Di water and copper pipe compatibility
Di water and copper pipe compatibility
(OP)
We were changing heat exchanger pipe material from c/s to s/s due to being advised that carbon steel will quickly contaminate the DI water. We now were asked to investigate making heat exchanger using copper pipe since the Induction power supply vendor rutinely runs DI water in copper manifold to cool their transformers.
- Is DI water flowing thru copper pipe compatible, or will there be a chemical reaction that will either significantly effect purity of DI water or attack the copper pipe walls?
- Is DI water flowing thru copper pipe compatible, or will there be a chemical reaction that will either significantly effect purity of DI water or attack the copper pipe walls?





RE: Di water and copper pipe compatibility
We use Al piping in several pure water streams.
RE: Di water and copper pipe compatibility
DI water will dissolve roughly 30 ppm Cu at ambient T and typical pH of 5, and more at higher T. Enough to visibly contaminate the water. Perforation is likely in the higher T portions of a closed system.
Of course, with enough Prestone, Peak, etc., you can use copper, brass, carbon steel, etc.
The only metals suitable for contact with pure DI wwater are noble metals (gold, platinum) and those with highly passive oxide films (304/316 SS, Ti, Zr). Aluminum 1100, 3003, 5052, etc. can be used to 100oC if 0.04 ppm dissolved Al is tolerable [value for steam condensate tanks of Al 3003].
Pure DI hot water systems typically use 304/316 SS or Kynar (PVDF). Pyrex was also used in the past, but not so much anymore.
RE: Di water and copper pipe compatibility
If the DI water is in contact with a source of oxygen, copper will fail rapidly.
RE: Di water and copper pipe compatibility
Copper in and of itself in condensate service doesn't normally cause problems. Some other factor has to be present before it becomes an issue. But if you've got copper, half of the equation is already in place. If I had copper tracing, I'd sewer the condensate rather than send it back to the boiler. It's not a corrosion issue that is so severe that it will affect the tubing - it's the potential for feedwater contamination.
RE: Di water and copper pipe compatibility
Fred Specht
Ajax Tocco Magnethermic
RE: Di water and copper pipe compatibility
= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Di water and copper pipe compatibility
RE: Di water and copper pipe compatibility
Please provide info on the corrosion-inhibiting properties of glycol.
My understanding is that glycols primarily extend the liquid water temperature range. Corrosion inhibition comes from azoles [a few ppm of mercaptobenzothiazole (MBT), benzotriazole or tolytriazole; more if chlorine is present]* or sodium silicate.
*ASM Handbook, vol. 13, Corrosion p. 497.
I do recall that glycols can react with & neutralize dissolved CO2 and some organic acids.