Packaging, Containers, and Means of Containment
Packaging, containers, and means of containment
This domain tests selection and condition of packaging. Expect UN specification marks, packing group performance, closure and compatibility, overpacks, and the difference between small and large means of containment.
Core rules
- A means of containment must be suitable for the goods, the mode of transport, and the quantity. It must prevent leakage under normal conditions.
- UN specification packaging is marked with the UN symbol, a code, the packing group performance, and other details. The mark is a performance claim, not a guarantee for every chemical.
- Performance letters: X is tested for PG I, II, and III; Y for PG II and III; Z for PG III only. A higher-rated package may be used for a lower PG, provided it is compatible.
- Closures must be tightened to the manufacturer's specification. Gaskets, liners, and valves must resist the goods. Liquids need sufficient ullage for expansion.
- An overpack must be marked and labelled to show the hazards of the goods inside, unless the inner marks remain visible.
Worked example
A shipper fills a PG II corrosive liquid into a drum marked UN 1A2/Y1.4/150. The Y rating is suitable for PG II. But the drum has a standard nitrile gasket, and the SDS says the product attacks nitrile. The performance mark does not cure chemical incompatibility. The shipper must select a compatible gasket or a different drum; otherwise the package is not suitable even though the UN mark is correct.
Traps
- Treating a UN mark as approval for any contents.
- Using a Z-rated package for PG II because it is new and clean.
- Overfilling a liquid drum with no ullage.
- Reusing a drum that held a different chemical without effective cleaning and mark removal.
- Forgetting that an overpack can hide labels and must carry its own.
Exam focus
Check four things in order: specification rating against PG, material compatibility, closure and condition, and marks. A package can pass one check and fail another.