ISO 19905-3:2021 石油および天然ガス産業—モバイルオフショアユニットのサイト固有の評価—パート3：フローティングユニット | ページ 6

3.1

activity specific operating guidelines

ASOG

document that sets out the activities that need to be undertaken at specific alert level thresholds (3.4) for specified changes in conditions

Note 1 to entry: These guidelines are in a document that sets out high level actions to be undertaken at specific alert level thresholds.

Note 2 to entry: The ASOG for drilling operations is often called the well specific operating guideline document (WSOG).

Note 3 to entry: An example ASOG for DP (dynamic positioning) and moored units is given in Annex A.

3.2

air gap

distance between the highest water elevation and the lowest exposed part of the primary deck structure and permanent equipment not designed to withstand associated environmental action effects

[SOURCE: ISO 19900:2019, 3.5, modified — “structure” and “action effects” not defined herein, “and permanent equipment” added and “for defined return period” deleted.]

3.3

alert level

condition when certain parameters are below the lower limit, or between limits, or above the upper limit

Note 1 to entry: Alert levels are often colour-coded. The colour-coding will often be green for normal, blue for advisory, yellow alert for reduced status, and red alert for emergency status. Parameters affecting the change of colour-coded alert levels can be, for example, approach of limiting metocean conditions, loss of equipment function, reduced available power levels, offset limits are reached [ watch circles (3.17) ], excessive vessel motions are predicted, etc. Actions to be taken can include, for example, discontinue drilling, disconnect riser, suspend lifts, etc.

3.4

alert level threshold

boundary between alert levels (3.3)

3.5

assessment

site-specific assessment

evaluation of a mobile floating unit and activity specific equipment to determine conformity with specific requirements

Note 1 to entry: The specific requirements are the requirements of this document (i.e. 19905-3).

Note 2 to entry: Definition derived from ISO 19905-1:2016, 3.4.

3.6

assessment situation

mobile floating unit configuration together with the metocean and ice actions that need to be assessed

3.7

assessor

entity performing the site-specific assessment (3.5)

[SOURCE: ISO 19905‑1:2016, 3.6]

3.8

extreme storm event

extreme combination of wind, wave and current conditions used for the assessment (3.5) of the mobile floating unit

Note 1 to entry: This is the metocean event used for ULS storm assessment and varies depending on what is being assessed. For example, the metocean event for the ULS assessment of the mooring system can be different from that used in the ULS assessment of the hull strength or air gap.

3.9

loss of position

unintended move of a dynamically positioned or thruster-assisted vessel from its intended location [ watch circle (3.17) ] relative to its set point position (3.13) , generally caused by loss of stationkeeping control or propulsion

Note 1 to entry: Loss of position can take on three main forms drift off, drive off, or force off.

3.10

operating manual

marine operations manual

latest approved document that defines the operational characteristics and capabilities of the mobile floating unit

[SOURCE: ISO 19905‑1:2016, 3.45, modified — “jack-up” has been replaced by “mobile floating unit”, Note 1 to entry has been deleted, and “manual” replaced by “latest approved document”.]

3.11

operator

representative of the company or companies leasing the site

Note 1 to entry: The operator is normally the oil company acting on behalf of co-licensees.

Note 2 to entry: The operator can be termed the owner or the duty holder.

[SOURCE: ISO 19900:2019, 3.35]

3.12

recognized classification society

RCS

member of the International Association of Classification Societies, with recognized and relevant competence and experience in mobile floating units, and with established rules and procedures for classification/certification of such units used in petroleum-related activities

[SOURCE: ISO 19901‑7:2013, 3.23, modified — “floating structures” has been replaced by “mobile floating units”, and “installations” has been replaced by “such units”.]

3.13

set point position

intended location of the unit (3.15)

3.14

sudden hurricane

hurricane that forms locally and, due to speed of formation and proximity to infrastructure at time of formation, might not allow sufficient time to evacuate manned facilities

Note 1 to entry: The population of storms used to derive the sudden hurricane at a given site can be defined in terms of the time horizon required to evacuate the site.

3.15

unit

complete assembly, including hull structure, topsides, and stationkeeping systems

3.16

unit owner

representative of the companies owning or chartering the unit (3.15)

[SOURCE: ISO 19905‑1:2016, 3.29, modified — Term “jack-up owner” has been replaced by “unit owner” and"jack-up" has been replaced by"unit".]

3.17

watch circles

concentric group of imaginary closed curves (e.g. circles) developed from the alert levels (3.3) with respect to the set point position (3.13) that indicate when specific activities need to be undertaken

Note 1 to entry: Watch circles, which are often colour coded to indicate the activities that need to be undertaken, are normally described in the activity specific operating guidelines.