One key aspect of any pipeline integrity management and verification program is to identify threats to a pipeline’s integrity. One threat that is receiving more attention in the gas pipeline industry is cyclic pressure induced fatigue. As with other integrity threats, the risk of fatigue should be understood and characterized correctly by a pipeline operator in order to prioritize responses and minimize the chance of fatigue impacting the integrity of a system. As part of understanding and characterizing the risk associated with cyclic fatigue a pipeline operator must be able to understand what scenarios (i.e. operating conditions, pressure levels, pipeline features) may lead to fatigue and what scenarios can reasonably be expected to pose no fatigue risk.
Although a variety of cyclic fatigue loading can occur in a pipeline system, (i.e. mechanical vibration, thermal loads, etc.), the following report is focused on internal cyclic pressure induced fatigue, where the internal pressure fluctuations experienced by a pipeline can result in fatigue crack initiation and propagation, under certain circumstances.
