Condition Assessment, Rehabilitation, and Validation of Advanced Pipe Inspection Tool for Aging 30-in. Steel Pipeline

Aurora Water and Jacobs Engineering Group Inc. (Jacobs) have developed a tiered approach for condition assessment for buried pipelines that minimizes risk for the client and helps the client make informed decisions on rehabilitation or replacement. The tiered approach considers the value added from low-cost evaluations prior to spending more money on costly advanced pipeline inspection tools. This paper discusses the tiered condition assessment approach, testing, rehabilitation selection and installation, and validation of condition assessment tools. In 2016, an investigation project was initiated to obtain background information about a 30-in. steel pipeline with a history of breaks. From background information, it was determined the pipeline had failures in a single concentrated reach, which was characterized by the presence of petroleum contaminated soils. The investigation focused on this particular reach, and corrosion control methods for the pipeline (e.g., coatings, linings, and cathodic protection) were evaluated. Based on the corrosion control assessment, appropriate advanced pipeline inspection tools were selected for detailed evaluation. The overall condition assessment conclusions suggested rehabilitation of the deteriorated section of pipeline. Sliplining with Fusible PVC (polyvinyl chloride) pipe was selected as the preferred technology to rehabilitate the pipeline. In 2021, sliplining rehabilitation was successfully installed. Two large sections of existing steel pipe were removed for the sliplining rehabilitation. These two sections of pipe were evaluated and used to successfully validate the results of the initial condition assessment.