Assessment of integrity of operating gas pipelines

Gas pipelines that have been in operation for many years require supervision, taking into account the places and conditions of their usage. The currently applicable normative regulations do not fully determine the scope of the integrity control of such gas pipelines. The standards provide general guidelines for monitoring corrosion phenomena in pipelines, allowing the use of simplified strength patterns based on a flat state of stress; in actuality, real objects usually have complex three-dimensional structures. Such an approach may be a reason for committing significant errors in determining the state of stresses and strains in the construction of pipelines, which is a significant problem in assessing the integrity of pipelines (when combined with the lack of a formulation of the appropriate admission criteria). This paper presents a methodology for assessing the integrity of pipeline structures operating at ambient temperatures based on conducting comprehensive measurements of wall thickness defects (in connection with performing necessary defectoscopy tests). The results of these measurements and non-destructive tests are the basis for the analysis of stress strength and MES deformation based on the verified real geometry as well as the method of supporting the pipelines. The information obtained on this basis regarding the pipeline structure areas of the highest efforts is the basis for selecting the critical areas of pipeline construction for which they should be repaired or modernized, or a monitoring program should be developed using non-destructive tests.