Definition
An overpack is an enclosure used by a single shipper to contain one or more packages and form one unit for handling and stowage. Typical examples are packages stacked on a pallet and shrink-wrapped or strapped together, or several boxes placed inside a larger box or crate.
Overpack vs. outer packaging
An outer packaging is part of a combination packaging and is what protects the inner containers. An overpack is different: it holds complete packages that already meet the packaging requirements. Using an overpack does not replace those requirements. Every package inside must still be properly packed, marked and labeled.
Marking an overpack
- If the required markings and labels on the packages inside are clearly visible through the overpack, they do not need to be repeated.
- If they are not visible, the overpack must be marked "OVERPACK" and show the markings and labels required for each package inside.
- Where a package inside needs orientation arrows, the overpack generally must show them as well.
Paperwork
The shipping paper or dangerous goods declaration must still describe each dangerous good inside, and for air shipments it must indicate that an overpack is used.
Things to watch
- Do not combine materials that are forbidden from being packed together.
- Make sure the overpack is strong enough that the packages stay secure and upright during handling.
- Check that total quantity limits for the mode of transport are not exceeded by the combined contents.
- Some materials, such as radioactive materials, have their own overpack rules.