DNV-OS-F101 pipeline standard gets update from DNV GL
The ‘most used and recognised offshore pipeline standard in the world’ has been updated to reflect new pipeline research and developments by leading industry players, including quality assurance and risk management company DNV GL.
Previously called DNV-OS-F101, the standard has been renamed to DNVGL-ST-F101. Across the world, around 65% of all new projects are designed to the standard which was first issued in 1976.
A series of joint industry projects by DNV GL and other industry players informed the new revisions. The joint industry projects presented the typical challenges that should be addressed in planning and design of marine operations and the common basis for installation design of pipelines, umbilicals and cables.
The new DNVG-ST-F101 incorporates input from a joint industry project concerning pipe-on-pipe systems. The standard now reflects findings on selection of safety classes, limit state criteria, additional guidelines specific to (PiP) and code breaks.
Requirements related to linepipe fabrication, welding and NDT have been updated to reflect state-of-the-art technologies, based on hands-on experience from DNV GL’s 14 laboratories and numerous field inspectors.
DNV GL’s joint industry project on subsea repair (DNVGL-RP-F113) which aimed to reduce the time and cost spent on the design and execution of pipeline repairs and a project on pre-commissioning of submarine pipelines (DNVGL-RP-F115) are also referred to and partially implemented to ensure consistency.
An additional modification to the standard is that the requirements for replacement of the system pressure test have become more flexible and no longer rule out pipelines in shallower water. Removing the requirement to fill the empty pipeline with water can significantly reduce cost for pipeline operators, according to a DNV GL statement, although some additional work will be required to prove an equivalent safety level.
“The standard illustrates what can be achieved when the industry works collaboratively. For example, the outcome of a workshop on dimensions including key industry players has now been built into the standard. The outcome was a compromise between pipe mills and installation contracts on how well pipe joints fit together to enable welding,” says Colin McKinnon, Chairman of DNV GL’s Pipeline Committee and technical director of subsea & export systems at Wood.
The revision also takes into account the findings from two joint industry projects run outside DNV GL: the Atteris Crossway project in Australia on shore crossings and the Atkins Safebuck project that provides a modified local buckling criterion.
“The offshore pipeline standard is a living entity, and is maintained by an active committee of users. DNV GL’s standards are updated to reflect the findings of joint industry projects, often involving DNV GL’s laboratories and test sites. These are the key factors to their success, widespread global adoption and continued progression,” says Elisabeth Tørstad, CEO DNV GL - Oil & Gas.
Another substantial change to the standards is the removal of the section on fracture assessment, which has been included in an updated revision of the recommended practice DNVGL-RP-F108. With the updates, the standard now gives requirements to when an Engineering Critical Assessment should be performed.