Risk-based underground pipeline safety management considering corrosion effect.

Due to the long term usage and irregular maintenance for corrosion checks, catastrophic accidents have been increasing in underground pipelines. In this study, a new safety management methodology of underground pipeline, risk-based pipeline management, is introduced reflecting corrosion effect. First, principle of the risk-based pipeline management is presented compared with an original method, qualitative measure. It is distinguished from the qualitative measure by reflecting societal risk and corrosion in safety management of underground pipeline. And then, it is applied to an existing underground propylene pipeline in Ulsan Industrial Complex, South Korea. The consequence analysis is based on real information, and the frequency analysis reflects degree of corrosion. For calculation of corrosion rate, direct current voltage gradient (DCVG) and close interval potential survey (CIPS) are conducted. As a result of applying the risk-based pipeline management, risk integral is reduced by 56.8% compared to the qualitative measure. Finally, sensitivity analysis is conducted on variables, which affect the risk of the pipeline. This study would contribute to introduce quantitative measure to pipeline management and increase safety of pipeline.