Section 12(4) in The Merchant Shipping (Cargo Ship Construction And Survey) Rules, 1974
(4)In every ship-(a)the doorways and similar openings in corridor bulkheads shall be capable of being closed by permanently attached doors or by shutters :(b)the number of ventilation openings in such bulkheads shall be kept to a minimum. Such openings shall, so far as is reasonably practicable, be in the lower part of the door.
