Research and application of natural gas pipeline assessment method in Location Class upgrading areas

With the development of society and economy in China, the Location Class of many natural gas pipelines has been upgraded compared with the as-built data. Location Class upgrading will lead to significantly increasing of failure risk in these areas. Thus, it is necessary to develop an assessment method to evaluate the continued service capacity of these pipe sections, and in order to provide a rational decision. On the basis of comparing specifications and regulations, a three-step assessment process is established, which is aimed to evaluate the pipeline step by step from the aspect of design compliance, pressure applicability, and risk acceptability, respectively. The assessment method is based on specification compliance, and is risk-oriented, which can be regarded as one of the important achievements in pipeline safety lifting phase. Besides, the best practice can be applied to other engineering in the future.