AWWA WQTC57167

As the deterioration of ageing drinking water distribution systems in North America threatens water quality and system reliability, utilities are exploring new methods of pipeline rehabilitation. In addition to preventing corrosion and improving flow hydraulic characteristics, obtaining any semi-structural enhancement of rehabilitated pipes is considered to be beneficial. Although spray linings are traditionally considered to be nonstructural, an innovative attempt is made in this study to evaluate the strength enhancement provided by an epoxy spray lining system. Pressure tests were performed by subjecting 20.3 cm (8 in.) diameter epoxy-lined ductile-iron pipe sections to an internal hydrostatic pressure of 827 kPa (120 psi). The results indicated that the epoxy lining sprayed at 2 mm (80 mils) thickness could protect underlying pipes that had corroded areas up to 3/4 in. diameter, under the test conditions. The lining sprayed at 1 mm (40 mils) thickness conventionally prescribed for holiday-free coating failed at the 3/4 in. diameter exposed areas under the test conditions. The coating at 1 mm thickness would still likely extend service life of the pipe by reducing red water complaints. Full-scale field tests and bench scale leaching tests in the laboratory were also conducted. Water samples were obtained from customers' taps that were connected to freshly lined water mains. By testing various water quality parameters, water passing through the epoxy-lined mains was determined to be of excellent quality. No leached chemicals were detected in field or laboratory water samples as long as the system was flushed according to standard lining procedure. Includes 25 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2002

Number of Pages:

19

File Size:

1 file , 390 KB