Canada Oil and Gas Installations Regulations (SOR/96-118)

Regulations are current to 2019-06-20 and last amended on 2009-12-31. Previous Versions

PART IIAnalysis and Design (continued)

Motion Response Characteristics

 The motion response characteristics of every floating platform shall be determined by analytical methods or by model tests for the six degrees of freedom for all relevant operational, transit and survival drafts.

Stability of Mobile Offshore Platforms

  •  (1) For the purpose of this section, lightship, in relation to a mobile offshore platform, means a platform with all its permanently installed machinery, equipment and outfit, including permanent ballast, spare parts normally retained on board and liquids in machinery and piping at their normal working levels, but not including liquids in storage or in reserve supply tanks, items of consumable or variable loads, stores and crew and their effects.

  • (2) Subject to subsection (3), an inclining test shall be carried out to determine the lightship weight and the location of the centre of gravity on every mobile offshore platform.

  • (3) Detailed weight calculations showing the differences of weight and centres of gravity may be used in lieu of the inclining test required by subsection (2), in respect of a surface or self-elevating mobile offshore platform of a design that is identical with regard to hull form and arrangement to that of a platform for which an inclining test has been carried out, if the accuracy of the calculations is confirmed by a deadweight survey.

  • (4) Subject to subsection (6), during each five-year survey that is required and carried out by a classification society of a surface or self-elevating mobile offshore platform, a deadweight survey shall be carried out and, where there is a significant discrepancy between the measurement obtained from that survey and the weight change as calculated from weight records,

    • (a) in the case of a surface platform, an inclining test shall be carried out; and

    • (b) in the case of a self-elevating platform, the allowable variable load in the elevated condition shall be adjusted in accordance with the deadweight survey and the stability in the floating mode shall be calculated.

  • (5) Subject to subsection (6), an inclining test shall be carried out during each five-year survey that is required and carried out by a classification society for every column-stabilized mobile offshore platform, except that after the second inclining test, the subsequent tests need only be carried out during every alternate five-year survey if there was no significant discrepancy between the weight records and the results of the second test.

  • (6) An inclining test is not required pursuant to subsection (4) or (5) where the platform is equipped with instrumentation that is capable of accurately measuring or providing data that permit an accurate calculation of the centre of gravity.

  • (7) A comprehensive and up-to-date record shall be kept of every change to a mobile offshore platform that involves a change in weight or position of weight.

  • (8) Where the weight of a mobile offshore platform changes by more than 1 per cent of the lightship weight, a deadweight survey shall be carried out at the earliest opportunity and an up-to-date value of the lightship centre of gravity shall be recorded in the operations manual.

  • (9) Subject to subsections (10) to (13), the analysis of intact and damage stability of every mobile offshore platform undertaken for the purpose of paragraph 41(1)(e) shall include a verification as to whether the platform complies with Chapter 3 of International Maritime Organization Code for the Construction and Equipment of Mobile Offshore Drilling Units, 1989.

  • (10) Every mobile offshore platform shall be designed so that, in the intact condition, when subjected to the wind heeling moments described in the Code referred to in subsection (9), it has a static angle of heel of not more than 15 degrees in any direction.

  • (11) Every column-stabilized mobile offshore platform shall be designed so that, in the intact condition, it has a metacentric height of at least 1 m when it is in the operating and transit draft and a metacentric height of at least 0.3 m in all other draft conditions.

  • (12) Every surface and self-elevating mobile offshore platform shall be designed so that, in the intact condition, it has a metacentric height of at least 0.5 m.

  • (13) Every mobile offshore platform shall be designed so that, in the damaged condition or where any compartment is flooded, the final angle of heel does not exceed 15 degrees in any direction and the area under the righting moment curve is at least equal to the area under the heeling moment curve.

Ballast and Bilge Systems

  •  (1) Every mobile offshore platform shall be equipped with ballast tanks the number, location and degree of subdivision of which, together with the associated equipment, are

    • (a) capable of ballasting and trimming the platform efficiently under all reasonably anticipated environmental conditions; and

    • (b) designed to be fail safe.

  • (2) Every floating platform shall have a ballast system so arranged that any ballast tank can be filled or emptied by any one of at least two ballast pumps or by controlled free flow.

  • (3) Each lower hull on a floating platform with two lower hulls shall be provided with at least two ballast pumps each with the capacity to fill or empty any ballast tank in that hull.

  • (4) The ballast system for a column-stabilized mobile offshore platform shall be designed to prevent uncontrolled transfer of water between tanks or through sea-connected inlets or discharges in any one of the following situations:

    • (a) the failure of any valve or valve actuator for the system;

    • (b) the failure in the means of control or indication for the system; and

    • (c) the flooding of any space that contains equipment associated with the system.

  • (5) Ballast piping in a ballast system for a floating platform that leads from a pump to more than one tank shall be led from readily accessible manifolds.

  • (6) All power-operated sea inlets, discharge valves and ballast tank isolating valves on a floating platform shall be designed to close automatically on loss of control power and remain closed when power is re-established until specific action is taken to open them.

  • (7) Where crude oil is to be stored in a floating platform, the platform shall have enough ballast capacity, segregated from the crude storage, to be able to float at minimum operating draft with no crude oil on board.

  • (8) Every floating platform shall be provided with a main ballast control station equipped with

    • (a) an effective means of communication with other spaces that contain equipment relating to the operation of the ballast system;

    • (b) a ballast pump control and status system;

    • (c) a ballast valve control and status system;

    • (d) a tank level indicating system;

    • (e) a draft indicating system;

    • (f) emergency lighting;

    • (g) heel and trim indicators;

    • (h) bilge and flood alarms; and

    • (i) remote control indicators for watertight closing appliances.

  • (9) Every column-stabilized mobile offshore platform shall be equipped with a secondary ballast control station equipped with

    • (a) an effective means of communication with other spaces that contain equipment relating to the operation of the ballast system;

    • (b) a ballast pump control and status system;

    • (c) a ballast valve control and status system;

    • (d) a tank level indicating system;

    • (e) emergency lighting;

    • (f) heel and trim indicators; and

    • (g) a permanently mounted ballast schematic diagram.

  • (10) The main and secondary ballast control stations required by subsections (8) and (9) shall be located above the waterline in the final condition of equilibrium after flooding when the platform is in a damaged condition.

  • (11) Every column-stabilized mobile offshore platform shall have a ballast system that is capable, with any ballast pump out of operation,

    • (a) of providing safe handling and operation of the platform under normal operating and transit conditions;

    • (b) of restoring the platform to a normal operating or transit draft and level trim from an inclination of 15 degrees in any direction; and

    • (c) of raising the platform from the deepest operating draft to severe storm draft within three hours.

  • (12) Every floating platform shall be equipped with a bilge system that has at least two bilge pumps connected to the bilge main and that is capable, under all conditions from upright to 15 degrees in any direction, of pumping or draining any watertight compartment except for those spaces permanently designated for the storage of fresh water, water ballast, fuel oil or liquid cargo and for which other effective means of pumping are provided.

  • (13) No floating platform shall be considered to comply with this section until the ballast and bilge system has been assessed through a failure modes and effects analysis.

 
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