this is from a pump turbulence,there is big chunks out of the pipe,I never seen nothing like this,chunks of copper missing from inside of pipe,I'm certain it has to do with the antifreeze they add in it for cooling towers


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## sparky (Jan 8, 2014)

gmchiurazzi said:


> Hello everyone,
> 
> I have a client who is experiencing pitting/spalling on the interior of their domestic cold water system. Nothing is chemically treated or softened, and the buildings on both sides of this one aren't having problems. Off the top of my head all I can think of is possibly electrolosis - Any ideas on what else might be causing this?
> 
> ...


Is it leaking???how and why did you cut this out???


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## Plumbus (Aug 4, 2008)

skoronesa said:


> It's likely because the re-circ. pumps run constantly. Fittings/valves introduce turbulence which causes erosion, as @Plumbus mentioned.
> Creating excessive velocity and it's partner turbulence.
> This can be mitigated by upsizing piping, slowing pump flow rates, insuring that all piping is properly reamed, and removing any debris from the system.
> This may not solve the problem, but it's a best practices attempt.


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## gmchiurazzi (3 d ago)

sparky said:


> Is it leaking???how and why did you cut this out???


Apparently they started having failures in the piping, and they found this when they cut into the system. Like I said, this is city water, no chemicals... Well, you know what I mean.

Recirc pump isn't a concern, in health care applications we routinely design them to run non-stop (Legionella mitigation). Velocity corrosion doesn't usually look like this (chunks missing) so I'm not sure. I think we may get a sparky in there to test electrical grounds.

Thanks everyone for the thoughts and comments, and good to meet you all!


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## Master Mark (Aug 14, 2009)

gmchiurazzi said:


> Apparently they started having failures in the piping, and they found this when they cut into the system. Like I said, this is city water, no chemicals... Well, you know what I mean.
> 
> Recirc pump isn't a concern, in health care applications we routinely design them to run non-stop (Legionella mitigation). Velocity corrosion doesn't usually look like this (chunks missing) so I'm not sure. I think we may get a sparky in there to test electrical grounds.
> 
> Thanks everyone for the thoughts and comments, and good to meet you all!


These things are a mystery sometimes..... I have seen copper water lines in homes get pinholes in them
where the line enters the building a few inches from the incomming stop.... the line coming into
the place is plastic and it this was just a working theory of mine to tell folks to install a grounding rod at that 
point of entry... 

what goes on in a huge commercial building is a whole nother animal---


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## jakewilcox (Sep 3, 2019)

gmchiurazzi said:


> The building is actually a forensics lab, but the only piping experiencing the problem is the domestic cold water serving the cooling towers. The rest of the building is fine as far as anybody knows. No water treatment, no softeners, water is probably in to 20-30 g/gal hardness range.


What additives are they using for their cooling water?

What are the processes that they are cooling with the water.

How old is the piping?

What is the pH of the water?

It looks to me like some how HCl or H2SO4 is being generated.

I would also check every ground in that system. Pumps, controls, relays, PLCs, VFDs. Every ground.


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## Plumbus (Aug 4, 2008)

When you say "domestic cold water serving the cooling towers", do you mean water that actually circulates through the towers, or is it just the make up water.
If it is circulating within the towers, how is the rest of the CW system protected from same?
If it is make up water, is it backflow protected?
I agree with the suggestion to have samples sent to a forensic lab (no pun intended) like the one suggested in an earlier text.


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