Q. Describe in brief the layout of chapters of IMDG code.
Ans. The layout of matter of the code is unique. Thus, part 3 or chapter 3 which contains list of dangerous goods is contained in volume 2. Rest all chapters are in volume 1. A brief description about the content is s follows:
Q. What is Generic or “not otherwise specified” (N.O.S.) entries? Where is it listed?
Ans. Appendix A provides, list of generic and N.O.S. proper shipping names for substances or articles not mentioned specifically by name in the Dangerous Goods List. Such a dangerous good may be transported only after its dangerous properties have been determined. Broad classification is according to the class definitions, tests and criteria. However, in the end, the group or generic term which most appropriately describes the substance or article shall be used as the proper shipping name. This proper shipping name shall be supplemented by the ‘technical name’, when special provision 274 or 318 has been assigned to the entry in column 6 of the Dangerous Goods List. This is for the purpose of documentation. Within each hazard class or division, the names have been placed into three groups as follows:
- specific entries covering a group of substances or articles of a particular chemical or technical nature;
- pesticide entries, for class 3 and class 6.1; and
- general entries covering a group of substances or articles having one or more general dangerous properties.
Let us look at the example: UN WXYZ Pesticide liquid NOS (pqrs). Thus, for UN WXYZ, (generic name), pqrs, the technical name must also be stated for documentation, when special provision 274 or 318 has been assigned.
Q. What is provided in column 3, 4, 5 & 6?
Ans. Column 4 is subsidiary risk which contains the class number(s) of any subsidiary risk(s) which have been identified by applying the classification system. This column also indicates if a particular dangerous good is also a marine pollutant: Letter P in this column indicates this nature.
The main class is 6.1, toxic substance. Additionally, the substance is also inflammable. Inflammable nature causes, the subsidiary risk. The substance is marine pollutant too.
Column 5 is packing group. This column contains the packing group number (i.e. I, II or III) where assigned to the substance or article. If more than one packing group is indicated for the entry, the packing group of the substance or formulation to be transported shall be determined, based on its properties and other criteria. Group I has most stringent criteria.
2.0.1.3 stated in column 5, leads to chapter 2. It provides the following: For packing purposes, substances other than those of classes 1, 2, 5.2, 6.2 and 7, and other than self-reactive substances of class 4.1, are assigned to three packing groups in accordance with the degree of danger they present:
Packing group I: substances presenting high danger;
Packing group II: substances presenting medium danger; and
Packing group III: substances presenting low danger.
The packing group to which a substance is assigned is indicated in the Dangerous Goods List. Any requirement for a specific packaging performance level is set out in the applicable packing instruction.
Column 6 is ‘special provisions’. This column contains a number referring to any special provision(s) indicated in chapter 3.3, that is relevant to the substance or article. Special provisions apply to all packing groups permitted for a particular substance or article unless the wording makes it otherwise apparent. Thus, the special provision 65, for UN 2984 is as follows:
65: Hydrogen peroxide aqueous solutions with less than 8% hydrogen peroxide are not subject to the provisions of this Code.
Q. What is provided in column 7a, 7b, 8, 9, 10 & 11?
Ans. Whether a dangerous cargo can be carried on board or not would be decided by the DOC but if a cargo has to be carried under certain specialized categories such as green channel or privileged route, it can be done either by 7a method or 7b method where certain relaxations are available to shipper. Column 7a takes the user to chapter 3.4 as shown below:
Column 7a is ‘limited quantities’. Thus if paint is carried in small bottles with total paint in full carton not more than 30 litres, placard on outside need not indicate class 3 sticker. The packages containing dangerous goods in limited quantities shall bear the mark shown below:
Dangerous goods shall be packed only in inner packagings placed in suitable outer packagings. Intermediate packagings may be used. The total gross mass of the package shall not exceed 30 kg. Maximum mass for shrink-wrapped or stretch-wrapped trays is 20 kg. Limited quantities of dangerous goods packed in such limited quantities, meeting the provisions of this chapter, are not subject to certain provisions of this Code. Column 7b takes the user to chapter 3.5 as shown below:
Column 7b is excepted quantities – this column provides an alpha-numeric code described in a E table, which indicates the maximum quantity per inner and outer packaging for transporting dangerous goods as excepted quantities in accordance with chapter 3.5. Dangerous goods which may be carried as excepted quantities in accordance with the provisions of this chapter are shown in column 7b of the Dangerous Goods List by means of an alphanumeric code as follows:
Thus, if UN 2552 is carried as limited quantity, the maximum net weight in the inner container can be 100 ml. The maximum that can be carried in the CTU being 30 lit. If it is carried as excepted quantity, the maximum quantities per carton will be given by E4. The CTU however, will not carry more than 1000 cartons. Thus, either the carriage will be as per 7a or as 7b, not both.
Column 8 is packing instructions – this column contains alpha-numeric codes which refer to the relevant packing instruction(s). The packing instructions indicate the packagings (including large packagings) which may be used for the transport of substances and articles. The code P002 is checked up in 4.1.4. A small part of P002 is reproduced as follows:
PP31: For UN Nos. 1362, 1463, 1565, 1575, 1626, 1680, 1689, 1698, 1868, 1889, 1932, 2471, 2545, 2546, 2881, 3048, 3088, 3170, 3174, 3181, 3182, 3189, 3190, 3205, 3206, 3341, 3342, 3448, 3449 and 3450, packagings shall be hermetically sealed.
A code including the letters “LP” refers to packing instructions for the use of large packagings. When a code including the letter(s) “P” or “LP” is not provided, it means that the substance is not allowed in that type of packaging.
Column 9 is special packing provisions. The number 4.1.4. leads to the chapter, where the special packing provisions can be read off. The alpha-numeric codes refer to the relevant special packing provisions. In respect of substance UN 2545, letters ‘PP’ refer to a special packing provision applicable to the use of a packing instruction bearing the Code “P”. A special packing provision including the letter “L” refers to a special packing provision applicable to a packing instruction bearing the code ‘LP’.
Column 10 is IBC packing instructions – this column contains alpha-numeric codes that refer to the relevant IBC instruction, which indicates the type of IBC that shall be used for the transport of the substance under reference. A code including the letters “IBC” refers to packing instructions for the use of IBCs. When a code is not provided, it means the substance is not authorized in IBC. Column 11 is IBC special provisions – this column contains an alpha-numeric code, including the letter “B”, which refers to special packing provisions applicable to the use of packing instructions bearing the code “IBC”.
Q. What information about the tanks is provided in column 13, 14, 15 & 16?
Ans. Column 13 is ‘tank and bulk container instructions’. This column contains T codes applicable to the transport of dangerous goods in portable tanks and road tank vehicles. When a T code is not provided in this column, it means that the dangerous goods are not authorized for transport in tanks unless specifically approved by the competent authority.
Instruction T4 leads to 6.7.2.4.2 & 6.7.2.6.2. These are reproduced below:
6.7.2.4.2
The cylindrical portions, ends (heads) and manhole covers of shells not more than 1.80 m in diameter shall be not less than 5 mm thick in the reference steel or of equivalent thickness in the metal to be used. Shells more than 1.80 m in diameter shall be not less than 6 mm thick in the reference steel or of equivalent thickness in the metal to be used, except that for powdered or granular solid substances of packing group II or III the minimum thickness requirement may be reduced to not less than 5 mm thick in the reference steel or of equivalent thickness in the metal to be used.
6.7.2.6.3
Every bottom discharge outlet, except as provided in 6.7.2.6.2, shall be equipped with three serially fitted and mutually independent shut-off devices. The design of the equipment shall be to the satisfaction of the competent authority or its authorized body and include:
.1 a self-closing internal stop-valve, that is a stop-valve within the shell or within a welded flange or its companion flange, such that:
.1 the control devices for the operation of the valve are designed so as to prevent any unintended opening through impact or other inadvertent act;
.2 the valve may be operable from above or below;
.3 if possible, the setting of the valve (open or closed) shall be capable of being verified from the ground;
.4 except for portable tanks having a capacity of not more than 1000 L, it shall be possible to close the valve from an accessible position of the portable tank that is remote from the valve itself; and
.5 the valve shall continue to be effective in the event of damage to the external device for controlling the operation of the valve;
.2 an external stop-valve fitted as close to the shell as reasonably practicable; and
.3 a liquid-tight closure at the end of the discharge pipe, which may be a bolted blank flange or a screw cap.
Portable tank special provisions Portable tank special provisions are assigned to certain substances to indicate provisions which are in addition to or in lieu of those provided by the portable tank instructions or the provisions in chapter 6.7. Portable tank special provisions are identified by an alpha-numeric designation beginning with the letters “TP” (tank provision).
TP1 The degree of filling prescribed in 4.2.1.9.2 shall not be exceeded.
EmS This column refers to the relevant emergency schedules for FIRE and SPILLAGE in “The EmS Guide – Emergency Response Procedures for Ships Carrying Dangerous Goods”. The first EmS code refers to the relevant Fire Schedule (F-A, F-B, etc). The second EmS code refers to the relevant Spillage Schedule (S-A, S-B, etc). Underlined EmS codes (special cases) indicate a substance, material or article for which additional advice is given in the emergency response procedures.
Column 16a is stowage and handling: This column contains the stowage and handling codes.
Column 16b is segregation: This column contains the segregation codes.
The excerpts from part 7 are as follows:
SG38 Stow “separated from” ammonium compounds.
SG39 Stow “separated from” ammonium compounds other than AMMONIUM PERSULPHATE (UN 1444).
SG62 Stow “separated from” sulphur.
Q. What information is provided in column 17?
Ans. Column 17 is properties and observations. In respect of UN 3210 the information provided in column 7 is, ‘when involved in a fire, may cause an explosion. Leakage and subsequent evaporation of the water of the solutions may present increased dangers as follows:
.1 in contact with combustible material (particularly with fibrous material such as jute, cotton or sisal) or sulphur, danger of spontaneous combustion;
.2 in contact with ammonium compounds, powdered metals or oils, danger of explosion. Transport of ammonium chlorate, aqueous solution is prohibited.
In general, this column contains properties of and observations on the dangerous goods listed. The provisions in this column are not mandatory. Properties of most gases include an indication of its density in relation to air. The figures in brackets give the density relative to air.
1 “lighter than air” when the vapour density is down to half that of air;
2 “much lighter than air” when the vapour density is less than half that of air;
3 “heavier than air” when the vapour density is up to twice that of air {note (1.2) & (1.4) in the column 17 for Phosphene and Propadiene Stabilized respectively.; and
4 “much heavier than air” when the vapour density is more than twice that of air.
When explosive limits are given, these refer to the volume percentage of the vapour of the substance when mixed with air. The ease and extent to which different liquids mix with water varies greatly and most entries have included an indication of miscibility. In these cases “miscible with water” normally means capable of being mixed with water in all proportions to form a completely homogeneous liquid.
Q. What are the different types of entries in part 3 of Code?
Ans. Entries in the Dangerous Goods List are of the following four types:
1. Single entries representing the substance individual capacity: e.g.
UN 2199 Phosphine
UN 1764 DICHLOROACETIC ACID
2. Generic entries representing a utility based group: e.g.
UN 1133 adhesives
UN 3142 DISINFECTANT, LIQUID, TOXIC, N.O.S.
UN 2777 MERCURY BASED PESTICIDE, SOLID, TOXIC
3. Specific N.O.S. entries covering say chemical property based group : e.g.
UN 2627 NITRITES, INORGANIC, N.O.S.
UN 1477 nitrates, inorganic, N.O.S.
UN 1987 alcohols, N.O.S.
4. General N.O.S. the group of substances meeting the criteria of one or more classes: e.g.
UN 1325 flammable solid, organic, N.O.S.
3089 METAL POWDER, FLAMMABLE, N.O.S.
Q. What are the special provisions given in part 3.3?
Ans. Special provision applicable to certain substances, materials or articles apply when column 6 of the Dangerous Goods List indicates that a special provision is relevant to a dangerous good, the meaning and requirement(s) of that special provision are as set out in chapter 3.3’
The special provision may includes:
a requirement for package marking;
required mark is in the form of specific wording;
a remark added to the general characteristic of the class as in 23;
a specific condition is stated that conditional to safe carriage as in 28;
a condition that will cause exemption from code as in 32 & 39; etc.
Special Provisions:
23 Even though this substance has a flammability hazard, it only exhibits such hazard under extreme fire conditions in confined areas.
28 This substance may be transported under the provisions of class 4.1 only if it is so packaged that the percentage of diluent will not fall below that stated, at any time during transport
32 When in any other form, this substance is not subject to the provisions of this Code.39 This substance, when it contains less than 30% or not less than 90% silicon, is not subject to the provisions of this Code.
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