# Pinhole leaks in copper



## Miguel (Aug 10, 2009)

Early this week I repaired a pinhole leak on a section of 1-1/4" copper DHW recirc'd line to a 24 unit apartment bldg. The piping seems to be mostly original (early '60's) with the odd repair here and there. Some of the branches and most of the recirc system have been replaced with PEX.

The section I cut out was within a foot of an elbow. It was so thin at the cut that I cut another foot out. Seemed somewhat better there so I drew the line and replaced only that portion. The owner stopped by and I showed him the half eaten Type L pipe I'd cut out (no thicker than foil!) and advised him that future leaks were imminent.

Since I'm confident that repiping with Type L copper would give another 40 yrs service life, my question is should we opt for a cheaper solution such as Uponor (the only PEX alternative I can think of) or just bust the hump and go with copper again, even though copper prices are still somewhat fkn nuts?

All opinions welcomed!


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## rjbphd (Feb 5, 2010)

How many units is this apt? 1.5 " just for a return line sounds like an overkill if it a small apt bldg..


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## rjbphd (Feb 5, 2010)

rjbphd said:


> How many units is this apt? 1.5 " just for a return line sounds like an overkill if it a small apt bldg..


Sorry, reread the op and yeap. Its a overkill for 1.5 return line with pump... since "they" see a 1.5 pipe, meaning a huge 1.5 hi vel pump which causes too much flow in pump and slowwly etched inside of pipe.


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## rjbphd (Feb 5, 2010)

rjbphd said:


> Sorry, reread the op and yeap. Its a overkill for 1.5 return line with pump... since "they" see a 1.5 pipe, meaning a huge 1.5 hi vel pump which causes too much flow in pump and slowwly etched inside of pipe.


 Again, I meant too much flow in pipe, not pump.. its Sunday's night...


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## plbgbiz (Aug 27, 2010)

The OP mentioned it was on the recirculating system. He didn't say it was the return line. And 1.25, not 1.5.

Still, pump sizing and excessive flow could be the problem.


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## MarkToo (Dec 17, 2011)

We've got pinholes upon pinholes in these parts.

While the increase in chlorination due to incidents of pollutants making their way into the system is definitely part of it, the rumour has always been that there was some bad copper being used in the '80's around here. That was before my time in the trade so, I can't say for certain this has any merit but I've been hearing this for years - long before getting into plumbing even. Most all of the repairs we're making are in copper that is 25 years old or less. A lot of times it's copper "M" but not always. Most of the pinholes are at 90 deg. bends but, sometimes in straight runs. Finding a spot to tie in is often a trick as the piping is sometimes so thin you could spit through it.

A re-pipe is always the recommended solution. I try to sell Wirsbo as a permanent fix. Not every customer is willing to have that much work done so, we try as least to take the repair back to the meter and go as far as we can with the budget we're given.

For the customers that just want a patch job, we recommend they put us on speed dial.


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## stillaround (Mar 11, 2009)

Question ...has the effect of circulation in general manifested itself in other places as a complete thinning of the pipe?? I thought it caused pinholes particularly at elbow areas but was not aware of thinning over a broader surface...not arguing , just wondering..


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## swedishcharm21 (Oct 29, 2011)

Go with the copper.


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## ToUtahNow (Jul 19, 2008)

Miguel said:


> Early this week I repaired a pinhole leak on a section of 1-1/4" copper DHW recirc'd line to a 24 unit apartment bldg. The piping seems to be mostly original (early '60's) with the odd repair here and there. Some of the branches and most of the recirc system have been replaced with PEX.
> 
> The section I cut out was within a foot of an elbow. It was so thin at the cut that I cut another foot out. Seemed somewhat better there so I drew the line and replaced only that portion. The owner stopped by and I showed him the half eaten Type L pipe I'd cut out (no thicker than foil!) and advised him that future leaks were imminent.
> 
> ...


Pictures would help a bunch.

Because of where you say the leak is it sounds like localized velocity erosion. If that is the case, you should check your pump sizing and lower it as much as you can. After that you really need to look at the leak history before you condemn everything.

Mark


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## user7551 (Oct 21, 2011)

If you get a chance to check any of the fittings out like the couplings, 90's or tee's . See if the pipe was reamed properly . It could be turbulence being caused by the reduction in the pipe not being properly reamed.


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## Radium (Dec 25, 2010)

I would use type k copper and propress fittings if you have the machine.

Sent from my iPad using PlumbingZone


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## CTs2p2 (Dec 6, 2011)

I agree with playme, on the turbulence.. Be certain your repairs are well reamed.

Is the recirculation on a timer, aquastat or both? This would extend the life of the pump and the piping..


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## union brother 1 (Feb 25, 2012)

Hmmm i have always wondered about the errand pin hole...
I have seen 90°'s beat up ,and places of disimilar metals compromise pipe, i also know in the 60's plenty if TP pipe was installed , ( can easily be confused for copper ) have seen that pipe become pitted, ... turbulance created by not reeming pipe? Maybee? My father was a plumber
old school,lead n oakum, thread galvi ,brass, era..and he would make me reem everything water , gas ect...
When i would ask why, he would say turbulance...i have to research, will get back.....


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## user7551 (Oct 21, 2011)

here's a little more info . 

http://www.copper.org/applications/plumbing/techref/cth/cth_3design_gencon.html
*Corrosion*

Copper water tube is corrosion resistant. It is very infrequent that waters or special conditions are encountered which can be corrosive to copper tube. When they are encountered, they should be recognized and dealt with accordingly.
Since World War II, over 18 billion pounds of copper plumbing tube has been produced in the United States, 80% of which has been installed in water distribution systems. This translates into more than 7 million miles of copper tube. The rare problems of corrosion by aggressive water, possibly aggravated by faulty design or workmanship, should be viewed in the context of this total record of outstanding service performance. In general, widespread use of copper plumbing tube in a locality can be taken as good evidence that the water there is not agressive to copper.
When corrosion problems do occur, they usually stem from one of the following causes:


aggressive, hard well waters that cause pitting;
soft, acidic waters that do not allow a protective film to form inside the copper tube;
system design or installation which results in excessive water flow velocity or turbulence in the tube;
unacceptable workmanship;
excessive or aggressive flux;
aggressive soil conditions.
 Aggressive pitting waters can be identified by chemical analysis and treated to bring their composition within acceptable limits. Characteristically, they have high total dissolved solids (t.d.s.) including sulfates and chlorides, a pH in the range of 7.2 to 7.8, a high content of carbon dioxide (CO2) gas (over 10 parts per million, ppm), and the presence of dissolved oxygen (D.O.) gas.
A qualified water treatment professional can specify a treatment for any aggressive water to make it non-aggressive to plumbing materials. In general, this involves raising the pH and combining or eliminating the CO2 gas. Sometimes simple aeration of the water (e.g., spraying in the open air) is treatment enough.
Pitting can also be caused or intensified by faulty workmanship which leaves excessive amounts of residual aggressive flux inside the tube after installation. If the joints have been overheated during installation and the excess residual flux has polymerized, the pitting problem can worsen.
Soft acidic waters can cause the annoying problem of green staining of fixtures or "green water." Raising the pH of such waters to a value of about 7.2 or more usually solves the problem, but a qualified water treatment professional should be consulted. A typical treatment for an individual well water supply is to have the water flow through a bed of marble or limestone chips.
Excessive water velocity causes erosion-corrosion or impingement attack in plumbing systems. As explained in the discussion of pressure system sizing beginning on page 10, to avoid erosion-corrosion (and noise) problems, the water velocity in a plumbing system should not exceed 5 to 8 feet per second—the lower limit applying to smaller tube sizes.
Velocity effects can be aggravated if the water is chemically aggressive due to pH or gas content as outlined above, or if solids (silt) are entrained in the flow. The combination of a velocity that is otherwise acceptable and a water chemistry that is somewhat aggressive can sometimes cause trouble that would not result from either factor by itself.
Erosion-corrosion can also be aggravated by faulty workmanship. For example, burrs left at cut tube ends can upset smooth water flow, cause localized turbulence and high flow velocities, resulting in erosion-corrosion.
Any metal pipe laid in cinders is subject to attack by the acid generated when sulfur compounds in the cinders combine with water. Under such circumstances, the tube should be isolated from the cinders with an inert moisture barrier, a wrapping of insulating tape, a coating of an asphaltum paint, or with some other approved material. With rare exception, natural soils do not attack copper.
Copper drainage tube rarely corrodes, except when misused or when errors have been made in designing or installing the drainage system. An improper horizontal slope can create a situation where corrosive solutions could lie in the tube and attack it. If hydrogen sulfide gas in large volume is allowed to vent back into the house drainage system, it can attack the tube.


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## plbgbiz (Aug 27, 2010)

playme1979 said:


> ....When corrosion problems do occur, they usually stem from one of the following causes:
> 
> 
> aggressive, hard well waters that cause pitting;
> ...


I find it odd that electrolysis didn't make the list.


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## AndrewTheScot (Feb 2, 2012)

What ever happens, recirculation of hot water at high speed will eat a copper pipe up. We always throttle the water down on the outlet side of the pump. Most pump flanges have ball valves that can serve that purpose. ABW


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## Piper34 (Oct 10, 2011)

I'm going with electrolysis very very difficult to locate problem pex sounds like a good solution but any copper left will succumb to the same fate , just an educated guess could be all the above good luck!!!😳


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## user7551 (Oct 21, 2011)

plbgbiz said:


> I find it odd that electrolysis didn't make the list.


your right that should be on the list , but from what I've seen with copper electrolysis usually only affects the area of the pipe that is touching a dissimilar metal. The other issues could effect the whole the system.


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## union brother 1 (Feb 25, 2012)

playme1979 said:


> your right that should be on the list , but from what I've seen with copper electrolysis usually only affects the area of the pipe that is touching a dissimilar metal. The other issues could effect the whole the system.


Thanks play, for the info


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## Downthepipe (Feb 14, 2012)

Have seen this plenty of times. In my opinions there are several contributing factors. 
1) installation this includes Reaming! Flux type, heating process, minimizing elbows, pipe sizing 
2) pump velocity should be minimal and pump should grounded individually 
3) water acidity ( i have seen this happen to a slew of houses in the same neighborhood that have private wells it stands to reason the water likely plays the biggest role )


I know of a new hospital in Wisconsin that entire water distribution system was replaced engineers determined primary cause was plumbing contractor failed to ream copper at installation. Imagine what that cost!


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## muleychaser (Feb 20, 2012)

I have come across entire copper systems in the past that are in the same state as what you have decribed and have had to price and do complete re and re's. Nowadays it is all about costs and building owners are always open to any form of cost cutting to save a buck. If he wants a price do a quote up for both copper and plastic alternatives. Not sure of your local codes but one thing to bear in mind is fire ratings for materials that you can use. Copper just may be the only option if fire ratings and product combustibility have to be factored into the equation. As a contractor up here i know that there are liabilities that can come back on a person if holes are pounded threw fire rated walls, floors and ceilings and are not properly repaired to maintain its fire rating needed if a fire does occurr. Good Luck.


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## Miguel (Aug 10, 2009)

Thanks for all the replies everyone. 

This was my first time in this particular bldg and sorry if I wasn't very clear: the 1-1/4" line is the main HW supply to the building. There IS a recirc system in place and I thought it worth mentioning but coulda been a bit clearer that this was not on the recirc (return) piping. There was plenty of evidence of repaired/replaced recirc piping, all of it small dia stuff (1/2" & 3/4").

Once I got the leak under control (tied a rag on it and directed the flow to a bucket :whistling2 the first thing I checked was the pump. But it's only a 3/4" bronze sweat 15-42 Grundfos. The pump is fairly old (20 or more yrs by the looks of it) and the system seems to be sized well so I don't believe it to be a flow issue _although_ I'm not discounting turbulence to be a contributing factor. ie: there was a repair just above mine about 4" from an elbow (90). Buddy simply made a hacksaw cut at the leak point and sweated a coupling in place. The 90 I believe to be original.

For my repair I knocked off the 90 and cut about a foot and a half away downstream. (First cut was a foot away but pipe was really thin so I took somemore). Original pipe was NOT reamed and neither was the prior repair. I have my doubts that *any* cut was ever reamed, other than my own. I ran my reamer around the "original" cut and felt around the inside of the pipe with my finger. meh, inconclusive but there is some loss of material evident, although the Type L seemed more like Type L than the thinner than DWV that I'd removed. I also reamed the new piece (I always do) but I did not ream the downstream end of the existing. There was more'n one reason for this but I just didn't. Go ahead and sue me. lol

One thing that I DID NOT do is use my multitester to check for voltage potential between the piping and ground and resistance of same. You'd be surprised at what you find sometimes by doing this but in this instance I didn't bother. If the bldg owner wants us to assess things further (which I hope he does) then I'll do that at that time. I did, however, check out bonding clamps both electrical and Bell/cable/etc that were evident (electrical rm was right next door. Didn't find anything unusual.

Again, thanks for all the replies. Whether they're helpful or not to me (most are) the resulting discussions are usually helpful to others.

'preciate it! :thumbsup:


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