The types of structures, equipment, and property included in this category are land; structures and improvements (e.g., office buildings); reservoirs, dams, and waterways; waterwheels, turbines, and generators; accessory electric equipment; miscellaneous power plant equipment; and roads, railroads, and bridges. The effect of corrosion on each of the major categories of structures, equipment, and property for hydraulic plants is discussed below. (reference)
The main impact of corrosion on the original costs of these items is for initial protective coatings on reinforcing bars, and design and fabrication provisions to minimize corrosion of rebar, forms, etc. during the construction process. The estimated increase in cost due to corrosion is 1%.
Corrosion affects waterwheels, turbines, and associated piping systems (e.g., valves) by requiring the use of corrosion- and erosion-corrosion-resistant materials such as specialty grades of stainless steels (e.g., Nitronic 60) for either the pressure boundary or for trim. The electric generator is affected by the need to have a chemistry control system for the cooling water system, and by the need for protective coatings for steel parts. These features are estimated to increase the cost of the equipment by 10%.
Corrosion affects the costs of electric power and instrumentation and control equipment mainly by requiring design features to exclude corrosive atmospheres and the use of special materials for some corrosion-sensitive parts, such as switches. These features are estimated to increase costs by 5%.
This equipment includes cranes for lifting and moving waterwheels and electric generators for maintenance, and machine shop equipment. Corrosion affects the original cost of this equipment by requiring the use of protective coatings and some design features to protect sensitive parts. These features are estimated to increase costs by 2%.
Corrosion affects the original cost of this equipment by requiring the use of protective coatings, and some design features to provide for drainage to minimize water-induced corrosion. These features are estimated to increase costs by 2%.