UN31A is the United Nations packaging classification for a rigid intermediate bulk container made of plastic for liquids. If a tote has a valid UN31A marking and the right ancillary data plate, it is cleared to ship most non-hazardous and some hazardous liquids in the United States, Canada, and most international corridors. Without that marking, the tote ships only as a non-regulated empty or under local exemptions.
What the test actually involves
The full UN31A approval cycle for a new tote includes, at minimum, these challenges:
- Drop test: loaded to capacity, dropped on a diagonal from a specified height (1.2 m for Packing Group II).
- Stacking test: held under a load equal to 1.8 times the stacked mass for 28 days.
- Leakproofness test: held at an air pressure of 20 kPa for ten minutes.
- Hydrostatic pressure test: held at 100 kPa for ten minutes (Packing Group II).
- Vibration test: on a standard platform for one hour.
For a refurbished tote the cycle is abbreviated but still meaningful. We run a leakproofness test on every rebottled unit and a random selection for hydrostatic.
The renewal schedule
A UN31A tote in active service should be retested every 2.5 years for leakproofness and every 5 years for full certification, measured from the original manufacture date stamped on the data plate. Most totes in commercial circulation in the US are within a 12-year window of original manufacture.
How to spot a counterfeit sticker
We see about one or two fake UN31A markings a month. They show up on totes that were re-sold outside the normal regulated supply chain. Tells:
- Missing the original manufacturer's code (a three-letter assigned designation).
- Missing the country-of-approval code (usually /USA/).
- Sticker applied over weathered HDPE with adhesive that looks newer than the tote underneath.
- Serial number that doesn't match the embossed number on the cage corner.
- No ancillary data plate with the actual test date.