Fault Tree Analysis on Risk Factors of Underground Gas Networks of Beijing City

Accident statistics on the underground gas networks in recent 6 years in Beijing City is carried out and the result shows that pipeline leakage is the main cause of accident.Analysis on risk factors of networks leakage is made with fault tree method.Analyzing results show that the leakage accidents of gas pipeline networks are most induced by third party's damage,corrosion or aging of pipe and installation defects.Safety and protection measures for the underground gas networks are proposed in order to increase operation safety and reliability for gas networks system.