Many millions of tonnes of packaged dangerous goods (DG) are transported each year. Most consignments are quite safely received, handled and conveyed, but serious accidents can happen if the relevant regulations are not met. The International Maritime Dangerous Goods (IMDG) Code is intended to ensure that carriage of DG by sea can be conducted safely. It has been mandatory since 2004, under the provisions of the SOLAS (Safety of Life at Sea) Convention and updated every two years by the International Maritime Organisation (IMO). 

The latest edition of the IMDG Code, as adopted at the 90^th session of the IMO's Maritime Safety Committee in May 2012, has been published. This 2012 edition has revised Volumes 1 and 2 and will become mandatory from 1 January 2014. However, it may be applied voluntarily from January 2013 (the transition year) and, as usual, the IMO recommends its early implementation. The IMDG Code Supplement, containing the supplements for the Emergency Responses, Medical First Aid Guide, CTU [Cargo Transport Units] Code, resolutions and circulars, has not been updated and the 2010 edition is still current. Updates to this supplementary volume are issued regularly by IMO and are freely available on their website (http://gisis.imo.org/Public/Default.aspx).

There have been significant enhancements to Part 7 'Provisions Concerning Transport Operations'.

Whilst this part is still concerned with 'stowage' and 'segregation', it has been subdivided, for ease of reference into specific types of vessel.

Whereas the previous version had a generic Chapter 7.4 'Transport of Cargo Transport Units on board ships', we now have four separate chapters specific to stowage and segregation on the different ship type

• Chapter 7.4 Stowage and segregation on containerships

• Chapter 7.5 Stowage and segregation on ro-ro ships

• Chapter 7.6 Stowage and segregation on general cargo ships

• Chapter 7.7 Shipborne barges on barge-carrying ships

Further changes include the introduction of a useful set of definitions in Chapter 7.1.2, explaining and redefining the meaning of some terms such as:

• Clear of Living Quarters;

• Closed Cargo Transport Unit;

• Combustible Material;

• Potential Sources of Ignition; and

• Protected from Sources of Heat

The last term replaces the older 'away from' in an easier to understand definition:

'Protected from sources of heat means that packages and CTUs shall be stowed at least 2.4m from heated ship structures, where the surface temperature is liable to exceed 55°. Examples of heated structures are steam pipes, heating coils, top or side walls of heated fuel and cargo tanks, and bulkheads of machinery spaces. In addition, packages not loaded inside a CTU and stowed on deck shall be shaded from direct sunlight. The surface of a CTU can heat rapidly when in direct sunlight in nearly windless conditions and the cargo may also become heated. Depending on the nature of the goods in the CTU and the planned voyage, precautions shall be taken to ensure that exposure to direct sunlight is reduced.'

This requirement in relation to dangerous goods could actually also be extended to certain perishable goods not normally designated as dangerous. The TT Club and ICHCA have seen examples of severely damaged containers after cargoes such as butter and cheese have been exposed to heat.

Chapter 7.2 'Segregation' also has its definitions brought together. In the main definitions in Part 1 there are several new entries:

"Foodstuff"

includes foodstuffs, feeds or other edible substances intended for consumption by humans or animals

and with respect to foodstuffs the previous categories of 'away from' and 'separated from' no longer exist. However, in addition certain classes of DG, the substance details identify which cargoes cannot be contained in the same CTU as foodstuffs (7.3.4.2.1) and a further list of dangerous goods that must be at least 3 metres away (7.3.4.2.2). As with many sections of the Code a detailed examination of the specific UN numbers need to be undertaken.

"Net Explosive Mass" (NEM) means

the total mass of the explosive substances without the packages, casings etc

. The previous 15 separate stowage categories for explosives have been re-grouped into just five, based on stowage categories (combinations of on deck, under deck, closed CTUs etc).

"Semi-trailer" is defined now as

means any trailer designed to be coupled to a motor vehicle in such a way that part of it rests on the motor vehicle and a substantial part of its mass and of the mass of its load is borne by the motor vehicle

The new entries in the Dangerous Goods List (Amendment 35-10 stopped at UN 3496) include such substances as:

• UN 3497 Krill Meal (Pink to red meal derived from shrimp-like Krill);

• UN 3498 Iodine Monochloride Liquid (a red liquid that reacts violently with water);

• UN 3499 Capacitor (articles intended to store electrical energy);

• UN 3500 Chemical Under pressure NOS, (Liquids, pastes or powders, pressurized with a propellant which meets the definition of a gas). This is followed by several UN entries for similarly classified chemicals with other properties or combinations of properties including 'flammable', 'toxic' and 'corrosive'.

Captain Richard Brough, the Technical Advisor to ICHCA International provided the above analysis; specific queries about any aspect of the IMDG Code can be answered by him via email: richard.brough@ichca.com. Copies of the new amendment to the IMDG Code can be purchased at a special discount from ICHCA (publications@ichca.com).