Protection of ductile iron water mains against external corrosion: review of methods and case histories
نویسندگان
چکیده
Ductile iron replaced grey cast iron as pipe material in the early 1970s. It has been estimated that almost half of all new water mains in North America are ductile iron. The main cause of the structural deterioration of all metallic mains is external corrosion, which is induced by environmental and operational conditions. Internal corrosion, on the other hand, can cause significant functional (hydraulic, water quality) deterioration within the distribution system. Methods for external corrosion protection include passive (coatings, wraps, etc.), active (cathodic protection) or a combination of both. Successes and failures have been reported on the usage of various methods under different conditions and circumstances. This paper provides the state of the practice in corrosion protection of ductile iron water mains, and describes case histories that have been reported from around the world. Some conclusions are drawn as to the suitability of methods to specific circumstances.
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