The rigid plastic IBC with its own frame: what the code means and why most caged totes are 31HA1 instead.
UN 31H1 is the packaging code for a rigid plastic intermediate bulk container for liquids, fitted with structural equipment designed to carry the whole load when IBCs are stacked. It holds up to 3,000 litres and carries packing group II and III liquids.
Decode a full 31H1 mark Ask for 31H1 containers
| Character | Meaning |
|---|---|
31 | IBC for liquids, rigid or composite |
H | Plastics |
1 | Fitted with structural equipment that carries the stacking load |
| Maximum capacity | 3,000 litres (1.2.1) |
|---|---|
| Maximum gross mass | Set per design and printed at the end of the mark |
The last two figures on an IBC mark are the stacking test load and the maximum permissible gross mass, both in kilograms.
Liquids of packing groups II and III, under packing instructions IBC02 and IBC03, with a performance level of Y or Z. The body is plastic of known specification; recycled plastic is allowed when marked REC. The rigid plastic body cannot be repaired: a damaged body is replaced.
| Test | What the design has to survive | Paragraph |
|---|---|---|
| Vibration | Filled with water and vibrated for an hour without leaking or breaking a weld. | 6.5.6.13 |
| Lifting | Bottom lift at 1.25 times its maximum gross mass; top lift at twice it. | 6.5.6.4, 6.5.6.5 |
| Stacking | Carries 1.8 times the gross mass of the IBCs that may stand on it, for 24 hours. | 6.5.6.6 |
| Leakproofness | Air at 20 kPa for at least 10 minutes, with no leak. | 6.5.6.7 |
| Hydraulic pressure | At least 10 minutes at the higher of the vapour-pressure figure and twice the static pressure of the contents. | 6.5.6.8 |
| Drop | Dropped on the most vulnerable part of its base from 1.2 m for packing group II or 0.8 m for III, without losing contents. | 6.5.6.9 |
Five years from the date of manufacture for dangerous goods, unless the competent authority approves otherwise (4.1.1.15). On top of that, the IBC is inspected before service and at most every five years, and checked externally with a leakproofness test at most every two and a half years. An IBC past its test date may not be filled; one filled before the date may travel for three months after it (6.5.4.4, 4.1.2.2). Our IBC inspection date checker works out the dates from the mark and the plate.
31HA1 is a composite: a plastic inner receptacle that depends on a steel casing. Most caged 1,000-litre totes are 31HA1, not 31H1. 31H2 is a freestanding rigid plastic IBC without structural equipment, and its stacking test runs 28 days at 40 °C.
UN 31H1/Y/04 25/GB/9099/10800/1200A plastic IBC, approved for packing groups II and III, up to 1200 kg gross, made in 04/2025, design approved in the United Kingdom.
| Part | On the mark | What it means |
|---|---|---|
| Packaging code | 31H1 | Plastic IBC (31 = IBC for liquids, H = plastic) |
| Performance level | Y | Approved for packing groups II and III (medium and low danger) |
| Month and year of manufacture | 04 25 | Made in 04/2025 |
| Approving country | GB | Design approved in the United Kingdom |
| Manufacturer or approval number | 9099 | Identifies the manufacturer or the approved design, as set by the approving authority |
| Stacking test load | 10800 | The load applied in its stacking test, 10800 kg |
| Maximum permissible gross mass | 1200 | 1200 kg, the heaviest the filled IBC may weigh |
IBC marks follow their own layout (UN Model Regulations 6.5.2). A stacking test load of 0 means the IBC is not designed to be stacked.
Another 31H1 mark, decoded: UN 31H1/Y/06 25/NL/VL836/2160/1200
We do not make this type of packaging. Send the contents and we will source a certified design.
31H1 is a rigid plastic IBC whose own body holds the liquid, with structural equipment to carry the stack. 31HA1 is a composite: a plastic inner receptacle inside a steel casing, the usual caged tote.
Not its body. The rigid plastic body of a 31H1 cannot be repaired; a damaged body is replaced.
The standards and regulations this page relies on, at their issuing body. Where a market rule is named here, check the current revision before you specify against it.
Checked against the UN Model Regulations, Rev. 24, and ADR 2025 on 5 October 2026. Decode any other mark with our UN packaging code decoder.
Send what goes in them, the size and where they ship. We reply with the design certified to this code, the plant named on its certificate, and a price.