scope:

This part of ISO 19905 specifies requirements and gives guidance 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 part of ISO 19905 addresses mobile floating units that are column stabilized, commonly referred to as semi-submersible; cylindrical/conical; or ship-shaped vessels. 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. The requirements of this part of ISO 19905 apply to hull and stationkeeping for all types of unit. The activity specific operating guideline document requirements can be modified to be appropriate to the situation being assessed. This part of ISO 19905 does not address all site considerations, and certain specific locations can require additional assessment. This part of ISO 19905 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 part of ISO 19905 does not address design; transportation to and from site; or installation and removal from site. This part of ISO 19905 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 metocean actions on the unit; - The hull structure and airgap is 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; and - ISO 13624-1 and ISO/TR 13624-2 is referenced for the assessment of the marine drilling riser of mobile floating drilling units. IMCA M 220[1], or a similar methodology, is referenced for developing an activity specific operating guideline. NOTE 1 - The scope of ISO 19904-1 specifically states that its requirements do not apply to mobile units, but the methodologies given for calculating metocean actions can be used. NOTE 2 - RCS rules and the IMO MODU code[2] provide guidance for design and general operation of mobile floating units.