(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), email@example.com
G.I. Zubailov, PhD in Engineering, AO Giproniigaz, firstname.lastname@example.org
Kazanorgsintez PJSC. TU 6-19-051-538–85 (specifications). Pipes from polyethylene of low pressure for gas pipelines. Specifications. [Accessed: 27 February 2023]. (Accessible under specific conditions in the owner’s local area network; in Russian)
Martynenko SN, Zubailov GI. Background and challenges of technical diagnostics of underground polyethylene gas pipelines as part of the industrial safety expert review. Part 1. Gas Industry [Gazovaya promyshlennost’]. 2023; 845(2): 84–90. (In Russian)
Main Directorate of Gas Facilities of the Ministry of Housing and Utilities of the RSFSR. Technological charts for repair of steel gas pipelines by broaching polyethylene pipes dated 13 April 1979. [Accessed: 27 February 2023]. (Accessible under specific conditions in the owner’s local area network; in Russian)
Interdepartmental Coordination Council on the Technical Improvement of Gas Distribution Systems and Other Utilities. SP 42-103–2003 (code of practice). Design and construction of polyethilene gas pipelines and renovation of underground gas pipelines. Available from: https://docs.cntd.ru/document/1200034119 [Accessed: 27 February 2023]. (In Russian)
Kuznetsova OV, Sergeev VI, Kalugina YeV, Gorbunova TL, Safronova IP, Kovriga VV. Polymer gas pipelines serve a long time. Plastic Pipes [Polimernyye truby]. 2007; 18(4): 50–55. (In Russian)
Malamatov AKh, Kozlov GV, Ligidov MKh, Pakhomov SI. Influence of free volume characteristics on gas permeability of modified polyethylene. Chemistry and Chemical Engineering [Khimiya i khimicheskaya tekhnologiya]. 2006; 49(4): 59–62. (In Russian)
Kuznetsov AV, Zubailov GI. On the issue of technical diagnostics of polyethylene gas pipelines. Plastic Masses [Plasticheskie massy]. 2021; (7–8): 39–47. https://doi.org/10.35164/0554-2901-2021-7-8-39-47. (In Russian)
Federal Agency for the Construction, Housing and Utilities. GOST R 52134–2003 (state standard). Pressure thermoplastic pipes and their jointing elements for water-supply and heating systems. General specifications. Available from: https://docs.cntd.ru/document/1200034446 [Accessed: 27 February 2023]. (In Russian)
Federal Agency on Technical Regulating and Metrology. GOST R 50779.22–2005 (ISO 2602:1980). Statistical interpretation of test results – Estimation of the mean – Confidence interval. Available from: https://docs.cntd.ru/document/1200039939 [Accessed: 27 February 2023]. (In Russian)
Euro-Asian Council for Standardization, Metrology and Certification. GOST 34715.1–2021. Gas distribution systems. Design, construction and liquidation of natural gas distribution networks. Part 1. Polyethylene gas pipelines. Available from: https://www.consultant.ru/document/cons_doc_LAW_381196/ [Accessed: 27 February 2023]. (Accessible for registered users; in Russian)
Ministry of Regional Development. SP 62.13330.2011. Gas distribution systems. Available from: https://docs.cntd.ru/document/1200084535 [Accessed: 27 February 2023]. (In Russian)