American Petroleum Institute

Design of Risers for Floating Production Systems (FPSs) and Tension-Leg Platforms (TLPs) - First Edition
 N RP 2RD

Annotation

SCOPE AND METHOD

This document addresses structural analysis procedures, design guidelines, component selection criteria, and typical designs for all new riser systems used on FPSs. Guidance is also given for developing load information for the equipment attached to the ends of the risers. The recommended practice for structural design of risers, as reflected in this document, is generally based on the principles of limiting stresses in the risers and related components under normal, extreme, and accidental conditions. This approach is often referred to as "working stress" design.

This document assumes that the risers will be made of steel or titanium pipe or unbonded flexible pipe. However, other materials, such as aluminum, are not excluded if risers built using these materials can be shown to be fit for purpose. Design considerations for unbonded flexible pipe are included primarily by reference to API RP 17B and API Spec 17J. Steel and titanium pipe will be called "metal" pipe and unbonded flexible pipe will be called "flexible" pipe.

Future development of these guidelines for riser system design will need to take account of the international focus on statistical methods to address uncertainties in creating and operating safe, functional, riser systems. Therefore, future release as an international standard should eventually incorporate statistical load and resistance factor design methodologies. Reliability-based limit state design principles may be applied provided that all relevant ultimate and serviceability limit states are considered. All relevant uncertainty in loads and load resistance should be considered and sufficient statistical data should be available for adequate characterization of those uncertainties.