To ensure that the vessel's design, arrangement and operational procedures are such as
to minimize the risk to the vessel, its crew and the environment, when carrying
liquefied gases in bulk.
18.1 General requirements
18.1.1 The provisions of this chapter should apply when liquid carbon dioxide (high
purity and reclaimed quality) and liquid nitrogen are carried.
18.1.2 The Administration may allow adjustments to specific requirements in the IGC Code
regarding the cargo containment, materials of construction, vent system for cargo
containment and cargo transfer, taking into account existing industry standards and
practices, if they are at least as effective as that required by the IGC Code.
18.1.3 Unless expressly provided otherwise, these provisions are additional to the
general provisions of the present Code.
18.1.4 In regard to the provisions connected to the cargo area, the vessel survival
capability and location of the cargo tanks, liquid carbon dioxide (high purity and
reclaimed quality) and liquid nitrogen should be regarded as a safety hazard substance
with type 2 ship having a flashpoint exceeding 60°C and not defined as a toxic.
18.1.5 Liquid carbon dioxide (high purity and reclaimed quality) and liquid nitrogen
should be carried in accordance with the applicable minimum carriage requirements
specified in chapter 19 of the IGC Code and the special requirements specified in
chapter 17 of the IGC Code for the respective products.
18.2 Accommodation, service and machinery spaces and control stations
Unless they are located at least 7 m away from the deck area as defined in 1.2.7.2,
entrances, air inlets and openings to accommodation, service and machinery spaces and
control stations should not face the cargo deck area. Doors to spaces not having access
to accommodation, service and machinery spaces and control stations, such as cargo
control stations and storerooms, may be permitted within such deck area, provided the
boundaries of the spaces have equivalent gas tightening to A-60 standard. Wheelhouse
doors and wheelhouse windows may be located within the limits specified above as long as
they are designed in such a way that a rapid and efficient gas and vapour tightening of
the wheelhouse can be ensured. Windows and sidescuttles facing the deck area and on the
sides of the superstructures and deckhouses within the limits specified above should be
of the fixed (non-opening) type. Such sidescuttles in the first tier on the main deck
should be fitted with inside covers of steel or equivalent material.
18.3 Cargo containment
The cargo tank should be in accordance with chapter 4 of the IGC Code. The design and
testing of the tanks for liquid nitrogen should be as required for independent tanks
type C.
18.4 Materials of construction
Materials of construction should comply with the requirements of chapter 6 of the IGC
Code.
18.5 Vent system for cargo containment
The vent system for cargo containment should comply with the requirements of chapter 8
of the IGC Code.
18.6 Cargo transfer
18.6.1 The cargo transfer system should comply with the requirements of chapter 5 of the
IGC Code.
18.6.2 Drip trays resistant to cryogenic temperatures should be provided at manifolds
transferring liquefied gases or at other flanged connections in the liquefied gas
system.
18.7 Vapour detection
Each enclosed space used for handling or storage of a liquefied gas should be fitted
with a sensor continuously monitoring the oxygen content of the space and an alarm
indicating low oxygen concentration. For semi-enclosed spaces portable equipment may
also be acceptable.
18.8 Gauging and level detection
The gauging and level detection arrangements should comply with the requirements of
chapter 13 of the IGC Code.
18.9 Emergency shutdown system
18.9.1 Emergency shut-off valves should be provided in liquid outlet lines from each
liquefied gas tank. The controls for the emergency shut-off valves should meet the
provisions given in 6.6.1.3 for remote shutdown devices.
18.9.2 In the case of transfer operations involving pressures in excess of 5 MPa,
arrangements for emergency depressurizing and disconnection of the transfer hose should
be provided. The controls for activating emergency depressurization and disconnection of
the transfer hose should meet the provisions given in 6.6.1.3 for remote shutdown
devices.
18.10 Personnel protection
Vessels carrying liquefied gases should have safety equipment on board in accordance
with 14.3.
18.11 Carriage on open deck
Instead of the use of permanently attached deck tanks, portable tanks meeting the design
of independent tanks type C may be used provided that the provisions of section 17.3 are
complied with.
18.12 Carriage of other liquefied gases listed in chapter 19 of the IGC Code
18.12.1 The present Code does not consider liquefied gases other than liquid carbon
dioxide (high purity and reclaimed quality) and liquid nitrogen. When a vessel is
intended for carriage of other liquefied gases listed in chapter 19 of the IGC Code,
flag Administration and coastal State Administrations involved should take appropriate
steps to ensure implementation of the relevant requirements of the IGC Code, taking into
account the unique design features and service characteristics of the vessel, as well as
the limitation. Furthermore, additional provisions should be established based on the
principles of the present Code as well as recognized standards that address specific
risks not envisaged by it. Such risks may include, but not be limited to:
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.1 fire and explosion;
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.2 evacuation;
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.3 extension of hazardous areas;
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.4 pressurized gas discharge to shore;
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.5 high-pressure gas venting;
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.6 process upset conditions;
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.7 storage and handling of flammable refrigerants;
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.8 continuous presence of liquid and vapour cargo outside the cargo containment
system;
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.9 tank overpressure and underpressure;
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.10 vessel-to-vessel transfer of liquid cargo; and
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.11 collision risk during berthing manoeuvres.
18.12.2 The Organization should be notified of the conditions for carriage prescribed by
the flag Administration and coastal State Administrations involved, so that the specific
liquefied gases may be considered for inclusion in the present Code.