Salt effect on Copper Water Pipes

[sesegal99]

Question:

I have copper water pipes that run behind my sump that feed my bar sink (1 hot, 1 cold) In the past year that have changed to green color from the salty humid air. I believe this is not a problem and actually slows the corrosion process. Just need some confirmation on this as I don't ever want my basement flooded.

Thanks.

[Randy Holmes-Farley]

Well, it is a sign that they are corroding. I don't know how far that will progress.

[sesegal99]

Here's the only info I could find....





Q: Does copper corrode in salt water? I plan to build a salt-water hot tub and wonder if the heater copper pipes will corrode in the "marine" environment. -- Bert G., Albuquerque, NM

Copper-nickel alloys hardly corrode at all in sea water. General corrosion rates for 90-10 and 70-30 copper-nickel alloys range between 2.5 and 25 microns per year. That's not much: 25 microns- -only twice the thickness of a human hair-- in a whole year.

[Corel] Feeding the hops into a copper brewing vat

Copper pipes will easily last the lifetime of a hot-tub heater, especially if the copper is a copper-nickel alloy.

The alloy doesn't continue corroding because an oxide film forms on copper's surface which stops further corrosion quickly, much like the chromium oxide film that keeps stainless steel shiny. The film can make the copper look brown, greenish-brown, or brownish- black. The presence of nickel and iron in the copper enhances the film's protective value.

The film gets better with time. In flowing water, the corrosion rate decreases continually over at least a 14-year period.