Mexico Water Commission Prevents Failure Cutzamala Pipeline
After prestressed wire break activity on the Cutzamala Pipeline, The Mexican National Water Commission (CONAGUA) intervened on two pipe sections that were near failure.
The wire breaks were identified by an Acoustic Fiber Optic (AFO) monitoring system that detects wire breaks on pipelines that utilize prestressing wires for structural stability; however, CONAGUA took quick and decisive action to prevent a failure.
After shutting down the pipeline, it took only 24 hours to assemble a crew that included almost 100 people to verify and replace the damaged sections and return the critical pipeline to operation. One of the distressed sections had visible corrosion while the section directly next to it had wire break activity but no visible damage.
The prevention of a major failure was crucial, as the Cutzamala system supplies water to about 5 million people living in Mexico City. The system features two parallel pipelines that stretch about 75 kilometers and are made 99-inch Prestressed Concrete Pipe (PCP) and Prestressed Concrete Cylinder Pipe (PCCP). Both pipe designs utilize high strength steel prestressing wire as the primary strength member. PCP differs from PCCP slightly in that it does not have the steel cylinder core, but instead is made of stronger concrete.
CONAGUA currently has AFO technology installed on about 70 kilometers (43 miles) of the two pipelines combined. The technology monitors the condition of prestressed pipe by recording the amount of wire breaks in each pipe section. The system allows CONAGUA to track pipeline deterioration and identify at-risk pipes before they fail.
Pipeline monitoring was initially adopted for the Cutzamala system due to a number of failures that disrupted service. After realizing that complete replacement was too expensive and unrealistic, CONAGUA decided to install AFO. The results have been positive so far, with the system identifying wire breaks along the monitored sections, allowing for the successful preventative repair of pipe sections.
In July 2012, CONAGUA also completed an electromagnetic (EM) condition assessment of the Cutzamala pipelines using PipeDiver® technology, a free-swimming tool that allows for non-destructive condition assessment of pipelines while they remain in service. The tool travels through the pipeline with the flow of water, collecting electromagnetic (EM) data that is analyzed to understand the baseline condition of the pipe.
The EM assessment provided CONAGUA with a baseline condition for each pipe section, while the monitoring system alerts operators about wire breaks on specific sections as they happen.