2.1 Segregation Table

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The following table shows the general provisions for segregation between the various classes of dangerous goods.?
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SINCE THE PROPERTIES OF SUBSTANCES, MATERIALS OR ARTICLES WITHIN EACH CLASS MAY VARY GREATLY, THE INDIVIDUAL SCHEDULES SHOULD ALWAYS BE CONSULTED FOR PARTICULAR REQUIREMENTS FOR SEGREGATION AS THESE TAKE PRECEDENCE OVER THE GENERAL REQUIREMENT. SEGREGATION SHOULD ALSO TAKE ACCOUNT OF A SINGLE SUBSIDIARY RISK LABEL.
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Numbers and symbols relate to the following terms as defined in this section:
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??1 – “Away from”
??2 – “Separated from”
??3 – “Separated by a complete compartment or hold from”
??4 – “Separated longitudinally by an intervening complete compartment or hold from”
??X – The segregation, if any, is shown the Dangerous Goods List of IMDG Code”
??* – See subsection 7.2.7.2 of IMDG Code 2004 for segregation within class 1
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3.0 Ventilation
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3.1 Ventilation for Goods of Class 2
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3.1.1 Receptacles for liquefied gases stowed under deck should be stowed in mechanically ventilated cargo spaces. Adequate measures should be taken to prevent the penetration of leaking gases into any other part of the ship. Gases may not necessarily be lighter than air and may sink to the lower levels of a cargo space where they may be accidentally ignited and “flashback” may occur, so mechanical ventilation should be provided which should effectively remove flammable vapours from enclosed cargo spaces. Attention should also be paid in this respect when toxic or suffocating gas is transported.
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3.1.2 Where gases are loaded in a closed cargo transport unit on ship, the required ventilation into the cargo transport unit should not be interpreted.
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3.1.3 When, for any reason, it is necessary to open the doors of a cargo transport unit, the nature of the contents and the possibility that the leakage may have caused an unsafe concentration of toxic or flammable vapours or have produced an oxygen-enriched or –depleted atmosphere should be considered. If such a possibility exists, then the interior of the cargo transport unit should be approached with caution.
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3.2 Ventilation for Goods of Class 3
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3.2.1 Ventilation should be provided which should effectively remove flammable vapours from the cargo spaces.
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3.2.2 Adequate measures should be taken to prevent the penetration of leaking liquid or vapour into any other part of the ship. Vapours may not necessarily be lighter than air and may sink to the lower levels of a cargo space where they may be accidentally ignited and a “flashback” to flammable liquid may occur.
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3.2.3 Whenever flammable liquids with a flashpoint of 23 0C c.c. or less are transported in portable tanks, the ventilation should be such that leaking vapours are unlikely to penetrate the accommodation, machinery spaces and other work areas via entrances or other openings in bulkheads or through ventilation ducts.
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3.3 Ventilation for Goods of Class 4.1, 4.2 and 4.3
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3.3.1 These substances are liable to give off vapours or dust which can form an explosive mixture with air, the stowage should be made in a well-ventilated space.
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3.3.2 Ventilation for Goods of Class AMMONIUM NITRATE, UN 1942 and AMMONIUM NITRATE FERTILIZERS, UN Nos. 2067, 2068, 2069, 2070, 2072 and Class 5.2, Classes 6.1, 8 which are also flammable liquids and Class 9. These substances should be stowed in a mechanically ventilated space and mechanical ventilation enables to exhaust any gases or fumes resulting from decomposition.
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4.0 Heat Protection
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4.1 Dangerous goods of classes 2, 3, 4.1, 4.2, 4.3 and 8 should be kept as cool as reasonably practicable during transit. They should, in general, be stowed “away from” all sources of heat. Adequate precautions should be taken to protect them from heat emanating from bulkheads or other sources.
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4.2 During transport, packages containing self-reactive substances, substances related to self-reactive substances or desensitized explosives should be shaded from radiant heat, which includes protection from direct sunlight.
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5.1 General Fire Precautions
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5.1.1 The prevention of fire in a cargo space of dangerous goods is achieved by practicing good seamanship, observing in particular the following precautions:
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(a) Keep combustible materials away from ignition sources;

(b) Protect flammable substances by adequate packing;

(c) Reject damaged or leaking packages;

(d) Stow packages protected from accidental damage or heating;

(e) Segregate packages from substances liable to start or spread fire;

(f) Where appropriate and practicable, stow dangerous goods in an accessible position so that packages in the vicinity of a fire may be protected.
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5.1.2 Enforce prohibition of smoking in dangerous areas and display clearly recognizable “NO SMOKING” notices or signs.
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5.1.3 The dangers from short-circuits, earth leakages or sparking will be apparent. Lighting and power cables, and fittings should be maintained in good condition. Cables or equipment found to be unsafe should be disconnected. Where a bulkhead is required to be suitable for segregation purposes, cables and conduit penetrations of the decks and bulkheads should be sealed against the passage of gas and vapours. When stowing dangerous goods on deck, the position and design of auxiliary machinery, electrical equipment and cables runs should be considered in order to avoid source of ignition.
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5.2 Special Fire Precautions for Class 1
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5.2.1 The greatest risk in the handling and transport of goods of class 1 is that of fire from a source external to the goods, and it is vital that any fire should be detected and extinguished before it can reach such goods. Consequently, it is essential that fire precautions, fire-fighting measures and equipment should be of a high standard and ready for immediate application and use.
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5.2.2 Compartments containing goods of class 1 and adjacent cargo spaces should be provided with a fire-detection system. If such spaces are not protected by a fixed fire-extinguishing system, they should be accessible for fire-fighting operations.
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5.2.3 No repair work should be carried out in a compartment containing goods of class 1. Special care should be exercised in carrying out repairs in any adjacent space. No welding, burning, cutting, or riveting operations involving the use of fire, flame, spark, or arc-producing equipment should be carried out in any space other than machinery spaces and workshops where fire-extinguishing arrangements are available, except in any emergency and, if in port, with prior authorization of the port authority.
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5.3 Special Fire Precautions for Class 2
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5.3.1 Effective ventilation should be provided to remove any leakage of gas from within the cargo space or spaces, bearing in mind that some gases are heavier than air and may accumulate in dangerous concentration in the lower part of the ship.
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5.3.2 Measures should be taken to prevent leaking gases from penetrating into any part of the ship.
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5.3.3 If there is any reason to suspect leakage of gas, entry into cargo spaces or other enclosed spaces should not be permitted until the master or responsible officer has take all safety considerations into account and is satisfied that it is safe to do so. Emergency entry under other circumstances should only be undertaken by trained crew wearing self-contained breathing apparatus, and protective clothing when recommended, and always under the supervision of a responsible officer.
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5.3.4 Leakage from receptacles containing flammable gases may give rise to explosive mixture with air. Such mixtures, if ignited, may result in explosion and fire.
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5.4 Special Fire Precautions for Class 3
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Flammable liquids give off flammable vapours which, especially in an enclosed space, form explosive mixtures with air. Such vapours, if ignited, may cause a “flashback” to the place which the substances are stowed. Due regard should be paid to adequate ventilation to prevent accumulation of vapours.
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5.5 Special Fire Precautions and Fire Fighting for Class 7
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The radioactive contents of Excepted, Industrial, and Type A packages are so restricted that, in the event of an accident and damage to the package, there is a high probability that any material released, or shielding efficiency lost, would not give rise to such radiological hazard as to hamper fire-fighting or rescue operations.
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Type B(U) packages, Type B(M) packages and Type C packages are designed to be strong enough to withstand severe fire without significant loss of contents or dangerous loss of radiation shielding.