How to Provide Indefinite Life for Municipal Metallic Transmission Pipelines

Three current corrosion strategies used for Municipal Metallic Transmission Pipelines (MMTP) (defined as concrete pressure pipe, ductile iron pipe, or steel pipe 24" diameter and larger) as part of a comprehensive Asset Management Program are: 1) Run to Failure, 2) Run to Failure and Repair as Required, and 3) Operate and Maintain to Provide an Indefinite Life (repair-free service life >100 years). The paper will discuss the short- and long-term impacts of each strategy and detail why the strategy of "Operating and Maintaining to Indefinite Life" provides the most reliable Municipal Metallic Transmission Pipelines with the fewest repairs at the lowest total cost of operation to the owner. It will be shown that the strategies of "Run to Failure" and "Run to Failure and Repair as Required" are overall more costly since both strategies accept corrosion, unscheduled repairs, planned failure of the pipeline and the resulting high replacement costs of the MMTP. The paper will focus on methods of design, corrosion protection, maintenance and installation which allow all MMTP materials to be equally operated and maintained for an indefinite life.