Corrosion of galvanized pipes in the hot water supply system

The paper describes the problem of steel pipes corrosion in domestic hot water supply systems. A case study of abnormally high rate of corrosion of galvanized steel pipes in a hot water supply system, installed in a complex of residential and public buildings, was considered. The rapid corrosion led to premature failure of these pipelines. Onsite visual inspection, chemical analysis of the tap water with LSI/RSI calculation and scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis were used during this study. The basic factors that lead to pitting corrosion were established: quality of source water (its high corrosion activity), high temperature and local increase in oxygen content near the pipe surface. A possibility of microbial corrosion was also assumed.