UN Packaging Codes: How to Read UN Codes


International Packaging Regulations:

The basis of all national and international regulations for the safe transport of dangerous goods is the UN Recommendations of the Transport of Dangerous Goods of the "UN Committee of Experts" as published in "The Orange Book".  There are five different (relevant) Modal Authorities who each publish their own regulation manuals in which they follow "The Orange Book". These are the:

The Technical Instructions for the Safe Transport of Dangerous Goods by Air published by the International Civil Aviation Authority (ICAO).

The International Maritime Dangerous Goods Code (IMDG) published by the International Maritime Organisation (IMO).

The European Agreement concerning the International Carriage of Dangerous Goods by Road (ADR) published by The United Nations Economic Commission for Europe (UNECE).

The International Agreement for the Carriage of Dangerous Goods by Rail (RID) published by The Intergovernmental Organisation for International Carriage by Rail (OTIF).

The Hazardous Materials Regulations (HMR) (Title 49 CFR Parts 100-185) published by The Office of Hazardous Materials Safety, US DOT.

The UN Marking System

The U.N. marking system indicates several characteristics of the packaging, as well as information on the test levels the packaging has successfully passed. Because these test levels are related to the hazard level and physical and chemical characteristics of the substance to be filled, the markings also indicate some of the properties of the materials that may be packed in each container. 

A sample UN Marking:  1H2 / Y1.8 / 100 / 2012 / F / DB / 1195


The United Nations Coding System


Type of Container

  1. 1 = Drums/Pails
  2. 2 = (Reserved, formerly Barrels)
  3. 3 = Jerricans
  4. 4 = Boxes
  5. 5 = Bags
  6. 6 = Composite Packaging
  7. 7 = (Reserved, formerly Pressure receptacle)


Material of Construction

Steel = A

Aluminum = B

Natural wood = C

Plywood = D

Reconstituted wood = F

Fibre = G

Plastic = H

Paper = M

Metal (Other than steel or aluminum)= N

Glass = P


Category Within Type

1.    Closedhead (non-removable lid)

2.    Openhead (open-top removable lid)


Packaging Group for which container was tested

X.    for Packaging Group I, II, III

Y.     for Packaging Group II and III

Z.    for Packaging Group III

Packaging Group I: Great Danger - high hazard level
Packaging Group II: Medium Danger - medium hazard level
Packaging Group III: Minor Danger - low hazard level


Density (relative density) or specific gravity of material packed
For packaging intended for Solids (powders, pills, capsules, tablets) or that have inner packaging, this marking will indicate the maximum gross mass (weight) in kilograms.


Hydraulic pressure (vapour pressure) in kilo-Pascal (100 kPa = 1 bar)
For packaging intended for Solids or that have inner packaging, an "S" in upper case will follow the gross mass.


Year of production (2012)


Country where container was manufactured


Code for manufacturing plant


Reference of UN homologation report