Is the proportion of radiographic testing for metal pipes related to the method of installation? Buried, overhead, etc

This post was last edited by Shutong on 2022-2-8 06:48. Non-destructive testing during the installation of buried pipelines. Welding during pipeline installation is one of the most important steps in pipeline construction. During the construction process, the installation unit, in addition to having ISO9000 quality system certification, must also establish a welding quality system for pipeline construction in accordance with the ISO9000 standards for quality management and quality assurance, with non-destructive testing being used to directly monitor the quality of pipeline welding work. As the steel grades, diameters, wall thicknesses, and transmission pressures of oil and gas pipelines increase nowadays, the difficulty of pipeline welding operations rises, and the requirements for non-destructive testing techniques of the butt welds in these pipelines become increasingly stringent. Industry standards that are commonly applied, such as SY 0401-1998 and GB 50235-2010, specify that a certain proportion of ultrasonic testing and X-ray testing must be carried out depending on the operating pressure of the pipeline, as well as the sections it passes through or the environment in which it operates. For pipelines that pass through certain areas, 100% ultrasonic testing and X-ray testing are required for the entire length of the butt welds. The operational standards for non-destructive testing are outlined in NB 47013. However, in practice, the testing proportions specified in these standards are no longer followed by most clients; instead, testing is carried out in accordance with the internationally accepted standards (based on the type of fluid transported). An analysis of the technical specifications for pipeline design reveals a common requirement across all cases: 100% X-ray testing along with a certain proportion of ultrasonic testing. For example, the testing specifications for the West-East Gas Pipeline state that for butt welds with a wall thickness of 26 mm and a diameter greater than 150 mm, 100% fully automated ultrasonic testing or 100% X-ray testing must be conducted. The determination of technical requirements for testing methods and inspection standards shall comply with API 1104-1999 and the relevant corporate standard SY/T 4109-2013

Thank you for your reply; I have learned a great deal from it.

Drawing on a passage from the ASME standards regarding the classification of welded joints: The classification used here refers to the location of the joint on the vessel, rather than the type of joint, and is intended to specify the special requirements regarding the type of pressure-bearing joint and the extent of inspection. Since these special requirements are determined based on factors such as purpose, materials, and thickness, they do not apply to every welded joint; therefore, only those joints that are subject to such special requirements are included in this classification.