What Are UN Ratings?

What are UN Marked Drums (sometimes referred to as UN Rated Drums or UN Tested Drums) and DOT 7A Marked Drums (sometimes referred to as DOT 7A Rated Drums or DOT 7A Tested Drums)?

Note:  This summary is offered as general overview and is for information purposes only.  Please refer to Code of Federal Regulations 49 for full and complete discussion of applicable regulations.  The information contained in this summary should not be used as a replacement for competent advice regarding the regulations.  Regulations are set forth in the Code of Federal Regulations, Title 49 – Transportation. (49 U.S.C. 5101 et seq.)  With respect to these markings, the regulations cover the method and frequency of tests to be performed on containers for shipping certain types of materials.  The types of test and frequency of testing varies by the type of container, type of material being transported and the level of potential hazard as classified under the regulation.  The entity shipping the material is tasked with assuring that the appropriate container is chosen for the material being shipped.  The manufacturer of the container is tasked with performing the prescribed tests at the prescribed intervals and certifying that the drums tested performed satisfactorily to the standard outlined in the regulation.

UN refers to standards set forth in the United Nations Recommendations (Transportation of Dangerous Goods).  DOT refers to the United States Department of Transportation

Liquid Materials

For Packaging of Liquid Materials, the format of the UN marking is six sections divided by a “/”:

SECTION 1 – Example:   1A2/X1.9/195/18/USA/000000

• 1 = Package Type (Drum)
• A = Steel (All types and Surfaces)
• 2 = Category (Open Head); 1 = Category (Closed Head)

SECTION 2 – Example:  1A2/X1.9/195/18/USA/000000

Packing Groups to which the drums meet testing requirements

• X = Packing Group I, II, III
• Y = Packing Group II, III
• Z = Packing Group III Only

Packing groups are enumerated in the regulations, but generally speaking “I” is the greatest hazard group and “III” the least hazard group

Specific Gravity (1.9 in example) this is the specific gravity of the liquid intended to be transported in the container.

SECTION 3 – Example:  1A2/X1.9/195/18/USA/000000

This is the Hydrostatic Test Pressure in kPa.  In the case of metal drums, current (2019) requirement is to subject test drums to the listed pressure for a period of 5 minutes with no leakage of liquid.

SECTION 4 – 1A2/X1.9/195/18/USA/000000

Last 2 digits of year of manufacture

SECTION 5 – 1A2/X1.9/195/18/USA/000000

The letters USA indicate that the packaging is manufactured and marked in the United States

SECTION 6 – 1A2/X1.9/195/18/USA/000000

Manufacturer’s Symbol as registered with the Associate Administrator

  

Solid Materials

For Solid Materials, the format of the UN marking is six sections divided by a “/”:

SECTION 1 – Example:  1A2/X43/S/18/USA/000000

• 1 = Package Type (Drum)
• A = Steel (All types and Surfaces)
• 2 = Category (Open Head); 1 = Category (Closed Head)

SECTION 2 – Example:  1A2/X43/S/18/USA/000000

Packing Groups to which the drums meet testing requirements

• X = Packing Group I, II, III
• Y = Packing Group II, III
• Z = Packing Group III Only

Packing groups are enumerated in the regulations, but generally speaking “I” is the greatest hazard group and “III” the least hazard group

Maximum Gross Mass (Drum plus contents) in Kg

SECTION 3 – Example:  1A2/X43/S/18/USA/000000

Solid Contents or Inner Packaging

SECTION 4 – Example:  1A2/X43/S/18/USA/000000

Last 2 digits of year of manufacture

SECTION 5 – Example:  1A2/X43/S/18/USA/000000

The letters USA indicate that the packaging is manufactured and marked in the United States

SECTION 6 – Example 1A2/X43/S/18/USA/000000

Manufacturer’s Symbol as registered with the Associate Administrator

DOT 7A Markings

DOT 7A Markings are required on containers for packaging and transportation of Class 7 materials under specific limits outlined in the regulation.  With respect to the drum manufacturer some of the differences required for these drums area:

The outside of these drums will incorporate features that allow for tamper evident seals.

They will also have a containment system that is securely closed by a positive fastening device that cannot be opened unintentionally or by pressure that may arise within the package during normal transport.

The regulations for shipping Class 7 materials are complex and several agencies have input for their area of expertise.  It is recommended that shippers get expert advice to assure that they are in compliance.