AWWA WQTC71622

This powerpoint presentation begins by providing a brief overview of copper plumbing, erosion corrosion and flow induced failure. Research objectives were to validate individual damage causing mechanisms by isolating and studying mechanisms, and evaluating the propensity to cause damage considering water chemistry (pH, chlorination, dosing of corrosion inhibitors) and temperature. Background information and research conducted on flow induced failure mechanisms are presented including: concentration cell corrosion; cavitation bubble implosion; particle impingement; high velocity impingement; and, electrification. Presentation summary indicates the following: concentration cell corrosion experiments - water chemistry controlled corrosion currents, high currents were not sustained, and weight loss was inconsistent with currents measured; cavitation and particle entrained flow - ultrasonically induced cavitation dramatically pitted copper samples, causing significant weight loss and even leaks, particles suspended in flow were not found to cause damage in a copper piping apparatus; combined mechanism jet tests - causes significant pitting and penetration of copper plates in heated saltwater, and combination of cavitation, concentration cell corrosion, and high velocity impingement; traditional erosion corrosion approach was deficient in explaining actual damage causing mechanisms - flow induced failure; copper pipe is susceptible to flow induced damage and premature failure - concentration cell corrosion, cavitation bubble implosion, high velocity impingement, and all mechanisms synergistically cause damage; and, water chemistry and temperature influenced failure - heated seawater was most susceptible, chlorine eliminated concentration cell corrosion, and higher temperatures increased concentration cell corrosion.