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Encyclopedia of Marine and Energy Technology

Engine room ventilation


Special attention should be paid to the engine room ventilation in order to ensure trouble free operation of all equipment. The air intake shall be located 4500mm above the freeboard deck or 2300mm above the superstructure deck as required by Load Line Convention for non-weathertight openings. Water spray, rainwater, dust and exhaust gases must not enter the ventilation trunks. Location of air intakes should be investigated from the stage of the conceptual design of the vessel to avoid problems later. The arrangement of main air trunks should be co-ordinated with hull structure to avoid cutting large openings in primary members.

The amount of air required for ventilation should be calculated from the total heat emission to evacuate. All heat sources shall be considered: main and auxiliary engines, exhaust gas piping, alternators, boilers with steam and condensate piping, electric appliances, lighting, and tanks.

The combustion air for main and auxiliary engines should be delivered through dedicated ducts close to the turbochargers.

Careful calculations are normally done to find the exact total amount of supply air, but as a quick estimate is often used. The following figures are for a diesel ship:

- Main engines: BHP X 6m3/h

- Auxiliary engines: BHP X 4.75 m3/h

- Boiler : kg steam/h X 1.25 m3/h

The total fan capacity will be the sum of the above consumption plus 50%. The ventilation air is to be equally distributed considering airflows from points of delivery towards the exits.