ABSTRACT
Concern about the corrosive effect of drinking water on distribution and plumbing systems traditionally has been economic and esthetic. It has been estimated that the annual economic loss from water corrosiveness is approximately $700 million. Metallic corrosion in water occurs when the corrosion products are at a lower free energy level than the parent metal. The dissolution of asbestos-cement pipe in the deterioration of cement mortar linings of cast iron water mains yields a number of undesirable contaminants in the potable water. Corrosion can also be controlled by the addition of various chemicals to the water that form a protective film on the interior surface of the pipe. These chemicals are commonly called inhibitors. Soluble silicates have been employed for more than 70 years to protect metals from the corrosive effects of water. It may be classified as corrosion inhibitors since a protective film may be formed onto various metal surfaces.
