A bulk bag that looks right can still be the wrong bag. Two FIBCs with the same body size, the same lifting loops and the same printed “safe working load” may differ in fabric weight, stitching, the test they passed and whether they may be used near flammable dust at all. The factory that fills the bag usually finds out at the worst moment: on a crane hook, at a customer’s silo, or when a dangerous-goods consignment is refused.

This guide is for plants, traders and logistics teams buying flexible intermediate bulk containers (FIBCs, also called jumbo bags or big bags) from manufacturers in Vietnam and elsewhere in Asia. It covers how to write the specification, which standard each requirement comes from, and what documents to collect before the first order.

💬 Buying FIBCs for powders, granules or dangerous goods? Send us your product, fill weight, filling and discharge method and destination, and we will find bag makers in Asia that match. Tell us about your bags.

Start from the product and the handling, not the bag size

Write down what goes in, how it is filled, lifted, stored and discharged, and whether the product or the area around it is flammable; the bag design follows from those answers.

A supplier cannot design a bag from “1-tonne jumbo bag, white”. The facts that decide the design are:

  • Product: name, bulk density, particle size, temperature at filling, moisture sensitivity, and whether it is classified as dangerous goods for transport.
  • Fill weight: the maximum mass you will put in one bag, not the average.
  • Filling: open top, filling spout (with diameter and length), or a duffle top.
  • Discharge: flat bottom, discharge spout, or full-open bottom.
  • Lifting: by forklift tines through loops, by crane hook, by a lifting frame; number of loops and whether loops are cross-corner or side-seam.
  • Atmosphere: whether the product is a combustible powder, whether solvents or flammable gas may be present where the bag is filled or emptied.
  • Storage and transport: stacked or single-tier, indoors or outdoors, by truck, container or bulk vessel.
  • Contact: food, feed, pharmaceutical or general industrial use.

This list is also what lets you compare quotations. Two quotes that answer it differently are for different bags, whatever the price says.

Safe working load and ISO 21898

For non-dangerous goods, ISO 21898:2024 is the international standard that sets materials, design, type-test and marking requirements for FIBCs; ask for the bag’s safe working load, the use it was tested for and the type-test report against that standard.

ISO 21898:2024, Packaging — Flexible intermediate bulk containers (FIBCs) for non-dangerous goods, is the second edition, published in August 2024. It replaced ISO 21898:2004. According to ISO’s abstract, it specifies materials, construction and design requirements, type test and marking requirements for FIBCs intended to contain non-dangerous solid materials in powder, granular or paste form and designed to be lifted from above by integral or detachable devices. It also gives guidance on the selection and safe use of FIBCs.

Three practical consequences follow:

  • Safe working load (SWL) is the maximum mass the bag is designed to carry in use. Ask for it on the drawing and on the bag’s label, and keep your maximum fill weight at or below it.
  • The type test proves the design, not each bag. A test report applies to a defined design: fabric, coating, loops, stitching, dimensions. If the maker changes any of those, the old report no longer covers the bag. Ask the maker to state that the bag you receive is the tested design, and to tell you if anything changes.
  • Single use or reuse. A bag designed and tested for one trip should not be refilled. If you plan to reuse bags, say so at enquiry, because the design and test basis differ.

Ask for the edition of ISO 21898 the report refers to. A report against the 2004 edition is not wrong in itself, but you should know which version the bag was tested under.

Specification lineWhat to writeWhy it matters
BodyDimensions, U-panel or circular woven, fabric weight, coated or uncoatedStrength, sift-proofing, moisture
Top and bottomSpout sizes, duffle or open, flat or spout bottomFits your filling and discharge equipment
LoopsNumber, length, position, colourFits your forklift or hook
LinerMaterial, thickness, form-fit or looseMoisture, contamination, static behaviour
Safe working loadMaximum mass in kgBasis of the type test
StandardISO 21898:2024, or the UN code for dangerous goodsDefines the test and the marking
Static typeType per IEC 61340-4-4 where relevantSafe use near flammable atmospheres
DocumentsType-test report, label sample, declarations for food contactLets you prove compliance later

Static: types under IEC 61340-4-4

If the product is a combustible powder or the bag is filled or emptied where flammable gas or vapour may be present, specify an FIBC type classified under IEC 61340-4-4 and follow its rules for safe use, including earthing where the type requires it.

Filling and emptying powders generates static electricity. In the wrong atmosphere a discharge from the bag can ignite dust or vapour. The international standard for this risk is IEC 61340-4-4:2018, Electrostatics — Part 4-4: Standard test methods for specific applications — Electrostatic classification of flexible intermediate bulk containers (FIBC). According to the IEC, it applies to FIBCs between 0.25 m³ and 3 m³ intended for use in hazardous explosive atmospheres, whether the atmosphere is created by the contents or exists outside the FIBC. It covers classification and labelling of FIBCs, classification of inner liners, test methods, design and performance requirements, safe use in the different hazardous zones, and type qualification and certification.

FIBCs are classified by lettered types. The 2018 edition, for example, raised the maximum resistance-to-ground limit for Type C FIBCs and revised the classification of inner liners. The point for a buyer is that a liner can change the electrostatic behaviour of the whole bag, so classify the bag and liner together.

What to do:

  • Ask your process-safety team or consultant which type is acceptable for your product and zone. Do not let the bag supplier make that decision for you.
  • Ask the maker for the IEC 61340-4-4 type-qualification report for the exact design, including the liner if one is used.
  • Check the label: the standard requires classification and labelling, and the 2018 edition added a labelling reference to IEC TS 60079-32-1 for earthing guidance.
  • If the type you use must be earthed, the earthing point on the bag and the earthing procedure at your filling station are part of the system. A correct bag used without earthing is not a safe system.

💬 Not sure which FIBC type your plant has approved? Send us the type, the zone and the product. We will collect the type-qualification reports from the makers we approach and compare them line by line with you. Ask about static-safe bags.

Dangerous goods: UN-coded flexible IBCs

If the product is classified as dangerous goods for transport, it must travel in a UN-marked flexible IBC of a type approved for that substance; an ISO 21898 bag is not enough.

The UN Recommendations on the Transport of Dangerous Goods treat FIBCs as flexible intermediate bulk containers (IBCs). National and modal rules then apply them. The US Hazardous Materials Regulations, for example, list the flexible IBC types in 49 CFR 178.710:

CodeConstruction
13H1Woven plastic without coating or liner
13H2Woven plastic, coated
13H3Woven plastic with liner
13H4Woven plastic, coated and with liner
13H5Plastic film
13L1 to 13L4Textile, from uncoated without liner to coated with liner
13M1, 13M2Paper, multiwall; 13M2 water resistant

Under 49 CFR 178.703, the mark shows, in order, the UN symbol, the IBC code, a letter for the performance level (X for Packing Groups I, II and III; Y for II and III; Z for III only), the month and year of manufacture, the country authorising the mark, the manufacturer or approval agency, the stacking test load in kg and the maximum permissible gross mass in kg. The design must have passed the tests for its type. For flexible IBCs, every design type needs the drop, tear and topple tests; the top-lift and righting tests apply to bags designed to be lifted from the top or side, and the stacking test to bags designed to be stacked (49 CFR 178.801 and 178.810 to 178.818).

For a buyer in Asia, the working rules are:

  • The shipper decides the UN number, packing group and permitted IBC types from the dangerous goods list for the mode of transport (for sea, the IMDG Code). Give the bag maker those facts.
  • Ask the maker for the design-type test report and for the document that authorises it to apply the UN mark, and check who issued it. The mark itself names the country authorising it and the manufacturer or approval agency.
  • Confirm that the approval covers the exact design and capacity you are buying.
  • Check the date of manufacture on the mark. Rules on how long a flexible IBC may be used after manufacture differ by regime; confirm the current rule for your mode and route.

We did not reproduce the UN Model Regulations text for this article. Confirm the IBC provisions against the current edition and the modal rules (IMDG Code, ADR, national regulations) for your route before you rely on them.

Food, feed and pharmaceutical contact

For food or feed, the bag and liner must meet the food-contact rules of the market where the food is sold, and the factory that makes them must keep the line clean; ask for a declaration of compliance and evidence of hygiene control, not only a “food grade” statement.

Most FIBC bodies and liners are polyolefins, usually polypropylene fabric and polyethylene film. In the EU, plastic materials in contact with food fall under Regulation (EU) No 10/2011, which requires a written declaration of compliance at marketing stages other than retail. In the US, olefin polymers are covered by 21 CFR 177.1520 when its conditions are met. Our article on food-contact compliance by market explains these rules in more detail.

For food-contact bags, also ask about:

  • whether the bags are made in a separate, controlled area and how foreign-matter risk is managed;
  • whether threads, loops and labels are cut and sealed to avoid loose fibres;
  • whether a recognised food-safety or packaging-hygiene certification covers the plant, and its scope and expiry date;
  • how bags are packed and protected from contamination before you open them.

From sample to repeat orders

Approve a sample of the exact design, keep it, and reorder on the same drawing and test report so each batch matches what you approved.

A practical sequence:

  1. Specification and drawing. Send the specification table above. Ask each maker to return a dimensioned drawing.
  2. Documents first. Collect the type-test report (ISO 21898 or UN), the IEC 61340-4-4 report where relevant, and food-contact declarations before you order samples.
  3. Sample check. Measure dimensions, weigh the empty bag, check stitching and loop attachment, check labels against the standard, and run a trial fill on your own line.
  4. Inspection before shipment. Check dimensions, labels, cleanliness and packing against the approved sample. Our note on pre-shipment inspection and AQL explains sampling.
  5. Shipping the bags. Empty FIBCs are usually baled and palletised. If they travel on wooden pallets across a border, the pallets fall under ISPM 15; see our guide to wooden and plastic pallets under ISPM 15.

Filled bags are cargo in their own right. Blocking and securing bulk bags inside a container is covered in our guide to container loading and dunnage.

Frequently asked questions

1. Is a “1-tonne bag” a specification?
No. It tells the supplier the rough size and nothing about fabric, loops, liner, safe working load, static type or test basis. Write the full specification and ask for a drawing.

2. Does ISO 21898 apply to dangerous goods?
No. ISO 21898:2024 covers FIBCs for non-dangerous goods. Dangerous goods need UN-marked flexible IBCs approved for the substance and mode of transport.

3. Which static type should I buy?
That depends on your product, liner and hazardous zone, and on your plant’s process-safety assessment. IEC 61340-4-4 sets the classification and safe-use rules; ask your safety team which type is permitted, then ask makers for the type-qualification report.

4. Can I reuse FIBCs?
Only if the design was made and tested for reuse and your inspection and cleaning process allows it. A bag made for one trip should not be refilled.

5. Can Sunsho Trade source branded or specific-maker bags?
We can search for bags to your specification from makers in Vietnam and elsewhere in Asia, including makers you name. We are not an authorised distributor of any bag brand, and we check each maker’s documents against the specification.

Summary

Specify the FIBC from the product, handling and atmosphere; buy against ISO 21898 for non-dangerous goods, a UN code for dangerous goods and an IEC 61340-4-4 type where static matters; and collect the reports before the first order.

Sunsho Trade is a trading company. For bulk bags we look for and vet makers in Vietnam and Asia, collect quotations on the same specification, check documents and samples, arrange inspection, and plan shipment with your other materials.

💬 Ready to source FIBCs? See our industrial packaging and logistics materials service, or send us your bag specification. For other plant materials, start from industrial sourcing.

Sources

Checked on 27 October 2026.