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 Copper pipes "reacts chemically" with concrete a "myth"?
Author: sum (FL)

I recently read this from copper.org.


It is completely acceptable to bury/embed both hard drawn and annealed copper water tube in concrete. Decades of satisfactory service experience with the use of copper tube for in-floor radiant heating systems, water distribution systems and snow melting systems attest to the compatibility of copper tube embedded, encased or in contact with concrete

The copper tube must be completely embedded in the concrete and adequate provision for thermal expansion should be provided where the tube enters/exits the concrete.

It is also acceptable to run a copper water tube through a concrete floor or wall, provided that allowance is made for the lateral thermal expansion and movement of the tube and protection of the tube from abrasion. This can be done by insulating the tube where it passes through the wall or by wrapping the tube with an approved tape (to avoid abrasion) and installing it through a sleeve. Please refer to your local plumbing code for specific requirements regarding the protection of pipes and tubes passing through concrete and masonry floors and walls.

Both of the protection methods outlined above and the requirements listed in most plumbing codes are simply to protect the copper tube from the fatigue and wear caused by thermal expansion and movement. These protective measures are in no way dictated by the interaction of the concrete and the copper tube.

According to the Portland Cement Association the interaction of copper with both dry and wet concrete should not cause a corrosion concern. However, copper should be protected when it comes in contact with concrete mixtures that contain components high in sulfur, such as cinders and fly-ash, which can create an acid that is highly corrosive to most metals including copper.

I have always been told the problem with copper and concrete is that concrete would have some sort of a chemical reaction with the copper which accelerates it's corrosion, according to this article, the only reason to shield the copper pipes underground would be for expansion/contraction reasons as well as prevent heat loss of hot water pipes?

Edited 3 times.

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 Re: Copper pipes "reacts chemically" with concrete a "myth"?
Author: hj (AZ)

Historically, I never insulated/protected them until I moved to this area. I have seen many corroded copper lines, but they were in the ground not the concrete.

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 Re: Copper pipes "reacts chemically" with concrete a "myth"?
Author: dlh (TX)

yep, lots of copper touching concrete.

75% or more of the slab leaks i encounter are caused by kinking the copper when trying to turn up into a wall

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 Re: Copper pipes "reacts chemically" with concrete a "myth"?
Author: LemonPlumber (FL)

Nice.not buying it.the expansion and vibration will only weaken the tubing to the tubing expansion.the concretes will only weaken the tubing to it's thermal expansion vibration .what is the aggregate?what is the composition of your concrete?Will there be rewire or re bar near the copper?The electrical discharge to ground can and will effect un-sleeved copper tubing.Same as it did old galvy.Electro chemical is still chemical.For Sum.ask about the separation of aggregate as it is not encapsulated in their product.where one edge of the mix sets against the piping.Will the ag. move????What is the new plastic or fiber mesh ag.?Core me half a sample with a sleeve in it and they know!!!What I call 3000 mix small stones in the mix used in block wall pours by pumpers will not even be able to keep stones from being shot at the tubing six feet or deeper in a wall cavity!!!

Edited 2 times.

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 Re: Copper pipes "reacts chemically" with concrete a "myth"?
Author: Scott the Plumber (PA)

I have seen too much rotted copper, unprotected, running through concrete to believe this story. As a matter of fact, copper manufacturers now produce soft copper already coated for under slab installation. It is so common that many building codes across the U.S. require protected copper when coming in contact with concrete.

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 Re: Copper pipes "reacts chemically" with concrete a "myth"?
Author: Paul48 (CT)

sum.........wanna deal with it in your retirement years? I had this discussion on here once before. My father told me that he had seen many slab leaks from early radiant floor heating systems.Oh, and decades could be 20 years.

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 Re: Copper pipes "reacts chemically" with concrete a "myth"?
Author: sum (FL)

I am not saying protection or sleeving should not be done, even with the minimum interpretation of the quoted paragraphs I would still sleeve my pipes to minimize strain caused by thermal expansion/contraction and shielding at least the hot side as much as possible saves energy. I was just always assumed the MAIN reason to sleeve it was chemical reaction with the concrete/cement that accelerates corrosion and here copper.org says otherwise.

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 Re: Copper pipes "reacts chemically" with concrete a "myth"?
Author: LemonPlumber (FL)

They are saying the chemical composition is not a cause.It is not.Lye .is corrosive?stones against concrete are ?What is the stone made of.The fine filament concrete is not a corrosive but the filament can change it's body by chemical change.Sleeve your copper and {wipe the excess flux} from the tubing.it will react poorly if left inside sleeved on copper.

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