Lifetime Assessment of Flexible Pipes

This paper presents a methodology for performing a lifetime assessment of flexible pipes applicable to re-qualification during the original design life and at life extension. A systematic approach is developed, providing flexible riser and flowline engineers a standardized methodology for determining the current integrity- and risk level. The objective is to provide methodology that is easy to implement, thus enabling consistent assessments of all flexible pipes in the operator’s portfolio. The methods described are taken from work performed in a recent JIP run jointly by MARINTEK/NTNU and 4Subsea, and is based on substantial experiences with lifetime assessment combined with a review of relevant guidelines and standards. Key areas are suggested for industry improvement and recommendations to further developments, to increase both efficiency and quality of the lifetime assessment process.