Cavitation and Erosion Corrosion Resistance of Nonleaded Alloys in Chlorinated Potable Water

The January 2014 Federal Reduction of Lead in Drinking Water Act reduced the lead content in brass used in water distribution operations and in premise plumbing from 8% to <0.25% Pb (termed “nonleaded”) to protect the public from lead exposure. The switch to nonleaded materials has created legitimate concerns for water utilities, because anecdotally, the new nonleaded alloys have sometimes been more susceptible to erosion corrosion than the older leaded brass alloys. This study investigated the performance of 12 nonleaded alloys vis-à-vis conventional leaded red brass using an ASTM standard cavitation test and an erosion corrosion pipe-loop method. All 12 nonleaded test alloys were more resistant to cavitation than red brass. Silicon brass C87500 had the greatest susceptibility to erosion corrosion, while stainless steel alloys witnessed negligible weight loss and demonstrated superior resistance to erosion corrosion. All other alloys had erosion corrosion damage comparable to (or worse than) the control red brass. This preliminary study is a critical first step toward determining the useful applications of each material in potable water systems, especially for pump impellers and plumbing fittings exposed to high velocity.