UN Ratings for IBC Containers: Decoding the Markings

Every IBC tote manufactured for the transport of regulated materials carries a UN certification marking — a coded string of letters, numbers, and symbols that tells you everything you need to know about that container's design, capabilities, and approved uses. Understanding these markings is essential for regulatory compliance, safe handling, and informed purchasing decisions. Yet for many people in the industry, the UN marking on their IBC totes is an inscrutable line of characters that they know is important but cannot actually read. This guide decodes the UN rating system for IBC containers, explaining each element of the marking, the IBC type classification system, packing group designations, and how these markings affect your ability to use a container for specific products.

The Structure of a UN Marking

A typical UN marking on an IBC tote looks something like this:

This string contains seven distinct data elements, each separated by a slash. Every element provides specific information about the container's design, performance rating, manufacturing origin, and approved capacity. Let us decode each element systematically.

Element 1: UN Symbol

The marking begins with "UN" (or the UN emblem, a circle enclosing "un"), which indicates that the container has been manufactured and tested in accordance with the United Nations Recommendations on the Transport of Dangerous Goods — Model Regulations. This is the international standard adopted by regulatory authorities worldwide, including the U.S. DOT under 49 CFR. Only containers that have passed the required type tests and are produced under a certified quality assurance program may bear the UN marking. The presence of "UN" on a container is your assurance that it meets internationally recognized performance standards.

Element 2: IBC Type Code (31HA1)

The type code is the most information-dense element of the UN marking. For our example, "31HA1" breaks down as follows:

• 31 = Rigid IBC designed for liquids (code 31 indicates a rigid IBC for liquids with a maximum capacity not exceeding 3,000 liters)
• H = The inner receptacle material. H designates plastic (specifically HDPE for most IBCs). Other codes: A = steel, B = aluminum, D = plywood, F = reconstituted wood, G = fiberboard, N = other metal
• A = The outer caging or body material. A designates steel. For composite IBCs, this refers to the cage/frame material surrounding the inner plastic receptacle
• 1 = The category within the type. For composite IBCs: 1 = rigid plastic inner with structural outer (cage); 2 = rigid plastic inner with structural outer forming the container

So "31HA1" means: a rigid IBC for liquids, with a plastic (HDPE) inner receptacle, in a steel outer cage, category 1. This is by far the most common IBC type in the United States — the standard white HDPE bottle in a galvanized steel cage that most people picture when they think "IBC tote."

Element 3: Packing Group Rating (Y)

The packing group letter indicates the level of hazard that the IBC is certified to contain. The UN system uses three packing groups based on the danger level of the material:

An important rule: a container rated for a higher hazard level is always approved for lower hazard levels. An X-rated IBC can hold PG I, II, or III materials. A Y-rated IBC can hold PG II or III materials. A Z-rated IBC can hold only PG III materials. You can always "over-rate" but never "under-rate." Most standard 31HA1 composite IBCs are rated Y (Packing Group II), which covers the majority of hazardous liquids commonly shipped in IBC totes. Packing Group I materials (the most dangerous) are less commonly shipped in IBCs and often require all-steel (31A) containers.

Element 4: Date of Manufacture (0822)

The date code indicates when the IBC was manufactured. The format is typically MMYY — so "0822" means August 2022. This date is critical for determining the container's age, remaining service life, and retest obligations. Under UN and DOT regulations, composite IBCs (types 31H) have a maximum service life of five years from the date of manufacture for hazardous materials transport. After five years, the IBC may not be filled and offered for transport with dangerous goods, regardless of its physical condition. The 2.5-year periodic retest interval is also calculated from this date (or from the date of the last retest or reconditioning).

Element 5: Country of Manufacture (USA)

This element identifies the country where the IBC was manufactured, using the standard ISO country code or the country name abbreviation. "USA" indicates manufacture in the United States. Other common codes include "D" for Germany, "F" for France, "CN" for China, and "GB" for the United Kingdom. The country code is important because it identifies which national authority approved the design type and which quality assurance standards were applied during manufacturing. IBCs manufactured in different countries are equally valid under the UN system as long as they bear proper UN markings — the system is internationally harmonized.

Element 6: Manufacturer Identification (ACME)

The manufacturer's name, logo, or registration code identifies who produced the IBC. This element provides traceability back to the manufacturing source, which is important for warranty claims, quality issues, and regulatory audits. In some cases, this field may contain a registration number assigned by the national competent authority rather than the company name. Major IBC manufacturers in the United States include Schutz, Mauser (now MAUSER Packaging Solutions), Greif, and Time Technoplast, among others. When purchasing used IBC totes, the manufacturer identification can help you assess the quality and reputation of the container's maker.

Element 7: Stacking Load and Maximum Gross Mass (10200/1200)

The final elements specify the IBC's maximum stacking load in kilograms (the weight that can be placed on top of the container) and the maximum gross mass in kilograms (the maximum combined weight of the container plus its contents). In our example, "10200" means the IBC can support a stacking load of 10,200 kg (22,487 lbs), and "1200" means the maximum gross mass is 1,200 kg (2,646 lbs). The stacking load rating is essential for warehouse storage and transport planning — it determines how many full IBCs can be safely stacked on top of one another. The maximum gross mass determines the heaviest product (by specific gravity) that can be filled to full volume.

Additional Markings: Retest and Reconditioning

In addition to the original manufacturing marking, IBCs may carry additional markings that indicate retesting, reconditioning, or rebottling. After periodic pressure testing, the retest date and testing facility identification are added to the container. After reconditioning (which under UN regulations means restoring the IBC to its original design type and performance standards), the reconditioner adds their identification, the reconditioning date, and the country code. After rebottling (replacing the inner HDPE receptacle), the new bottle carries its own date of manufacture, and the complete UN marking is reapplied. These additional markings provide a history of the container's service life and are essential for determining its current compliance status.

How UN Ratings Affect Your Purchasing Decisions

Understanding UN ratings enables smarter purchasing. When buying reconditioned IBC totes, check the manufacture date to determine remaining service life and retest status. Verify the packing group rating matches your intended contents. Confirm the type code is appropriate for your application (31HA1 for standard liquid storage, 31A for aggressive chemicals). Check the maximum gross mass against the specific gravity of your product to ensure the container is rated for the weight. For hazmat applications, verify that all markings are legible and complete — a container with damaged or illegible UN markings may not legally be used for regulated transport.

The UN rating system may seem complex at first glance, but it is a logical, standardized framework that provides all the information you need to use IBC totes safely and compliantly. By learning to read these markings, you gain the ability to evaluate any IBC tote's suitability for your specific application — a valuable skill for anyone who purchases, uses, or manages IBC containers.