UN packaging markings tell you what the packaging was performance-tested for.
Difference: combination packagings for solids show gross mass; liquid packagings show specific gravity and (usually) hydrostatic test pressure.
Example formats (as on your poster)
Solids / combination packaging example
UN 4G / X3 / S / 19 / USA / LM0000
- 4G = fiberboard box (outer)
- X = PG I performance (also ok for II & III)
- 3 = max gross mass (kg) for that tested configuration
- S = solids or inner packagings (combination packaging)
Liquids packaging example
UN 1A1 / X1.5 / 250 / 19 / USA / LM0000
- 1A1 = steel drum, non-removable head
- X = PG I performance (also ok for II & III)
- 1.5 = max specific gravity (SG) allowed
- 250 = hydrostatic test pressure (kPa) for liquids
1) UN symbol
“UN” confirms the packaging has passed UN performance tests and can be used for regulated DG when used within the marked limits and tested configuration.
2) Packaging identification code (what “4G”, “1A1”, etc. mean)
| Code | Meaning | Practical use |
| 4G | Fiberboard box | Common outer for combination packaging |
| 1A1 | Steel drum, non-removable head | Common for liquid DG |
| 1A2 | Steel drum, removable head | Often for solids or inner packagings |
| 3H1 | Plastic jerrican, non-removable head | Common for liquids (solvents) |
UN packaging code legend (type + material)
| Element |
Code |
Meaning |
| Packaging type | 1 | Drum |
| Packaging type | 2 | Wooden barrel |
| Packaging type | 3 | Jerrican |
| Packaging type | 4 | Box |
| Packaging type | 5 | Bag |
| Packaging type | 6 | Composite packaging |
| Packaging type | 7 | Pressure receptacle |
| Material | A | Steel |
| Material | B | Aluminum |
| Material | C | Natural wood |
| Material | D | Plywood |
| Material | F | Reconstructed wood |
| Material | G | Fiberboard |
| Material | H | Plastic |
| Material | L | Textiles |
| Material | M | Paper, multiwall |
| Material | N | Other metal |
| Material | P | Glass, porcelain, stoneware |
Drums — head type (3rd character)
- 1 = Non-removable head → 1A1
- 2 = Removable head → 1A2
Bags — common codes
- 5M1 = Multiwall bag
- 5M2 = Multiwall, water-resistant
How to read examples:
4G = box (4) made of fiberboard (G).
1A1 = steel drum with non-removable head.
5M2 = water-resistant multiwall bag.
3) Packing group performance level: X / Y / Z
- X = tested to PG I level → acceptable for PG I, II, III (if other limits also met).
- Y = tested to PG II level → acceptable for PG II & III only.
- Z = tested to PG III level → acceptable for PG III only.
4) “Gross mass” vs “Specific gravity”
Solids / combination packaging
- Shows max gross mass (kg) of the complete package as tested.
- Example: X3 means 3 kg max gross mass at PG I test level.
Liquids packaging
- Shows max specific gravity (SG) of the liquid.
- Example: X1.5 means SG ≤ 1.5 at PG I test level.
5) Hydrostatic test pressure (liquids)
For liquid packagings, a number like 250 indicates the hydrostatic pressure test (kPa) the packaging passed for liquids.
6) Year and location of manufacture
- “19” = year of manufacture (last two digits).
- Country code indicates location/approval traceability (e.g., USA, D).
7) Manufacturer / certification mark
Identifies the manufacturer or approval/certification symbol for traceability.
Critical rule: UN packaging approval is for a tested system. Changing closure, inserts, inner arrangement, or exceeding marked limits can invalidate approval.