IMDG hazard classes

• A list of the nine hazard classes of dangerous goods, and descriptions of each, may be found in Chapter 2 of the IMDG Code.

Dangerous goods must meet one or more of the hazard class definitions. There are nine hazard classes listed in the International Maritime Dangerous Goods (IMDG) Code — some of which are further subdivided into divisions. The definitions summarized below should be used as guidelines only.

Complete specifications for each hazard class and division can be found in Chapter 2 of the IMDG Code.

• Class 1 – Explosives: Any substance or article, including a device, which is designed to function by explosion, or which by chemical reaction within itself can function in a similar manner even if not designed to function by explosion. Class 1 is subdivided into six divisions:
  • Division 1.1: Explosives that have a mass explosion hazard. A mass explosion ignites almost the entire load instantaneously (e.g., dynamite, nitroglycerine).
  • Division 1.2: Explosives that have a projection hazard, but not a mass explosion hazard (e.g., detonators, flares).
  • Division 1.3: Explosives that have a fire hazard and either a minor blast hazard, a minor projection hazard, or both, but not a mass explosion hazard (e.g., commercial fireworks, rocket propellant).
  • Division 1.4: Explosives that present a minor explosion hazard. The explosive effects are largely confined to the package, and no projection of fragments of appreciable size or range is to be expected. An external fire must not cause virtually instantaneous explosion of almost the entire contents of the package (e.g., ammunition, consumer fireworks).
  • Division 1.5: Insensitive explosives which have a mass explosion hazard but are so insensitive that there is very little probability of initiation, or of transition from burning to detonation, under normal conditions of transport (e.g., blasting agents).
  • Division 1.6: Extremely insensitive explosives which do not have a mass explosion hazard. This division consists of articles which do not detonate easily during transportation.
• Class 2 – Gases: Any substance which has a vapor pressure greater than 45.5 psi (300 kPa) at 122° F (50° C) or is completely gaseous at a standard pressure of 14.7 psi (101.3 kPa) at 68° F (20° C). Class 2 is broken into three divisions:
  • Division 2.1 (flammable gas): Any gas that:
    • Is ignitable when in a mixture of 13 percent or less by volume with air, or
    • Has a flammable range with air of at least 12 percent, regardless of the lower limit.
  • Division 2.2 (non-flammable, non-toxic gas): Any gas that:
    • Is an asphyxiant gas which dilutes or replaces the oxygen normally in the atmosphere, or
    • Is an oxidizing gas which may cause or contribute to the combustion of other material more than air does, or
    • Does not fall under any other division in Class 2.
  • Division 2.3 (toxic): Any gas that:
  • Is known to be so toxic to humans as to pose a hazard to health, or
    • Is presumed to be toxic or corrosive to humans because they have an LC50 value of not more than 5,000 mL/m3 when tested.
• Class 3 - Flammable liquids: Any liquid which gives of a flammable vapor at temperatures of not more than 140° F (60° C) in a closed cup test or not more than 150° F (65.6° C) in an open cup test. Class 3 does not have subdivisions.
• Class 4 - Flammable solids: Any flammable solid that falls into one of the following three divisions:
  • Division 4.1 (flammable solid): Flammable solids consist of:
    • Solids that are readily combustible or may cause or contribute to a fire through friction under conditions normally encountered during transport, or
    • Self-reactive substances and polymerizing substances that are likely to undergo a strong exothermic reaction, or
    • Desensitized explosives that may explode if not sufficiently diluted.
  • Division 4.2 (spontaneously combustible): A substance that is likely to heat up under conditions normally encountered during transportation or likely to catch fire when exposed to air.
  • Division 4.3 (dangerous when wet): A substance that when it encounters water:
    • Is liable to become spontaneously flammable, or
    • Gives off flammable gas.
• Class 5 Oxidizing substance & organic peroxides: Any material which falls into one of the following two divisions:
  • Division 5.1 (oxidizing): A substance that may, generally by yielding oxygen, cause or enhance the combustion of other materials.
  • Division 5.2 (organic peroxide): Any organic compound containing oxygen (O) in the bivalent -O-O- structure and which may be considered a derivative of hydrogen peroxide, where one or more of the hydrogen atoms have been replaced by organic radicals.
• Class 6 – Toxic and infectious substances: Any material that falls into one of the following two divisions:
• Division 6.1 (toxic): A material which is likely to cause death, injury, or harm to humans if swallowed, inhaled, or contacts the skin.
• Division 6.2 (infectious substance): A material known or reasonably expected to contain a pathogen. A pathogen is a microorganism (including bacteria, viruses, parasites, fungi) or other agent, such as a proteinaceous infectious particle (prion), that can cause disease in humans or animals.
• Class 7 Radioactive material: Any material containing radio nuclides where both the activity concentration and the total activity in the consignment exceed the values specified in Chapter 2.7 of the IMDG Code.
• Class 8 Corrosive: A substance that causes irreversible damage to skin, or if leaked, will materially damage or destroy other goods or transport vehicle.
• Class 9 Miscellaneous: A material which, during transport, presents a danger not covered by other hazard classes.

IMDG packing groups  

• Some dangerous goods are further categorized into packing groups, which indicates the level of danger (high to low) that the dangerous goods present.

Some dangerous goods are further subdivided into packing groups. The packing group indicates the degree of danger presented by the dangerous goods.

• Packing Group I — high danger
• Packing Group II — medium danger
• Packing Group III — low danger

Packing groups have been developed for dangerous goods in Class 3, Class 4, Division 5.1, Division 6.1 and Class 8 materials. Some hazardous materials are assigned more than one packing group. Because packing groups impact the type of packaging that can be used, it is critical that each material is assigned to the correct one. The criteria for determining packing groups are included in the IMDG Code as follows:

• Chapter 2.3 — Class 3 (flammable liquid) materials
• Chapter 2.4 — Class 4 (flammable solid) materials
• Chapter 2.5 — Division 5.1 (oxidizing) materials
• Chapter 2.6 — Division 6.1 (poisonous) materials
• Chapter 2.8 — Class 8 (corrosive) materials

Some substances in Class 9, liquids in Division 5.1, and waste in Division 6.2 have been assigned packing groups according to the Dangerous Goods List in IMDG Code Chapter 3.2. Requirements for a specific packaging performance level can be found in the applicable packing instruction.

Marine pollutants

The IMDG Code requires shippers to also classify dangerous goods as a marine pollutant if:

• A “P” is listed in column 4 of the Dangerous Goods List,
• A “P” is listed in a column titled “MP” in the Index, or
• It meets the requirements of a marine pollutant listed in Chapter 2.9.3.

UN numbers and proper shipping names

Once the hazard class and packing group have been determined, the shipper must select an appropriate UN number and proper shipping name from the Dangerous Goods List in Chapter 3.2. If the dangerous good is listed by name, that name must be used. If the dangerous good is not listed by name a generic or not otherwise specified (n.o.s.) name must be used.

Multiple hazards under the IMDG

• Some dangerous goods will meet the definition of more than one hazard class. Usually, the hazard class that poses the greater hazard during transport will be the primary hazard.

Occasionally, there will be situations when dangerous goods meet the definition of more than one hazard class, and it’s not specifically listed by name in the Dangerous Goods List. In this case, you must determine which of the hazard classes will be the primary hazard. Typically, the hazard class that poses the greater hazard during transport would take precedence and become the primary hazard.

The hazard classes listed below in order take precedence:

1. Class 1,
2. Class 2,
3. Liquid desensitized explosives of Class 3,
4. Self-reactive substances and solid desensitized explosives of Class 4.1,
5. Pyrophoric substances of Class 4.2,
6. Class 5.2,
7. Class 6.1 with a packing group I vapor inhalation toxicity,
8. Class 6.2, and
9. Class 7.

Hazard classes not listed above must be classed according to the precedence of hazard table located in Chapter 2.0.3.

Samples under the IMDG

• The IMDG Code has provisions to allow a shipper to classify and ship small samples of unknown dangerous goods to a laboratory for analysis.

The International Maritime Dangerous Goods (IMDG) Code has provisions which allow a shipper to classify and ship unknown dangerous goods to a laboratory for analysis. The samples of unknown dangerous goods may be classified by the shipper and assigned a tentative shipping description, based on the: 

• Defining criteria of the IMDG Code,
• Hazard class of precedence, if required, and
• Shipper’s knowledge of the material.

Proper shipping name

When shipping samples of unknown dangerous goods the shipper must include the word “sample” in conjunction with the proper shipping name, for example:

• Flammable liquid, n.o.s., sample

When a “not otherwise specified” (n.o.s.) entry is used for the sample, the proper shipping name does not need to include the technical name.

The most severe packing group possible must be used for the selected proper shipping name.

Limitations

Samples using the exception must not be:

• Prohibited,
• Explosives,
• Infectious substances, or
• Radioactive.

Self-reactive substances and organic peroxides samples must meet the conditions in sections 2.4.2.3.2.4.2 and 2.5.3.2.5.1, respectively.

All samples must be transported in combination packaging with a net weight not exceeding 2.5 kgs and not packed with any other goods.

Inherently unstable dangerous goods under IMDG 

• Inherently unstable dangerous goods are those that may be prone to explosion, polymerization, or emission of flammable or toxic gases. Special handling measures must be followed for transport.

Inherent instability in goods may take different dangerous forms, including:

• Explosion,
• Polymerization with intense evolution of heat, or
• Emission of flammable, toxic, corrosive, or asphyxiant gases.

Because of this potential for instability, the Dangerous Goods List prohibits certain dangerous goods, or dangerous goods in a specific form, concentration, or state, from transport by sea. These prohibited goods are not suitable for transport by sea under normal conditions of transport. In some cases, the inherent instability can be controlled by suitable packaging, dilution, stabilization, addition of an inhibitor, temperature control, or other measures to make transport by sea possible.

Precautionary measures required

If precautionary measures are shown in the Dangerous Goods List for a dangerous good (for example, that it must be stabilized or diluted), that dangerous good may not be transported without taking those measures. Exceptions to this may exist if the item in question is listed elsewhere (such as in class 1) without any indication of precautionary measures, or with different measures indicated.

Polymerization and dangerous reactions

Certain substances can polymerize or otherwise react in a dangerous manner under certain conditions of temperature or in contact with a catalyst. To mitigate this tendency:

• Special transport conditions may be required, or
• Chemical inhibitors or stabilizers can be added to the product.

Unless these products are sufficiently stabilized to prevent any dangerous reaction during the voyage, transport of the products is prohibited.

Proper shipping names under IMDG

• Proper shipping names accurately describe the type of dangerous goods to be shipped, and must be included with the transport document.

The proper shipping names of dangerous goods are listed in the Dangerous Goods List. The index to the List includes synonyms, secondary names, initials, abbreviations of names, etc., in alphabetical order, to facilitate the search for the proper shipping name.

The proper shipping name is the part of the entry that accurately describes the goods in the Dangerous Goods List. It is shown in upper-case characters along with other numbers or letters that are an integral part of the name. An alternative proper shipping name may be shown in brackets following the main proper shipping name.

Only the most appropriate proper shipping name must be shown in the transport document and package marks when:

• A combination of several distinct proper shipping names is listed under a single UN number, and
• They are separated by “and” or “or” in lower case or are punctuated by commas.

Proper shipping names may be used in the singular or plural as appropriate.

Commercial or military names for goods of class 1 that contain the proper shipping name supplemented by additional text may be used.

Many substances have an entry for both the liquid and solid state or for the solid and solution. These are given separate UN numbers that are not necessarily adjacent to each other. Details can be found in the alphabetical index to the List.

If it is not already included in the proper shipping name, the word “MOLTEN” must be added when a substance that is solid is offered for transport in the molten state. Also check requirements for elevated temperature substances in 5.4.1.4.3.4.

Note that special requirements apply to proper shipping names for:

• Samples (section 2.0.4), and
• Wastes (section 5.4.1.4.3.3).

Stabilized dangerous goods under IMDG

• If a dangerous good is forbidden from transport unless it is stabilized first, the word STABILIZED must be added to the proper shipping name.

Except for self-reactive substances and organic peroxides, and unless it is already included in capital letters in the proper shipping name shown in the Dangerous Goods List, the word “STABILIZED” must be added to the proper shipping name of any substance that, without stabilization, would be forbidden from transport due to its potential to dangerously react under conditions normally encountered in transport (for example, TOXIC LIQUID, ORGANIC, N.O.S., STABILIZED).

When temperature control is used to stabilize these substances to prevent development of dangerous excess pressure or evolution of excessive heat, or when chemical stabilization is used in combination with temperature control, then:

• For liquids and solids where the self-accelerating polymerization temperature (SAPT) is less than or equal to prescribed levels, special provisions may apply;
• Unless it is already included in capital letters in the proper shipping name, the words “TEMPERATURE CONTROLLED” must be added;
• For gases: the conditions of transport must be approved by the competent authority.

Hydrates may be transported using the proper shipping name for the anhydrous substance.

IMDG generic or not-otherwise specified entries 

• Generic and n.o.s. names must include supplemental information as specified in the Dangerous Goods List, so that the dangerous good being transported can be properly identified.

Generic and “not otherwise specified” (n.o.s.) proper shipping names that are subject to special provision 274 or 318 in column 6 of the Dangerous Goods List must be supplemented with the technical or chemical group names. This does not apply if:

• It is a controlled substance, and
• A national law or international convention prohibits its disclosure.

For explosives of class 1, descriptive text may be added to the proper shipping name to indicate commercial or military names. Technical and chemical group names must be entered in brackets immediately following the proper shipping name.

The technical name must be:

• A recognized chemical or biological name, or
• Another name currently used in scientific and technical handbooks, journals, and texts.

Trade names must not be used for this purpose. For pesticides, use only:

• ISO common name(s),
• Other name(s) in the WHO Recommended Classification of Pesticides by Hazard and Guidelines to Classification, or
• The name(s) of the active substance(s).

When mixtures or articles containing dangerous goods are described by one of the n.o.s. or generic entries subject to special provision 274, not more than the two constituents that most predominantly contribute to the hazard or hazards need to be shown. This requirement does not apply to controlled substances when their disclosure is prohibited by national law or international convention.

If a package containing a mixture is labeled with any subsidiary hazard label, one of the two technical names shown in brackets must be the name of the constituent that compels the use of the subsidiary hazard label.

For proper documentation for n.o.s. entries classified as marine pollutants, the recognized chemical name of the constituent that most predominantly contributes to the classification as marine pollutant must be added to the proper shipping name. Exceptions to this are found in special provision 274.

Mixtures or solutions under IMDG

• If a substance is a mixture or solution, the word MIXTURE or SOLUTION should be added as part of the proper shipping name. If the substance is composed of two of more dangerous goods, use the entry that most precisely describes the mixture or solution.

If a substance is specifically listed by name in the Dangerous Goods List, it must be identified in transport by the proper shipping name in the List. A substance listed by name that contains technical impurities or additives for stability or other purposes that affect its classification must be considered a mixture or solution.

A mixture or solution is not subject to the International Maritime Dangerous Goods (IMDG) Code if the characteristics, properties, form, or physical state of the mixture or solution are such that it does not meet the criteria for inclusion in any class.

If a mixture or solution meets the classification criteria of a single predominant substance identified by name in the List and has one or more substances not subject to the provisions of this Code and/or traces of one or more substances identified by name in the List, then assign the UN number and proper shipping name of the predominant substance named in the List.

This requirement does not apply if:

• The mixture or solution is identified by name in the List;
• The entry for the substance named in the List specifically indicates that it applies only to the pure substance;
• The hazard class or division, subsidiary hazard(s), packing group, or physical state of the mixture or solution is different from that of the substance named in the List; or
• The hazard characteristics and properties of the mixture or solution necessitate emergency response measures different from those required for the substance identified by name in the List.

Qualifying words such as “MIXTURE” or “SOLUTION,” as appropriate, must be added as part of the proper shipping name. The concentration of the mixture or solution may also be indicated after the basic description.

For a mixture or solution composed of two or more dangerous goods, use the entry that most precisely describes the mixture or solution.

Segregation groups under IMDG

• The Dangerous Goods list classifies dangerous goods that have similar properties into in segregation groups, indicating which ones may be transported together and which ones may not.

Dangerous goods with similar chemical properties are grouped together in segregation groups. Some substances, mixtures, solutions, or preparations falling within a segregation group are not listed in the International Maritime Dangerous Goods (IMDG) Code by name, but are shipped under n.o.s. entries. Although n.o.s. entries are not listed in the segregation groups, the consignor must decide whether including them under the segregation group is appropriate and, if so, must note that fact in the transport document.

The segregation groups in the IMDG Code do not cover substances that fall outside the classification criteria of the Code. Some non-hazardous substances have similar chemical properties as substances listed in the segregation groups. If the consignor or the person responsible for packing the goods into a cargo transport unit has knowledge of the chemical properties of those non-dangerous goods, they may voluntarily use the segregation provisions of a related segregation group.

The segregation groups are identified in the IMDG Code Section 3.1.4, and include:

• Acids,
• Ammonium compounds,
• Bromates,
• Chlorates,
• Chlorites,
• Cyanides,
• Heavy metals and their salts,
• Hypochlorites,
• Lead and its compounds,
• Liquid halogenated hydrocarbons,
• Mercury and mercury compounds,
• Nitrites and their mixtures,
• Perchlorates,
• Permanganates,
• Powdered metals,
• Peroxides,
• Azides, and
• Alkalis.

Breakdown of the IMDG Dangerous Goods List 

• The Dangerous Goods List is divided into 18 columns, each one referencing the section in the IMDG code where additional information about requirements can be found.

The Dangerous Goods List is found in the International Maritime Dangerous Goods (IMDG) Code Chapter 3.2. The List is divided into 18 columns. Each column includes a reference to the appropriate section in the IMDG Code that provides additional information for that requirement.

• Column 1 contains the United Nations (UN) number assigned by the United Nations Sub-Committee of Experts on the Transport of Dangerous Goods.
• Column 2 contains the proper shipping names.
• Column 3 contains the class assigned to the dangerous good. For class 1, the division and the compatibility group are also included.
• Column 4 contains the class number(s) of any subsidiary hazard(s) that have been identified. This column also identifies marine pollutants.
• Column 5 contains the packing group number (I, II or III) assigned to the substance or article.
• Column 6 contains a number referring to any special provision(s) relevant to the substance or article.
• Column 7a provides the maximum quantity per inner packaging or article for transporting dangerous goods as limited quantities.
• Column 7b provides a code that indicates the maximum quantity per inner and outer packaging for transporting dangerous goods as excepted quantities.
• Column 8 contains codes that refer to the relevant packing instruction(s). The packing instructions indicate which packagings may be used to transport each substance or article.
• Column 9 contains codes that refer to relevant special packing provisions.
• Column 10 contains codes that refer to the relevant intermediate bulk container (IBC) packing instructions, indicating the type of IBC that must be used for transport of the substance under reference. When a code is not provided, it means the substance is not authorized in IBC.
• Column 11 contains a code indicating IBC special provisions, which refers to special packing provisions that apply to the use of packing instructions bearing the code “IBC.”
• Column 12 is reserved.
• Column 13 contains codes for tank and bulk container instructions that apply to the transport of dangerous goods in portable tanks and road tank vehicles.
• Column 14 contains TP notes indicating tank special provisions that apply to the transport of dangerous goods in portable tanks and road tank vehicles. The notes in this column apply to the portable tanks specified in column 13.
• Column 15 refers to the relevant emergency schedules for FIRE and SPILLAGE in “The EmS Guide ¬ Revised Emergency Response Procedures for Ships Carrying Dangerous Goods.” For n.o.s. or other generic entries, the most relevant emergency response procedures may vary with the properties of the hazardous constituents. Shippers may have to declare different EmS codes from those indicated, if, to their knowledge, such codes are more appropriate. The provisions in this column are not mandatory.
• Column 16a contains the stowage and handling codes.
• Column 16b contains the segregation codes.
• Column 17 contains properties and observations for the dangerous goods listed. The provisions in this column are not mandatory.
• Column 18 contains the UN number, as shown in column 1, for ease of use of the table.

Special provisions

When column 6 of the Dangerous Goods List indicates that a special provision applies to a dangerous good, the requirements of that special provision are listed in numerical order amid nearly a thousand entries in Chapter 3.3 of the Code.

If a special provision includes a requirement for package marking, the provisions of section 5.2.1.2 must be met. If the required mark is specific wording in quotation marks, the size of the mark must be at least 12 mm, unless otherwise indicated in the special provision or elsewhere in the Code.

Limited quantities under IMDG

• Dangerous goods that are packed in limited quantities and meet the requirements in IMDG Code Chapter 3.4 are subject to reduced requirements.

The International Maritime Dangerous Goods (IMDG) Code Chapter 3.4 details the conditions that apply to transport of dangerous goods of certain classes packed in limited quantities. Dangerous goods that are packed in limited quantities and meet the requirements in this chapter are subject to reduced requirements.

For each substance in the Dangerous Goods List, the quantity limit for the inner packaging or article is specified in column 7a. The quantity “0” in this column indicates that the entry is not permitted to be transported under the provisions for limited quantities.

Limited quantities: Packing

Dangerous goods must be packed only in inner packagings that are placed in suitable outer packagings. Intermediate packagings may be used. Additional requirements apply to articles of division 1.4, compatibility group S. The use of inner packagings is not necessary for transport of certain articles containing aerosols or gas.

In some cases, shrink-wrapped or stretch-wrapped trays are acceptable as outer packagings for articles or inner packagings containing dangerous goods. Inner packagings that could break or be easily punctured, such as those made of glass, porcelain, stoneware or certain plastics, must be placed in suitable intermediate packagings, and must be designed to meet the construction requirements of the IMDG Code Section 6.1.4. The total gross mass of the package may not exceed 20 kg.

Liquid goods of class 8, packing group II in glass, porcelain, or stoneware inner packagings must be enclosed in a compatible and rigid intermediate packaging.

Limited quantities: Stowage

Dangerous goods packed in limited quantity are allocated stowage category A, which is defined in the IMDG Code Section 7.1.3.2. The other stowage provisions indicated in column 16a of the Dangerous Goods List do not apply.

Limited quantities: Segregation

Different dangerous substances in limited quantities may be packed in the same outer packaging, only if:

• The substances comply with section 7.2.6.1; and
• The segregation provisions of chapter 7.2, including the segregation provisions in column 16b of the Dangerous Goods List, are taken into account. Under certain conditions, notwithstanding the individual provisions specified in the Dangerous Goods List, substances in packing group III within the same class may be packed together.

The segregation provisions of the IMDG Code Chapter 7.2 to 7.7 and the segregation provisions in column 16b of the Dangerous Goods List do not apply for packagings containing dangerous goods in limited quantities or in relation to other dangerous goods. However, articles of division 1.4, compatibility group S must not be stowed in the same compartment, hold, or cargo transport unit with dangerous goods of class 1 of compatibility groups A and L.

Limited quantities: Marking and placarding

Packages containing dangerous goods in limited quantities must bear the mark detailed in the IMDG Code Section 3.4.5.

The minimum dimension per side is 100 mm.

Packages of dangerous goods packed according to Part 3, Chapter 4 of the ICAO Technical Instructions for the Safe Transport of Dangerous Goods by Air may bear a “Y” in the center of the mark to certify conformity with the provisions (minimum 100 mm per side).

The mark must be:

• Readily visible, legible, and able to withstand open weather exposure; and
• Square-shaped and set at an angle of 45°.

The top and bottom portions and the surrounding line must be black. The center area must be white or a suitable contrasting background. Minimum dimensions apply, and all features must be in proportion. If the size of the package necessitates, the outer dimensions may be reduced to not less than 50 mm × 50 mm as long as the mark remains clearly visible.

Limited quantities: Multimodal recognition of marks

Packages containing dangerous goods bearing the “Y” mark for transport by air, with or without the additional labels and marks for air transport, meet the marking requirements and need not bear the mark without the “Y”.

Packages containing dangerous goods in limited quantities bearing the limited quantities mark and conforming with the ICAO Technical Instructions for the Safe Transport of Dangerous Goods by Air, including all necessary marks and labels specified in parts 5 and 6, meet the IMDG Code requirements for limited quantities.

When packages containing dangerous goods packed in limited quantities are placed in an overpack or in a unit load, the overpack or the unit load must be marked with the limited quantity mark unless the marks representative of all dangerous goods in the overpack or the unit load are visible. In addition, an overpack must be marked with the word “OVERPACK” unless required marks representative of all dangerous goods in the overpack are visible. The lettering of the “OVERPACK” mark must be at least 12 mm high. Other provisions for overpacks and unit loads apply if other dangerous goods not packed in limited quantities are contained in the overpack or in a unit load.

Limited quantities: Placarding and marking of cargo transport units

Cargo transport units containing dangerous goods packed in limited quantities with no other dangerous goods must not be placarded nor marked according to the marking requirements for dangerous goods. Instead, they must be marked on the exterior with the mark in the IMDG Code Section 3.4.5.5.4.

Cargo transport units containing dangerous goods and dangerous goods packed in limited quantities must be placarded and marked according to the provisions that apply to the dangerous goods that are not packed in limited quantities. However, if no placard or mark is required for the dangerous goods not packed in limited quantities, the cargo transport units must be marked with the mark in IMDG Code Section 3.4.5.5.4.

The mark must be readily visible, legible, and still be identifiable on cargo transport units surviving at least three months’ immersion in the sea. The mark must be at least 250 mm × 250 mm and displayed in locations specified in IMDG Code Section 5.3.1.1.4.1.

Limited quantities: Documentation

In addition to the documentation requirements in chapter 5.4, the words “limited quantity” or “LTD QTY” must be included on the dangerous goods transport document, along with the description of the shipment

Excepted quantities under IMDG 

• Excepted quantities of certain dangerous goods that meet the provisions of the International Maritime Dangerous Goods Code Chapter 3.5 are subject to reduced requirements.

Excepted quantities of certain dangerous goods that meet the provisions of the International Maritime Dangerous Goods (IMDG) Code Chapter 3.5 are subject to reduced requirements.

For radioactive material, the provisions for excepted packages are found in IMDG Code Section 1.5.1.5.

Dangerous goods that may be carried as excepted quantities are indicated in column 7b of the Dangerous Goods List. The code in column 7b indicates the maximum net quantity allowed for the inner and outer packaging.

Excepted quantities: Packagings

Packagings used to transport dangerous goods in excepted quantities must comply with certain conditions.

There must be an inner packaging and each inner packaging must meet construction requirements detailed in IMDG Code Section 3.5.2. The closure of each inner packaging must be held securely in place by positive means. If a receptacle has a neck with screw threads, it must also have a leakproof threaded cap. The entire closure must be resistant to the contents.

Each inner packaging must be securely packed in intermediate packaging with cushioning material so that they cannot break, be punctured, or leak the contents under normal conditions of transport.

For liquids, the intermediate or outer packaging must contain sufficient absorbent material to absorb the entire contents of the inner packagings. The absorbent material may also serve as the cushioning material. Dangerous goods must not react dangerously with or reduce the integrity of the packaging materials. Regardless of its orientation, the package must completely contain the contents in the event of breakage or leakage.

The intermediate packaging must be securely packed in a strong, rigid outer packaging.

Each package must be large enough to apply all necessary marks.

Overpacks may be used and may also contain packages of dangerous goods or goods not subject to the IMDG Code.

Excepted quantities: Tests for packagings

The complete package as prepared for transport must be capable of withstanding the tests detailed in IMDG Code Section 3.5.3 without breaking or leaking and without a reduction in effectiveness. The testing must be appropriately documented.

Excepted quantities: Marking

Packages containing excepted quantities of dangerous goods must be marked with the mark shown in IMDG Code Section 3.5.4. The primary hazard class of each of the dangerous goods contained in the package must be shown in the mark. If the name of the consignor or consignee is not shown elsewhere on the package, this information must be included within the mark.

* The class or division number(s) must be shown in this location.

** The name of the consignor or of the consignee must be shown in this location if it does not appear elsewhere on the package.

The mark must be a square with the border hatching and symbol in black or red, on white or suitable contrasting background. The minimum dimensions are 100 mm × 100 mm. If dimensions are not specified for a feature, it must be in approximate proportion to those shown.

Overpacks and the unit loads containing excepted quantities must be marked with the excepted quantities mark unless the marks representative of all dangerous goods in the overpack or the unit load are visible. Overpacks must also be marked with the word “OVERPACK” unless marks representative of all dangerous goods in the overpack are visible.

Excepted quantities: Maximum per transport unit

A maximum of 1,000 packages containing dangerous goods packed in excepted quantities may be carried in any cargo transport unit.

Excepted quantities: Documentation

In addition to the documentation requirements in chapter 5.4, the words “dangerous goods in excepted quantities” and the number of packages must be included on the dangerous goods transport document, along with the description of the shipment.

Excepted quantities: Stowage

Dangerous goods packed in excepted quantity are allocated stowage category A (defined in IMDG Code Section 7.1.3.2). The stowage provisions in column 16a of the Dangerous Goods List do not apply.

Excepted quantities: Segregation

The segregation requirements of IMDG Code Chapter 7.2 to 7.7 do not apply for:

• Packagings of dangerous goods packed in excepted quantities, or
• Different dangerous goods in excepted quantities in the same outer packaging, if they do not react dangerously with each other.

Appendices

Appendix A to Part 3 of the IMDG Code contains the list of generic and n.o.s. proper shipping names. The name in the Dangerous Goods List that most appropriately describes the substance or article must be used as the proper shipping name. The main generic entries and all the n.o.s. entries given in the Dangerous Goods List appear in Appendix A.

General and n.o.s. names are grouped according to their hazard class or division. Within each hazard class or division, the names are in one of three groups, including:

• Specific entries that cover 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 that cover a group of substances or articles with one or more general dangerous properties.

Appendix B contains a glossary of terms applicable to Part 3 of the IMDG Code.

IMDG dangerous goods transport document: Required information 

• The five elements of a dangerous goods description must be shown in the proper order on the dangerous goods transport document.

Information required on the dangerous goods transport document begins with the dangerous goods description.

For each dangerous substance, material, or article offered for transport, the document must provide:

1. The UN number preceded by the letters “UN”;
2. The proper shipping name;
3. The primary hazard class or, when assigned, the division;
4. Subsidiary hazard class or division number corresponding to the subsidiary hazard label required to be applied;
5. Where assigned, the packing group for the substance or article.

The five elements of the dangerous goods description must be shown in the order listed above, with no information interspersed, except as allowed by the International Maritime Dangerous Goods (IMDG) Code. Unless permitted or required by the Code, additional information being included must be placed after the dangerous goods description.

IMDG proper shipping names: Supplementary information

• The proper shipping name in the dangerous goods description must be supplemented with additional information when appropriate, such as technical names, dangerous goods that are wastes, dangerous goods that are marine pollutants, and more.

The proper shipping name in the dangerous goods description must be supplemented with the following information, when appropriate:

• Technical names for “n.o.s.” and generic descriptions: These must be supplemented with their technical or chemical group names.
• Empty uncleaned packagings, bulk containers, and tanks: Empty means of containment that contain the residue of dangerous goods of classes other than class 7 must be described by placing the words “EMPTY UNCLEANED” or “RESIDUE LAST CONTAINED” before or after the dangerous goods description.
• Wastes: For waste dangerous goods (other than radioactive wastes) being transported for disposal or for processing for disposal, the word “WASTE” must precede the proper shipping name unless it is already a part of the proper shipping name.
• Elevated temperature substances: If the proper shipping name of an elevated temperature substance does not convey the elevated temperature condition, the word “HOT” must immediately precede the proper shipping name. This applies to substances:
  • In a liquid state at a temperature equal to or exceeding 100°C, or
  • In a solid state at a temperature equal to or exceeding 240°C.
• Marine pollutants: Unless an exception applies, if the goods to be transported are marine pollutants, the goods must be identified as MARINE POLLUTANT.
• Flashpoint: If liquid dangerous goods have a primary or subsidiary hazard of class 3 and a flashpoint of 60°C or below, the minimum flashpoint must be indicated.
• Damaged/defective lithium cells or batteries and lithium cells or batteries for disposal or recycling: When lithium cells or batteries are offered for transport under certain special provisions, “DAMAGED/DEFECTIVE”, “LITHIUM BATTERIES FOR DISPOSAL”, or “LITHIUM BATTERIES FOR RECYCLING” must be indicated, as appropriate.

IMDG additional required information

• The following is a list of information that must be included on a transport document, in addition to the dangerous goods description.

In addition to the dangerous goods description, the following information must be included after the dangerous goods description on the transport document:

• Total quantity: Except for empty uncleaned packagings, the total quantity of dangerous goods covered by the description of each item of dangerous goods bearing a different proper shipping name, UN number, or packing group must be included.
• Limited quantities: When dangerous goods are transported according to the exceptions for dangerous goods packed in limited quantities, the words “limited quantity ”or “LTD QTY ”must be included.
• Salvage packagings and salvage pressure receptacles: For dangerous goods transported in salvage packaging, the words “SALVAGE PACKAGING” or “SALVAGE PRESSURE RECEPTACLE” must be included.
• Substances stabilized by temperature control: If the word “STABILIZED” is part of the proper shipping name when stabilization is by means of temperature control, the control and emergency temperatures must be indicated in the transport document.
• Self-reactive substances, polymerizing substances, and organic peroxides: For these substances that require temperature control during transport, the control and emergency temperatures must be indicated on the transport document.
• Infectious substances: The full address of the consignee must be shown on the document, with the name of a responsible person and their telephone number.
• Radioactive material: Consignments of class 7 material must include detailed information about the contents, shown in the order given in the International Maritime Dangerous Goods (IMDG) Code. The transport document must also include a statement regarding:
  • Actions, if any, that must be taken by the carrier related to loading, stowage, transport, handling, and stowage;
  • Restrictions; and
  • Emergency arrangements.
• Aerosols: If the capacity of an aerosol is above 1000 mL, this must be declared in the transport document.
• Explosives: Additional information for class 1 goods is required addressing n.o.s. entries, water/phlegmatizer content, packaging, and hazards.
• Viscous substances: Viscous substances transported under IMDG Code Section 2.3.2.5 must include the following statement: “Transport in accordance with 2.3.2.5 of the IMDG Code. ”
• Segregation: For certain substances, mixtures, solutions, or preparations classified under n.o.s. entries, the appropriate segregation group name or segregation group code (SGG) preceded by the phrase “IMDG Code segregation group ”must be included in the transport document after the dangerous goods description.
• Bulk: Bulk containers other than freight containers must indicate that the bulk container is approved by the competent authority.
• Intermediate bulk containers (IBCs): For transport of IBCs or portable tanks after the date of expiry of the last periodic test or inspection, a statement indicating the applicable section of the Code allowing the use must be included in the transport document.
• Excepted quantities: When dangerous goods are transported under the exceptions for dangerous goods packed in excepted quantities, the words “dangerous goods in excepted quantities” must be included.
• Fireworks: When certain fireworks are transported, the dangerous goods transport document must include a classification reference issued by the competent authority.
• Classification where new data is available: For transport under IMDG Code Section 2.0.0.2, a statement to that effect must be included in the transport document.
• Transport of UN Nos. 3528, 3529 and 3530: For transport of these materials, the transport document must contain the following additional statement “Transport in accordance with special provision 363. ”
• Actual holding time: For portable tanks carrying refrigerated liquefied gases, the consignor must enter in the transport document the date at which the actual holding time ends.

Consignor certification

The dangerous goods transport document must include a certification or declaration that the consignment is acceptable for transport and that the goods are properly packaged, marked, and labeled, and in proper condition for transport according to the applicable regulations. The certification must be signed and dated by the consignor.

If the documentation is presented to the carrier via electronic data processing (EDP) or electronic data interchange (EDI) transmission techniques, the signature may be electronic or may be replaced by the name (in capital letters) of the person authorized to sign.

When the dangerous goods transport information is given to a carrier by EDP or EDI techniques and subsequently the dangerous goods are transferred to a carrier that requires a paper dangerous goods transport document:

• The carrier must ensure that the paper document indicates “Original received electronically,” and
• The name of the signatory must be shown in capital letters.

IMDG container/vehicle packing certificate 

• Those who pack or load dangerous goods into a container or vehicle must provide a container/vehicle packing certificate, which certifies that the operation has been carried out properly.

When dangerous goods are packed or loaded into a container or vehicle, those responsible for packing the container or vehicle must provide a “container/vehicle packing certificate.” The certificate must specify the container/vehicle identification number and certify that the operation has been carried out according to certain conditions, including that:

• The container or vehicle is clean, dry, and fit to receive the goods;
• Applicable segregation requirements have been met;
• Packages have been inspected for damage and only sound packages have been loaded;
• Drums have been stowed in an acceptable position, and all goods have been properly loaded and, where necessary, adequately braced;
• Bulk goods have been evenly distributed in the container/vehicle;
• For goods of class 1 other than division 1.4, the container/vehicle is structurally serviceable;
• The container/vehicle and packages are properly marked, labeled, and placarded;
• When substances presenting a risk of asphyxiation are used for cooling or conditioning purposes, the container/vehicle is externally marked according to requirements; and
• A dangerous goods transport document has been received for each dangerous goods consignment loaded in the container/vehicle.

Note that the container/vehicle packing certificate is not required for portable tanks.

The information required in the dangerous goods transport document and the container/vehicle packing certificate may be incorporated into a single document; if not, these documents must be attached.

If the information is incorporated into a single document, the document must include a signed declaration indicating that the packing of the goods into the container/vehicle has been carried out in accordance with the applicable provisions. This declaration must be dated and the person signing it must be identified on the document.

If the certificate is presented to the carrier via EDP or EDI transmission techniques, the signature may be electronic or may be replaced by the name (in capital letters) of the person authorized to sign.

If the certificate is given to a carrier by EDP or EDI techniques and subsequently the dangerous goods are transferred to a carrier that requires a paper container/vehicle packing certificate, the carrier must ensure that:

• The paper document indicates “Original received electronically,” and
• The name of the signatory is shown in capital letters.

IMDG documentation required aboard the ship 

• Each ship that carries dangerous goods and/or marine pollutants must have a list, manifest of stowage plan that shows which goods are on board and where on the ship they are located.

Each ship carrying dangerous goods and marine pollutants must have a special list, manifest, or stowage plan setting out the dangerous goods (except dangerous goods in excepted packages of class 7) and marine pollutants and the location of those goods on the ship.

This special list or manifest must be based on the documentation and certification required in the International Maritime Dangerous Goods (IMDG) Code. In addition to the information in the dangerous goods transport documents, it must contain the stowage location and the total quantity of dangerous goods and marine pollutants.

A detailed stowage plan that identifies by class and sets out the location of all dangerous goods and marine pollutants may be used in place of a special list or manifest.

Each ship carrying excepted packages of class 7 must have a special list, manifest, or stowage plan setting out these excepted packages and their location.

A copy of the documents must be made available before departure to the person or organization designated by the port State authority.

IMDG emergency response information

• For each consignment of dangerous goods, appropriate information must be made available for use in emergency response to accidents and incidents involving the dangerous goods.

For consignments of dangerous goods, appropriate information must be immediately available at all times for use in emergency response to accidents and incidents involving dangerous goods in transport. The information must be:

• Available away from packages containing the dangerous goods, and
• Immediately accessible in the event of an incident.

Methods to comply with this requirement include:

• Entries in the special list, manifest, or dangerous goods transport document; or
• A separate document, such as a safety data sheet; or
• Separate documentation, such as the Revised Emergency Response Procedures for Ships Carrying Dangerous Goods (EmS Guide) for use with the transport document and the Medical First Aid Guide for Use in Accidents Involving Dangerous Goods (MFAG).

Other required certificates and documents for IMDG shipments

• Occasionally, special certificates or other documents must accompany shipments of dangerous goods, in addition to the transport document.

In certain circumstances, special certificates or other documents are required when offering dangerous goods for transport.

A weathering certificate is required in some individual entries of the Dangerous Goods List.

A certificate exempting a substance, material, or article from the provisions of the International Maritime Dangerous Goods (IMDG) Code must accompany the consignment. For examples, see the individual entries for charcoal, fish meal, and seed cake.

New self-reactive substances and organic peroxides, or new formulation of currently assigned self-reactive substances and organic peroxides, must include a statement of the approved classification and conditions of transport.

Multimodal dangerous goods form

The Multimodal Dangerous Goods Form found in the IMDG Code Section 5.4.5 meets the requirements of SOLAS, chapter VII, regulation 4; MARPOL, Annex III, regulation 4; and the IMDG Code provisions for documentation.

The information required by the documentation provisions of the Code is mandatory, however, the layout of the form is not mandatory.

This form may be used as a combined dangerous goods transport document and container/vehicle packing certificate for multimodal carriage of dangerous goods.

Segregation and stowage under the IMDG

• The IMDG Code offers segregation requirements for various materials to ensure that incompatible substances do not come in contact with one another during shipping.

Segregation refers to the process of separating incompatible substances to avoid undue hazards should the packages leak or spill, or otherwise come in contact with one another in an accident.

The segregation table can be found in the International Maritime Dangerous Goods (IMDG) Code Section 7.2.4.

The codes listed in the table are as follows:

• X – Consult the Dangerous Goods list to verify whether there are specific segregation provisions
• * - See the IMDG section 7.2.7.1 for the segregation provisions of Class 1 explosives
• 1 – “away from”
• 2 – “separated from”
• 3 – “separated by a completed compartment or hold from”
• 4 – “separated longitudinally by an intervening complete compartment or hold from”

Additional segregation groups and special provisions and exceptions can be found in the IMDG Code Sections 7.2.5 and 7.2.6.

A helpful segregation flow chart can be found in the IMDG Code Chapter 7.2 Annex (for informational purposes only).

Segregation and stowage on containerships

Chapter 7.4 of the IMDG Code covers the stowage and segregation requirements on containerships. Containers meet the definition of a container in the International Convention for Safety Containers, 1972. These are containers transported on deck and in the cargo holds of containerships or on deck and in the cargo holds of other types of ships (provided the positions are fitted to give permanent stowage of containers during transport). If ships are not properly fitted for the permanent stowage of containers, then refer to IMDG Code Chapter 7.6.

Segregation and stowage on roll-on/roll-off ships

Chapter 7.5 of the IMDG Code covers the stowage and segregation of cargo transport units (CTUs) that are transported in roll-on/roll-off (ro-ro) cargo spaces. If a ro-ro ship has stowage positions that are fitted to give a permanent stowage of containers during transport, then the IMDG Code Chapter 7.5 applies. If the ro-ro ship has conventional cargo spaces, then refer to IMDG Code Chapter 7.6.

Segregation and stowage on general cargo ships

Chapter 7.6 of the IMDG Code covers the segregation and stowage of dangerous goods stored conventionally on board general cargo ships.

There are stowage and handling provisions based on class of dangerous goods. In general for all classes of dangerous goods:

• The minimum stacking height for testing packages is 3 meters.
• Drums must always be in an upright position.
• Dangerous goods must be arranged to provide clear walkways and access to all parts of the ship necessary for its safe operation.
• Fiberboard packages, paper bags, or other packages that could be damaged by water must be stowed under deck, or, if stowed on deck, protected so that they aren’t exposed to weather or seawater.
• Portable takes cannot be overstowed unless they are designed for that purpose.
• Cargo spaces and decks must be kept dry and clean and free of dust (to reduce ignition risks).
• If packages are found to be damaged or leaking, they cannot be loaded on the ship. Excess water, snow, ice, etc., must be removed before loading onto a ship.
• Packages must be braced and secured against movement and fittings must be protected.

Consult IMDG Code Chapter 7.6 for additional provisions specific to dangerous goods class.

Shipborne barges on barge-carrying ships under the IMDG

• The IMDG Code offers requirements for shipping dangerous goods on barges, which must be designed and maintained to handle dangerous goods transportation.

Barges may contain packaged dangerous goods or solid bulk materials. Barges must be designed and maintained to handle dangerous goods transportation. Complete details on the requirements for shipborne barges on barge-carrying ships can be found in the International Maritime Dangerous Goods (IMDG) Code Chapter 7.7.

Leaking, damaged, or sifting packages cannot be loaded onto a shipborne barge.

Dangerous goods packages, cargo transport units (CTUs), or any other dangerous goods within a shipborne barge must be secured for the trip. Packages must be loaded so that the likelihood of damage is minimized. Fittings on packages or tanks must also be protected from damage.

Some types of dry dangerous goods may be transported in bulk on a shipborne barge. If allowed, it will show the code “BK2” in column 13 of the Dangerous Goods List. Bulk materials transported on shipborne barges must be evenly distributed and secured.

Shipborne barges must be visually examined to check for damage affecting the barges’ watertight integrity. If a barge is damage, it cannot be used to transport packaged or bulk dangerous goods.

Flexible bulk containers can be transported via barge, but they must be stowed in a way that there aren’t spaces in between the containers. If the containers do not completely fill the barge, then measures must be taken to ensure the cargo is completely secured against shifting. If these containers are stacked, they can be stacked no more than three high.

Segregation on barges is covered in the IMDG Code Section 7.7.5.

Incidents and fire precautions under the IMDG

• While not mandatory, the IMDG Code offers requirements and procedures to be followed in the event of an accident or fire involving dangerous goods.

International Maritime Dangerous Goods (IMDG) Code Chapter 7.8 covers special requirements in the event of an incident or fire involving dangerous goods. The provisions of the chapter are not mandatory. If a ship is involved in an accident or is leaking while in port, port authorities should be contacted for appropriate procedures.

General fire precautions are as follows:

• Keep combustibles away from ignition sources,
• Protect flammables with adequate packing,
• Reject damaged packages or packages that are leaking,
• Protect packages from damage,
• Follow segregation rules, and
• Enforce no smoking rules.

IMDG stowage categories 

• Stowage categories offered by the IMDG Code identify whether a material can be stored on deck, under deck, or is prohibited.

The International Maritime Dangerous Goods (IMDG) Code uses stowage categories to identify if cargo can be stored On Deck, Under Deck, or Prohibited. Column 16a of the Dangerous Goods List displays the stowage category for each material. Stowage categories are split into two groups, Class 1 and Classes 2 - 9.

Stowage Category for Class 1 (Other than Division 1.4S packed in limited quantity)

Stowage Category for Classes 2 – 9 (Including Division 1.4S packed in limited quantity)

Always check IMDG Code Chapter 7 for any additional stowage requirements or provisions that may be required for the dangerous goods.

IMDG stowage codes 

• Stowage codes can be used along with stowage categories to identify additional requirements as needed for various dangerous goods.

Stowage codes identify additional requirements for the stowage of dangerous goods and can be used with the stowage categories. Stowage codes are recognized by the “SW” before a number and are generally used for individual substances. Column 16a of the Dangerous Goods List also displays the stowage code for each material.

International Maritime Dangerous Goods (IMDG) Code Chapter 7 contains additional stowage codes.

IMDG handling codes 

• Handling codes are an additional tool to be used along with stowage categories and stowage codes to identify how to handle dangerous goods safety during transport.

Handling codes identify additional requirements for the stowage of dangerous goods and can be used with stowage codes and stowage categories. Handling codes are recognized by the “H” before a number and are generally used for individual substances. Column 16a of the Dangerous Goods List also displays the handling code for each material.

IMDG segregation 

• Dangerous goods that may cause a hazard when interacting with another material must be segregated from those materials during shipping.

Dangerous goods, substances, or articles that are incompatible and may react violently with each other due to leakage, spillage, or any other accident must be segregated from one another for shipment by vessel. Segregation can be obtained by maintaining separation between incompatible dangerous goods or by requiring the presence of one or more steel bulkheads or decks between them, or a combination thereof.

Determining the segregation requirements between two or more substances requires referencing the Segregation Table in the International Maritime Dangerous Goods (IMDG) Code Chapter 7.2 and the segregation codes in Column 16b of the Dangerous Goods List. The segregation code description can be found in IMDG Code Chapter 7.2. If there are conflicting segregation requirements in the IMDG Code, the provisions of Column 16b of the Dangerous Goods List will always take precedence.

Segregation codes

A portion of the segregation codes given in Column 16b of the Dangerous Goods List are specified below:

IMDG Code Chapter 7 should always be referenced for complete segregation requirements, codes, and specifications.

IMDG Cargo Transport Units (CTU) 

• The IMDG Code offers specific requirements for shipping dangerous goods in a cargo transport unit (CTU).

Cargo Transport Units (CTU) are versatile so they can be used with different modes of transportation. The versatility of the CTU has made it one of the most used forms of packaging for vessel shipments.

All CTU must be constructed in a way to prevent the loss of contents. When appropriate, the CTU must have a means to facilitate securing and handling cargo inside the unit. CTU must be adequately maintained.

Packing CTU

In the past, there have been instances where CTU were not packed in a safe manner. As a result, the CTU was overloaded or contained loose cargo, which resulted in severe incidents. To prevent future incidents the International Maritime Dangerous Goods (IMDG) Code requires the following actions to be taken when packing a CTU:

• CTU must be checked prior to use to ensure it is fit for intended purpose.
• Interior and exterior of CTU must be inspected prior to loading to ensure there is no damage that could affect its integrity or that of the packages loaded inside it.
• Packages must not be loaded in the CTU if found to be damaged, leaking, or sifting.
• Excessive water, snow, ice, or foreign matter adhering to packages must be removed before packing into CTU. If handling provision “keep as dry as reasonably practicable” (H1) is assigned in column 16a of the Dangerous Goods List, then the CTU must be kept as dry as reasonably practicable.
• Drums of dangerous goods loaded in a CTU must always be stowed in an upright position unless otherwise authorized by the competent authority.
• CTU must be loaded in compliance with IMDG Code Section 7.3.4 (Segregation provisions) so that incompatible dangerous or other goods are segregated appropriately.
• Specific loading instructions such as orientation arrows, do not stack, keep dry, or temperature control requirements must be met.
• Liquid dangerous goods must be loaded below dry dangerous goods whenever possible.
• Packaged dangerous goods and unpackaged dangerous articles must be secured within the CTU to prevent any movement during transport that would change their orientation or cause them to be damaged.
• Dangerous goods transported in a CTU with other goods (e.g., heavy machinery or crates), all goods must be secured to prevent the release of dangerous goods.
• If restraints such as banding, or straps are used they must not be over-tightened to cause damage or deformation of the package or the securing points (such as D-rings) within the CTU.
• Packages must be packed to minimize the likelihood of damage to fittings during transport.  Fittings on packages must be adequately protected.
• If restraints such as banding or straps with integral container fittings are used, packer must use care to ensure the Maximum Securing Load (MSL) of the fittings is not exceeded.
• Packages must not be stacked unless designed for that purpose. When necessary stacked packages must be prevented from damaging the package below using load bearing devices.
• Cargo must be entirely contained inside the CTU. Oversized cargo may project outside the CTU provided the cargo does not leak or spill outside of the CTU.
• CTU containing dangerous goods and non-dangerous goods, the dangerous goods must be loaded closest to the door with the labels visible.
• If CTU doors are locked, the lock must be able to be opened quickly in case of an emergency.
• If venting is required, the vent must be kept clear and operable.
• CTU must be marked and placarded according to IMDG Code Chapter 5.3.
• All unauthorized markings, labels, and placards must be removed prior to loading the CTU.
• CTU must be loaded so the weight is evenly distributed throughout the container.
• Flex bulk containers must not be loaded in a CTU.
• Those responsible for packing dangerous goods inside a CTU must provide a “container/vehicle” packing certificate.

Segregation and CTU

Dangerous goods that must be segregated from each other according to the International Maritime Dangerous Goods (IMDG) Code Chapter 7.2 segregation requirements must not be loaded in the same CTU. However, dangerous goods that must be segregated “away from” each other may be transported in the same CTU with approval from a competent authority.

Dangerous goods with primary or subsidiary hazard classes 2.3, 6.1, 6.2, 7, 8, and dangerous goods with a reference to the IMDG Code Section 7.3.4.2.1 in Column 16b of the Dangerous Goods List must not be loaded with foodstuffs in the same CTU.

General provisions for packagings, IBCs, and large packagings under IMDG

• Generally, packaging used for dangerous goods must be strong enough to withstand shipping, closed according to manufacturer instructions, compatible with the material it is holding, and more.

The International Maritime Dangerous Goods (IMDG) Code requires packagings, intermediate bulk containers (IBCs), and large packagings to follow certain provisions. The provisions are intended to ensure the dangerous goods are packed and shipped in a safe secure manner. The following general provisions apply to dangerous goods packagings, IBCs, and large packagings. The packagings must be:

• Good quality and strong enough to withstand shocks normally encountered during transport.
• Closed in accordance with the package manufacturers closure instructions.
• Clean with no dangerous residue on the outside of the package.
• Compatible with the dangerous goods they are holding.
• In conformance with applicable design specifications.
• Filled to allow sufficient ullage (outage) for product expansion without damaging the package.
• Capable of withstanding pressures encountered when transported by air if the package is also being transported on an aircraft.
• Inner packages to be facing upright and contain cushioning absorbent material to keep them secure in the outer package.
• Hermetically sealed, when required.
• Treated as full when containing residue.
• Sift-proof or contain a liner when filled with powdery or granular materials.
• Secured from movement when inside a Cargo Transport Unit.

IMDG packing instructions and special provisions 

• Packaging instructions for Classes 1-9 are subdivided into three categories: Intermediate bulk containers (IBCs), large packagings, and packagings other than IBCs or large packaging.

The International Maritime Dangerous Goods (IMDG) Code provides packing instructions for dangerous goods in hazard classes 1 through 9. Packing instructions show the acceptable packagings that are authorized for a dangerous good. For combination packagings, the packing instructions list the acceptable outer packagings, inner packagings and when applicable, the maximum permitted quantity in each inner or outer packaging.

The packaging instructions are subdivided into three subsections according to the type of packaging being used and are designated by a code. The codes are alphanumeric, and the code prefix designates what package it is intended for. The packing instructions are detailed in IMDG Code Section 4.1.4.

Any packing instruction left blank or does not contain a code means that type of packaging is not authorized.

Special provisions may also be specified in the packing instruction for individual substances or articles. They provide additional guidance or requirements when packaging substances or articles. Special provisions are also designated by an alphanumeric code comprising the letters.

Typically, packing instructions do not provide guidance on compatibility. The shipper is responsible for checking that the substance is compatible with the packaging material selected (such as, most fluorides are unsuitable for glass receptacles). Where glass receptacles are permitted in the packing instructions, porcelain, earthenware, and stoneware packagings are also allowed.

Example: For UN1789, Hydrochloric Acid, PG II, the Dangerous Goods List shows packing instructions are P001 for single/combination packages, IBC02 for intermediate bulk containers and does not list any packing instruction for large packagings. The special provisions are B20.

IMDG general provisions for portable tanks for Class 1 and Classes 3-9

• The IMDG Code requires that portable tanks containing dangerous goods must follow certain provisions.

The International Maritime Dangerous Goods (IMDG) Code requires portable tanks to follow certain provisions. The provisions are intended to ensure the dangerous goods are packed and shipped in a safe secure manner. The following general provisions apply to Class 1 and Classes 3-9 dangerous goods in portable tanks:

• Tanks must adhere to specific design, construction, inspection, and testing requirements.
• Tanks must be protected against damage to the shell and service equipment.
• Steps must be taken to prevent dangerous decomposition, transformation, or polymerization during transport for unstable substances.
• The temperature of the outer surface of the shell must not exceed 158° F (70° C) during transport.
• Treated as full when containing residue.
• Must not be transported in adjoining compartments of shells when they may react dangerously with each other or may cause:
  • Combustion or evolution of heat,
  • Flammable, Toxic, or asphyxiant gases,
  • Formation of corrosive or unstable substances,
  • Dangerous rise in pressure.
• Owners must keep and provide (when requested) the design approval certificate and test reports for the portable tank.
• Not overfilled according to packing specifications.

IMDG general provisions for portable tanks for Class 2 (non-refrigerated gases)

• The IMDG Code requires that portable tanks containing dangerous goods in Class 2 (non-refrigerated gases) must follow certain provisions separate from those associated with Class 1 and Classes 3-9.

The International Maritime Dangerous Goods (IMDG) Code requires portable tanks to follow certain provisions. The provisions are intended to ensure the dangerous goods are packed and shipped in a safe secure manner. The following general provisions apply to Class 2 (non-refrigerated gases) dangerous goods in portable tanks:

• Tanks must adhere to specific design, construction, inspection, and testing requirements.
• Tanks must be protected against damage to the shell and service equipment.
• Steps must be taken to prevent dangerous decomposition, transformation, or polymerization during transport for unstable substances.
• The temperature of the outer surface of the shell must not exceed 158° F (70° C) during transport.
• Treated as full when containing residue.
• The design approval certificate must be made available when required.
• Not overfilled according to packing specifications.

IMDG packing instructions and special provisions for portable tanks 

• Portable tank special provisions are assigned to specific dangerous goods in Column 14 of the Dangerous Goods List.

Portable tank instructions and special provisions are applicable to dangerous goods authorized to be transported in portable tanks.

Each portable tank instruction is identified by an alpha-numeric designation (T1 to T75). Column 13 of the Dangerous Goods List indicates the portable tank instruction that must be used for each substance permitted for transport in a portable tank. When no portable tank instruction appears in the Dangerous Goods List, transport of the substance in portable tanks is not permitted unless a competent authority approval is granted.

Portable tank special provisions are assigned to specific dangerous goods in Column 14 of the Dangerous Goods List. They provide additional guidance or requirements when packaging substances or articles in portable tanks. Each portable tank special provision is identified by an alpha-numeric designation that always begin with “TP” (such as TP1). A listing of the portable tank special provisions is provided in International Maritime Dangerous Goods (IMDG) Code Section 4.2.5.3.

IMDG package codes

• Package codes are a combination of alphanumeric characters that describe the type and material of the package.

Package codes are alphanumeric characters that describe the type/kind of package and the material it is made of. Package codes are typically two or three digits long. However, they can be up to five digits long.

Codes that contain only one capital letter indicate a single package, and can be deciphered as follows:

The first numeral designates the kind of packaging:

• 1 = Drum
• 2 = Reserved
• 3 = Jerrican
• 4 = Box
• 5 = Bag
• 6 = Composite packaging

The letter indicates the material of construction:

• A = Steel (all types and surface treatments)
• B = Aluminum
• C = Natural wood
• D = Plywood
• F = Reconstituted wood
• G = Fiberboard
• H = Plastic
• L = Textile
• M = Paper, multi-wall
• N = Metal (other than steel and aluminum)
• P = Glass, porcelain, or stoneware

A second numeral indicates the category of packaging within the packaging:

• 1 = Non-removable head (for drums)
• 2 = Removable head (for drums)

Examples:

• 1A1 indicates a steel drum with a non-removable head.
• 4D indicates a plywood box.

Codes that contain two capital letters indicate composite packages. The first letter designates the material for the inner receptacle, and the second, the material for the outer packaging.

Example:

• 6HA1 would be a plastic receptacle in a steel drum with a non-removable head.

Performance levels

• X = for packagings meeting Packing Group I, II and III tests
• Y = for packagings meeting Packing Group II and III tests
• Z = for packagings meeting only Packing Group III tests

Solids or inner packaging

• S = packagings intended to contain solids or inner packagings

IMDG package markings

• UN specification markings included on a package indicate that the packaging has been tested to meet strict performance requirements.

Packages and containers for dangerous goods must pass rigorous performance testing prior to use. The UN specification marking is an indication that the package has met stringent requirements set forth by the United Nations.

The UN specification marking must include, in the following order:

• 1. UN symbol - A lower-case “u” over a lower case “n” in a circle,
• 2. Package code – Code that indicates the package type and material,
• 3. Performance level:
  • X = meets Packing Group I, II and III test
  • Y = meets Packing Group II and III tests
  • Z = meets only Packing Group III tests
• 4. Gross mass or specific gravity,
• 5. Solids or inner packages (indicated by an “S”), or hydrostatic test pressure,
• 6. Year of manufacture,
• 7. Country of authorization and marking,
• 8. Manufacturer symbol or name and address.

IMDG general package requirements

• All packages must meet general safety requirements even if they are not UN specified.

All packages containing dangerous goods must meet general package requirements even if they are not a UN specification package. While the requirements may seem like common knowledge, they are often forgotten or overlooked.

Packages must be:

• Sturdy enough to withstand conditions normally encountered during transport.
• Designed and constructed to prevent loss of contents.
• Closed in accordance with the manufacturers closure instructions.
• Compatible with the contents they are designed to hold.

Package testing under IMDG

• Some types of UN specification packaging testing include a drop test, leakproofness test, and a stacking test.

UN specification package testing is a series of tests and requirements used to determine the integrity and safety of the package when facing various situations. The tests are designed to simulate common conditions that are encountered during transportation. Not all packages are required to accomplish each type of test. For example, a package designed for solids does not need to have a leakage test.

Types of tests include:

• Drop test – performed on all packages and verifies the package’s ability to protect goods in free fall.
• Leakproofness test - performed on packages designed to contain liquids.
• Pressure test – performed on metal, plastic, and composite packages intended to hold liquids.
• Stacking test – performed on all package types except bags.

A test report containing the following information must be made available to the users of the package:

• Name and address of the test facility,
• Name and address of the applicant (when applicable),
• A unique test report identification,
• Date of test report,
• Description of package design type, manufacture methods, and drawings,
• Maximum capacity,
• Characteristics of test contents
• Test descriptions and results,
• Signature, with name and status of signatory.

The complete requirements for package specifications can be found in International Maritime Dangerous Goods (IMDG) Code Chapter 6. Chapter 6 should be referenced any time there are any requirements for package specifications.

IMDG general requirements and exceptions

• Many of the general regulations regarding the sea transport of dangerous goods also apply to shipments of radioactive materials.

The International Maritime Dangerous Goods (IMDG) Code applies to the sea transport of radioactive materials. This includes packaging design and packaging manufacturing along with the preparation of a radioactive material for loading/unloading, offering a radioactive material for transportation, and in-transit storage of the material. All subsidiary hazards of the radioactive material must be taken into account when determining the documentation, markings and labels, segregation, and other requirements.

The IMDG Code requirements on radioactive materials do not apply to:

• Diagnostic or treatment-related radioactive materials implanted in a person or animal;
• People being transported for treatment because the person was exposed (either accidentally or deliberately) to radioactive materials or contamination.
• Radioactive material in consumer products which have received regulatory approval, following their sale to the end user;
• Natural material and ores containing naturally occurring radionuclides, under certain conditions;
• Non-radioactive objects with radioactive substances present on any surfaces in quantities up to the limits identified in the “contamination” definition; or
• Radioactive materials that are part of the means of transport.

Specific provisions for excepted packages can be found in the IMDG Code, section 1.5.1.5.

Special arrangements, which are special provisions approved by competent authorities, can be made for radioactive materials shipments that do not conform to the regulatory standards but that provide an equivalent level of safety; see IMDG section 1.5.4 for details.

IMDG miscellaneous requirements

• The IMDG Code offers other miscellaneous requirements for shipping various types of radioactive materials by sea.

Classification of radioactive materials, transport index (TI), and criticality safety index (CSI)

Details on the classification of radioactive materials can be referenced in the International Maritime Dangerous Goods (IMDG) Code, Chapter 2.7, Classification.

Details on determining the transport index (TI) and criticality safety index (CSI) can be found in the IMDG Code Section 5.1.5.3.

Fissile materials

Specific provisions for the consignment of fissile materials are referenced in the IMDG Code Section 5.1.5.5.

Package approvals for radioactive materials

See the IMDG Code Section 4.1.9. for special packing provisions for radioactive materials. This section covers excepted packages; Type IP-1, IP-2, and IP-3 packages; and Type A, B(U), B(M), and C packages. Fissile material packages and packages containing uranium hexafluoride are subject to additional requirements.

Before packages are used for radioactive materials, it must be confirmed that they meet the manufacturing and design standards.

Additionally, IMDG Code Chapter 6.4 covers the details on the construction, testing, and approval of packages for radioactive material and for the approval of such material.