The authors present the lessons learned from this incident through their direct involvement with the incident investigation as well as a review of previous, similar incidents investigated by the United States Environmental Protection Agency (EPA). The root cause and contributory factors for this explosion are discussed and recommendations provided on how similar incidents might be avoided in the future. One of the authors serves on the NFPA committee responsible for publishing the standard on safe storage, handling and use of ethylene oxide, and the paper concludes with an regulatory and industry perspective on alternative designs and equipment that could have prevented the exp.
Archives du mot-clef polyethylene tape coating
Failure analysis of stress corrosion cracking in a gas transmission steel pipeline
Abstract
In January 2010, stress corrosion cracking was occurred in a high-pressure gas pipeline steel in northern regions of Iran, after almost 40 years since its installation. In this study, failure mechanisms were determined based on available documents and metallographic studies conducted on this pipeline. The results showed that the applied polyethylene tape coating on the external surface of the pipeline became opened and disbonded in the corroded area causing external surface of buried pipeline to be exposed to wet soil around it. As a result of the chemical interactions and formation of carbonate/bicarbonate solution and with the presence of tensile stresses, stress corrosion cracking occurred in the longitudinal direction and at the outer surface of the pipe. In addition, mechanisms and morphology of cracks propagation due to stress corrosion cracking to internal side of the pipe wall were studied.
Keywords: API 5L X60; Stress corrosion cracking; Pipeline; Intergranular