To reflect the changing needs of the oil and gas pipeline sector, DNV GL has worked together with its industry partners to update two recommended practices (RP). The first for corroded pipelines (DNV-RP F101) and the second for integrity management of submarine pipeline systems (DNV-RP-F116).
The updates have been developed through the completion of joint industry projects. The revisions aim to further support the decision-making processes related to maintaining the integrity of pipeline systems in the following areas:
• Extension of in-service operation
• Costly repairs and replacements
• Long-term planning of activities based on balanced evaluations of both technical and non-technical issues; and
• Continuous improvement of integrity management systems.
“By its very nature, the pipeline sector is constantly evolving to meet regulatory requirements, address technology advances and react to an often volatile economic market. Likewise, recommended practices must keep ahead with these changes,” says Felix Saint-Victor, principal engineer for Pipelines & Materials, DNV GL Oil & Gas.” The latest revisions to two RPs for the pipeline sector will help ensure that best practice is adhered to and that decision-makers have the most appropriate guidelines at their fingertips.”
First issued in 1999, the latest update to DNV-RP F101 includes a new assessment methodology on how to estimate the pressure resistance of a pipeline containing long axial grooving (the methodology is also applicable for pipelines with other patterns of internal corrosion), and assessment of internal corrosion development with time.
Updates have also been made to achieve better compliance with the newest edition of the offshore standard DNV-OS-F101 rev. 2013-10, e.g. with regard to pressure definitions and terminology, characteristic material properties, partial safety factors and fractile values, and supplementary material requirements.
Integrity management is climbing further up the agenda as the industry looks to get the most from life extension of ageing pipelines. Corrosion in particular poses a major threat to these pipelines. Revisions to DNV-RP F101 aim to improve corrosion defect assessments, through thorough probabilistic evaluation, corrosion development evaluations and pressure resistance calculations accounting for system effects.
The February 2015 revision of DNV-RP-F116 provides more comprehensive guidelines on carrying out risk assessments. Guidelines regarding integrity management reviews as well as recommendations for identifying key performance indicators have also been revised and updated. These can be used to further develop risk assessment methods for company governing documentation.
“The listed indicators in the RP are based on a combined integrity management and barrier philosophy mind-set where barriers to risk can be seen as preventative and reactive. The updated RP provides guidelines on how to further embrace technical, human and organizational elements working together. This will provide a valuable framework to deliver risk evaluations for planning integrity management activities,” says Felix Saint-Victor.