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How To Test UN-Rated Bulk Bags

By Codefine
, June 9, 2026

Blog, Sustainability and Environmental Impact

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UN FIBC Bags: What Are They?

Performance testing is a standard for any bulk bag. However, UN-certified bulk bags are required to meet far stricter requirements than the average bulk bag. Several tests are required for FIBCs to become UN-approved bags, guaranteeing their suitability for handling dangerous goods and materials in storage and transit.

A UN-certified bulk bag may look largely identical to a standard one. However, they’re generally sturdier in design and are made up of reinforced panels. This robust construction is essential for bulk bags to pass the demanding requirements of righting and topple testing. UN-certified bulk bags also have a higher Safety Factor (SF). Typical FIBCs have a 5:1 SF, which is the industry standard. However, a UN-approved FIBC must have a safety factor of 6:1.

Preparing FIBC Bulk Bags for Testing

To become a UN-certified FIBC, bulk bags must undergo a gamut of rigorous tests. However, consistency counts when assessing FIBC bulk bags. As such, each bag needs to be carefully prepared before testing begins.

Every bag that undergoes testing needs to be filled to at least 95% capacity. What’s more, stored contents need to be distributed evenly within the container itself. Certain tests also need to be carried out using the same material that a bag will ultimately be used to store and transport. In the case of drop testing, an identical material or a non-hazardous alternative with shared properties must be used.

Key Testing Methods

The table below summarises every test an FIBC must pass to carry UN certification, with the parameters and pass criteria for each. Test requirements are set out in Chapter 6.5 of the UN Model Regulations on the Transport of Dangerous Goods, and mirrored in ADR in Europe and 49 CFR Part 178 in the United States. Before any test begins, bags for solid contents are filled to at least 95 per cent of maximum capacity with the contents evenly distributed.

Test	What it measures	Test parameters	Pass criteria	Applies to
Stacking	Resistance to crushing under the weight of bags stacked above it in storage and transit	Filled to safe working load and placed on a level surface. A superimposed load of 1.8 times the combined maximum gross mass of the bags that may be stacked above it is applied for 24 hours.	No leakage of contents and no permanent deformation that would make the bag unsafe for transport	FIBC designs intended to be stacked. Bags not tested for stacking must carry the “do not stack” marking.
Drop	Structural integrity under sudden impact during handling and loading	Dropped onto a rigid, non-resilient, flat surface from a height set by packaging group. The bag is oriented so the most vulnerable part of the base takes the impact. See the drop height table below.	No loss of contents. A slight discharge from a closure on impact, with no further leakage, is not a failure.	All FIBC design types
Righting	Ability to be lifted from a fallen position without the lifting points or fabric failing	The filled bag is laid on its side and lifted to an upright position clear of the floor at a speed of at least 0.1 metres per second. Two-strap bags are lifted by one device, four-strap bags by two.	No damage to the bag or its lifting devices that would make it unsafe for transport	FIBC designs intended to be lifted from the top or the side
Vibration	Endurance of sustained road, rail and sea movement over a long journey	Placed on a vibrating platform for 60 minutes. The frequency is raised until the bag momentarily lifts clear of the platform surface.	No rupture, no leakage and no deterioration that would reduce transport safety	Applicability differs by market. Required for IBC design types under 49 CFR 178.819 in the United States; under the UN Model Regulations the requirement attaches to design types for liquid contents. Confirm scope with your certifying body.
Topple	Integrity when the bag falls over onto its top rather than its base	Filled to safe working load and toppled onto a rigid, non-resilient surface so that the top of the bag strikes the target. Drop height matches the packaging group heights used for the drop test.	No loss of contents	All flexible IBC design types
Tear	Resistance to a puncture spreading into a full rupture	A 100 mm cut is made through one wall at 45 degrees to the principal axis, midway between the base and the top of the contents. A load of twice the maximum gross mass is then applied for at least 5 minutes. Bags designed for lifting are then suspended clear of the floor for a further 5 minutes.	The cut must not propagate by more than 25 per cent of its original length	All flexible IBC design types
Top lift	Strength of the lifting straps, seams and fabric under overload	Filled to safe working load and suspended by its lifting straps. A downward force is applied so the bag carries six times its maximum permissible gross mass, held for 5 minutes.	No damage to the bag or its lifting devices that would make it unsafe for transport or handling	FIBC designs intended to be lifted from the top, which covers most standard configurations

A separate bottom lift test applies to IBC designs intended to be lifted from the base. Most FIBCs are top-lifted, so it is rarely part of the certification route for a standard bulk bag. There is no partial pass: a design type must complete every applicable test successfully to carry UN certification.

Drop Test Heights by Packaging Group

Packaging groups classify substances by the degree of danger they present. The more hazardous the contents, the greater the drop height the packaging must survive.

Packaging group	Hazard level	Drop height	Example materials
Packaging Group I	High danger	1.8 m for IBCs generally. Flexible IBCs are not authorised for Packaging Group I substances, so no FIBC is certified at this level.	Substances presenting a high degree of danger in transport, which must travel in rigid packaging
Packaging Group II	Medium danger	1.2 m	Many oxidising solids, certain flammable solids, and toxic or corrosive solids of medium hazard
Packaging Group III	Low danger	0.8 m	Lower-hazard corrosive and toxic solids, and many environmentally hazardous solid substances

Because flexible IBCs are restricted to Packaging Groups II and III, UN-certified bulk bags are marked either Y, meaning approved for Packaging Groups II and III, or Z, meaning approved for Packaging Group III only. The same heights apply to the topple test. Always confirm that the packaging group on the bag marking covers the substance you intend to ship, because a Z-rated bag cannot legally carry a Packaging Group II material.

FIBC bulk bag testing procedures might seem extensive, but every bag needs to undergo them to become UN certified. Below is a breakdown of every testing protocol an FIBC bulk bag will come up against.

Stack Testing

If FIBCs are going to be stacked, they’ll need to undergo the stacking test to receive UN certification. A bulk bag is first filled to its safe working load capacity and placed on an even surface. Next, pressure is applied to the top of this bag for 24 hours. This pressure is intended to simulate the combined weight of two filled bulk bags of comparable size.

Once the 24 hours have passed, the original bag is inspected to ensure there has been no leakage of material and there is no evidence of structural damage. If the FIBC has endured the strain, it passes the stacking test.

Drop Testing

The drop test is one of the most important testing stages of UN certification. Before being dropped, bags are filled according to the latest UN testing guidelines. All FIBC types are subject to drop testing. The drop itself is fairly self-explanatory, with filled bulk bags dropped from incremental heights.

These heights vary depending on the packaging group being tested. In every case, the drop is oriented so that the most delicate part of the bag impacts the ground. To pass the drop test, the bag must survive the impact intact. Any sign of a rupture or leakage typically rules out an FIBC earning UN certification.

Righting Testing

An FIBC may need to undergo righting testing to receive UN certification, depending on its lifting features. This test applies to any FIBC that needs to be lifted from the side, the top, or both. Testing begins by moving the FIBC to its side. The filled bag is then lifted upright. Next, the bag is lifted at varying speeds.

To pass this test and receive UN certification, a bag with two lifting straps needs to be able to be lifted by a lifting device that has been preapproved. Bags with four lifting straps need to be able to be lifted by two lifting devices to receive UN certification.

Vibration Testing

Another important assessment for UN certification is vibration testing. FIBC bags are placed on a platform that vibrates for a full 60 minutes. During this time, vibration frequencies are raised to such a level that the FIBC itself lifts from the surface of the platform. This is a staple test for UN certification and all FIBCs must pass it to receive approval. For successful certification, FIBCs must show no sign of rupture or leakage after the hour is up.

Topple Testing

Every UN-certified FIBC needs to undergo the topple test before receiving approval. This test involves a bulk bag being toppled from a set height, with the bag positioned on a platform after being filled to its safe working load capacity. As the platform is raised, the bag will eventually topple. For an FIBC to pass this test, it must endure being toppled without losing any of its stored material.

Tear Testing

This is another essential test that applies to any bulk bag looking for UN certification. The tear test involves the wall of the FIBC container being punctured at a specific 45-degree angle. This is done with a knife, with the puncture made around the midpoint of the bag wall. There are actually two stages to the tear test.

Firstly, a tear test is performed with the FIBC filled with a top load that’s twice the safe working load. For a bag to pass this initial test, the FIBC must remain in one piece for a minimum of five minutes after the puncture is made.

The second part of the tear test involves the bag being suspended after a puncture is made. Bags are suspended for a minimum of five minutes. After this time elapses, the condition of the puncture is assessed. If the puncture has grown by more than 25%, it fails the test. If the puncture size has remained largely stable, it earns a pass and receives UN certification.

Top Lift Testing

In this stage of FIBC testing, a bulk bag is filled to its safe working load capacity, before being suspended. A hydraulic cylinder is then used to apply downward pressure to the contents of the bag. If the top lift of the FIBC can withstand six times its safe working load for at least five minutes, it secures UN approval.

Frequently Asked Questions

1. How often do UN-certified bulk bags need to be retested?

UN certification applies to the design and manufacturing specification of a bag, not to individual units over time. However, any bag that has been repaired, modified, or subjected to conditions that may have compromised its integrity should be withdrawn from service rather than retested, as ongoing certification cannot be assumed.

2. What happens if a bag fails one of the UN testing stages?

A failure at any point in the UN certification process means the bag does not qualify for UN approval. The bag design would typically need to be reviewed and improved before retesting. Partial passes do not exist; all required tests must be completed successfully.

3. Does UN certification differ between transport modes such as road, rail, and sea?

The underlying UN testing standards are consistent across packaging types, but specific transport regulations may impose additional requirements depending on the mode. Businesses shipping hazardous materials across multiple transport types should confirm that their certified packaging meets the applicable modal regulations for each leg of the journey.

4. Can third-party suppliers provide UN-certified bags, or must they be tested by the original manufacturer?

UN certification is tied to the specific bag design and manufacturing process, not exclusively to the original manufacturer. However, businesses sourcing UN-certified bags from a supplier should always request valid certification documentation and verify that the bag specification matches what was tested and approved.

5. Are UN-certified bulk bags required for all chemical shipments, or only specific categories?

UN certification is required for packaging used to transport substances classified as dangerous goods under international regulations. Not all chemicals fall into this classification. Businesses should refer to the relevant regulatory framework for their transport route to determine whether their specific materials require UN-certified packaging.

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Remain Compliant with UN-Certified Bulk Bags

If you’re storing or transporting dangerous substances and chemicals regularly, you can’t cut corners when it comes to bulk bags. To adhere to the latest regulations from the United Nations, you’ll need to be using UN-certified FIBCs. Offering a more robust construction and higher safety factor than standard bulk bags, they bring peace of mind that you’re handling hazardous materials safely and securely.

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