Ballast pumps and piping
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - International Codes - 1989 MODU Code – Code for the Construction and Equipment of Mobile Offshore Drilling Units, 1989 – Resolution A.649(16) - Chapter 4 – Machinery Installations for all Types of Units - 4.9 Ballast pumping arrangements on column-stabilized units - Ballast pumps and piping

Ballast pumps and piping

  4.9.1 Units should be provided with an efficient pumping system capable of ballasting and deballasting any ballast tank under normal operating and transit conditions. Alternatively, Administrations may permit controlled gravity ballasting.

  4.9.2 The ballast system should provide the capability to bring the unit, while in an intact condition, from the maximum normal operating draught to a severe storm draught, or to a greater distance, as may be specified by the Administration, within 3 hours.

  4.9.3 The ballast system should be arranged to provide at least two independent pumps so that the system remains operational in the event of failure of anyone such pump. The pumps provided need not be dedicated ballast pumps, but should be readily available for such use at all times.

  4.9.4 The ballast system should be capable of operating after the damage specified in 3.5.10 and have the capability of restoring the unit to a level trim and safe draught condition without taking on additional ballast, with any one pump inoperable. The Administration may permit counter-flooding as an operational procedure.

  4.9.5 The ballast system should be arranged and operated so as to prevent inadvertent transfer of ballast water from one tank or hull to another, which could result in moment shifts leading to excessive angles of heel or trim.

  4.9.6 It should be possible to supply each ballast pump required by 4.9.3 from the emergency source of power. The arrangements should be such that the system is capable of restoring the unit from an inclination specified in 4.1.4.1 to a level trim and safe draught condition after loss of any single component in the power supply system.

  4.9.7 All ballast pipes should be of steel or other suitable material having properties acceptable to the Administration. Special consideration should be given to the design of ballast lines passing through ballast tanks, taking into account effects of corrosion or other deterioration.

  4.9.8 All valves and operating controls should be clearly marked to identify the function they serve. Means should be provided locally to indicate whether a valve is open or closed.

  4.9.9 Air pipes should be provided on each ballast tank sufficient in number and crosssectional area to permit the efficient operation of the ballast pumping system under the conditions referred to in 4.9.1 to 4.9.9. In order to allow deballasting of the ballast tanks intended to be used to bring the unit back to normal draught and to ensure no inclination after damage, air pipe openings for these tanks should be above the worst damage waterline specified in chapter 3. Such air pipes should be positioned outside the extent of damage, as defined in chapter 3.

Parent topic: 4.9 Ballast pumping arrangements on column-stabilized units
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