Inspection of pipelines may reveal crack-like anomalies. United States standards require that crack-like features by repaired or removed from pipelines. In contrast, Canadian standards permit an engineering critical assessment (ECA) of crack-like features. ECA utilizes pipeline dimensions, operating pressures, material properties, fracture mechanics, and inspection data to determine the disposition of crack-like anomalies. Methods for performing an ECA are reviewed. They include estimation of failure conditions for toughness-controlled fracture and the potential of crack growth by fatigue, stress-corrosion cracking, or corrosion fatigue. Application of the failure assessment diagram (FAD) as well as inelastic fracture mechanics is discussed. The importance of pressure cycle counting is pointed out. The rain flow cycle counting method is extended to incorporate cyclic frequency so time/cycle-
dependent crack growth can be evaluated. Practical examples are presented to illustrate the application of ECA.