3.2 Arrangements below the bulkhead deck
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Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC.1/Circular.1320 – Guidelines for the Drainage of Fire-Fighting Water From Closed Vehicle and Ro-Ro Spaces and Special Category Spaces of Passenger and Cargo Ships – (11 June 2009) - Annex – Guidelines for the Drainage of Fire-Fighting Water From Closed Vehicle and Ro-Ro Spaces and Special Category Spaces of Passenger and Cargo Ships - 3 Drainage Arrangements for Passenger Ships - 3.2 Arrangements below the bulkhead deck

3.2 Arrangements below the bulkhead deck

  3.2.1 Below the bulkhead deck, except as provided in paragraph 1.1.2 above, an efficient bilge pumping system should be provided to ensure that the combined waterflow from the fixed fire-extinguishing system and the required number of fire hoses can be rapidly collected and led to suitable arrangements for discharge overboard. The bilge system capacity should be not less than that required by paragraph 3.2.3.

  3.2.2 The bilge piping system should be arranged in accordance with SOLAS chapter II-1. At least four bilge wells should be located on each side of the protected space, uniformly distributed fore and aft.

  3.2.3 The bilge pumping system on each side of the ship should have an aggregate capacity of not less than 125% of the maximum flow rate of the fixed fire-extinguishing system water pumps plus the flow from two fire hoses (four, if required by SOLAS regulation II-2/19.3.1.2).

  3.2.4 The required area of the main and branch bilge pipes for the protected space should be adequate to ensure a maximum waterflow of 2 m/s in each section of piping in accordance with paragraphs 3.2.4.1 to 3.2.4.3.

  3.2.4.1 If the drainage system is a bilge pumping system, the following three criteria should be satisfied:

where:

Qbpump is the combined capacity of all power bilge pumps except the emergency bilge pump in m3/s;

Q is the combined waterflow from the fixed fire-extinguishing system and the required number of fire hoses in m3/s;

AM is the sectional area of the main bilge pipe of the protected space in m2;

∑AB is the total sectional area of branched bilge pipes for each side in m2.

  3.2.4.2 If the drainage system is based on gravity drains leading to a reservoir tank, the minimum required area of drains and connected piping should be determined by paragraph 3.1.4.

  3.2.4.3 If the drainage system is a combined system, the relevant dimensioning for each part of the system should be determined using paragraphs 3.2.4.1 and 3.2.4.2.

  3.2.5 The required capacity of each bilge well should be at least 0.15 m3.

  3.2.6 If the system includes a reservoir tank, the tank should have adequate capacity for at least 20 min of operation at the required drainage capacity for the affected space.

Parent topic: 3 Drainage Arrangements for Passenger Ships
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