Regulation on Pump-room Bottom Protection

 

• The term pump room means Cargo pump room.

• Ballast piping is permitted to be located within the pump-room double bottom provided any damage to that piping does not render the ship's pumps located in the "pump-room" ineffective.

• This regulation applies to oil tankers of 5,000 tonnes deadweight and above constructed on or after 1 January 2007.

• The pump-room shall be provided with a double bottom such that at any cross-section the depth of each double bottom tank or space shall be such that the distance 'h' between the bottom of the pump-room and the ship's baseline measured at right angles to the ship's baseline is not less than specified below: 

                                            h = B/15 (m)

                                            (or)
                                            h = 2 m, whichever is lesser

                                            The minimum value of h = 1 m

• In the case of pump rooms whose bottom plate is located above the baseline by at least the minimum height required as mentioned above, there will be no need for a double bottom construction in way of the pump room.  

• Ballast pumps shall be provided with suitable arrangements to ensure efficient suction from double bottom tanks.

• The double bottom protecting the "pump-room" can be a void tank, or ballast tank or unless prohibited by other regulations, a fuel oil tank.

• Bilge wells may be accepted within the double bottom provided that such wells are as small as practicable and the distance between the well bottom and the ship's baseline measured at right angles to the ship's baseline is not less than 0.5h.

• Where a portion of the pump-room is located below the minimum height as mentioned above, then only that portion of the pump-room is required to be a double bottom. 

• Notwithstanding the provisions of the regulation with respect to the minimum height mentioned above, where the flooding of the pump-room would not render the ballast or cargo pumping system inoperative, a double bottom need not be fitted.  

Reference: IMO Publications & Documents - International Conventions - MARPOL - Annex I