Analysis of ruptures and trends on major Canadian pipeline systems

摘要

Number of ruptures per year is one of the National Energy Board's measures of safety performance of the federally-regulated oil and gas pipelines in Canada.This measure was examined and analyzed over 20, ten, and five year periods with respect to the rupture causes, ignitions, fatalities, injuries, pipeline age, in-line inspections, and the Board's safety interventions. There were 46 ruptures over the 20-year period, 23 over the ten-year period, and seven over the five-year period on the 43,000km of regulated pipelines. The average time from the pipeline installation to the time of rupture for the time-dependent rupture mechanisms was 28 years. There were three fatalities and 14 injuries caused by ruptures of federally-regulated pipelines over the past 20 years. Ruptures associated with fires on the gas and high-vapour pressure pipelines caused most of the fatalities and injuries. The dominant rupture causes are external corrosion, stress-corrosion cracking, and third-party damage, in this order of magnitude.The pipelines that ruptured during the last five years were internally inspected; however, the in-line inspection tools could not properly detect the defects that caused the ruptures. Regulatory interventions, such as public inquires, Board Orders, and regulatory requirements, have reduced the number of ruptures due to the targeted cause, and the number of ruptures and safety consequences associated with them have decreased over the last ten years.