A Risk Based Approach to Optimize Inspection and Maintenance Resources

Pipelines have been used to transport oil and gas for more than a century. The first wooden gathering line for oil, about 9 miles in length, was built in 1865. The first Crude oil trunk line, named Tidewater, was built in 1879. Since then pipelines have played a very important role in the transportation of oil and gas. Now there are some 460,000 miles of oil and gas transmission pipelines in US, with about 300,000 miles of gas pipelines and about 160,000 miles of liquid pipelines. Pipelines have connected most of our families together to form an energy transporting network. With the increasing network of pipelines around our society and the increasing construction activity near pipelines, pipeline accidents due to third party damage has become a serious concern for pipeline industry and regulatory bodies. On January 17, 2006, the Pipeline and Hazardous Materials Safety Administration (PHMSA) issued an advisory bulletin raising the concern that “excavation damage continues to be one of the three leading causes of pipeline damage. PHMSA has seen an increase in pipeline operators damaging their own pipeline facility”. PHMSA requested the pipeline operators to reinforce the need for safe excavation practices and recommended that pipeline operators integrate the Operator Qualification regulations into their marking, trenching, and backfilling operations to prevent excavation damage mishaps. This paper will first analyze the pipeline damage data from the past 30 years. The data is divided into three categories: natural gas distribution incident data, natural gas transmission incident data, and hazardous liquid accident data. The analysis, with statistical data from 1968 up to today, indicates that the third party damage, corrosion, and defects in design/construction have being the top three causes on both the frequency of accidents and the values of property damages. This paper will focus on the analysis of the causes of “Outside Force Damage” and “Corrosion”. Through the data analysis the proportion of the risks from these two causes will be presented. The results will provide recommendations for different loss control plans based on the risks from the two causes in different stages of the service life of pipelines.