УДК 620.19::622.691.4::678.5-9
(UDK 620.19::622.691.4::678.5-9)
(BACKGROUND AND CHALLENGES OF TECHNICAL DIAGNOSTICS OF UNDERGROUND POLYETHYLENE GAS PIPELINES AS PART OF THE INDUSTRIAL SAFETY EXPERT REVIEW. PART 2)
Service life of the first-generation polyethylene pipes (commissioned before introduction of minimum required strength classification) in gas distribution networks has come close to 40 years. Even though the pipes were made from raw materials with inferior performance characteristics compared to modern grades of polyethylene, they continue to successfully perform their functions. Inspection of such gas pipelines is now becoming an urgent task for gas distribution companies in Russia. However, due to the lack of nondestructive testing assessment techniques for mechanical and physical characteristics of polyethylene pipes, making reasonable decisions on the possibility and the conditions of their further operation appear to be a serious problem requiring the support of appropriate research and experiments.
The second part of the article2 presents the results of laboratory tests of welded joints on first-generation polyethylene pipes after almost 35 years of operation, and tests for resistance to internal hydrostatic pressure. Based on experimental studies, it is shown that testing of pipes under internal pressure is the best option for obtaining quantitative reliability characteristics and for conducting further calculations. It has been proved that the pipe material is in very good condition even after decades of use.
Practical possibilities for assessing the serviceability status of long-operated polyethylene gas pipelines have been considered. A comprehensive approach to predicting their service life has been proposed. A possible calculation estimate has been given, which showed the suitability of pipes under examination for further operation within at least expected 50 years.
2 “Background and challenges of technical diagnostics of underground polyethylene gas pipelines as part of the industrial safety expert review. Part 1” article was published in Gas Industry [Gazovaya promyshlennost’] Journal No. 2 (845) in 2023.
S.N. Martynenko, AO Giproniigaz (joint-stock company) (Saratov, Russia), niigaz@niigaz.ru
G.I. Zubailov, PhD in Engineering, AO Giproniigaz, niigaz@niigaz.ru
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