UN Specification Marking — Section 6.0.4
IATA DGR Section 6.0.4 — UN marking code anatomy. Every UN-approved packaging has this code legibly printed on its exterior, summarising the packaging type, performance level, test year, and manufacturer in a single line. Packaging without this marking cannot be used for dangerous goods transport.
UN Marking Example — Full Anatomy
UN Symbol
The UN approval symbol indicates that the packaging has passed United Nations performance tests and is certified. Displayed as circled UN letters or capital 'UN'.
Packaging Type Code
The first digit indicates the packaging category, the letter indicates the material type. UN Model Regulations define categories 1-7 and material codes A-P.
Packing Group Performance Level
Indicates the Packing Group level the packaging has been tested for. X is the most stringent, Z the least. A higher-rated letter also covers lower PG levels (X covers PG I+II+III).
Maximum Gross Mass (kg) or Specific Gravity
For solids: Maximum gross mass (kg) the packaging was tested at. For liquids: The specific gravity (density) value the inner packaging was tested at.
Content State
Indicates the physical state of contents the packaging was tested for. Solids and liquids require different test parameters.
Test Year (Last 2 Digits)
The last two digits of the year in which the type approval test was performed. Periodic renewal is mandatory — typically re-tested every 5 years.
Country Code (ISO 3166)
ISO 3166-1 alpha-2 code of the country whose competent authority granted the test approval. The packaging has international validity regardless of the issuing country.
Manufacturer / Testing Body Code
Short code for the manufacturer or testing body. This code is assigned by the competent authority and ensures traceability.
Packaging Category Codes (1-7)
First digit of the UN marking code — packaging physical form
| Code | Definition | Examples |
|---|---|---|
| 1 | Drum | 1A (steel), 1B (aluminium), 1G (fibre), 1H (plastic) |
| 2 | Barrel (wood) | 2C (wood) |
| 3 | Jerrycan | 3A (steel), 3H (plastic) |
| 4 | Box | 4A (steel), 4C (wood), 4D (plywood), 4G (fibreboard) |
| 5 | Bag | 5H (woven plastic), 5M (multiwall paper) |
| 6 | Composite packaging | 6HA (plastic+steel), 6HG (plastic+fibreboard) |
| 7 | Pressure receptacle (gas only) | Cylinders, tubes (DOT/EN standards) |
PG Performance Letter Compatibility Rule
Packaging tested to a more stringent level can be used for less hazardous PG levels. However, the reverse is invalid — Z-rated packaging can never be used for PG II or PG I substances.
| Performance Letter | PG I | PG II | PG III |
|---|---|---|---|
| X | Suitable | Suitable | Suitable |
| Y | Not Suitable | Suitable | Suitable |
| Z | Not Suitable | Not Suitable | Suitable |
UN Marking Verification Checklist
- • UN symbol is legible and not erased
- • Packaging type code matches the PI for the substance being shipped
- • Performance letter (X/Y/Z) meets the substance's PG requirement
- • Gross mass or specific gravity is not exceeded by actual load
- • S/L letter matches the physical state of the contents
- • Test year is not older than 5 years (periodic renewal period)
- • Manufacturer code is readable and traceable
References
- • IATA DGR 67th Ed Section 6.0.4 (UN Specification Marking)
- • UN Model Regulations Rev. 22+ Chapter 6.1 (Orange Book)
- • ISO 3166-1 — Country Codes