From time-to-time seawater handling systems are subjected to lay-up which can produce chemical and biological changes, and conceivably alter the corrosion resistance of metals used in piping and other equipment. In the case of reverse osmosia/membrane technology type desalination equipment, sanitizing agents may be introduced atler draining. Simulation tests were conducted to determine any effect of a bisulfite sanitizing treatment when used between periods of normal seawater flow. Corresponding tests were conducted with lay-up comprising non-refreshed seawater which ultimately stagnated. Test results for CuNi alloy C71500 indicated that repeated cycling between seawater exposure and bioulfite treatments was detrimental in reducing that alloy’s resistance to general corrosion, and to a lesser degree its crevice corrosion resistance. The typical pitting and crevice corrosion behavior of NiCu alloy N04400, found upon exposure to slowly moving, aerated seawater was neither dhninished or accelerated by cyclic lay-up with either stagnant seawater or the candidate bisulfite-containing
solution. However, some increase in general corrosion was observed.