best technical choice, however the use of titanium condenser tubes has been virtually eliminated by the sharp increases in the costs for this material. The tube lengths range to about 85 ft (26 m) for modern power plants, depending on the size of the condenser. The size chosen is based on transportability from the manufacturers’ site and ease of erection at the installation site. The outer diameter of condenser tubes typically ranges from 3/4 inch to 1-1/4 inch, based on condenser cooling water friction considerations and overall condenser size. Waterboxes The tube sheet at each end with tube ends rolled, for each end of the condenser is closed by a fabricated box cover known as a waterbox, with flanged connection to the tube sheet or condenser shell. The waterbox is usually provided with man holes on hinged covers to allow inspection and cleaning. These waterboxes on inlet side will also have flanged connections for cooling water inlet butterfly valves, small vent pipe with hand valve for air venting at higher level, and hand-operated drain valve at bottom to drain the waterbox for maintenance. Similarly on the outlet waterbox the cooling water connection will have large flanges, butterfly valves, vent connection also at higher level and drain connections at lower level. Similarly thermometer pockets are located at inlet and outlet pipes for local measurements of cooling water temperature. In smaller units, some manufacturers make the condenser shell as well as waterboxes of cast iron. Corrosion On the cooling water side of the condenser: The tubes, the tube sheets and the water boxes may be made up of materials having different compositions and are always in contact with circulating water. This water, depending on its chemical composition, will act as an electrolyte between the metallic composition of tubes and water boxes. This will give rise to electrolytic corrosion which will start from more anodic materials first. Sea water based condensers, in particular when sea water has added chemical pollutants, have the worst corrosion characteristics. River water with pollutants are also undesirable for condenser cooling water. The corrosive effect of sea or river water has to be tolerated and remedial methods have to be adopted. One method is the use of sodium hypochlorite, or chlorine, to ensure there is no marine growth on the pipes or the tubes. This practice must be strictly regulated to make sure the circulating water returning to the