Mechanical Damage of Pipelines at Low Operating Pressure Available to Purchase

The paper presents the results of a testing program to characterize mechanical damage (dents and gouges) to pipelines at low operating pressures (i.e., at stress levels below 40% of the Specified Minimum Yield Strength, SMYS of the pipe material). The testing program was performed on pipelines of different sizes and grades; and the pipes were subjected to various gouges and dents when pressurized at 40% SMYS. The results of rupture tests on the pipes were compared with the ‘European Pipeline Research Group (EPRG) Simplified Model’ criterion. The results show that the model is sufficiently conservative to be used for evaluating mechanical damage of low-stress gas pipelines. The results provide guidelines for gas utilities to assess the damage at these stress levels. These guidelines allow a pipeline operator to assess the repair needs of a pipeline based on its operating pressure and damage level.