Reference
31HA1/Y/0426
USA/M1234
That string on the plate riveted to your cage tells you what the container is, what it is approved to carry, when it was built and who built it. Here is how to read every field of it.
The short answer
A composite IBC's UN marking breaks into five parts: the design type (31HA1 — composite IBC, plastic inner, steel outer, for liquids), the packing group (X, Y or Z), the build date, the country of approval, and the manufacturer or approval code. The marking does not expire, but the individual container needs leakproofness retesting every 2.5 years and full requalification every 5.
From the yard
Anatomy of a marking
Field by field
| Field | Example | Meaning |
|---|---|---|
| UN symbol | u / n in a circle | Certifies the packaging meets UN performance standards |
| Type — first digits | 31 | 31 = composite IBC for liquids; 11 = for solids, discharged by gravity; 21 = for solids, under pressure |
| Inner receptacle material | H | H = plastic. The bottle. |
| Outer casing material | A | A = steel. The cage. (B = aluminium, N = other metal, H = plastic, D = plywood, G = fibreboard) |
| Category digit | 1 | Designed for liquids under the pressure conditions of the standard |
| Packing group | Y | X = PG I, II, III · Y = PG II, III · Z = PG III only |
| Test pressure / stacking | e.g. 100 | Hydraulic test pressure in kPa, and stacking load where marked |
| Build date | 04 26 | Month and year of manufacture. Drives retest scheduling. |
| Country of approval | USA | State that issued the design type approval |
| Manufacturer / approval code | M1234 | Identifies the manufacturer or the approval holder |
| Maximum gross mass | e.g. 1250 | Kilograms, container plus contents |
| Capacity | e.g. 1040 L | Nominal capacity in litres |
Codes
The material letters
| Letter | Material |
|---|---|
| A | Steel (all types, all surface treatments) |
| B | Aluminium |
| C | Natural wood |
| D | Plywood |
| F | Reconstituted wood |
| G | Fibreboard |
| H | Plastic material |
| L | Textile |
| M | Paper, multi-wall |
| N | Metal other than steel or aluminium |
Codes
The type numbers
| Code | Type |
|---|---|
| 11 | Rigid IBC for solids, filled or discharged by gravity |
| 21 | Rigid IBC for solids, filled or discharged under pressure |
| 31 | Rigid IBC for liquids |
| 13 | Flexible IBC for solids, gravity discharge |
| 31HA1 | Composite IBC, plastic inner, steel outer, for liquids |
| 31HZ1 | Composite IBC, plastic inner, other outer, for liquids |
| 31A | Metal IBC for liquids |
| 31H1 | Rigid plastic IBC with structural equipment, for liquids |
Retest
The part that catches people out
The design type approval does not expire. The individual container's authorisation to carry regulated product absolutely does.
| Interval | Requirement | What it covers |
|---|---|---|
| Every 2.5 years | Leakproofness test and external inspection | Container integrity, service equipment condition, marking legibility |
| Every 5 years | Full requalification | Leakproofness plus internal and external inspection and, where applicable, structural verification |
| After repair | Retest before return to service | Any repair affecting the containment boundary or structural equipment |
| Ongoing | Marking of test date | The date of the most recent test must be marked on the container |
The full DOT and UN compliance guide, including who is responsible for what →
What a plate does and does not prove
A UN marking on a container proves that the design type was tested and approved. It does not, on its own, prove that this particular container is currently authorised to carry regulated product.
Three things have to be true simultaneously: the marking is genuine and legible, the container is within its retest window with the test date marked, and any repair or reconditioning was performed by a facility registered to do it.
This is where a great deal of used-container selling becomes dishonest. A rusty cage with a legible plate from a yard that has never held a reconditioner registration is not a compliant container. It is a container with a plate on it.
Ask three questions
- Are you a registered reconditioner, and what is your registration number?
- What is the last test date marked on the container, and can I see the record?
- What repairs were performed, and were they retested afterwards?
A seller who can answer all three is selling you compliance. A seller who cannot is selling you risk that lands on you, because as the offeror you carry the legal responsibility for the shipment.
What we do
We supply UN-marked units where the marking is valid and the retest is current, primarily through rebottling, where the requalification is handled as part of the job. Where we sell general used stock, we describe it as used stock and do not imply a compliance status it does not have.
If you are not shipping regulated product
None of this applies to you. Storing water, fertilizer or non-regulated chemistry on your own site does not require a UN-marked container at all, and paying for one is money you could spend on a better valve. Compliance matters when the tote moves on a public road with regulated product in it.
Questions people actually ask
+What does 31HA1 mean?
+What does the Y mean?
+How long is a UN marking valid?
+Does a used tote with a UN plate mean it's compliant?
Quick reference
Numbers worth having open in another tab
The figures that come up in almost every conversation, whichever page you arrived on.
275 gallon · 1040 L
48×40×46
- Tare
- 130 lb
- Gross, water
- 2,425 lb
- Stack full
- 2 high
- Stock
- Always in stock
330 gallon · 1250 L
48×40×53
- Tare
- 160 lb
- Gross, water
- 2,915 lb
- Stack full
- 2 high
- Stock
- Always in stock
264 gallon · 1000 L
48×40×46
- Tare
- 125 lb
- Gross, water
- 2,325 lb
- Stack full
- 2 high
- Stock
- Usually in stock
350 gallon · 1325 L
48×40×56
- Tare
- 175 lb
- Gross, water
- 3,095 lb
- Stack full
- 2 high
- Stock
- Order in
From the yard notes
Longer reading on this
32 articles written by the people who wash, grade, weld and dispatch. No marketing copy in any of them.
- Reconditioning · March 15, 2022 · 3 minWhen to Rebottle Instead of WashingReplacing fifty pounds of the container to save ninety. The single highest-leverage thing this industry does.
- Texas · March 6, 2024 · 3 minRainwater Harvesting That Survives a Texas SummerAlmost every disappointing rainwater system was sized against annual rainfall. The constraint is the gap between storms.
- Logistics · June 16, 2022 · 3 minWhat a Flatbed Load of Totes Teaches You About SecurementTwo rows of ten, stringers fore and aft, strapped over the cage rail. Everything else is a way to fold a cage.
On the yard this week
More answers
While you're here
Pulled from the full FAQ, which runs to forty-plus answers across buying, grades, food safety, sizes, selling, compliance, delivery and care.
- Where we are
- 3505 Montopolis Dr, Austin, TX 78744
- Yard hours
- Mon–Thu 7:30a–5p · Fri 7:30a–4p · Sat 8a–12p · Sun closed (Central Time)
- Coverage
- 68 Texas counties on scheduled routes, from one Austin yard.
+How high can I stack totes?
+What thread is the outlet?
+How many totes fit on a truck?
+How much does a full 275 gallon tote weigh?
+What are standard IBC tote dimensions?
Tell us the packing group.
If you're shipping regulated product, the packing group and the material decide which units we can supply. Send it with your request and we'll quote units with valid marking and current retest.