Baltimore Removes Transmission Main Ready For Failure
Pure Technologies worked with Baltimore City Public Works on July 16, 2012 to dig up a 54-inch pipe section that was ready to fail along the Gwynns Falls/Southwestern Transmission Main.
The excavated pipe section was severely damaged, and had it failed, would have caused significant damage, inconvenience and financial cost. The removal of the distressed pipe section shows Baltimore City’s commitment to preventing major failures in The City’s water system.
A feature story on WBAL-TV 11 from July 17 shows Pure working on verifying their results of the Gwynns Falls/Southwestern Transmission Main.
Pure engineers inspected this line in March 2012 using PipeDiver® — a free-swimming tool that uses Electromagnetics (EM) to detect broken prestressing wires in Prestressed Concrete Cylinder Pipe (PCCP) – and found that the pipeline had wires broken in several sections.
In recent months, the situation became critical and removal of a severely damaged pipe section was strongly recommended when prestressing wires began breaking more frequently. The increase in wire break activity was detected early on through Pure’s Acoustic Fiber Optic (AFO) monitoring system that was installed during a 2007 project with Howard County. This system gives utilities an early warning alarm when pipelines begin to rapidly deteriorate, ultimately allowing the utility to resolve problems early on and prevent catastrophic failure.
After the city shut down and dewatered the transmission main, Pure’s team mobilized on site to inspect the distressed pipe section more closely. In the verification process, the wire break locations were confirmed through impact testing. Two large cracks were also found upon visual inspection, which created a hollow section in the pipe, confirming Pure’s suspicion that a failure could have occurred at any time.
Pure also inspected the distressed pipe section with an EM verification tool. After a combined analysis of data collected from the EM tool, PipeDiver®, and the AFO monitoring system, a good correlation was found between the distressed locations predicted by all three technologies. As a result, the damaged pipe was removed from the ground and the pipe was returned to operation on Saturday, July 21, 2012.
Through proactive measures, The City of Baltimore was able to avoid a major failure that would have caused significant disruptions to service and substantial financial cost. The City is committed to Pure’s proactive approach in pipeline management to continue preventing major failures.
In early March, a group of reporters and video crews from local news stations gathered around the insertion site for a high profile PipeDiver® electromagnetic inspection in Baltimore, Maryland. It was necessary to perform the inspection without shutting down service to residents.
Specifically designed for structural assessment of Prestressed Concrete Cylinder Pipe (PCCP) lines that are live or can’t be taken out of service due to a lack of redundancy or operational constraints.
Large diameter prestressed concrete cylinder pipelines (PCCP) are a significant investment for many water and wastewater agencies. Assessing and monitoring the condition of these pipes is becoming an increasingly important and challenging task.