21.7.1 Effective means of ventilation should be
provided to all enclosed spaces which are entered by personnel.
21.7.2 Mechanical ventilation should be provided
to all accommodation spaces on vessels which are intended to make
long international voyages or operate in tropical waters. As a minimum,
mechanical ventilation should be capable of providing 6 changes of
air per hour, when all access and other openings (other than ventilation
intakes) to the spaces are closed.
21.7.3 Air conditioning systems are to provide
a minimum of 25m3 of air per hour, per person accommodated
in the ventilated space during normal operating conditions.
21.7.4 Enclosed galleys are to be specially considered,
and where air conditioning is not fitted should have, as a minimum,
a mechanical supply of 20 fresh air changes per hour and a mechanical
exhaust of 30 changes.