Want to plate the inside of fire protection piping in situ to replace lost wall thickness
December 12, 2017
Q. I'm exploring the feasibility of electroplating the interior of an existing mild steel, low-carbon, piping network for the purpose of remove existing corrosion and replacing lost wall thickness. Conditions inside the piping network are typically a stagnant solution of old city tap water, iron oxide, microbiological influenced corrosion and associated byproducts. I'm leery of adding salts or the liquid byproducts due to compatibility with thread sealants, cutting oils, rubber gaskets in grooved fittings, and flammability are all concerns. I'm not thinking the gas byproducts will be a large concern as I am planning to Install air release vents on the piping network high points that will vent to the exterior. I'm currently envisioning temporarily installing a steel anode down the center of the pipe and grounding the outer pipe wall. I'm thinking the system will need to be flushed out before and after. Any thoughts, cautions or suggestions?
Fire Protection - Phoenix, Arizona, USA
A. Hi Scott. Regrettably, I feel the feasibility is zero. You need to get the interior of the pipe really clean (water-break-free), then rinse it thoroughly, then acid treat it, then rinse it thoroughly, then plate it (what do you want to plate it with, iron?). If you were planning a major research and development effort, to subsequently be employed in tens of thousands of buildings, I would not declare it impossible ... but for a single one-time application? And the thickness would probably build up most where you don't need it and least where you do :-(
A sandblasting and epoxy coating system has been developed for copper piping, and you might review topic 32428 for a quick intro to it and see if it has any applicability to your needs. Good luck.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"
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