A Big Bag is a large flexible textile bag designed for the transport of bulk solid materials, typically holding 500 kg to 2,000 kg per bag. Also called a Flexible Intermediate Bulk Container (FIBC) or supersack, the standard format is woven polypropylene with built-in lifting loops. UN-certified big bags ship dangerous solid cargoes; non-UN versions ship non-DG bulk solids. Big bags are the dominant packaging for bulk solid chemicals at scale, ammonium sulphate, urea, soda ash, citric acid, calcium chloride, sodium sulphate, and many others ship internationally in 1-tonne FIBC format.
UN codes for FIBC
| UN code | Lift configuration | Typical use |
|---|---|---|
| 13H1 | Single-trip top lift only (woven PP) | Lower-cost solid DG cargo, single-cycle use |
| 13H2 | Single-trip top lift, with coating | Moisture-sensitive solid DG cargo |
| 13H3 | Multi-trip top lift, woven PP | Reusable for solid DG; higher quality construction |
| 13H4 | Multi-trip top lift, with coating | Reusable for moisture-sensitive solid DG |
| 13L1 | Single-trip with various lift configurations | Specific cargo types |
| 13M1, 13M2 | Multi-wall paper outer | Moisture-sensitive solid DG; less common |
The 13H1 single-trip woven PP bag is the workhorse for routine solid chemical shipments. 13H4 multi-trip coated bags are used where the bag fleet is owned and reused.
Standard big bag dimensions
Most big bags converge on standard formats sized to fit container loading:
| Dimension | Typical |
|---|---|
| Base | 90-120 cm × 90-120 cm |
| Height (when filled) | 100-180 cm |
| Capacity | 1.0-1.5 cubic metres |
| Fill capacity by mass | 500-2,000 kg depending on cargo density |
| Lifting loops | 4 corner loops, single top loop, or various other configurations |
For typical 1,000-kg fill bags of urea (bulk density ~0.75 t/m³), a 20-foot container fits 18-20 bags (cargo weight ~18-20 MT). Higher-density cargoes (sodium sulphate at ~1.5 t/m³) would weigh more per bag at the same fill volume, so containers fill out by weight before by volume.
When big bag is the right packaging
Big bag is right for:
- Bulk solid commodities at 1-20 MT scale, fertilisers, soda ash, sodium chloride, citric acid, sodium bicarbonate
- Granular and powdered cargoes that do not require dust-tight packaging, most industrial chemistry that is not finely divided or hygroscopic
- Cargoes that downstream users dispense from the bag directly, a 1-tonne bag at the buyer’s site discharged into a process vessel
- Markets with bag-handling infrastructure, most chemical-importing destinations have forklifts and bag-lifters for FIBC handling
When big bag is the wrong packaging
Big bag is wrong for:
- Volume bulk shipments above ~50 MT per shipment, pneumatic bulk handling or break-bulk shipping is more economical
- Highly hygroscopic or moisture-sensitive solids, even coated bags eventually allow moisture ingress; sealed drums or moisture-barrier inner liners are preferable
- Fine powders prone to dusting, bag handling generates dust escape; closed packaging is needed for dust-control workplaces
- Cargoes requiring temperature control during transport, bag thermal mass is unfavourable
Coated vs uncoated big bags
A coated big bag has an inner coating (typically PE) added to the woven PP fabric to reduce moisture and dust permeability. The coating adds USD 1-3 per bag in cost. Common cargo-coating combinations:
- Uncoated: bulk industrial chemicals not sensitive to humidity (urea bagged for fertiliser distribution; soda ash bagged for water treatment)
- Coated: hygroscopic chemicals (calcium chloride, magnesium chloride), pharmaceutical-grade or food-grade chemicals, finer powders
Some shipments combine an uncoated outer bag with an inner moisture-barrier liner (typically PE film). The inner liner provides moisture protection while keeping the outer bag cost low. This combination is common for crystalline ammonium sulphate, urea prills, and similar cargoes.
The container loading economics
For a 20-foot container loaded with 1,000-kg big bags:
| Cargo bulk density | Bags per container | Container payload |
|---|---|---|
| 0.6 t/m³ (light, e.g. fluff) | 16-18 | ~16 MT |
| 0.8 t/m³ (urea prills, ammonium sulphate) | 18-20 | ~18-20 MT |
| 1.0 t/m³ (most powders) | 20 | ~20 MT |
| 1.4-1.5 t/m³ (heavy salts, sodium sulphate) | 14-16 (filled to 80% by volume to avoid weight overage) | ~21-22 MT (close to weight limit) |
The optimisation tradeoff: more bags per container = more handling per shipment but better volumetric utilisation. Fewer bags = lower handling cost but lower utilisation. For volume buyers the per-bag handling cost is significant, so fewer larger bags often wins.
Operator note: the bag-lifting-failure problem
The single most common big-bag operational failure is a bag failing during lifting at the destination, a torn lifting loop or a fabric tear that drops the bag’s contents on the floor or dock. The cargo itself is recoverable (sweep up the spillage, run through a bagging operation again), but the cleanup cost and time can be significant.
Causes:
- Lower-quality bags (13H1 single-trip cargo loaded 1,500+ kg) used past their rated capacity
- Loops weakened by UV exposure during outdoor storage
- Tears propagated from earlier lift cycles in multi-trip bags
For buyers running heavy-cargo shipments, specifying 13H4 multi-trip coated bags rated at 1,500 kg or higher is the conservative choice, even at higher per-bag cost. The lift-failure cost on a single failure exceeds the cumulative bag-cost savings over multiple shipments.
Related terms
IBC, the rigid-frame intermediate bulk alternative, more typical for liquids. Drum, for smaller solid parcels (200-220 kg). Supersack is a synonym for big bag. IMDG Class 4.1 substances like sulphur ship in big bags. Twenty-foot container is the standard container for big-bag cargo.