Applicability of current design coefficient to OD 1 422 mm pipelines in China-Russia East Natural Gas Pipeline

In China-Russia East Natural Gas Pipeline engineering, large-diameter (OD 1 422 mm) high pressure gas transportation pipeline are used and new technologies and materials are involved. One of the technical problems related to this pipeline engineering is whether the pipe wall thicknesses determined by the design coefficient stipulated in China's pipeline design standards can ensure the pipeline safety during its operation. By virtue of the research achievements of China's natural gas pipeline reliability design and assessment technologies, three wall thicknesses (i.e., 21.4 mm, 25.7 mm and 30.8 mm) were obtained in the pipeline engineering based on the current design coefficient in combination with the regional levels, pipe properties and construction, operation and maintenance parameters of OD 1 422 mm pipes in this engineering. Then, failure probability of pipelines was calculated and analyzed by the reliability method. The failure probabilities of pipelines in ultimate limit state are 1.27×10^-7/(km·a), 3.66×10^-10/(km·a) and 3.53×10^-15/(km·a), respectively, and they all satisfy the reliability targets of China-Russia East Natural Gas Pipeline. It is indicated that the pipe wall thickness derived from the current design coefficient is applicable to the design of OD 1 422 mm pipelines, and it can guarantee the safe and smooth operation of the pipeline after it is built up.