Baltimore City Prevents PCCP Pipe Failures
The steel used in Class IV PCCP was the strongest used in the manufacturing of PCCP lines, but the same factors that gave the steel wires high strength have also made them vulnerable to brittleness when exposed to corrosive conditions, and therefore more likely to break.
Broken wires in PCCP are the main indication that the pipe will eventually fail. Unlike metallic pipe materials that typically fail after a long period of leakage, PCCP is prone to sudden failures when too many wires break in one area. The diagram below demonstates how PCCP typically fails.
To prevent failures, BPW began installing monitoring equipment in its PCCP to alert staff when the prestressing wires break, BPW also regularly inspects its transmission mains for deterioration using EM technology that locates wires that are already broken.
In summer 2012, Baltimore City Public Works (BPW) intervened on a critical 54-inch PCCP pipe that was showing signs of distress. The pipe section was replaced and service resumed after avoiding a major pipe failure.