Dedham, Massachusetts 30-year-old brass plumbing valve failure

Dealloying (dezincification) of a brass valve over 30 years caused a flood with half a million dollars damage.

Dealloying attack happens in copper-zinc alloys for example, copper-aluminum alloys, a few other alloys, where one very reactive metal — zinc in brass alloys — can be leached out, leaving behind almost pure copper residue. That's very porous, very weak. It's a very slow process. The only real failure I think from this was a 30-year-old plumbing valve down in Dedham, Massachusetts. It had been leaching away over 30 years and just lost most of its strength, caused a flood, half a million dollars damage.