A packing group (PG) is a classification defined by the level of danger presented by a hazardous material being packaged for shipment. There are 3 packing groups for hazardous materials:
- Packing Group I: high danger
- Packing Group II: medium danger
- Packing Group III: low danger
How Packing Groups Are Assigned
Class 3 Flammable Liquids
| PG | Flash Point | Boiling Point |
|---|---|---|
| I | ≤ 95°F | |
| II | ≤ 73°F | > 95°F |
| III | ≥ 73°F but ≤ 141°F | > 95°F |
Class 4 Flammable Solids
Division 4.1 – Flammable Solids
| PG | Substance | Parameters |
|---|---|---|
| II | Readily combustible solids | Burning time must be less than 45 s and the flame passes the wetted zone |
| Powders of metal or metal alloys | If the zone of reaction spreads over the whole length of the sample in 5 min or less | |
| III | Readily combustible solids | Burning time must be less than 45 s and the wetted zone stops flame propagation for 4 min or more |
| Powders of metal | If the reaction spreads over the whole length of the sample in more than 5 min but less than 10 min |
Division 4.2 – Spontaneously Combustible
- PG I: Pyrophoric solids and liquids
- PG II: Self-heating materials with a positive test result when tested using a 25 mm cube sample at 284o F
- PG III: Self-heating materials with a positive test result when tested using a 100 mm cube sample at 2840 F
Division 4.3 – Dangerous When Wet
- PG I: Materials that react vigorously with water at ambient temperatures
- Produces a flammable gas at 10 L per Kg of material or more
- PG II: Materials that react readily with water at ambient temperatures
- Produces 20 L per Kg of flammable gas per kg of materials, but does not meet the requirements for PG I.
- PG III: Materials that react slowly with water at ambient temperature
Class 5 – Oxidizers
Division 5.1 – Oxidizing Substances
- PG I: A material that exceeds an average burning time less than a 3:2 part mixture of potassium bromate and cellulose
- PG II: A material that exceeds an average burning time less than a 2:3 part mixture of potassium bromate and cellulose
- PG III: A material that exceeds an average burning time less than a 3:7 part mixture of potassium bromate and cellulose
Class 6 – Toxic Substances
Each packing group is determined by using a measure of a lethal dose (LD50) in mg absorbed per kilograms of body weight.
| Packing Group | Oral Toxicity | Dermal Toxicity | Inhalation Toxicity |
|---|---|---|---|
| I | < 5 | < 50 | < 0.2 |
| II | > 5 and < 50 | > 50 and < 200 | > 0.2 and < 2 |
| III | > 50 and < 300 | > 200 and < 1,000 | > 2 and < 4 |
Class 8 – Corrosive Substances
- PG I: Materials that destroy full thickness of intact skin tissue within 60 minutes after an exposure that lasted less than 3 minutes.
- PG II: Materials that destroy full thickness of intact skin tissue within 14 days of exposure, lasting at least 3 minutes but less than 60 minutes.
- PG III: Materials that corrode steel or aluminum surfaces exceeding ¼ in per year.
Class 9 – Miscellaneous Dangerous Materials
Class 9 materials have packing groups that are typically listed in the hazardous materials table or should be determined by a hazardous materials specialist or expert.
Leave Packing to the Experts
At Maine Labpack, we are equipped with personnel trained to assess chemicals to properly assign materials with hazmat packing groups. We know that chemicals are not always as straightforward as the guidelines listed above. If you need assistance shipping materials and are unsure how to appropriately assign packing groups, identification numbers, or reportable quantities, contact us today to get help!