# Pin holes?????



## Plumberpilot (Apr 13, 2009)

Here's my question and a little history. 
Q. What are the opinions as to how copper pipe develops pinholes in domestic H/W re circulation lines?
We've installed several with not so good results. They were mostly installed in houses on municipal water systems with neutral PH levels so acid didn't play a roll. They usually have a 1/40th hp or smaller pump and at least 3/4" pipe size through-out. The earlier installs ran continuously and the later ones have thermostats and timers. I've yet to get pin holes in the later installs but I'm still a little worried just due to the havoc we encountered with the continuous systems. I've also started using cpvc on the entire loops and have had no problems with those yet but if I leave just a short nipple of copper anywhere it causes problems.
I've been told it's an Ox problem due to too much velocity. I've been told it's a copper quality problem but I doubt it due to so many different jobs with the same problem and all were type L copper. We've even seen pinholes if fittings.
What do you think?


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## ILPlumber (Jun 17, 2008)

My opinion would be one of 2 things.

Too much velocity. I use a 92 watt B&G circ pump.

or

When you cut out a section that has pin-hole leaks, does it have an excessive amount of residual flux in the area of the hole?


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## Plumberpilot (Apr 13, 2009)

I tend to think velocity is the killer too. The sections we've cut out don't really look to be corroded as in too much flux, they look more eroded like too much flow. Maybe I need to use the much smaller pump along with the Tstat and a timer. ILPlumber have you had any of these pinhole problems?


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## Protech (Sep 22, 2008)

I agree with the velocity theory. It's only happening on the recirc lines and not the rest of the system right? If that's the case, the constant erosion of the pipe due to velocity must be playing a major role. If you have been using cpvc without any problems then why not just use plastic from now on?


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## Plumberpilot (Apr 13, 2009)

Protech said:


> I agree with the velocity theory. It's only happening on the recirc lines and not the rest of the system right? If that's the case, the constant erosion of the pipe due to velocity must be playing a major role. If you have been using cpvc without any problems then why not just use plastic from now on?


That's what we've decided to do on new or accessible work, I'm searching for more info for the inaccessible retro fits that are piped with copper. I just want to know what people are running into. We are constantly asked to cut the wait times for H/W to master baths and kitchens and I don't like the single pipe systems due to the luke warm water in the cold side. I'd like to hear from plumbers that have used recirc lines with copper pipe to see if they are seeing pin holes, and if not how are they piped. I just hate not knowing the actual cause of the pinholes or the correct way to do the install. It's just a pet peeve of mine.


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## Va. Plumber (Dec 8, 2008)

I've run acroos many places where the design engineers oversize the recirc pumps. I guess they just want to make sure circulation is eveywhere. What I've done in the past is install automatic control valves on each recirc line in a high rise condo and their pinhole problems almost totally went away. They were made by Griswold Controls and were called "K Valve". They can be ordered for whatever GPM you want. I believe what I installled were 3/4 GPM. You only need a little flow to keep the hot water available and these keep the velocity down no matter how oversized the pump is.


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## ILPlumber (Jun 17, 2008)

Plumberpilot said:


> ILPlumber have you had any of these pinhole problems?


 
Never. We have never in 30 some odd years in business had to repair a pinhole leak. It must be a combination of the feet per second flow with the chemical makeup of the water.

With the loop insulated the flow is VERY low. I use these to set flow. Made by Tour and Andersson. They also come in solder end. Couldn't find a pic of that in my 20 second search.


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## Protech (Sep 22, 2008)

They have great water in Il. Lucky ba****ds


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## Cal (Jun 17, 2008)

I'm ALWAYS fixing pin hole leaks ,,,, hot and cold lines . Doesn't work with the pump theories .

I think is manufacturer AND flux . 

My .02


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## Plumberpilot (Apr 13, 2009)

Cal
Are you talking well systems? Low PH can eat copper in short order but it won't be found in public water systems. Do a PH test next time and you might be able to sell a acid nutralizer.


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## Hyper Piper (Nov 29, 2008)

Use water soluable flux, ream all tubing, make sure pump is not oversized. Once you see pinholes, the dammage is done.


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## Cal (Jun 17, 2008)

Plumberpilot said:


> Cal
> Are you talking well systems? Low PH can eat copper in short order but it won't be found in public water systems. Do a PH test next time and you might be able to sell a acid nutralizer.



NO SIR !! Public water systems . Fairfax County Va . BIG city system . 

Happens ALL the time


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## Protech (Sep 22, 2008)

In my area it seems to be related to chlorine and flux. The PH is always in the low 8s and the chlorine is 3.4 to 3.8 ppm. The leaks are almost always at or near the locations of flux and usually on the bottom of the pipe where the flux collects when liquid. The older hard copper systems with minimal flux used (better workmanship) last longer than the newer soft copper systems. I don't ever do repairs on soft copper systems that are flared or compression (no flux used). It seems that the chlorine somehow accelerates the corrosive abilities of the flux.


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## Protech (Sep 22, 2008)

I also notice that 9 out of 10 leaks are on the cold side of the system. This is due to the fact that the anode in the heater tank reacts with the chlorine in the water and causes it to precipitate out of solution. This theory is supported by evidence of an increase of pin holes on the hot sides of systems with newly installed tankless heaters (no anode). Water velocity and the total volumes that the pipe has seen also play a role though to a lesser extent than the chlorine and flux.

I hope this helps. Please keep in mind that water chemistry is complex and what I have observed in my area may not apply to your area. Water in Fl and Il is different, and so is the water in your area.


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## Phat Cat (Apr 1, 2009)

Question - By velocity, are you referring to the rate at which the water flows through the copper? or the general velocity of hot water vs. cold? Hot water from a water heater is not identical to the water from the main. Could the answer be that it is directly related to the heat properties and not the constant motion of the water being recirculated? If my question is stupid, just disregard and don't slam me. 

"Water is a compound made of the elements hydrogen and oxygen. The smallest
particle of water is a molecule made of two hydrogen atoms and one oxygen atom.
Unless the temperature is absolute zero (0 K), all molecules are in constant motion.
When the sample is a solid, the molecules are touching, but vibrate continuously. If
the sample is a liquid, the molecules are still touching and move in random
directions, tumbling over one another, colliding with each other and the walls of the
container. This activity will demonstrate the result of molecular collisions and how​a change in temperature affects this molecular motion. . .

At higher temperatures, molecules contain more kinetic energy. (Kinetic energy is
energy due to motion.) The reason they contain more kinetic energy is they are
moving at greater speed. This greater velocity results in more collisions per second.
Furthermore, these collisions are more energetic. This means that, in the warm
water, the faster molecules will be distributed throughout the container more​rapidly"


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## Protech (Sep 22, 2008)

Yes.

No.



PlumbCrazy said:


> Question - By velocity, are you referring to the rate at which the water flows through the copper? or the general velocity of hot water vs. cold? Hot water from a water heater is not identical to the water from the main. Could the answer be that it is directly related to the heat properties and not the constant motion of the water being recirculated? If my question is stupid, just disregard and don't slam me.
> 
> "Water is a compound made of the elements hydrogen and oxygen. The smallest
> particle of water is a molecule made of two hydrogen atoms and one oxygen atom.
> ...


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## trick1 (Sep 18, 2008)

Another source of pinholes that I come across is "copper chloride". When we have larger size homes with 4 or 5 bathrooms and two people living there, all of the piping doesn't always get used. That standing water causes the chlorine from the municipality to destroy the protective layer formed inside the tubing (cupros oxide) and then the chlorine eats the tubing from the inside out. 

We usually tell our clients to operate all fixtures at least every two weeks.

Not that this addresses the op's problem, but it's interesting what actually destroys copper tubing. 

I believe that errosion of copper tubing begins to happen at 8feet per second, but I could be wrong.


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## Associated Plum (Nov 4, 2008)

Protech said:


> I It's only happening on the recirc lines and not the rest of the system right? If that's the case, the constant erosion of the pipe due to velocity must be playing a major role.


Would not the velocity of the water be the same throuhgout the system on the hot side? If so then the entire hot side should have pinholes and not just the recirc line.


quote=trick1;38395]Another source of pinholes that I come across is "copper chloride". When we have larger size homes with 4 or 5 bathrooms and two people living there, all of the piping doesn't always get used. That standing water causes the chlorine from the municipality to destroy the protective layer formed inside the tubing (cupros oxide) and then the chlorine eats the tubing from the inside out.[/quote]

I will agree to this. We mostly see it on 1/8" copper ice maker lines.

Another possiblilty is stray voltages of electricity (millivolts/amps). This voltage may come from an appliance that is tied to the water line, within the electrical field of a wire, etc...

If the problem is under a slab the lines could be buried in "Donna Fill" with out any protection.


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## Protech (Sep 22, 2008)

How does standing water cause a reaction to take place?

As far as the voltages, I say hog wash. Where would these voltages becoming from? An AC power source? AC does not cause corrosion only DC. Dc currents do not produce moving magnetic flux lines and therefore cannot induce a voltage into neighboring pipes.


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## Redwood (Sep 8, 2008)

Protech said:


> How does standing water cause a reaction to take place?
> 
> As far as the voltages, I say hog wash. Where would these voltages becoming from? An AC power source? AC does not cause corrosion only DC. Dc currents do not produce moving magnetic flux lines and therefore cannot induce a voltage into neighboring pipes.


Ever hear of galvanic corrosion? The stuff we use dielectric nipples and unions to prevent? The water touching 2 widely different metals can induce it's own voltage. 

The pipes are often bonded and a bad main panel ground, perhaps a high resistance connection on the neutral lots of juce could be flowing through the pipes...

Ever do the science experiment where you make a battery out of various fruits and vegetables, a penny, and a nickel? The longer that water is stagnant the more stuff leaches into is and the more corrosive it becomes...


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## trick1 (Sep 18, 2008)

Protech said:


> How does standing water cause a reaction to take place?
> 
> As far as the voltages, I say hog wash. Where would these voltages becoming from? An AC power source? AC does not cause corrosion only DC. Dc currents do not produce moving magnetic flux lines and therefore cannot induce a voltage into neighboring pipes.



The standing water allows chlorine from the municipal water supply to destroy the protective layer inside the copper tubing. The protective layer, cupros oxide, forms within the first month of two of the pipe being in service. This layer is what gives copper its longevity. If water just sits idle in a line for an extended period of time, the chlorine destroys this layer and eventually the tubing itself. 

The reason that I know this is because I would replace tubing with pinholes and never really questioned why. I mean, if a client would ask me, shouldn't I have an answer and a fix to the problem and provide steps to prevent it from happening again? So I hit the internet and searched for all types of copper tubing corrosion and using the patina particles and cross section of the tubing that was bad, I found my cause

If you work in larger homes or better yet that water cooler/fountain in the far corner of a factory or commercial building, see if those patina colored particles come out of the fountain's outlet. Then if you have to replace the line, check the interior walls of the tubing.You'd be amazed at what the field of chemistry has on our profession:thumbsup:


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## Associated Plum (Nov 4, 2008)

Protech said:


> How does standing water cause a reaction to take place?
> 
> As far as the voltages, I say hog wash. Where would these voltages becoming from? An AC power source? AC does not cause corrosion only DC. Dc currents do not produce moving magnetic flux lines and therefore cannot induce a voltage into neighboring pipes.


Depending on the situtation the interior of the pipe would look like the corrosion inside galvanized except green.

Stray voltages and we are talking millivolts/amps this can be from any appliance that has water going to it, a ground wire ie: Telephone, etc.., Dissimilar metals among just a few reasons.

I have seen it, back years ago when the telephone company would ground to the copper water lines, if you were touching the copper when the phone rang you would get a shock. I never noticed it on Galvanized only copper.

One of the worst I saw for this was when we were repiping a house with copper and on the last day I was putitng the last coupling together between the new copper and exisiting copper water service and got lit up.
Another plumber was outside at the water meter and got shocked. Needless to say we shut off the power, an electrician was called and couldn't find a problem. Come to find out they had replaced the majority of the electrical appliances numerous times and the meter reder had also been shocked over the years.

I believe there a thread on site about this.

One of the worst situtation I sawfor pinholes was at a water meter. The meter was located about 3' from a utiltiy pole with a ground coming off it. I don't remember what the voltage was, but the underground copper was beign replaced about every 18 months until the utiltiy company did what they had to do to correct the situation.


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## Plumbus (Aug 4, 2008)

Here's some info from the Copper Development Assoc.
http://www.copper.org/applications/plumbing/techcorner/designing_piping_systems.html
And another site that discusses all kinds of erosion:
http://www.xs4all.nl/~cdewaard/#ErCor

Would not the velocity of the water be the same throughout the system on the hot side? If so then the entire hot side should have pinholes and not just the recirc line.
Velocity as measured in feet per second is a function of gallons per minute flowing through the pipe and the cross sectional area of the pipe through which the water flows. Since recirc lines are often smaller than hot supply lines, their velocities are generally higher. That's why they fail more ofter when velocity and/or turbulence are the cause of the leak. 

Of the suggestions made to prevent pin hole leaks I would add the use of 3/4" tube as a minimum and long turn 90's on return lines. Keeping temps below 140°f is also crucial because as water in the pipes gets above that temp it effects the copper molecules, causing them to loosen their bonds allowing the water to pull copper atoms right off the walls of the tube, eventually causing leaks.


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## stillaround (Mar 11, 2009)

I'll chime in having more experience than knowledge in the area. 
1. 17 years ago in Florida the copper was imported and the rate of pinhole leaks "seemed" to increase on non circulated systems-no discernable reason except:
2. Electricians ground to copper pipe and phone company also--any leaks in the neutrals charged the line
3. Had a house that was eaten up and I put a meter on the pipe and detected small voltage--it can eat it fast.
4' They were bonding to the copper harness on whirlpools and it alo created a loop for leakage.
5.Some areas of circulated systems pinholed and the mirror side of the house(big house) with same system didnt.
6. Insurance company after 6 years wanted to subrogate against my insurance company stating defective copper. Reasonable expectation or whatever the legal term is kept it from going thru. They asked me why it was leaking and I told them if they knew that answer they could call it a day. 
7. I say bad foreign copper with more lax standards, elecrolysis of some sort we know can eat it up, and I think theres something to this velocity issue because recirc systems do have higher instances.


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## SPH (Nov 4, 2008)

CPVC RECIRC?? baad news, we have made a small fortune replacing fittings and pinhole leaks in CPVC. usually takes about 8 years or so and the leaks start appearing.

From what ive seen the better you secure the CPVC the longer your recirc line will last, but really in my opinion its a ticking timebomb.

Personally i would only pipe a recirc in copper with a timer or stat. maaybe in wirsbo but id like to see how it performs the next few years first.


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## Protech (Sep 22, 2008)

The science experiment you are talking about is with DC voltage. It doesn't work with AC voltage.



Redwood said:


> Ever hear of galvanic corrosion? The stuff we use dielectric nipples and unions to prevent? The water touching 2 widely different metals can induce it's own voltage.
> 
> The pipes are often bonded and a bad main panel ground, perhaps a high resistance connection on the neutral lots of juce could be flowing through the pipes...
> 
> Ever do the science experiment where you make a battery out of various fruits and vegetables, a penny, and a nickel? The longer that water is stagnant the more stuff leaches into is and the more corrosive it becomes...


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## Protech (Sep 22, 2008)

I have a pretty good background in chemistry and I fail to see how the chlorine sitting there is any worse than continuously moving freshly chlorinated water into the line.



trick1 said:


> The standing water allows chlorine from the municipal water supply to destroy the protective layer inside the copper tubing. The protective layer, cupros oxide, forms within the first month of two of the pipe being in service. This layer is what gives copper its longevity. If water just sits idle in a line for an extended period of time, the chlorine destroys this layer and eventually the tubing itself.
> 
> The reason that I know this is because I would replace tubing with pinholes and never really questioned why. I mean, if a client would ask me, shouldn't I have an answer and a fix to the problem and provide steps to prevent it from happening again? So I hit the internet and searched for all types of copper tubing corrosion and using the patina particles and cross section of the tubing that was bad, I found my cause
> 
> If you work in larger homes or better yet that water cooler/fountain in the far corner of a factory or commercial building, see if those patina colored particles come out of the fountain's outlet. Then if you have to replace the line, check the interior walls of the tubing.You'd be amazed at what the field of chemistry has on our profession:thumbsup:


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## Protech (Sep 22, 2008)

:laughing::laughing::laughing::lol::lol::icon_lol::icon_lol:.......

Dude, you should at least research something a little before you make it up and put it on the internet. Phone lines never have more than 30volts on them and that's not going to shock you unless you put them on your tongue.



Associated Plum said:


> Depending on the situtation the interior of the pipe would look like the corrosion inside galvanized except green.
> 
> Stray voltages and we are talking millivolts/amps this can be from any appliance that has water going to it, a ground wire ie: Telephone, etc.., Dissimilar metals among just a few reasons.
> 
> ...


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## Protech (Sep 22, 2008)

You mean a crack right? I never seen or heard of cpvc having a pinhole leak EVER. Cracks, yes. Pinholes, no.



SPH said:


> CPVC RECIRC?? baad news, we have made a small fortune replacing fittings and pinhole leaks in CPVC. usually takes about 8 years or so and the leaks start appearing.
> 
> From what ive seen the better you secure the CPVC the longer your recirc line will last, but really in my opinion its a ticking timebomb.
> 
> Personally i would only pipe a recirc in copper with a timer or stat. maaybe in wirsbo but id like to see how it performs the next few years first.


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## Protech (Sep 22, 2008)

It's too late at night and too much bad info to go line by line with you so let me just say this again. AC VOLTAGES DO NOT CAUSE ACCELERATED CORROSION!! ONLY DC. Look it up:yes:



stillaround said:


> I'll chime in having more experience than knowledge in the area.
> 1. 17 years ago in Florida the copper was imported and the rate of pinhole leaks "seemed" to increase on non circulated systems-no discernable reason except:
> 2. Electricians ground to copper pipe and phone company also--any leaks in the neutrals charged the line
> 3. Had a house that was eaten up and I put a meter on the pipe and detected small voltage--it can eat it fast.
> ...


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## plumbingexpert (Apr 24, 2009)

*Pin holes*

Hi there,

pH in monitored utility drinking water quality rules it out as a likely cause.
There are other external chemical resistance issues too broad to discuss here.
High velocity is possible but unlikely if it is less than 3 m/s.
I have seen this phenomenon in substandard pipe.
I have seen this in pipe due to internal copper corrosion, and theory is bacterial action causes copper corrosion in warm water (low temp).
A likely cause is stray current corrosion, and this can only be verified by a corrosion expert.


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## Associated Plum (Nov 4, 2008)

Protech said:


> :laughing::laughing::laughing::lol::lol::icon_lol::icon_lol:.......
> 
> Dude, you should at least research something a little before you make it up and put it on the internet. Phone lines never have more than 30volts on them and that's not going to shock you unless you put them on your tongue.


What is there to research when it has happened to you (me) and others.

I never said it was a drop to the ground heart stopping shock.

I don't know how long you have been performing plumbing or how old the houses are you work on are, but I DO KNOW it happens. These type of phones were the old rotary dial type, not the "new fangled" touch tone type. Up until probably the mid 80's the telephone company grounded to the water lines, but not as much as they were back in the 60's or before.

Ever heard of the Tucker Telephone. This is a modified version of the hand crank phone and it would produce a bit more than a tingle.

The situation could have been just right for it to happen. It could have been a bad telephone, laying under the house on the damp ground repipiping the house.

H**l I'm just a dumb plumber all I know is payday is on Friday and water flows downhill, but I'm not even sure about that, becasue if I put a pump on it I can make it go up.


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## Plumberpilot (Apr 13, 2009)

Here's my conclusion, too much flow. Here's my solution, a flow restricting valve, a pump with a timer and a aquastat. 
Here's another question, will restricting the flow of a 1/40th HP recirc pump to say 3/4 gal a min. damage the pump?
I pretty much discount the bad copper, too much flux, stray voltage, and water chemistry in my case because the pinholes are always and only on the recirc lines and never on either the hot non circ lines or the cold lines. Not that I haven't seen pinholes in other copper applications but this is a specific problem that's been repeated several times in the same way.

Thanks for the input
Ricky


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## plumbingexpert (Apr 24, 2009)

*Stray current corrosion case*

For interest

Recently, a project was disrupted during construction when leaks began occurring in the underground copper water pipes. Only in the ground six months, and the pipes were showing signs of advanced corrosion.

We were asked to investigate the causes of failure of the underground copper service pipes. 

Our first observations were that the soil conditions appeared normal. We had seen copper corrosion on industrial and fill sites, but external corrosion of copper in native soils or imported backfill is rare and usually requires an external factor such as Acid Sulphate Soils of low pH, muriatic acid or, coke/slag backfill.

Some parts of the water installation were more severely corroded than others, so valves were installed and affected parts disconnected.

It was necessary to maintain the water supply to the partly occupied site, and so the water was tested and found to be within the drinking water guidelines. The corrosion was external of the pipes and not affecting water quality.

A site investigation was carried out and several sets of pipes were cut out and removed with soil samples from the trenches.

Also undisturbed soil samples were taken at pipe depth away from the trench areas to compare with the other samples removed from pipe surroundings. 

Samples of soil collected on site were analysed for saturated resistivity and pH according to the relevant Standards. These are relatively simple tests which whilst not capable of quantifying rates of corrosion are able to identify soils of high or unusual corrosion propensity.

The saturated resistivity results indicated that the imported backfill used as a pipe surround was essentially non-corrosive. The clay/loam native soils at all sites were corrosive, but not sufficient to cause any significant issues for the copper pipes. All the pH results were essentially near-neutral and non-corrosive.

Copper pipes exposed to these soils, even without imported backfill, would not cause the rapid corrosion rates observed on this site without the imposition of an accelerating factor such as stray currents. 

‘Stray Current’ corrosion or ‘Electrolysis’ is a well-understood form of corrosion which has the capacity to cause extensive perforation and corrosion damage in a relatively short space of time. As it is well-understood it is found in most major corrosion text books and is the subject of legislation in Australia.

Electrolysis can be caused by stray currents from either Cathodic Protection (CP) systems operated by a third party or electrified rail and train traction systems. A CP system can interface with other buried structures such as plumbing systems.

Corrosion is caused when current that flows onto an unconnected structure from the anode system then discharges.

When a CP system is installed or re-energised, it is usual to conduct ‘interference testing’ to determine whether the normal operation of the system will cause unacceptable corrosion effects. When a system is ‘passed’ it is issued an operating licence although changes to conditions can occur after the licence is issued.

We found that a water utility operated a CP system on one of their major water mains close to the boundaries of the property. It is unclear what testing was carried out on this system and whether any testing took place before or after the installation of the copper plumbing systems.

Arrangements were made for the water utility CP system to be shut down overnight. A chart recorder was installed and the chart itself examined the following day. The observable ‘jump’ in the chart had occurred when the water utility CP system was switched off. It appeared that the change in potential shift in the measured voltage on the copper plumbing system was directly related to the water utility CP system. However, the chart recorder showed that no traction currents from any rail or train systems were influencing the copper pipe network.

Readings were also obtained of potential of the copper pipe system using a standard copper/copper sulphate reference cell both before and after the water utility CP system was switched off. These readings showed the magnitude of the potential shift and also provided an explanation as to the concentration of corrosion issues in that part of the property, where several failures had previously been experienced, the potential shifts between ‘on’ and ‘off’ by as much as 800mV. This is forty (40) times the allowable maximum under existing regulations. Other areas had lesser but still significant anodic (corrosive) swings in potential.

It was interesting to see that at that part of the property closest to the CP system, the reverse potential shift was occurring; that is, the system was negative when the water utility CP system was ‘on’ and changed positively when ‘off’. The negative state implied cathodic protection and was probably where CP current entered the copper plumbing network. 

Where the current discharged, the positive or anodic sites, is where accelerated corrosion was occurring. We found that this stray current corrosion was the prime cause of premature corrosion at the property.

The final analysis

The extent of the corrosion and the widespread rapid perforation (6-10 months) of water copper pipes at the site could not be explained by natural soil conditions or other factors introduced by the building program although some native soils were corrosive, it appeared quite insufficient to cause the observed extensive corrosion.

External corrosion of copper in native soils or imported backfill is quite rare and usually requires an external factor such as Acid Sulphate Soils of very low pH, muriatic acid spills, unsuitable coke/slag backfill or stray current corrosion to provide perforation in this very short time period.

The evidence was overwhelming that the rapid onset of corrosion was caused by stray currents originating from the water utility Cathodic Protection (CP) system.

Stray current corrosion of copper plumbing on suburban building projects is rare. Copper as a material for underground water and gas plumbing has proven over many years to be durable, and well suited to the vast majority of projects.

Unfortunately, the only practical solution for this site was to replace all of the existing underground copper water piping with an approved polyethylene (PE) pipe.

The above extract from my article to Plumbing Connection Magazine


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## Redwood (Sep 8, 2008)

Protech said:


> :laughing::laughing::laughing::lol::lol::icon_lol::icon_lol:.......
> 
> Dude, you should at least research something a little before you make it up and put it on the internet. Phone lines never have more than 30volts on them and that's not going to shock you unless you put them on your tongue.


Hold on to the wires while I call you! 
You ain't gonna like the ring voltage!
It pulses... Feels like a damn electric fence...
Oh yea... it's DC.


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## Redwood (Sep 8, 2008)

Protech said:


> The science experiment you are talking about is with DC voltage. It doesn't work with AC voltage.


Uh huh....:whistling2:

And dc voltage is when metal can disappear in a hurry...:yes:

What do you think they use for electroplating...

What kind of current occurs in galvanic corrosion?

Oh Boy....Young grasshopper... You need to seek the wisdom....


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## Double-A (Aug 17, 2008)

As for AC not being a cause of corrosion in copper pipes, the Copper Development Institue and the American Water Works Journal disagree with you, but not entirely. See the first link below for details.

Please take a look at this article and tell us if this is the type of pitting you are seeing (shiny surfaces, U-shaped pits that show directionality, etc.). [see figure 11 in the second link below for an example of corrosion caused by high velocities (those above about 1.2 feet per second.)

These two articles discuss corrosion in underground copper pipes and corrosion by potable water in building systems (steel and copper). They both lend a great deal of insight and help put to bed the discussion as to if Alternating Current causes corrosion. 

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

http://www.copper.org/publications/pub_list/pdf/material_performance_a1070.pdf


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## Protech (Sep 22, 2008)

The ring voltage is about 25 volts if I remember correctly. I will gladly hold onto any house hold phone wire at any time. 25 volts will not shock you under normal conditions. If you had an open cut touching both wires on a 25volt dc system you would feel a little tingle back that's about it.



Redwood said:


> Hold on to the wires while I call you!
> You ain't gonna like the ring voltage!
> It pulses... Feels like a damn electric fence...
> Oh yea... it's DC.


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## Protech (Sep 22, 2008)

Galvanic voltage is self induced and is not a "stray" current.



Redwood said:


> Uh huh....:whistling2:
> 
> And dc voltage is when metal can disappear in a hurry...:yes:
> 
> ...


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## SPH (Nov 4, 2008)

Protech said:


> You mean a crack right? I never seen or heard of cpvc having a pinhole leak EVER. Cracks, yes. Pinholes, no.


Pinholes yes, in the backsides of 90's and TEE's mostly due to cavitation.


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## Protech (Sep 22, 2008)

That water must have been screeeeaaming thru that pipe. I've seen hole houses fed from 1/2 cpvc with no apparent cavitation damage. I guess if you give it enough time it will get thru but I've never seen it. Good to know.


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## stillaround (Mar 11, 2009)

I appreciate the vast info available here. I have seen severe corrosion on a house system including supply tubes where a small voltage was present. I have disconnected ground wires at a water heater and it stopped a corrosion issue where the other side of the house was similarly piped and had no issue. I have felt tingling sensations in the ground ( this is where I might lose you) and pinholing was taking place. I also remember having to be careful in chicago when disconnecting grounds near the water meter because there could be a strong charge (with no apparant deterioration of the galv. piping that I can remember.) I was told that closed systems, because there was no fresh ionic influx didnt experience as bad results on dissimilar metals. An electrician warned me about the bonding of copper piping systems especially in multiple locations including the phone companies ground at hose bibs. Whatever it is or isnt, can or cant be Ive seen it and it doesnt scare me anymore--geesh.


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## Redwood (Sep 8, 2008)

Ah Young Grasshopper...
For being a repipe specialist there is a bit you should know about copper corrosion...
You could learn a lot from the old men of plumbing if you wisely listen to them...
We might not have it all right but for the most part we know a thing or two...
I was wrong the ring tone is AC But that damn 90 volts 20 hertz will pulse like something else...



> The ringing signal sent to a customer's telephone is AC at 90 volts and 20 hertz in North America.http://en.wikipedia.org/wiki/Ringtone


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## KratzerPlumbing (Feb 23, 2009)

I did not see any one mention a simple reaming of the pipe. There is 1 company around here that would never ream. The D.A. asked the company I was with at the time to pull apart joints on the circ line for inspection. On about 10 houses that were having pinhole prob's they had not reamed any of the pipes. The D.A's experts testified that this was causing cavitation that was causing the pinhole leaks. I was just a laborer at the time but the lesson to always ream the pipe stuck with me.


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## Redwood (Sep 8, 2008)

Yep Yep !
The turbulence caused by unreamed tubing will cause corrosion.


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## Protech (Sep 22, 2008)

I tried it. All I got was a little tingle and I had to get hand wet just to get that. So what side of the phone system gets grounded? It would have to be the positive side for it to cause corrosion of metallic pipe. If it was the negative side it would actually preserve the pipe.

And I'm all ears.



Redwood said:


> Ah Young Grasshopper...
> For being a repipe specialist there is a bit you should know about copper corrosion...
> You could learn a lot from the old men of plumbing if you wisely listen to them...
> We might not have it all right but for the most part we know a thing or two...
> I was wrong the ring tone is AC But that damn 90 volts 20 hertz will pulse like something else...


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## Redwood (Sep 8, 2008)

Protech what you missing out on is that the voltage needed isn't big...
A few stray millivolts cause tremendous damage.

Whether it is a galvanic action or leakage through a grounded piece of electrical equipment.

Ah damn why am I talking about this with you...:whistling2:

Just rip it out and repipe it with PEX!


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## nhmaster3015 (Aug 5, 2008)

Under the right conditions you can get a hell of a jolt from a phone line.


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## Protech (Sep 22, 2008)

I couldn't agree more. Copper is so finicky. You have to make sure every joint has been reamed. You can't use too much flux or too little. You can't let it touch a metal that is higher up on the galvanic series. You have to keep the water velocity down. You have to make sure the water going thru it isn't aggressive (which is a whole career it's self). You have to make sure the soil it will be installed in won't attack it (if under ground). And it goes on and on.

Or you could just install pex:thumbsup:





Redwood said:


> Protech what you missing out on is that the voltage needed isn't big...
> A few stray millivolts cause tremendous damage.
> 
> Whether it is a galvanic action or leakage through a grounded piece of electrical equipment.
> ...


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## Down N Dirty (Mar 12, 2009)

Be careful on the too much or too little flux quote. Right now we are in a insurance/ lawsuit fight over that very thing. The piping at the circ. pump was reamed and installed with proper flow and etc., HOWEVER the lawyers stated that there was an extraordinary amount of flux that was used causing a small bead of solder build up around the edge of the inside of the pipe. We inspected the pipe, it was sanded well on the outside and showed a beautiful solder job on the outside, but there was a small hump around the inside, very small. No notice of extra flux inside of the pipe or a pool of it either. Not sure how we are to fight this one other than apparently someone has to pay and they are looking to us.


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## stillaround (Mar 11, 2009)

Dont expect justice. These things are built for settlement. They dont need any truth but rather a reasonable possibility to make it unprofitable to defend. You are right. I told a local plumber to stop saying flux was the cause of the leaks for this very reason. Even a judge wont understand that weve seen hundreds of manifolds oozing with flux on 35 year old structures and no leaks. All they have to do is think it could be and boom-settlement.


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## Protech (Sep 22, 2008)

flux on the inside is worse than flux on the outside.


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## stillaround (Mar 11, 2009)

Protech said:


> flux on the inside is worse than flux on the outside.


Geesh, The assumption being a lot of flux on the outside suggests a possibility of an inordinate amount on the inside. 2+2=4


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## Protech (Sep 22, 2008)

Not if it is water soluble.


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## stillaround (Mar 11, 2009)

How much water soluble flux was used 35 years ago? Did you even think there might be a point to the post other than chemistry. Arent you the guy who doesnt believe in stray voltage corrosion. Your earlier post about "its too late to deal with so much bad info" was not well taken. Have you had to deal with suits and expert witnesses yet, have you ever seen accellerated corrosion due to small voltages. Are you on some kind of mission to prove yourself right. Relax a bit.


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## Protech (Sep 22, 2008)

I don't believe AC grounding has any effect on copper pipe. DC is a different story. It's very rare that a DC voltage causes a leak in my area. It's usually flux+chlorine.


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## stillaround (Mar 11, 2009)

Chemistry or physics concerned thats probably right ( I aced Analytic chem, got a C in organic and gave up the program, didnt even go to P-chem )and in Chi-town there were meters that dimmed the lights when the ground was disconnected and no accellerated corrosion. Something was causing it in the instances Ive been involved with on the copper and disconnecting a ground solved a problem for me. An electrician said multiple grounds on the copper was not good. The looping and leakage on neutrals was his claim whether or not thats true I dont know. The ground tingling situations I've seen twice and both times eating copper. I dont know if it was a moisture induced situation or inductive.
On another note since you are in Fla.--cpvc has been brittling here after 8-10 yrs to an extreme, but it wasnt Flowgard. We switched to pex anyway. 
Cheers


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## Plumber (Jan 18, 2009)

*Its the Chinese Drywall*

Chinese drywall has high sulfur content which corrodes just about everything including copper pipes.


http://www.vbgov.com/file_source/dept/mcg/WebPage/HotTopics/Document/Chinese_drywall.pdf said:


> Some of the gases emitted from Chinese drywall can corrode metals, particularly copper.
> Corroded metals such as brass fittings, copper coils, and electrical wires may pose an
> immediate health risk because it could cause gas pipes to leak. You could be exposed to Freon
> or natural gas if parts of your air conditioning unit are corroded. Corroded electrical wires may
> cause smoke and carbon monoxide detectors not to function correctly.


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## Protech (Sep 22, 2008)

Well, I can agree with you on the cpvc:thumbsup:



stillaround said:


> Chemistry or physics concerned thats probably right ( I aced Analytic chem, got a C in organic and gave up the program, didnt even go to P-chem )and in Chi-town there were meters that dimmed the lights when the ground was disconnected and no accellerated corrosion. Something was causing it in the instances Ive been involved with on the copper and disconnecting a ground solved a problem for me. An electrician said multiple grounds on the copper was not good. The looping and leakage on neutrals was his claim whether or not thats true I dont know. The ground tingling situations I've seen twice and both times eating copper. I dont know if it was a moisture induced situation or inductive.
> On another note since you are in Fla.--cpvc has been brittling here after 8-10 yrs to an extreme, but it wasnt Flowgard. We switched to pex anyway.
> Cheers


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## Protech (Sep 22, 2008)

Chinese drywall? Why would we buy drywall from china? It's heavy, bulky and cheap. The cost to ship it from china would exceed the cost of the dry wall. What's next, Chinese concrete?



Plumber said:


> Chinese drywall has high sulfur content which corrodes just about everything including copper pipes.


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## Airgap (Dec 18, 2008)

Protech said:


> Chinese drywall? Why would we buy drywall from china? It's heavy, bulky and cheap. The cost to ship it from china would exceed the cost of the dry wall. What's next, Chinese concrete?


 This story made national news a couple of weeks ago. There was some drywall from China that had been relabeled and used in homes around the country. This drywall was actually destroying wires, pipe, about anything that wasn't wood or plastic.
In most cases pieces had to be tested to see if it was the chinese made. I think they've determined that it mostly came from large builders when there was a shortage in domestic sheetrock.


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## Redwood (Sep 8, 2008)

Protech said:


> Chinese drywall? Why would we buy drywall from china? It's heavy, bulky and cheap. The cost to ship it from china would exceed the cost of the dry wall. What's next, Chinese concrete?


Never underestimate the ability of the Chinese to make something cheaper so it actually becomes profitable to export even though shipping may comprise most of the cost.

How much does a Chinese wheelbarrow operator cost a day to operate?:whistling2:


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## Protech (Sep 22, 2008)

Wow. Chinese drywall. I've seen everything now.


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## SlickRick (Sep 3, 2009)

A local plumber called and ask me what the of pinholes in recirc. lines are caused by. After reading this thread, am I safe to say that we really don't know why it occurs?


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## SlickRick (Sep 3, 2009)

bump


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## Ruudplumber (Feb 21, 2011)

the problem i have seen is when they use the lines as a grounding source or some electrical conduction going through the line that has caused pin holes. just a theory


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## Protech (Sep 22, 2008)

If it's ONLY on the recirc and nothing else, my bet is high water velocity and/or unreamed pipe ends. I'd bet on an over sized pump that runs for extended periods of time.



SlickRick said:


> A local plumber called and ask me what the of pinholes in recirc. lines are caused by. After reading this thread, am I safe to say that we really don't know why it occurs?


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## SlickRick (Sep 3, 2009)

Protech said:


> If it's ONLY on the recirc and nothing else, my bet is high water velocity and/or unreamed pipe ends. I'd bet on an over sized pump that runs for extended periods of time.


I talk to the plumber an he said it is on a extended care facility. And the fittings are getting pin holes. Could be from turbulence due to not reaming. The recirc. line is just an extension of the hot water system. Seems strange that it just affects the recirc. end of the system


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## easttexasplumb (Oct 13, 2010)

Texas has started importing water from Florida.


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## Hairyhosebib (Mar 10, 2011)

It is my opinion that most pin holes form pretty close to where a fitting has been sweat onto a copper pipe. Most of the time nobody bothers to ream the inside edge of the pipe after cutting it. Removing this ridge is THE most important part of getting the pipe ready for use in any plumbing system. As water passes over this ridge the water actually swirls around thus causing a phenomenon called "HYDRAULIC JUMP". When I worked at Purdue, a couple of guys came from the COPPER ASSOCIATION and gave us some hands on training on how to sweat copper and MED GAS pipe and a really cool demonstration of the COOL GEL product. The guys from the copper association showed us the inside of the pipe with the pinholes. They look like backward horseshoe prints worn in the pipe.

http://www.copper.org/


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## Plumber3653 (May 5, 2010)

Hairy, you referring to hydraulic turbulence, not hydraulic jump. I think we all get what you're saying though. Just wanted to create some clarity for those not familiar.


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## ToUtahNow (Jul 19, 2008)

Hairyhosebib said:


> It is my opinion that most pin holes form pretty close to where a fitting has been sweat onto a copper pipe. Most of the time nobody bothers to ream the inside edge of the pipe after cutting it. Removing this ridge is THE most important part of getting the pipe ready for use in any plumbing system. As water passes over this ridge the water actually swirls around thus causing a phenomenon called "HYDRAULIC JUMP". When I worked at Purdue, a couple of guys came from the COPPER ASSOCIATION and gave us some hands on training on how to sweat copper and MED GAS pipe and a really cool demonstration of the COOL GEL product. The guys from the copper association showed us the inside of the pipe with the pinholes. They look like backward horseshoe prints worn in the pipe.
> 
> http://www.copper.org/


It's actually called localized velocity erosion and the turbulence is cavitation.

Mark


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## SlickRick (Sep 3, 2009)

There have been several studies done, but I can't find one that is conclusive.


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## Hairyhosebib (Mar 10, 2011)

Ok. That is the term I learned in the 90's from the Copper Association. New science always has to have a new name for the same incident. I have learned that from 30+ years of experience working at two Universities.


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## ToUtahNow (Jul 19, 2008)

Hairyhosebib said:


> Ok. That is the term I learned in the 90's from the Copper Association. New science always has to have a new name for the same incident. I have learned that from 30+ years of experience working at two Universities.


Hydraulic Jump is found in plumbing systems but it is in drain lines rather than water lines. It sounds like when you got your training it was still the "Copper Development Association". That training program and most of everything else done by the "Copper Development Association" was written by William E. Coffey, long time President of the "Copper Development Association". 

In the early 90s I was representing a Plumbing Contractor on a large High-Rise lawsuit which in part involved velocity erosion in the copper pipes. Imagine my surprise when we sat down for mediation and my opposing Expert was Bill Coffey. It was probably the only time I was ever intimidated by the other Expert. Coffey had all of the facts straight from his book. I had the fact that the Acoustical Engineer had up sized all of the pipe sizing so the small pipe even to a fixture was 3/4". The velocity was so low there could not be any erosion even if the joints were unreamed (which they never proved existed). The plumber did not pay anything on the copper issue.

Mark


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## Hairyhosebib (Mar 10, 2011)

Interesting. All the training material I got from that burned up in a barn fire so I'm uncertain about my info. Only a recollection of a term.


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## Plumber3653 (May 5, 2010)

So let me get this right ToUtahNow...unreamed pipe creates hydraulic turbulence which produces localized velocity erosion and cavitation is a result. Or unreamed pipe produces localized velocity erosion and cavitation is a result.
I would like to know the whole story if possible.


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## Protech (Sep 22, 2008)

Depending on the velocity of the water yes. If the velocity is low enough, unreamed ends don't matter. 

If the velocity is high enough, cavitation and/or impingement will occur even in straight sections of pipe. If that were the case though, you would see failures at sharp turns and valves 1st (even if the pipe was reamed and chamfered).



Plumber3653 said:


> So let me get this right ToUtahNow...unreamed pipe creates hydraulic turbulence which produces localized velocity erosion and cavitation is a result. Or unreamed pipe produces localized velocity erosion and cavitation is a result.
> I would like to know the whole story if possible.


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## ToUtahNow (Jul 19, 2008)

It is a disruptions of laminar flow which can cause cavitation. In that localized area velocity can increase up to 10-fold. A few feet later it return to a laminar flow.

Here is a link which explains laminar flow.

http://en.wikipedia.org/wiki/Laminar_flow

Mark


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## Hairyhosebib (Mar 10, 2011)

LOL!! See what I mean about all these names!!?? You should all be professors!


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## Redwood (Sep 8, 2008)

The laminar flow vs. cavitation and turbulence can have a big effect on metals and the damage can happen quickly. Even properly selected materials if they are not shaped correctly can fail rapidly from erosion caused by the cavitation and turbulence.

Some years ago my boss had a problem on his 65' "Go Fast" Sport-Fishing Boat where he was breaking prop shafts and losing the propeller. The boat was an engineering marvel of lightweight super strong construction with heavy use of composites but after breaking several Inconel prop shafts the lab came back with a finding of cavitation erosion which was cured by changing the radius of one of the steps machined into the prop shaft.

The velocity has a big effect in how much turbulence there is and how far the turbulence extends from the obstruction causing causing it. 

The medium doesn't really matter whether it is a gas or, fluid, turbulence exists in all of them when a "rough" shape is introduced into the flow. In the video below you can see a visualization of turbulence over a wing in a wind tunnel. Notice how the smoke continuously beats against the same places on the wing in the turbulent flow. This would indicate how water turbulence would beat against the pipe wall causing erosion and eventual failure.


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## sparky (Jan 8, 2014)

ILPlumber said:


> Never. We have never in 30 some odd years in business had to repair a pinhole leak. It must be a combination of the feet per second flow with the chemical makeup of the water.
> 
> With the loop insulated the flow is VERY low. I use these to set flow. Made by Tour and Andersson. They also come in solder end. Couldn't find a pic of that in my 20 second search.


Or a regular ball valve will do the same thing


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## Tango (Jan 13, 2018)

sparky said:


> Or a regular ball valve will do the same thing


10 years after...never too late I guess.


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## sparky (Jan 8, 2014)

Tango said:


> 10 years after...never too late I guess.


That up is correct,it's so slow around here just tryin to jump start things


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## Tango (Jan 13, 2018)

sparky said:


> That up is correct,it's so slow around here just tryin to jump start things


Time for booster cables! Plumbers who like to type are few and far between. Plus it's summer and a lot are absent.


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## sparky (Jan 8, 2014)

Tango said:


> Time for booster cables! Plumbers who like to type are few and far between. Plus it's summer and a lot are absent.
> [/QUOTE
> Yeppers


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## Debo22 (Feb 15, 2015)

sparky said:


> That up is correct,it's so slow around here just tryin to jump start things


It wouldn’t be slow if the mods didn’t chase off @ShtRnsdownhill because of a couple whiny b!tches. Say what you want about him but he kept the conversation going.


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## sparky (Jan 8, 2014)

Yes


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