19/30399562 DC - BS ISO 19905-3. Petroleum and natural gas industries. Site-specific assessment of mobile offshore units. Part 3. Floating units

19/30399562 DC

BS ISO 19905-3. Petroleum and natural gas industries. Site-specific assessment of mobile offshore units. Part 3. Floating units

Status : Current, Draft for public comment   Published : October 2019



This document specifies requirements and recommendations for the site-specific assessment of mobile floating units for use in the petroleum and natural gas industries. It addresses the installed phase, at a specific site, of manned non-evacuated, manned evacuated and unmanned mobile floating units.

This document addresses mobile floating units that are monohull (e.g. ship-shaped vessels or barges); column-stabilized, commonly referred to as semi-submersibles; or other hull forms (e.g. cylindrical/conical shaped). It is not applicable to tension leg platforms. Stationkeeping can be provided by a mooring system, a thruster assisted mooring system, or dynamic positioning. The function of the unit can be broad, including drilling, floatel, tender assist, etc. In situations where hydrocarbons are being produced, there can be additional requirements.

The requirements of this document apply to the hull and stationkeeping system for all types of mobile units. The activity specific operating guideline document requirements can be modified to be appropriate to the situation being assessed.

This document does not address all site considerations, and certain specific locations can require additional assessment.

This document is applicable only to mobile floating units that are structurally sound and adequately maintained, which is normally demonstrated through holding a valid RCS classification certificate.

This document does not address design, transportation to and from site, or installation and removal from site.

This document sets out the requirements for site-specific assessments, but generally relies on other documents to supply the details of how the assessments are to be undertaken. In general:

  • ISO 19901-7 is referenced for the assessment of the stationkeeping system;

  • ISO 19904-1 is referenced to determine the effects of the metocean actions on the unit;

  • ISO 19906 is referenced for arctic and cold regions;

  • the hull structure and airgap are assessed by use of a comparison between the site-specific metocean conditions and its design conditions, as set out in the RCS approved operations manual;

  • ISO 13624-1 and ISO/TR 13624-2[1] are referenced for the assessment of the marine drilling riser of mobile floating drilling units. Equivalent alternative methodologies can be used;

  • IMCA M 220[5] is referenced for developing an activity specific operating guidelines. Agreed alternative methodologies can be used.


RCS rules and the IMO MODU code[4] provide guidance for design and general operation of mobile floating units.

Standard Number19/30399562 DC
TitleBS ISO 19905-3. Petroleum and natural gas industries. Site-specific assessment of mobile offshore units. Part 3. Floating units
StatusCurrent, Draft for public comment
Publication Date07 October 2019
Normative References(Required to achieve compliance to this standard)ISO 13624-1:2009, ISO 19901-7:2013, ISO 19906, ISO 19900, ISO 19901-1, ISO 19904-1
Informative References(Provided for Information)ISO 19905-1:2016, ISO 19901-2, ISO/TR 13624-2
International RelationshipsISO/DIS 19905-3
Draft Expiry Date30 November 2019
DescriptorsData, Petroleum, Floating structures, Natural gas, Industries
Title in FrenchIndustries du pétrole et du gaz naturel — Évaluation spécifique au site d'unités mobiles en mer — Partie 3: Unité flottante Partie 3: Unité flottante
File Size588 KB
NotesWarning: this draft is not current beyond its expiry date for comments.

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