Coatings designed for high temperature, underground applications were studied using Electrochemical Impedance Spectroscopy. The study involved testing the following coating systems: a two-layer fusion bonded epoxy, a single-layer fusion bonded epoxy, a two-layer tape wrapped polyethylene and a three-layer tape wrapped polypropylene. The
performance of these coating systems was evaluated as a function of time at six temperatures: room temperature, 180, 210, 230, 250 and 270°F, with the coatings being continuously immersed in highly saline solution. In general, under the test conditions, the total impedance for the two-layer fusion bonded epoxy coating system assumed higher values for longer times than the single-layer fusion bonded epoxy coating system. The results for the two-layer tape wrapped polyethylene and the three-layer tape wrapped polypropylene coating systems will be published subsequently. Keywords: pipeline coatings, organic coatings, fusion bonded epoxy coatings, electrochemical impedance spectroscopy,
life prediction, high temperature coatings