Submarine pipelines are more often than before required to operate in harsh environments, especially for systems deployed in ultra-deep water. In order to minimize the installation tension due to the hanged section, they are installed empty and therefore the external pressure is often the prime load parameter for the design.
New discoveries and associated technical challenges have generated important research and development endeavors in a wide range of disciplines in order to improve efficiency and reliability, but also keeping the risks associated with the new scenarios within an acceptable range. Some aspects that can be mentioned include, for instance, steel line grade improvements and manufacturing innovations of pipe products; more powerful lay vessels and development of new pipeline installation methods; determination of the mechanical behavior and the expected failure modes of concern for deep and long pipelines under combined loads; and the improved different design criteria like the DNV-OS-F101 (1) and API RP-1111 (2) codes.
The intention of this paper is to review and compare three different pipeline design criteria well established in the oil and gas industry. The pipeline wall thickness design for pipe pressure containment (bursting), local buckling (system collapse) and propagating buckling for DNV-OS-F101 (1) and API RP-1111 (2) are discussed as well as the parameters used, definitions, safety philosophy and code limitations. A pipeline example is used to illustrate and compare the results.