From Pilot to Permanent: Evolution of LWC's PCCP Condition Assessment Program

On May 13, 2009, a 60-inch prestressed concrete cylinder pipe (PCCP) transmission main carrying potable water failed. Customers in the area experienced low pressure or no water. The break quickly poured out millions of gallons of potable water on to the ground flowing downhill and inflicting thousands of dollars of damage to the adjacent properties. Many of Louisville Water Company's (LWC) large diameter PCCP mains do not have redundant feeds. Instead of relying on the wait-and-see approach on these critical transmission mains, LWC chose to be proactive and create a condition assessment program for this class of pipe. The original 10-year $18.6 million program covering 105 miles of PCCP pipe was approved as part of LWC's 2010 Capital Improvement Budget. The program was initiated with two pilot projects before implementing the final 25 projects. The pilot projects were selected by management based on criticality, redundancy, the ability to take out of service, potential damages if failure occurs, and the availability of technology. During the design and implementation of the pilot projects, issues were encountered in creation of specifications, suitability of repair materials, the proper way to set up the projects to ensure competitive bidding, how to best address identified damaged pipe sections in a timely manner, and many others. Following the pilot implementation, the program was recalculated based on costs obtained from the bidding of the two projects and lengthened to include two 10-year inspection cycles. The proactive identification and repair of damaged sections has allowed LWC to optimize rate-payer funds while gaining positive publicity.