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Electrochemical techniques are described of direct use to chemical processors for optimum material selection in designing and maintaining new plants as well as corrosion monitoring and control in operating existing plants. Reference is made to the three corrosion forms most responsible for failures in chemical equipment, i.e.: general corrosion, localised corrosion, and stress‐corrosion cracking. Practical examples are given of successful industrial application of electrochemical methods: 1) for controlling active corrosion of a stainless alloy in pressure reactors operated with hot sulphuric acid solution and 2) for preventing stress corrosion cracking of a low‐alloy steel in a pressure absorption tower operated with hot alkali carbonate solution.

Recently acquired quantitative data on the initial corrosion rate of steel vs. the Ryznar index of natural waters are given as a basis of provision of overall service life of steel piping. In the light of the available fundamental knowledge of aqueous corrosion, the mechanism of high‐rate localised attack of coated steel piping from carbonated waters is outlined. A representative case history of multiple perforation of bitumen‐coated steel piping from localised corrosion is reported for a municipal potable water distribution system. Practical protective measures and corrosion monitoring techniques are considered in relation to the most aggressive waters.