Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.
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28 NOVEMBER 2017 MATERIALS PERFORMANCE NACE INTERNATIONAL: VOL. 56, NO. 11 T FEATURE ARTICLE Historic Corrosion Tools Tell the Story of Early Corrosion Control A Collection of Antique Instruments Illustrates the Rich History of the East Bay Municipal Utility District's Corrosion Department Mark Lewis, East Bay Municipal Utility District, Oakland, California, and Kathy Riggs Larsen, MP Editor The world of corrosion engineering, finding its roots in electric street railways (also called trolleys or streetcars), came into exis- tence and blossomed between the 1880s and mid-1930s. Most streetcars relied on direct current (DC) for their traction, and the rails not only supported the cars but also served as one leg of the electric circuit—the return path for the large amounts of DC (many hundreds of amperes) required to operate the system. Rail sections were connected with mechanical bonds (metal straps or cables) to establish long lengths of electrically continuous track. If a rail lost its electrical continuity, from faulty or missing rail bonds, the current would enter the ground and force its way back to the source (the substation) by taking whatever path it could. This often included water mains, gas lines, and other linear metallic utilities that were buried just beneath the city streets. Where the current left the pipe, it took metal with it, which led to rapid failure of buried water and gas pipelines. This phenome- non was referred to as electrolysis and was considered to be caused by "vagrant" or "vagabond" current, which is known pres- ently as electrical interference or stray current. At the time, all corrosion of buried utilities was blamed on electrolysis, and many electrolysis departments, committees, and engineers came into existence as a result. The East Bay Municipal Utility District (EBMUD) (Oakland, California), organized in 1923 to provide reliable, high-quality water for the people of San Francisco's East Bay area, employed a corrosion engineering staff early on to help mitigate corrosion of its buried water pipe infrastructure. Known originally as the Elec- trolysis Department of the East Bay Water Co., this group helped pioneer the implementation of corrosion-control techniques for EBMUD, including the use of cathodic protection (CP) on large water transmission mains, which was groundbreaking at the time. Their corrosion laboratory was housed on the second floor of the District's Claremont Center building, a critical pump station in Berkeley, California. The Electrolysis Department used a variety of equipment to conduct comprehensive surveys to track the flow of the electrical current. Results of the surveys were recorded by hand, compiled, and mapped. Before the pump station building was demolished and reconfigured in 1996, a collection of historic instruments used by the District was discovered—antique tools that date from about 1893 through 1950. The tools span the period from the beginnings of commercial- ization of electricity in the 1880s to the development of CP in the 1930s, and beyond. Aside from the fact that these antique instru- ments are beautifully and artfully crafted of fine materials such as black walnut, cherry, mahogany, oak, and polished nickel and brass, they represent what might be called the golden age of elec- trical instrumentation. Also retrieved from the building were his- torical records of the Joint Committee for the Protection of Under- ground Structures in the East Bay Cities, a group formed in 1922 that was dedicated to the preservation of underground utilities. The instruments in this collection were used not only in the early studies of electrolysis, but were also witness to the emer- gence of electrical bonds as a method of corrosion mitigation. The electrolysis engineers recognized that bonding the rail to buried pipelines was one method of mitigating stray current. Where