6. Causes of Corrosion in Coastal Areas

Corrosion of metal fasteners and connectors is accelerated when a certain level of surface wetness is exceeded, initiating electrochemical reactions among the metal, salts, and air. The conditions that accelerate the rate of corrosion near the coast have been studied at a few field stations and in research laboratories. The studies identified the major factors that contribute to accelerated corrosion rates as including proximity to the shoreline, high temperature, high humidity, elevation, exposure class (see text box) including sheltering, and certain airborne pollutants. While it may be infeasible to determine the rate of corrosion at specific sites, it is helpful to understand the factors that contribute to corrosion so that appropriate design, construction, and maintenance activities can be implemented.