Internal sealing of raw water piping to arrest corrosion has been utilized in municipal applications for over twenty-five years. This process consists of an EPDM rubber seal that is positioned over the affected area and is locked in place with two hydraulically expanded stainless steel retaining bands, located at each end of the seal. In cooling water-piping systems, numerous leaks often suggest that large sections of pipe may need to be replaced, although in many cases the deterioration is limited to the pipe joints. Preferential attack at welded joints is a common problem and deteriorated conditions can also be found at flanged and bell and spigot connections. Typically, repairs range from complete replacement of the affected area to welded patches and belly bands. This relatively simple method to repair and isolate deteriorated areas can be completed in piping diameters ranging from 16 inches to 18 feet. As many as 100 smaller diameter seals can be installed, inspected and tested during a 48-hour time period.
03-18: Internal Pipe Seals for Repair of Cooling Water Piping
John A. Charest, Universal Utility Services