This RP provides specific aspects related to design criteria, local analyses and material description valid for risers made of titanium or a mix of titanium and steel. For the latter, the RP covers only the titanium part of the riser.

It shall be pinpointed that the majority of available information discusses results obtained for material group I, described in Sec.5 B, and the calibration of the design requirements given in Sec.5 will be based on the titanium grades given in this group.

General design philosophy, loads and global analysis aspects valid for all riser materials are covered by DNV-OSF20 1.

The RP is applicable to all new built riser systems and may also be applied to modification, operation and upgrading of existing risers.

The scope covers design, materials, fabrication, testing and operation of riser systems. Aspects related to documentation, verification and quality control are also addressed

The main purpose is to cover design and analysis of top tensioned and compliant titanium riser systems operated from floaters and fixed platforms. The standard applies for permanent operation (e.g. production and export/import of hydrocarbons and injection of fluids), as well as for temporary operation (e.g. drilling and completiodworkover activities).

This RP is applicable to structural design of all pressure containing components that comprise the riser system, with special emphasis on:

- single pipes with a ratio of outside diameter to wall thickness less than 30 (D/t < 30)

• riser connectors and other riser components such as tension joints and stress joints.

There are, in principle, no limitations regarding floater type, water depth, riser application and configuration. However, for novel applications where experience is limited, special attention shall be given to identiSl possible new failure mechanisms, validity/adequacy of analysis methodology and new loads and load combinations.

Guidance note: For application of this project RP to new riser typeshoncepts (e.g. novel hybrid systems, complex riser bundles etc.) it shall be documented that the global load effects can be predicted with same precision as for conventional riser systems. This may typically involve validation of computational methodology by physical testing. As an alternative an appropriate conservatism in design should be documented.