14.4 Packing Group
Packing groups are used in dangerous goods transport to indicate the degree of danger presented by a material. This section explains what packing groups are, how they're assigned, and their impact on packaging, documentation, and handling requirements.
What is a Packing Group?
A packing group (PG) is a designation assigned to dangerous goods (except for Classes 1, 2, 6.2, and 7) that indicates the degree of danger and determines the packaging requirements for safe transport. Packing groups are essential for selecting appropriate packaging, determining quantity limitations, and establishing handling procedures.
There are three packing groups, which represent different levels of danger:
Packing Group I
High Danger
Materials presenting high danger or severe hazard in transport.
- Requires the most stringent packaging
- Strictest quantity limitations
- Most extensive testing requirements
Packing Group II
Medium Danger
Materials presenting medium danger or significant hazard in transport.
- Intermediate packaging requirements
- Moderate quantity limitations
- Standard testing requirements
Packing Group III
Low Danger
Materials presenting low danger or minor hazard in transport.
- Less stringent packaging requirements
- Larger quantity allowances
- Reduced testing requirements
Important for SDS compliance: Section 14.4 of a Safety Data Sheet must specify the packing group (if assigned) for any material classified as dangerous for transport. If no packing group is assigned, this should be stated. Omitting applicable packing group information could lead to non-compliance with regulations and potentially unsafe transport conditions.
Hazard Classes That Use Packing Groups
Not all dangerous goods are assigned a packing group. The following classes use packing groups:
Classes Using Packing Groups
- Class 3 - Flammable Liquids
- Class 4 - Flammable Solids
- Class 5 - Oxidizing Substances
- Class 6.1 - Toxic Substances
- Class 8 - Corrosive Substances
- Class 9 - Miscellaneous (some entries)
Classes Not Using Packing Groups
- Class 1 - Explosives (use compatibility groups)
- Class 2 - Gases (use divisions only)
- Class 6.2 - Infectious Substances (use categories)
- Class 7 - Radioactive Materials (use categories)
- Some Class 9 materials (have specific provisions)
How Packing Groups Are Assigned
Packing groups are assigned based on specific criteria for each hazard class. Here are some examples:
| Hazard Class | Packing Group I | Packing Group II | Packing Group III |
|---|---|---|---|
| Class 3 Flammable Liquids |
Flash point < 23°C Initial boiling point ≤ 35°C |
Flash point < 23°C Initial boiling point > 35°C |
Flash point ≥ 23°C and ≤ 60°C Initial boiling point > 35°C |
| Class 6.1 Toxic Substances (Oral) |
LD₅₀ ≤ 5 mg/kg | LD₅₀ > 5 and ≤ 50 mg/kg | LD₅₀ > 50 and ≤ 300 mg/kg |
| Class 8 Corrosive Substances |
Destruction of intact skin within 60 min | Destruction of intact skin within 60 min to 4 hours | Destruction of intact skin within 4 hours to 14 days |
The criteria mentioned above are simplified. The actual assignment of packing groups involves comprehensive testing according to specified methods in the relevant transport regulations.
Examples of Substances with Their Packing Groups
| UN Number | Proper Shipping Name | Hazard Class | Packing Group |
|---|---|---|---|
| UN 1090 | ACETONE | 3 | PG II |
| UN 1830 | SULFURIC ACID with more than 51% acid | 8 | PG II |
| UN 1170 | ETHANOL | 3 | PG II |
| UN 1193 | METHYL ETHYL KETONE | 3 | PG II |
| UN 1950 | AEROSOLS | 2.1/2.2 | Not applicable |
| UN 1052 | HYDROGEN FLUORIDE, ANHYDROUS | 8 (6.1) | PG I |
| UN 1202 | DIESEL FUEL | 3 | PG III |
Impact of Packing Groups on Transport Requirements:
- Determines the type, design, and testing requirements for packaging
- Affects quantity limitations per package, especially for air transport
- Influences limited quantity provisions and excepted quantity allowances
- May determine whether dangerous goods can be transported on passenger aircraft
- Affects documentation requirements and emergency response procedures
- Influences segregation and stowage requirements for marine transport
Packaging Requirements Based on Packing Groups
The packing group directly determines the packaging performance level required:
Packing Group I
Performance Level: X
Packagings must meet the highest performance standards, suitable for substances in all packing groups.
Example Marking: UN 4G/X20/S/22/USA/ABC
Packing Group II
Performance Level: Y
Packagings must meet medium performance standards, suitable for substances in PG II and III.
Example Marking: UN 1A1/Y1.4/150/22/NL/VL824
Packing Group III
Performance Level: Z
Packagings must meet lower performance standards, suitable only for substances in PG III.
Example Marking: UN 3H1/Z/APR22/USA/+xyz
Common Mistakes with Packing Groups
- Using incorrect packing group: This can lead to insufficient packaging and unsafe transport conditions
- Omitting packing group information: Results in incomplete transport documentation
- Confusing GHS categories with packing groups: These are different systems with different criteria
- Using packaging not rated for the required packing group: For example, using PG III packaging (Z) for a PG II material
- Not updating packing group when formulation changes: Changes in composition can affect the packing group assignment
Special Cases and Exceptions
Limited Quantities
Materials packed in limited quantities may have reduced packaging requirements, but the maximum quantity allowed per inner packaging depends on the packing group:
- PG I: Often not eligible for limited quantity provisions
- PG II: Smaller allowed quantities (e.g., 1 L for flammable liquids)
- PG III: Larger allowed quantities (e.g., 5 L for flammable liquids)
Excepted Quantities
Very small amounts of certain dangerous goods may be transported as excepted quantities, with simplified requirements:
- PG I: Either not permitted or extremely small quantities (e.g., code E0 or E1)
- PG II: Small quantities permitted (e.g., code E2)
- PG III: Larger quantities permitted (e.g., code E1)
View excepted quantity codes
Properly Completing Section 14.4 of an SDS
For a flammable liquid (acetone) with Packing Group II:
Correct format:
14.4 Packing group
- ADR/RID: II
- IMDG: II
- IATA: II
For materials without a packing group:
14.4 Packing group
- ADR/RID: Not applicable
- IMDG: Not applicable
- IATA: Not applicable
For non-dangerous goods:
14.4 Packing group
Not applicable
Best Practice: When preparing a Safety Data Sheet, always check the current edition of the applicable transport regulations to confirm the correct packing group assignment. For borderline cases or mixtures, laboratory testing according to the methods prescribed in the regulations may be necessary to determine the appropriate packing group.
Excepted Quantity Codes
Excepted quantities allow very small amounts of dangerous goods to be transported with minimal regulatory requirements. Each dangerous good is assigned an E-code based on its hazard class and packing group.
| Code | Maximum quantity per inner packaging | Maximum quantity per outer packaging |
|---|---|---|
| E0 | Not permitted as Excepted Quantity | Not permitted as Excepted Quantity |
| E1 | 30g / 30mL | 1kg / 1L |
| E2 | 30g / 30mL | 500g / 500mL |
| E3 | 30g / 30mL | 300g / 300mL |
| E4 | 1g / 1mL | 500g / 500mL |
| E5 | 1g / 1mL | 300g / 300mL |
Excepted Quantity Assignment Examples:
- Many Packing Group I substances: E0 (not permitted)
- Flammable liquids (Class 3), PG II: E2
- Flammable liquids (Class 3), PG III: E1
- Toxic substances (Class 6.1), PG I, inhalation: E0
- Toxic substances (Class 6.1), PG I, oral/dermal: E5
- Corrosive substances (Class 8), PG I: E0
- Corrosive substances (Class 8), PG II: E2
- Corrosive substances (Class 8), PG III: E1
Excepted quantity shipments must still comply with specific requirements including packaging testing, marking, documentation, and training.
