Pipe Corrosion Experiments, Catskill Supply, New York City

Abstract

The corrosion problem has several aspects, which may be classified, as follows: 1. Prevention or reduction of red water. 2. Reduction of corrosion of the metal. 3. Leakage due to pitting and eating away of metal. 4. Clogging of pipes in buildings, and reduction in carrying capacity of mains. Prior to the present experiments, the entire Catskill supply was treated for six months with soda ash, 0.5 grain per gallon, sufficient to remove all free carbonic acid, to increase average alkalinity from 8 to 15 p.p.m., 2 p.p.m. of which was neutral carbonate, and to cause average pH of 8.5. Red water was prevented and soon noted by many. Three buildings were chosen in different parts of the City, one two-years and the other about fifteen-years old, the former having galvanized steel and one of the latter galvanized wrought iron. For six months prior to treatment and during the six months treatment weekly samples of the cold supply to the buildings and of the hot and cold supplies after exposure to several floors of piping in the buildings were analyzed on the spot. There was no certain evidence