6.—(1) In every ship of Class I there shall be provided—
(a)in each special category space an effective power-ventilation system sufficient to give at least 10 air changes per hour; the Secretary of State may require an increased number of air changes when vehicles are being loaded and unloaded;
(b)in each cargo space, other than a special category space intended for the carriage of motor vehicles with fuel in their tanks for their own propulsion, an effective power-ventilation system sufficient to give at least 10 air changes per hour for ships carrying more than 36 passengers and 6 air changes per hour for ships carrying not more than 36 passengers.
(2) The power-ventilation systems referred to in paragraph (1) shall be entirely separate from other ventilation systems and shall be operated at all times when vehicles are in such spaces. Ventilation ducts serving such spaces capable of being effectively sealed shall be separated for each such space. The system shall be capable of being controlled from a position outside such spaces. In addition—
(a)the ventilation shall be such as to prevent air stratification and the formation of air pockets;
(b)means shall be provided to indicate on the navigating bridge any loss or reduction of the required ventilating capacity;
(c)arrangements shall be provided to permit a rapid shut-down and effective closure of the ventilation system in case of fire, taking into account the weather and sea conditions.