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IBC Recycle USA
Blog · May 11, 2022 · 6 min read

Understanding UN31HA1/Y: The Stamping on Every Cage

The UN marking on the side of an IBC cage is the regulatory passport for that container. Here is the character-by-character walkthrough — what each part means and why it matters when you receive a reconditioned tank.

RegulationsPost #3 of 34

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Position by position

  • UN — confirms this is a UN-rated container.
  • 31 — IBC code: 31 means "rigid plastics IBC."
  • H — primary material: H is HDPE; A is aluminum; B is steel.
  • A1 — design type: A1 is freestanding (rigid plastics); A2 is composite (rigid plastics inner with structural outer).
  • /Y — packing group: Y indicates Group II/III (X is Group I/II/III).
  • Then date of manufacture (YY).
  • Country code of approval (US).
  • Manufacturer identification code (unique to the producer).

What you should check on intake

That the stamp is legible. That the date and packing group are consistent with the use case. That the manufacturer code is one you can look up. For reconditioned units, also that the most recent requalification date stamp is within the regulatory window (2.5 years for retest).

When the stamp is missing or illegible

A tank with no legible UN stamp cannot be used for hazmat duty under U.S. regulations. It can still be used for non-regulated applications, and many of our Wash-grade and Bottle Tight units fall into this category.

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