Stray Current and Segmented Ductile Iron Pipelines

Paper ID: C2025-00439 ABSTRACT: Stray direct current, commonly called stray current, is an electrolytic process that typically is associated with buried metallic structures. Often, this mechanism of electrochemical action is generated from various sources, such as cathodic protection systems, direct current power trains or street cars, arc-welding equipment, direct current transmission systems, and electrical grounding systems. The one of most frequency is the cathodic protection systems, specifically of the impressed current form. All too often, corrosion engineers deal with this issue, stray current corrosion, in the welded-steel, electrically continuous pipeline business. This paper will be focusing on segmented metallic pipelines or sometimes referred to as electrically discontinuous pipelines.
The idea of segmented metallic pipelines being less inclined to be affected by stray current corrosion has long been known. Often most of the buried metallic structure installations are quite commonly considered remote from stray current sources; therefore, polyethylene encasement conforming to ANSI/AWWA C105/A21.5 is more than adequate to shield against this type of electrolytic activity. However, when an impressed current cathodic protection ground (anode) bed is found to be relatively close to any proposed buried metallic structure, then a more far-reaching measure for mitigation is considered necessary.