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Thursday, March 22, 2018

Preparing structural steel surfaces for painting, coating standards

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Mill scale, dirt, laser scale, rust, heat-treat scale, grease, and dust interfere with paint and coatings’ adhesion to structural steel and must be removed before steel members can be coated. What are structural steel fabricators doing about surface preparation, and what options are available? Surface preparation can run from simple chemical cleaning to abrasion methods such as grinding and abrasive blasting. Many fabricators’ projects come with surface specifications prescribed by The Society for Protective Coatings (SSPC) standardsMill scale. Dirt. Laser scale. Rust. Heat-treat scale. Grease. Dust. And did we mention heavy mill scale? When these come between your structural steel and your paint or coating, bad things happen. And when the steel you fabricate holds up bridges, overpasses, buildings, and stadiums, bad things are big bad things.So what are structural steel fabricators doing about surface preparation, and what options are available? Surface preparation can run from simple chemical cleaning to abrasion methods such as grinding and abrasive blasting. How to know which methods to use?Many fabricators’ projects come with surface specifications prescribed by The Society for Protective Coatings (SSPC) standards (see Figure 1). The methods used are specified in the contract or project documents, according to SSPC Certification Program Manager Joe Berish, PCS, MCI, who administers the program. The primary documents are the specification and product data sheets, he said. The data sheets provide the surface preparation that the coatings manufacturer used when it tested its materials and demonstrated the performance applicable to the intended use and service life, according to Berish. “The coating systems manufacturers test for adhesion and performance. When they do that, they do it with a specified profile range. For example, if you were using a certain brand’s product on a bridge, the data sheet might tell you that it was tested in a laboratory at a 2- to 4-ml profile, and this would mean you might need 3 to 5 ml of paint. It’s going to give you the profile range, the thickness of the coating that you can apply, how much thinner you can and cannot use … whether you can put it over a pickled surface or a chemical-treated surface or an abrasive-blasted surface. It’s going to tell you all of that information.“What that means is that the coating manufacturer, in the laboratory, has taken a piece of metal that met that description and they have actually tested it and here are the test results,” Berish continued. “And to get the paint manufacturer to provide a warrantee, it has to be known that it was applied under those same conditions.” The surface preparation’s standard name indicates the method used, and all surface preparation standards use the prefix SP, he said. “For example [SSPC] SP 5, SP 6, and SP 10 are all defined as abrasive blast cleaning standards. SSPC SP 8 is the standard for pickling as a means of surface preparation. The differences in all of these standards are the cleaning methods, cleanliness levels, and surface profile. Different methods may produce a similar level of cleanliness, but each will still result in differences such as surface profile or flash rusting.”Why would a customer choose abrasive or blast cleaning over pickling or solvent cleaning—or vice versa? “The contract or specification and coating product data sheet may require a surface profile which cannot be achieved by pickling, chemical stripping, or solvent cleaning,” Berish said. “Also, the coating being applied may not be compatible with all methods of surface preparation. In addition, some choices may be made dependent on the availability of equipment that the fabricator may have.”  Cost is also a consideration, which depends on the amount of surface area to be prepared, Berish continued. “For example, if it is just a few square feet and does not require a surface profile, chemical stripping may be cost-effective; conversely, if there are several thousand square feet of surface to be prepared, pickling or abrasive blasting would be more cost-effective.”Whether or not the waste produced would need to be disposed of as hazardous has an effect on the methods used as well.“The customer will give the fabricator a build sheet, if you will,” Berish said. “’We want it to be fabricated like this: the bolts located here, with this diameter.’ It’s the same with the surface condition. Just by the material they’re going to use, they’re going to go to that material data sheet that will tell what surface standard is compatible with that material—SP 1, SP 2 or 3, SP 6 or SP 10.” Figure 1
The SSPC’s surface preparation’s standard name indicates the method used, and all surface preparation standards use the prefix SP.SSPC-SP 1: Solvent CleaningThe first line of defense is simply cleaning the structural member with acetone, a thinner, or another type of solvent. “Cleaning with a solvent and a cloth is a precursor to every other surface preparation standard out there. It’s a given,” Berish said.Cortec® Technical Service Engineer John Wulterkens said that fabricators can remove mill scale, oxides, and corrosion from the metal surface using either VpCI®-422 or VpCI-426 water-based liquids (see Figure 2). “VpCI-422 is more ‘ecofriendly’ (biodegradable); VpCI-426 is stronger and works faster. Depending on the application, the gel versions of both products can be used on vertical or overhead surfaces, or on parts that cannot be treated in a dip bath.”After the scale is removed, cleaning and neutralization should be performed with a water-based alkaline cleaner, he added. “This will leave behind a cleaner surface for painting, coating, and welding. The cleaners (and rust/oxide/scale removers) contain flash corrosion inhibitors, so after the neutralization and cleaning stage, the surface will remain flash rust-free for up to a week, depending on conditions.”SSPC 2, SSPC 3: Hand Tool, Power Tool CleaningBass Mechanical, a structural steel fabricator in Elizabethtown, Pa., has 40- by 80-foot drive-through bays that handle both medium- and large-scale structural steel fabrication. The company fabricates and welds carbon steel, aluminum, stainless, and nickel aluminum into trusses, box girders, plate girders, beams, columns, mezzanines, stairways, and railings.Before sending its products out for coating, the company performs some minimal surface prep, according to Jerry Miller, chief operations officer. “We usually go to an SSPC-SP 2 or SP 3, which requires the steel to be free of grease, moisture, contaminants, heavy mill scale, and rust.” Miller said the company uses a thinner and a power tool to remove the contaminants. Then it uses high-pressure air to blow the dirt or dust and rust away,” Miller said. Standards SP 2 and SP 3 require the use of a hand or power tool to satisfy the requirement, Berish said. “By standard, SP 2 means that the surface is clean of all oils and loosely inherent material. So SP 2 is hand cleaning with the use of hand tools—a wire brush or a scraper. The use of a chemical treatment alone cannot make it an SP 2 because you cannot remove inherent materials with chemicals alone.” SP 3 is the standard for cleaning and removing loosely inherent material using a power tool, such as a grinder (see Figure 3).SSPC-SP 6, Blast CleaningTo achieve an SSPC-SP 6 grade surface cleanliness, fabricators use a shotblast cleaning machine (see Figure 4). An SSPC-SP 6 finish is the most common for structural steel, according to Alex Berghouse, product manager for blast equipment at Peddinghaus, Bradley, Ill. “That will get all the difficult residue off the steel—mill scale, rust, dirt, and so forth.”Berghouse explained how the blast machines work: The raw structural steel enters the shotblast machine, and as the material passes through the zero point, the operation is initiated. The turbines engage when the machine senses the material’s presence. The turbines throw the shot or abrasive onto the material to clean the steel. With an adjustable brush mechanism, the machine cleans off the excess abrasive and returns it to the hopper to be recycled and used again and again. The process continues until the full piece passes through the entire turbine orientation. “The speed can vary, but it is normally set about 3 to 5 feet per minute, depending on the structural profiles that are being processed. So the steel goes in laden with rust, dirt, and scale and comes out clean and ready for the next fabrication process,” Berghouse said. “The primary application for the blast determines the number of turbines you need to achieve the proper clean surface requirements,” Berghouse said.Figure 2
At left is a metal surface with corrosion removed using VpCI®-422; at right, a metal surface before the corrosion was removed. Photos courtesy of Cortec Corp., St. Paul, Minn.“There are all different types of classifications for blast cleaning, depending not only on the postprocess, such as painting or welding, but also on which application, such as for bridge construction or building construction,” he said.Before entering the blast machine, a structural steel member must be cleaned of oil and grease, Berghouse cautioned. “If a structural member goes into the blast system with any kind of excessive moisture, oil, or liquids, a filtering problem can arise. The filter cartridges will become gummed up with contaminants and won’t filter properly.”Peddinghaus designs its filtration system with inverted, conical-type filtering units intended to keep the particles loose and allow them to flow freely into the collection system. The blast system can be a stand-alone system or it can be an integrated part of the structural steel fabrication line. This includes material handling technology for moving profiles via roller conveyor and cross transfer systems, according to Peddinghaus Chief Sales Officer Lyle Menke. “Conveying systems bring the beams into the machines, which minimizes overhead crane handling.” The operator loads the structural member onto the cross transfer, which moves it to the infeed roller conveyor that delivers it to the blast machine, he continued. After it has been cleaned, the member is rolled to an outfeed transfer which can deliver into a band sawing machine; then to a structural drilling machine; and finally (if required) into a thermal cutting machine for cutting of copes, blocks, and similar design shapes. An arc writing machine uses plasma technology to write the layout, welding, and fitting information for each beam. “The welding personnel then can locate the marking and weld identification and weld each piece to finalize the structural section.”SSPC-SP 8, P&ODave Hansen, co-owner and production manager of Hansen Steel Services, Santa Fe Springs, Calif., said that the company mostly just grinds the scale to remove it from spot areas that call for only minimal joining, such as welding a base plate. Otherwise, many of the components they fabricate undergo pickling and oiling (P&O) to chemically (acid) remove the scale before fabrication and then apply an oily rust inhibitor afterward while it’s being stored before downstream processes. “One of the concerns facing beam fabricators is that base plates must have drilled holes. When a hole is drilled, it requires cooling oil for the cut. All of that oil that has now stained the base plate needs to be cleaned free of residue before a paint primer can be applied. So not only is sanding and grinding needed for prep, but the removal of all oil.  It’s not just ‘blow and go,’ unfortunately,” Hansen said. SSPC-SP 10, Near-whiteSP 10 is an abrasive blast cleaning standard. “We call that near-white metal,” SSPC’s Berish said. “By the nature of the definition of the standard, it’s gone through abrasive blasting, would completely remove all old paint, mill scale, and rust, leaving no more than 5 percent of staining—discoloration with no volume.”The surface profile that results depends on the type of abrasive used. “Abrasives can leave anywhere from a 0.5 profile to a 5- or 6-mm profile,” Berish said. “You’ll have the best paint adhesion with that finish, because it’s run at a slower speed through the machine,” Berghouse said.“SP 10 is the standard for bridge builders, because bridges are exposed to the elements and support transportation,” Menke added. “For bridge components, special types of paint are applied in addition to the primers to avoid rust and so that when the original coat starts to peel, paint can be reapplied in the field years afterward.” How to Know If Achieved?How do fabricators know and verify that they have achieved the desired surface condition? A trained and certified inspector evaluates the surface to the standards in the contract. Visual guides and written industry standards provide the evaluation criteria, Berish said. “Without proper training, they would not be qualified to provide the evaluation with a clear understanding of the standards.”Figure 3
SSPC-SP 3 is the standard for cleaning and removing loosely inherent material using a power tool, such as a grinder. Photo courtesy of Bass Mechanical, Elizabethtown, Pa.The SSPC is an ANSI-accredited organization, and the consensus standards have been developed through an ANSI process. Bass Mechanical, 717-367-0890, www.bassmechanical.comCortec® Corp., 651-429-1100, www.cortecvci.comHansen Steel Services,  562-692-6900, www.hansensteel.comPeddinghaus Corp., 815-937-3800, ext. 1145, www.peddinghaus.comThe Society for Protective Coatings, 412-281-2331, ext. 2235, berish@sspc.org, www.sspc.orgFigure 4
To achieve an SSPC-SP 6 grade surface cleanliness, fabricators use a shotblast cleaning machine. Photo courtesy of Peddinghaus, Bradley, Il

Saturday, May 6, 2017

Copper pipe electrolysis from touching galvanized steel?

Read article : Copper pipe electrolysis from touching galvanized steel?
topic 24664

An ongoing discussion from 2003 through 2016 . . .

(2003)electrolysis in copper pipe

Q.I recently had a 1/2" TYPE L HMP flexible copper pipe that sprung a leak, unfortunately it was inside the wall going up to the second floor. After splicing the pipe where it was leaking another spot started leaking. I noticed inside the pipe a bunch of green "blobs" & the outside of this (HOT) water pipe a lot cleaner than the other pipe (COLD) that would have been put in at the same time, 20-25 years ago I'm guessing. I did notice one spot where the copper pipe was touching an old galvanized pipe seemed to be wet and green. Could there have been some electrolysis going on that caused this pipe to start getting finer than pin hole leaks & how much damage might have been done to the rest of the plumbing if that is the case?

THANK YOU FOR YOUR HELP,

Alex H [last name deleted for privacy by Editor]
do-it-myself-er - Cedar Rapids , Iowa

(2003)

A.Copper pipes can corrode in at least three different ways, but the differences are quite technical. I would suggest that the corrosion could be induced by a galvanic couple caused by contact with the galvanised pipe and this results in an induced local anodic polarisation of the copper pipe. I would normally expect such a failure to occur where the two pipes come into contact, but if this point is dry, no corrosion will occur and the effects of the galvanised pipe will be transmitted onto the copper pipe where it will react in a more favourable wet environment. Your photograph clearly shows the green copper salts on the inside of the failed straight pipe, so it must have been in an area where the copper is oxidised and failed. The propensity for copper pipes to fail is related to how the pipe was made, the local water composition and the environment it is used in. I would suggest there may be other not be other problems with your copper pipes, as there has already been a failure of an induced polarity, but if there are other non-compatible pipes in contact with each other, there could be a repeat of this. It may be wise to ask a plumber to check your system out.

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK

(2004)

Q.I was told by a local plumber that electrolysis can occur in copper pipes when the hot water heating system is part of a forced hot water boiler system. The solution is to put nylon fittings between the copper connections and the galvanized boiler system so as to prevent any electrolysis action from taking place in the copper pipes running throughout the building. I would like to get other opinions since this is an expensive fix and it takes a long time to determine whether the fix in fact works.

Dan W [last name deleted for privacy by Editor]
property management - Juneau, Alaska

(2004)

A.It is the right advise, Dan. For galvanic corrosion to occur you need a metallic circuit and an electrolyte circuit. If you break the conductive metal circuit between the copper and galvanized pipe, galvanic corrosion ("electrolysis")" does not occur. This is not to say that no form of corrosion will ever occur though.

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
(2004)

A.Copper pipe failure began to occur approximately eight years after completion of a new home in Brewster Co. Texas. The leaks were always in the cold line.

A split-core ammeter revealed a slight current flow between the steel gas pipe and the hot side of the copper system. No current could be detected between the cold copper pipe and the hot, or the steel gas line. This led me to conclude that the cold line was acting as a sacrificial anode between the other two while absorbing all voltage drop.

No electrical bonding could be found.

My solution was to isolate the steel line (which included some galvanized parts), from the copper system with a PVC adapter.

Current flow cannot now be detected unless a jumper is placed between the steel and copper.

Is the problem solved? I don't know! What can be said is that there is no further measurable evidence of electrolytic activity in this particular system.

Sam D [last name deleted for privacy by Editor]
- Alpine, Texas
(2004)

A.As others have mentioned, there are three different ways for holes to develop in a copper line, and I have seen all three.

A typical trade mark of electrolysis is pit on the inside of the pipe where the electrical current has actually eaten away at the piping, this doesn't sound like what is going on.

Another way is corrosion from the outside, normally when the piping in in a damp location with high acid soils, or even in an unsealed sleeve (copper run inside another pipe, usually PVC, and normally from the meter to the house). This is evidenced by pitting on the outside of the pipe.

The last one I have come across, and am still researching, is what it sounds like this gentleman has. It typically will have build-up on the inside of the piping and will often times leave large "blobs" of build up. I don't know what this is for sure, but I do know it isn't electrolysis, and it has nothing to do with water that is too clean (mentioned on another website as a possible answer). I think it has to do with the water quality to a certain degree, but I think it may be the molecular structure not the chemicals used. I think the buildup is a protectant for a "micro-atmosphere" high in maybe hydrogen. But I could be wrong, I am still researching this. I will post any further findings.

Jereme Grisenti
plumbing - Blountville, Tennessee

(2005)

Q.If we were to rivet or otherwise attach a copper sleeve to galvanized chimney pipe, would this cause the galvanized pipe to fail? We have fireplace chimneys on the beach. we have several copper clad chimneys that are doing well, but the maker went out of business. Now we have only galvanized pipe to work with and the outside of it corroding causes an eye sore.

Bryan Malt
- San Diego, California
(2006)

Q.This is a piggy back question.

Three 1/2 inch copper pipes running from my basement to the Laundry room one floor above show the same kind of erosion as the picture accompanying the original question. In each case the green copper salts and pin holes developed where the pipes pass through the floor. You can see the leaking water from below but not from the laundry room level.

After one of two plumbers to replace one of the leaky pipes stated that at one point he felt a very mild electrically shock, I had an electrician check the system. The electrician said he could not find a problem. The electrician checked the system before and after the plumber felt the shock. We could not duplicate the shock with the plumber or the electrician.

The plumber reinstalled the three pipes and wrapped the new pipes in electrical tape at the point where the pipes go through the floor.

Since we have not yet found a source of electrical charge would it be prudent to ground the copper line to an unused galvanized pipe so any current would flow to the unused galvanized pipe? Any help would be appreciated.

Greg Butts
- Stafford, Virginia
(2007)

Q.When copper pipes are plastered over into walls do they need to be protected from corrosion either by cement or plaster?

Mrs M Bridger
Homeowner - Steyning, West Sussex, England
(2007)

Q.I have a brick wall in my bathroom and want to cut a groove in the brick run the copper pipe inside and cement it back up. Will this have a long term effect on the pipe
thanks daz

Dario Ruberto
designer - Toronto, Canada
(2007)

Q.I have some questions regarding electrolysis, or galvanic corrosion between the copper and galvanized water pipes in my house. The house in on a municipal system and it is my understanding that acidic or soft water is not a problem in my area.

I have extremely low pressure in the upstairs bathrooms, and moderately low on the main floor kitchen. In my basement I have galvanized pipes coming in from the street, they supply the hot water heater, and they run the hot water for a few feet beyond the tank. At one point they are connected directly to copper pipes which take the hot and cold supply upstairs to the bathrooms.

I intend to replace the galvanized pipe, but I am trying to decide whether or not to replace the copper pipes going upstairs, and as well the hot water heater.

To make this decision I need to understand a little more about what is going on with the electrolysis. Before discussing the ramifications with the hot water heater, I have the following questions:

1. Where the galvanized and copper connect in the basement, does the electrolysis happen only locally? It seems that the electrons would travel only within the magnetic field created by the metals and therefore only affect the pipes within about a foot or so of the connection. Or, since the water exists through all the pipes, does the electrolysis affect the copper all the way to the upstairs bathrooms?
2. Once the galvanized pipe is removed, will the electrolysis cease? (I understand that new copper and old copper will also create electrolysis but I assume this condition is not as severe.)
3. I understand why galvanized pipe corrodes when coupled with copper but I don't understand why it is that the galvanized pipe becomes filled with gunk on the inside and restricts flow, I would think the corroding would make it get slightly wider on the inside, not more narrow.
4. If I remove the galvanized pipe, can I clean out the remaining copper pipe to make sure there is no corrosive material setting in them? How is this performed?

As far as the hot water heater is concerned, galvanized pipe feeds it and takes the water out of it, however, there is copper flexible tubing that actually connects directly to it. I assume this means the heater has corrosive material in it and will likely not last as long. If I leave the existing heater in place and wait for it to fail, will it contaminate any new piping that I put in?

Also, if I run the new copper water service through the front yard within a few feet of the gas line will this cause electrolysis? If yes, will it affect the pipes inside the house or just in the front yard? Which pipe will get holes and which will narrow? Can I insulate the copper to prevent this?

Justin Zavislak
buyer, hobbyist - Seattle, Washington
July 13, 2008

Q.I have type k copper coming from the main to the shutoff in the house. after reporting a leak it was dug up to be repaired and all was found was a pipe with walls that have thinned considerably and covered in grooves resembling termite damage on wood. it was also riddled with pinholes.

the ground for my electrical is connected to this pipe. could that be a possible cause. please help. there other houses in the area that have had there lines replaced twice in the last 20 years.

thanks, cy

cyrus lambert
hobbyist - conne river, Newfoundland, Canada
July 20, 2008

A.Where I work they were having problems with the copper pipes. The anode rods in the water storage tanks had been all wore down. Plumbers found the electrical system grounding rod had been disconnected & everything was grounding through the plumbing, causing the problems. You might want to check but I think it is a code violation now to ground through your plumbing only.

Alex Hatfield
- Cedar Rapids, Iowa

August 30, 2008

Q.I have a problem identical to to the lead in this thread. Green spots on rigid type L 1/2 in copper pipe with water seepage. This 14+ ft run of pipe is leading from my gas fired hot water heater (after a few short copper fittings) across the drywall finished basement ceiling to a T that feeds hot water to most of the house. I noticed a small spot of mold on the ceiling, cut it open and found this pipe with green spots like the picture above and two of the spots (at different ends of this one section of pipe) have water seepage. There are several other copper pipes , cold water and feeds for hot water heating that have no green spots,(only this one length of hot water has the spots) and also a flexible gas line in the same bay. My fix is to replace this entire length. A difficult job for me, tight spaces overhead, and hope there are no other bad pipe in the house. Please confirm the cause of this. Is it likely to be elsewhere or reoccur?

David Goldman
- W Milford, New Jersey
September 3, 2008

A.In response to the gentleman who experienced a leak on a 1/2 copper pipe and then he split it exposing this thick green blob running on the inside for some unknown length. well from dealing with similar repairs and from years of experience in the field this green corrosion that you are talking about stands far from electrolysis. this green gunk/blob is what we use to solder/sweat our copper pipes with better known as FLUX this product is applied to the outside of the copper pipe once it has been cleaned and reamed. putting too much flux on the pipe and fitting will cause the excess to flow into the pipe and will settle on the inside of the pipe until the system gets energized and water flows flushing out the excess flux. if it was not flushed out and was left as is; guess what? call your plumber.....thanks.

Armando Olvera
- Costa Mesa, California

September 14, 2008

Q.Within the last 9 weeks we have called the plumber 3 times regarding a 4 ft. section of hot water copper piping. Each time a pinhole sealing leak about 4-6 feet away from a recently replaced(5 months ago that our plumber installed) electric hot water heater. After replacing 2 inch copper pipe sections at a time we finely asked him to change a length of pipe but, only last night we developed another leak, a foot over from the new pipe, closer to the water heater. Our house is 15 years old and we use city water. The leaky pipe had green discoloration at the leak points. The plumber says this problem could be expected in this area in homes using well water after about 20 years due to the highly acidic soil but we use city water and our pipes are in the sealing. He's suggesting we may need to replace all of our pipes but it seems strange that the leaks are all near the water heater. Could the water heater be faulty or it's installation be the problem?

Chris McQuillen
homeowner - Crescent City, California
September 14, 2008

A.Hi, Chris. I'd be pretty confident that is has to do with something electrical rather than well water. I think I'd call an electrician rather than calling the plumber again.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

(2005)September 30, 2008

Q.can a copper water line be spliced to an existing galvanized water pipe line?

Keith Medved
- Dyer, Indiana

A.Hi, Keith. When you transition from one kind of metal pipe to another, the correct thing to do is to use dielectric unions =>

These are unions that include a plastic insulator so there is no metal-to-metal contact. I'm not saying that this is always done, but it is the right way to insure that there can be no galvanic corrosion.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

October 24, 2008

Q.How can one determine the cause of frequent deterioration of a 3/4" copper water supply line? The section going bad is located underground at the block wall of the foundation. The home owner had to replace this line two times within the past year. The deterioration seems to occur on the outside of the pipe. There were no problems prior to the first replacement of this pipe section 9 months ago. The home has city water and uses a sump pump due to a high level of ground water. I don't know the pH level of the water. The basement is dry, but uses on a "floating slab" to channel away the ground water. I conducted load tests of the electric panel to verify the electric wiring. All tests proved satisfactory with only about .2 amps or less flowing to the ground wire. This is when a 35 amp load is applied to each 120 volt leg. This proves that practically all current is flowing back through the neutral conductor. The electric service is lacking the required two, 8 foot ground rods. There is only one ground rod, and it appears to have been installed as a ground for the telephone system. At this point I'm thinking the corrosion and deterioration was not caused by excessive current flowing top ground via this water supply line.

Dave Baylor
- Pittsburgh, Pennsylvania
May 22, 2009

Q.Hi, Our house is 6 years old and from the time we moved in we have had this "green" problem. It has ruined my hair and has left stains in the sinks and toilets. We have had 2 different water softeners and 2 water heaters. We discussed this with the last water softener person and I guess they didn't have a clue about this problem. No one has until I
talked to some nerd at the company that tests the water for the city. He said that it was probably because of the fittings that the water softener company put on the copper pipes and if we didn't rectify the problem, we would eventually have pin size holes in the pipes and leaks! What do we do, who do we call and how do we go about fixing this problem! I want long hair again! Thanks!

Kathy L. Maxwell
- Grover Beach, California
December 8, 2009

A.While replacing the copper piping in a 150 year old home, I was puzzled by the green buildup inside of the pipe. Tracing the pipe I discovered that a ground clamp and wire from the circuit breaker box was connected to the cold water line 15' from the water meter where a jumper wire was also connected to the pipe from the street. In the circuit breaker box the Neutral buss was bonded to the Ground buss. That was okay. I also checked the sub panel to make sure the Ground buss and Neutral buss were not connected.

The wire mains from the electrical meter are aluminum. Current will find the least path of resistance, therefore current leakage to the piping is occurring. The remedy for this is to drive a conductive rod into the ground as deep as local code requires and connect a ground wire. Additionally I moved the ground clamp to the incoming side of the water meter, and removed the grounding jumper. As the water meter has dielectric connections the leakage can not return into the water piping since it is no longer grounded.

Bert Cooper
Equipment Designer - Williamsport, Pennsylvania

June 11, 2010

Q.Type K soft copper pinholes. We are having numerous issues with 3/4" and 1" and even a couple 2" services running from the mainline in the street to the property. 10 years ago or so we started having pinhole leaks appear on the copper always next to a flaired fitting so naturally everyone blamed it on a bad flair, then the specs changed and we were allowed to use compression fittings. This is now happening with the compression fittings as well, now everyone is blaming it on not de-burring the copper properly.

We just had to dig up a leak and found the pinhole leak in the middle of the 1" copper run (no fittings even close) and the copper was in a 4" sleeve under a major street which would eliminate the corrosive soil theory which the supplier will want to use, also the leak was on the top of the copper so a rubbing situation is not the answer. I have a question, is it possible for the copper at the time of production to have impurities introduced causing an electrolysis situation? Do you know of any other town having this problem. The suppliers here have no idea and have never even heard of this problem before which I find hard to believe. Thank you for your time and opinion

Bill Williams
water company - Tucson, Arizona
September 9, 2010

Q.I have recently installed and new water softener with an aerater in my home. My home is 26 years old and several weeks after the installation I noticed a blueish/green tint. I have had the water tested and the copper level is high, can the new system cause this?

Rachele Cancia
home owner -Sunrise, Florida
November 26, 2010

Q.I had an odd situation and was wondering if there is a known reason.
Last evening we noticed water dripping from the ceiling. Upon cutting open the ceiling, I noticed that the 3/4 hot water heating pipe (not sure if supply or return) was pressing firmly against the 1/2 hot water supply pipe, and that a leak had developed in the (smaller) hot water pipe where they touched. Fortunately, the heating pipe was connected to flexible copper to go up through the floor, and I was able to push the pipes apart and repair the supply line easily, but I am concerned what might have caused this leak.

Mike Paulson
former kitchen contractor, retired -falls church, Virginia

December 17, 2010

Below is an excerpt from Wikipedia's "Tap Water" page at en.wikipedia.org/wiki/Tap_water

"Pin-hole leaks can occur anytime copper piping is improperly grounded and/or bonded; nonmetal piping, such as Pex or PVC, does not suffer from this problem. The phenomenon is known technically as stray current corrosion or electrolytic pitting. Pin-holing due to poor grounding or poor bonding occurs typically in homes where the original plumbing has been modified; homeowners may find a new plastic water filtration device or plastic repair union has interrupted the water pipe's electrical continuity to ground when they start seeing pinhole water leaks after a recent install. Damage occurs rapidly, usually being seen about six months after the ground interruption."

Q.So if I understand this correctly, adding a union may cause this problem? How does one connect copper pipe to galvanized steel then, or how to bond from copper pipe (cold water line, for example) to iron pipe (gas line, for example)? What materials is the bond conductor made of?

Andy Roberts
-Maynard, Massachusetts

May 13, 2011

A.I have seen electrolysis occur with galv. steel straps, hangers and supports, with copper. It usually occurs at the point.
Pin Hole leaks are mostly caused by incorrect installation of plumbing pipes.
For example, If a plumber uses a pipe cutter, to cut a pipe, it leaves a ridge on the inside of the pipe. This causes a ripple in the flow of water going through the pipe, and will eventually start eating away at the pipe, from the inside out. This was a common occurrence back when track homes were booming, and the track rats were doing high volume production, and not installing correctly.
You can verify this, by separating the pipes at the soldered joint, and stick you finger in the pipe and feel the edge. If you feel a sharp edge, then the fitter never filed the inside edge to remove this. Which this is why it will happen in multiple places in your home. Also the reason it happens more to cold water lines, is because you use your cold water more that your hot.

Keith Van Aalst

-Anaheim California


February 3, 2012 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q.I need to run natural gas to an outside heater. I have a 3/4" gal water line which is no longer used, am hoping to run type 'L' flex 1/2" copper line thru this line to supply gas to out side heater, is that possible or is there something I could wrap the copper with to make it work?

Bob Hendrickson
-Pontiac, Illinois, USA
February 25, 2012

Q.I have a bunch of copper fittings. 1/2", 3/4" & 1"; I had the fittings for a year or more. Some of the fittings are starting to get corrosion on them, a greenish thick coating. What is causing this and how do I control/stop it. All the fittings are new and never used.

Ken Kramlich
-Sacramento, California, USA
February 27, 2012

A.Hi, Ken.

Copper corrodes, but usually not that quickly. The simplest fix is probably to put them in a plastic bag with desiccant. Sodium benzotriazole is a copper preservative. You can use brass lacquer if you are trying to protect them for artistic rather than functional use. Good luck.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

December 18, 2012

A. After reading all of the postings about plumbing -
There are a lot of factors to touch on.

Any type of pipe can be connected to a different type of pipe with the right connectors that can be found at big box or good hardware store.

The green spots inside or outside of a copper pipe is cause by Flux.
Flux is an acid that is used by plumbers when the copper piped is fitted together and soldered.
When a plumber puts too much flux on the copper fittings or pipe - It stays inside the pipe and causes the pipe and or fittings to corrode because the water does not get hot enough to melt flux in order to get it flushed out of the pipe or fittings.
Even if you air pressure out the lines, all of the flux will not move out of the copper pipe because flux is a paste, and what little amount of flux that does move will stick to any joining type of Copper or Plastic or PVC or Galvanized pipe or fittings.
Green spots on the outside of a copper pipe or fittings usually means the plumber did not wipe off any left over flux on the out side of the copper pipe or fittings, or the copper pipe has started to corrode from the inside out from using too much flux inside the pipe and the flux has made its way to the outside of the copper pipe or fittings and needs to be replaced.

As far as electric or electric ground going through copper - Electricity will slowly soften up the excess flux that was used on the copper pipe or fittings.
As the flux softens, and because Flux is an acid, it will slowly break down the copper pipe or fittings and needs to be replaced.

NOTE:
Most electric or electric ground going through a copper pipe is not a high enough voltage to melt flux -- it will only soften the flux.

NOTE:
If your phone line is grounded to the copper line then this alone is enough to soften the flux.
If you put some flux on both the neg. and pos. post of a small charged 9 volt battery you will find that the flux will soften.
If you leave the flux on the battery the flux will corrode the battery because flux is an acid.

NOTE:
If your phone or cable is grounded to your copper pipe this is enough electric for a person to get a small shock when touching the copper pipe.
After a person touches the pipe and gets a small shock, it takes quite a while for the electric to build back up because the voltage is quite low.
It is because the voltage is so low that when a person touches a copper pipe and gets a small shock you have depleted the electric in the copper pipe and a shock will not happen again until the electric builds back up in the copper pipe.

NOTE:
Anytime you have to run a copper pipe behind a wall that will be closed in, only use HARD copper pipe (NOT ROLLED TUBING OR SOFT TUBING). Place the copper pipe inside of a piece of PVC pipe and do not have any fittings or couplings that have been soldered inside the PVC pipe.
If you need to soldier on fittings - Solder the fittings on after you have cleared the wall that will be closed in. It will also be helpful to use liquid foam between the copper pipe and the PVC pipe to stop any pipes from clanking when the water is turned on or off. You can pre make up the pipe with the foam in order to let the liquid foam set up.

I hope this information is helpful.

Jim Drake
- Fredericksburg, Virginia, USA

April 20, 2013

A.To those dismissing the "green blobs" as residual flux are not understanding what I think are the inquisitors' issues. We built our home in 2004 and within a couple of years we started experiencing problems in our master shower. Initially, I was able to disassemble the hot water supply in the manifolds and clear out the green "blobbish" crystals. Our master shower is large and has multiple shower heads and two shower manifolds. Since then the problem appear to only exist in the master bath "hot" water lines. I have never had any issue with the cold water lines.

To give a little more detail. The green blobs I am experiencing a hard crystals and not any type of pasty or flux consistency. I have found galvanized steel nipples between the copper supply lines and the brass shower fittings. Two years ago the galvanized nipple on the shower with the most serious blockage, had nearly corroded away completely. Fortunately I had decided inspect the inside of the shower wall after suspecting some sort of "electronic" cause. This morning I found the same union on the second shower head that is now almost completely blocked.

I should have recognized something was wrong in the construction of our plumbing lines during the build simply because of the sloppy solder joints. I have a rudimentary knowledge of plumbing as my father was a plumber. Unfortunately, I was traveling extensively and didn't have time to address the bootleg plumbers my builder contracted.
I guess I was depending on the inspectors to alert us of any issues, but I have learned that lesson.

In summary, I would conclude that the green crystals are formed from kind electric current activity in addition to the hardness of your water. Our municipal water is very hard and my water softener is worthless so we are going to rip out the bathroom walls to see what other surprises we have in store and get a new water softening system.

Vaughn Broadnax
- Carmel, Indiana, USA

copper pipe secured with metal straps
May 21, 2013

Q.During a bathroom remodel, the plumber used some metal strapping (likely galvanized steel)to further secure the copper piping from the shower valve to the shower outlet. (see photo) Days later, my contractor had secured a loose toilet supply valve with a plastic part and explained that a metal material could negatively interact with the copper and eventually cause a leak. (I think he himself had just come upon this info when he went to home depot to pick-up the part.)
I then remembered seeing how the plumber used the metal strapping to basically tie back the copper piping. The wall has since been scratch coated and is about to be floated. I've alerted my contractor about this and am awaiting a reply. I really do not want the float to happen until I know for sure that there is definitely no problem with the set-up, or, until it is corrected. Any input on this would greatly be appreciated.

Jack Goldstein
- Mission Viejo, California, USA

May 22, 2013

A.Hi Jack. You need 3 things for galvanic corrosion:
- dissimilar metals so there is an inherent voltage between them,
- metallic contact path between the two metals so that electrons can flow from one metal to the other,
- a moist and conductive ionic path so that positively charged ions can follow the electrons, transporting atoms of metal from one point to another.

You certainly have the first two, but whether the third condition is met well enough for serious concern is always the question, and sometimes hard to define. When such a condition is sealed behind a wall, it sounds to me like poor practice -- then again, I'm not a plumber. You might see if you can find anything in the plumbing code about it. The problem would have been easy to avoid with any kind of plastic between the pipe and strap; you can hopefully get a scrap of Visqueen in between them without much damage to the wall. Good luck.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

June 3, 2013

Q.Having pin hole issues on the cold water line repeatedly over approx. 8 years -- same area.
The house used to have copper pipe coming in from the street and we did not have a ground strap on it. I can see how the pin holes would happen then. Then the copper pipe was replaced with PVC out to the street so there seemed to be no need for the ground on the street side of the meter, but I left the ground connected on the house side (still copper here). Was this wrong? Still another pin hole problem this year.
Tired of water leaks, Tom

Tom Canarecci
- Mishawaka, Indiana, USA
July 11, 2013

Q.We have an apartment building that keeps getting leaks in the first apartment. I have read everything and understand the problem, but we don't have money to replace all the pipes, so every few months there is a leak. The last time we had to replace all the carpet because it was leaking over a full weekend.

I have been told by one plumber that he heard of a product that can be put in the pipes that would coat the insides and help prevent the pinholes from developing.
Is there any such product?

Also someone told me of a product that can be painted on the pipes like a silicone or latex component that might be able to help.

If you know of any products like this that I can try, please let me know.

Thank you.

Lisa Keylon
- Fountain Valley, California, USA
February 11, 2016

Q. I just noticed there is corrosion at the elbo 90 connector of hot water copper pipe going out of water heater. Both are copper pipes - so wondering what's causing the corrosion. Otherwise I'm planning to
Simply planning to use fix-it stick/Keeny pipe wrap tape as temporary fix until I get time to call plumber to cut the pipe and rejoin.
Please advise:
1) is it ok to fix temporarily
2) if I need to dig in further to find the cause before I fix it.
3) are there any other things I need to check / replace while I'm fixing it.
Btw- this is house is 10 yrs old.

Venu Reddy
- Waukee, Iowa

April 8, 2016

A. You can also use a brass nipple between copper and galvanize .

Rodolfo ruiz
- Pasadena California usa
April 2016

thumbs up signThanks, Rudolfo. Yes, you can use a brass nipple between them ... but I don't think it will do much towards stopping galvanic corrosion.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
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