The UN Committee has assigned all dangerous goods to one of three Packing Groups: Packing Group I (high danger), II (medium danger) and III (low danger). The list of dangerous goods and the Packing Group for each can be found in the ICAO Technical Instructions, the IMDG Code or the TDG Regulations. The Committee has also developed what is referred to as ‘UN packaging’. UN packagings have been performance tested for their resistance to drop, stacking and internal pressure, the severity of the test varying with the Packing Group. Each packaging is marked with a code that indicates the type of packaging, Packing Group, form (liquid or solid), relative density, inner packagings, etc. for which the packaging was tested by the manufacturer and can, therefore, be used.

It is the shipper’s responsibility to select the appropriate packaging for dangerous goods. Shippers should become familiar with the code used in the UN package mark. To select a UN packaging that is suitable for their product, they need the following information:

• the Packing Group for their product,
• the compatability of their product with the packaging material,
• the vapour pressure at 55ºC or 50°C and the relative density (liquids),
• the net mass (solids).

2.Packaging Code:

3. Packing Group:

4. The relative density (liquids. If the relative density isn’t marked, it is considered to be 1.2) or the gross mass in kg (solids) for which the packaging was tested.

5. The hydrostatic test pressure in kPa (liquids) or the letter ‘S’ meaning the package was tested for solids or inner packagings.

6. Year of manufacture.

7. Country code for the country authorizing the allocation of the mark.

8. Name or registered symbol of the manufacturer.

9. Transport Canada design registration number.

10. Nominal thickness of the material of construction (metal drums only); top head/body/bottom head

1. Single Packagings. Single packagings are constructed of a single component (e.g., steel drums).

• permitted for the product by Part II of standard CAN/CGSB 43.150-97
• with a marked Packing Group at or above that for the product;
• in which the material in contact with the product is compatible with and impermeable to the product;
• with a marked relative density at or above that for the product (liquids);
• with a marked test pressure suitable for the product (liquids):

• with a marked gross mass that is adequate for the product (solids);
• with a nominal thickness 1.1/0.8/1.1 (top head/body/bottom head) or greater if it’s a steel drum over 150 litres capacity and to be reused in Canada for dangerous goods. There are also requirements for reconditioning some steel drums reused for liquid transport, see section 18 of standard CAN/CGSB-43.150-97.

  Packagings may be used for products having a form or Packing Group different from that in the marking, within the following limits:

  - PG I packagings for liquids may be used for PG II liquids with a relative density not exceeding the greater of 1.8 or [1.5 X the marked relative density]*;

  - PG I packagings for liquids may be used for PG III liquids with a relative density not exceeding the greater of 2.7 or [2.25 X the marked relative density]*;

  - PG II packagings for liquids may be used for PG III liquids with a relative density not exceeding the greater of 1.8 or [1.5 X the marked relative density]*;

  - A packaging for liquids may be used for solid products if the gross mass (kg) doesn’t exceed the packaging’s capacity (litres) X the marked relative density;

  - PG I packagings for liquids may be used for PG II solid products if the gross mass (kg) doesn’t exceed the packaging’s capacity (litres) X 1.5 X the marked relative density*;

  - PG I packagings for liquids may be used for PG III solid products if the gross mass (kg) doesn’t exceed the packaging’s capacity (litres) X 2.25 X the marked relative density*;

  - PG II packagings for liquids may be used for PG III solid products if the gross mass (kg) doesn’t exceed the packaging’s capacity (litres) X 1.5 X the marked relative density*;

  *packagings should be capable of withstanding a 3m high stacking load at the higher relative density

  2. Combination Packagings. Containers having inner packagings are called ‘combination packagings’ (e.g., fibreboard box containing bottles):

  When ordering packaging from a supplier, specify a UN combination packaging

  • permitted for the product by Part II of standard CAN/CGSB 43.150-97
  • with a marked Packing Group at or above that for the product;
  • in which the material in contact with the product is compatible with and impermeable to the product;
  • with a marked gross mass that is adequate for the product and packaging;
  • that has been tested with the inner packagings to be used for the product;

  A packaging may be used to contain inner packagings that differ from those that were used in the tests, within the following limits:

  - A lesser number of inner packagings may be shipped in the box if voids are filled and cushioning is maintained.

  - If a box was tested with several different types of inner packagings, inners from each design may be shipped together in the box.

  - Inner packagings that are similar in design to the inners that were tested with the box (shape, same or smaller openings, similar type of closure, equivalent or smaller size, equivalent or better materials) may be shipped in the box.