H.2 Performance and design of ventilation systems

H.2 Performance and design of ventilation systems
H.2.1 In cargo ships, ventilation fans shall normally be run continuously whenever vehicles are on
board. Where this is impracticable, they are to be operated for a limited period daily as weather permits
and in any case for a reasonable period prior to discharge, after which period the ro-ro or vehicle space
shall be proved gas-free. One or more portable combustible gas detecting instruments are to be carried
on board for this purpose.
H.2.2 The system shall be entirely separate from other ventilating systems. Ventilation ducts serving
ro-ro or vehicle spaces shall be capable of being effectively sealed for each cargo space. The system
shall be capable of being controlled from a position outside such spaces.
H.2.3 The ventilation system shall be such as to prevent air stratification and the formation of air
pockets.
H.2.4 An independent power ventilation system is to be provided for the removal of gases and vapours
from the upper and lower part of the cargo space. This requirement is considered to be met if the
ducting is arranged such that approximately 1/3 of the air volume is removed from the upper part and 2/3
from the lower part. Supply ventilation may be natural and be introduced into the cargo spaces at the top
of these spaces.