Neutralizing interference

Potential sources of corrosion are wide-ranging. We commonly think of moisture on steel leading to rust. But many electro-chemical reactions have the ability to undermine the effective lifespan of a pipe or tank system. That’s why high-quality inspections pay for themselves.

A natural-gas utility was experiencing significantly depressed cathodic-protection readings in a specific location along their Midwestern pipeline. We identified this with an indirect assessment tool. Prior to our analysis, the client was not aware of this issue. In most instances, this situation is an unplanned and unknown foreign CP system or foreign source of current that interferes with our client’s ability to maintain an effective level of cathodic protection. 

While conducting an external corrosion direct assessment (ECDA) inspection on a 30-inch, high-pressure gas main, CPM uncovered a major electrical interference issue that, if left unaddressed, would have resulted within months in a major gas leak and potential explosion.

In this instance, an international pipeline company had installed a new aboveground storage tank (AST) farm inside of a larger company facility adjacent to our client’s pipeline. CPM made contact with the AST farm's managers to communicate our client's issue and research any recently installed CP systems. CPM identified a new CP system recently installed and energized by the ASTs' owners. After conducting interference testing, the effect of that new system was defined and identified as the foreign source of current.

Result: CPM installed 50 semi-deep cathodic protection systems in an urban setting to bring the gas-distribution system into compliance with federal regulations.


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