scope:

This publication covers the Society's involvement in Classification of a mobile offshore Unit's operational phase (Fleet in Service) and is applicable for the following structural designs types and services:

- ship-shaped Units

- column-stabilised Units

- cylindrical Units

- self-elevating Units

- tension-leg type

- deep draught type

intended for the following services:

- drilling

- well intervention

- accommodation

- heavy-lifting

- wind turbine installation

- general offshore support

- hydrocarbon production

- hydrocarbon storage and offloading

- hydrocarbon loading

- LNG/LPG production

- LNG/LPG storage and offloading

- LNG/LPG loading.

Guidance note:

Although this publication refers primarily to liquefied natural gas (LNG) and liquefied petroleum gas (LPG), the principles herein may also be used for other offshore gas installations such as those involving primarily compressed natural gas (CNG), and gas to liquid (GTL) products.

This publication does not cover the operational phase of offshore fish farms, modular systems for drilling and well or diving systems. These are covered by separate Rules DNVGL-RU-OU-0503, DNVGL-RU-OU-0294 and DNVGL-RU-OU-0375.

This publication addresses floating steel structures. Concrete structures, both floating and bottom fixed have also been proposed for offshore gas applications. For such designs see DNVGL-ST-C503 Concrete LNG terminal structures and containment systems. Where such Units are classified, the principles in this document may be applied.

This publication shall be seen in conjunction with the other Rules for Offshore Units as listed in [5.2] that provide requirements for the design and construction phase of a mobile offshore Unit.