Tampa Bay Completes Condition Assessment Raw Water Pipeline
To proactively address its large-diameter Prestressed Concrete Cylinder Pipe (PCCP) for deterioration, Tampa Bay Water (TBW) completed a leak and gas pocket survey and electromagnetic (EM) inspection of the South-Central Hillsborough Regional Wellfield Transmission Main in April 2013.
TBW maintains a large pipeline network that serves the Tampa Bay and St. Petersburg metropolitan area and includes approximately 80 miles of PCCP. The pipeline inspections were completed on 8 miles of 42, 48 and 54-inch PCCP that convey wellfield supply to the Lithia Water Treatment Facility.
A leak and gas pocket survey was completed using SmartBall® technology as a forerunner for the EM condition assessment and provided TBW with an initial condition of the pipeline. The inspection was very successful, with the tool travelling steadily throughout and reaching all the tracking points. Several members of Tampa Bay Water were on hand at the retrieval to see the tool in action.
Early identification and repair of leaks can reduce Non-Revenue Water, but also helps determine the baseline condition of a pipeline, since leaks can be an indication that a pipeline might fail. In addition, locating and eliminating gas pockets reduces pressure on the pumps that are attempting to push water past a pocket. As pockets grow in size, they can significantly affect the flow of water and capacity of the pipeline if not released.
In the following days, TBW prepared for the EM inspection using PipeDiver®, a free-flowing EM tool that is able to accurately locate and quantify broken wire wraps in PCCP. The wire wraps in PCCP act as the main structural component; broken wraps are the main indication that this type of pipe will eventually fail.
After completing inspection and analysis, Tampa Bay Water will have a wire wrap break estimate for each section of PCCP on this pipeline, which will allow them to make a prioritized rehabilitation and re-inspection plan.
The PipeDiver inspection was completed on schedule with the tool tracked throughout and retrieved successfully at the Lithia Water Treatment Plant. Results from both inspections are currently being analyzed for Tampa Bay Water.