Reading the UN plate: 31HA1 and more

Reading 31HA1

The letters after the code, X, Y or Z, show the packing groups the tote is approved for. The plate also states the month and year of manufacture, the country, the maker's mark, the stacking test load and the maximum gross mass.

Why it matters when you buy

The plate is the one document that stays with the tote. It shows how old the tote is, what it was approved for and the load limits. A tote without a legible plate cannot be sold into hazmat service, and we grade it accordingly. See 49 CFR 178.703 for the marking rule.

• Look for a clear month and year.
• Note the stacking load.
• Check the maximum gross mass.
• Look for retest and inspection marks added later.
• Photograph it before you buy.

Retest marks

After the original plate, the tote may carry marks for later tests and inspections. Under 49 CFR 180.352, these show the date and the person who did them. A plate with no later mark on an old tote means it is overdue or was never retested.

If the plate is missing

A missing or unreadable plate is a reason to downgrade the tote. For non-regulated uses, such as rain or irrigation, it matters less. For anything shipped as a regulated product, it matters a great deal.

In South Florida

A tote that came off a ship at the Port of Miami or a truck from Port Everglades usually carries a clear plate with a recent manufacture date. A tote that has circulated for years, moved between warehouses and weathered in a yard may have a faded or painted-over plate. Wipe it with a damp cloth and photograph it in raking light; embossed letters often show when ink has faded.

Dates, tare and the stacking figure

Three numbers on a plate are worth a second look. The month and year of manufacture tell you the age of the bottle and set the clock on the first retest. The tare mass, the weight of the empty tote, lets you work out the liquid inside by weighing a full one on a scale. The stacking test load, given in kilograms, is the weight the tote was tested to carry on top of it; divide by the weight of a full tote above to see how many may be stacked, and then halve it for a wet, uneven yard. If the figure is missing or scratched, treat the tote as unrated for stacking.

Common misreadings

People read 31HA1 as a size, a grade or a brand. It is none of those. It describes construction and approval only. People also read the manufacture date as the date of last use. It is the date of manufacture, nothing more. A plate that looks new may belong to a bottle that was filled with many products.