Flow-induced failure mechanisms of copper pipe in potable water systems

Erosion or velocity-induced copper pipe corrosion is a significant problem in potable water systems, especially hot water recirculation systems. The little scientific work done in freshwater has not always been able to scientifically isolate the key factors causing these failures; in fact, most existing recommendations rely on anecdotal and/or experiential knowledge from forensic analysis of field failures, which are not confirmed by complementary laboratory research. Consequently, this comprehensive review summarizes prior observations that include mechanical and electrochemical attack induced by water chemistry, temperature, velocity, hydrodynamic conditions, presence of particulate matter, and other variables thought to influence/exacerbate erosion corrosion. Distinct phenomena thought to contribute to erosion corrosion or "flow-induced failure", including concentration cell corrosion, cavitation, particle/bubble impingement, and high velocity impingement, are explored in detail along with conventional erosion corrosion testing methods. Existing recommendations to prevent erosion corrosion in copper pipes are evaluated and inconsistencies in available guidelines are examined.