UN/DOT Ratings for IBC Totes, Explained

The string of letters and numbers stamped on an IBC data plate looks cryptic, but it is a precise language. Read correctly, a UN marking tells you exactly what the tote is certified to carry and, just as importantly, when that certification expires.

This guide walks through the marking piece by piece so you can tell at a glance whether a tote is legal for your product and still within its testing window.

Breaking down a marking like 31HA1/Y

Consider a common composite tote marked 31HA1. Each element carries meaning, and the sequence follows the UN model regulations that DOT adopts for domestic hazmat transport.

• 3 identifies the container as an IBC
• 1 indicates it is intended for liquids
• H shows the inner receptacle is rigid plastic
• A shows the outer frame is steel, giving the familiar caged composite tote
• The trailing 1 designates the specific IBC type within that family

So a 31HA1 is a composite IBC for liquids with a plastic bottle inside a steel cage. Swap the H for a different code and the inner material changes; swap the A and the outer frame changes. Learning these four positions lets you classify most totes you will ever handle.

Packing groups: X, Y, and Z

After the type code you will usually see a slash and a letter. This letter maps the tote to a Packing Group, which reflects the degree of danger of the goods it is authorized to carry.

1. X approves the tote for Packing Groups I, II, and III, the most hazardous goods
2. Y approves the tote for Packing Groups II and III, medium and low danger
3. Z approves the tote for Packing Group III only, the lowest danger tier

The logic is that a container built to the strictest standard can also carry less dangerous goods, but not the reverse. A Z-rated tote may not legally carry a Packing Group I substance, so you match the letter on the plate to the packing group of your product before you fill.

The dates that quietly disqualify a tote

Even a perfectly rated tote falls out of compliance if it is overdue for testing. UN-approved IBCs used for hazardous liquids require a periodic leakproofness test every 2.5 years and a more thorough inspection every 5 years, with the results and dates recorded on the plate.

If the last recorded retest is older than the required interval, the tote may not be offered for hazmat transport, regardless of how sound it looks. This is one of the most common ways a fleet slips out of compliance without anyone noticing, because the tote itself gives no outward sign.

What to check on the plate before shipping hazmat

• The full UN type code, such as 31HA1, matches the container in front of you
• The packing-group letter X, Y, or Z permits your product
• The stated specific gravity and test pressure cover your liquid
• The 2.5-year and 5-year test dates are current, not expired
• The manufacture date is present and the tote is within any age policy you follow

Keeping totes retested and in compliance also keeps them in service longer, which is central to how we approach reconditioning. A tote that stays legal is a tote that keeps working instead of becoming scrap.