Using the See Snake Remote Field Testing (RFT) tool, PICA inspected approximately 3,300 feet of 12-inch ductile iron pipe (DIP) to determine whether numerous breaks over a 15-year time span were indicative of the poor condition of the entire line or if the problem areas were localized to specific areas of the water main.
Chlorine tubes were used to deploy an in-line RFT inspection tool and minimize downtown for the mostly industrial customers connected to the main. The inspection identified 1,582 pitting indications, with 144 of those sizing deeper than 80% wall loss (this includes 33 indications with 0% remaining wall). Despite the high defect count, the data confirmed the engineers’ suspicion that the main was not severely corroded for its full length. Instead, the corrosion appeared to flare up in localized areas, allowing City engineers to focus their attention on those areas. Using the inspection results, the City devised an approach that combined 300 feet of main replacement with a number of surgically placed repair clamps and anodes, thereby extending the remaining useful life of the main.