To ensure that arrangements are provided for enclosed spaces in the cargo area to
control the accumulation of flammable and/or toxic vapours.
10.1 Application
10.1.1 For vessels to which the present Code applies, the provisions of this chapter
replace the requirements of SOLAS regulations II-2/4.5.2.6 and 4.5.4.1.
10.1.2 However, for products addressed under 9.1.3, except acids and products for which
15.12 and/or 15.17 of the IBC Code applies, SOLAS regulations II-2/4.5.2.6 and 4.5.4.1 may apply in lieu of the provision of 10.2 of this
chapter.
10.1.3 For non-flammable products addressed under 9.1.2, except acids and products for
which 15.12
and/or 15.17
of the IBC Code applies, the provisions for permanent installations in 10.3 may apply
for spaces required to be entered during normal cargo handling operations.
10.2 Spaces normally entered during normal cargo handling operations
10.2.1 Cargo pump-rooms, spaces containing cargo handling equipment and other enclosed
spaces where cargo vapours may accumulate should be fitted with fixed mechanical
ventilation systems, capable of being controlled from outside such spaces. The
ventilation should be run continuously to prevent the accumulation of toxic vapours. A
warning notice requiring the use of such ventilation prior to entering should be placed
outside the compartment.
10.2.2 Mechanical ventilation inlets and outlets should be arranged to ensure sufficient
air movement through the space to avoid accumulation of toxic or asphyxiant vapours, and
to ensure a safe working environment.
10.2.3 The ventilation system should have a capacity of not less than 30 changes of air
per hour, based upon the total volume of the space.
10.2.4 Where a space has an opening into an adjacent more hazardous space or
area, it should be maintained at an overpressure. It may be made into a less hazardous
space or non-hazardous space by overpressure protection in accordance with standards
acceptable to the Organization.footnote
10.2.5 Ventilation systems should be permanent and should normally be of extraction
type. Extraction from above and below the floor plates should be possible.
10.2.6 Ventilation intakes should be so arranged as to minimize the possibility of
recycling hazardous vapours from any ventilation discharge opening.
10.2.7 Ventilation ducts serving hazardous areas should not be led through
accommodation, service or machinery spaces or control stations.
10.2.8 Electric motors driving fans should be placed outside the ventilation ducts that
may contain flammable vapours. Ventilation fans should not produce a source of ignition
in either the ventilated space or the ventilation system associated with the space. For
hazardous areas, ventilation fans and ducts adjacent to the fans should be of
non-sparking construction, as defined below:
-
.1 impellers or housing of non-metallic construction, with due regard being paid
to the elimination of static electricity;
-
.2 impellers and housing of non-ferrous materials;
-
.3 impellers and housing of austenitic stainless steel; and
-
.4 ferrous impellers and housing with not less than 13 mm design tip clearance.
10.2.9 Any combination of an aluminium or magnesium alloy fixed or rotating component
and a ferrous fixed or rotating component, regardless of tip clearance, is considered a
sparking hazard and should not be used in these places.
10.2.10 Where fans are required by this chapter, full required ventilation capacity for
each space should be available after failure of any single fan or spare parts should be
provided comprising a motor, starter spares and complete rotating element, including
bearings of each type.
10.2.11 Protection screens of not more than 13 mm square mesh should be fitted to
outside openings of ventilation ducts.
10.2.12 Where spaces are protected by overpressure the ventilation should be designed
and installed in accordance with standards acceptable to the Organization.footnote
10.3 Spaces not normally entered
Enclosed spaces where cargo vapours may accumulate should be capable of being ventilated
to ensure a safe environment when entry into them is necessary. This should be capable
of being achieved without the need for prior entry. For permanent installations, the
capacity of 8 air changes per hour should be provided and for portable systems, the
capacity of 16 air changes per hour. Fans or blowers should be clear of personnel access
openings, and should comply with 10.2.8.