Glossary of Terms


Antistatic bags: see electrostatic bags.

Bag inflation: The practice of inflating an FIBC prior to filling in order remove creases or pleats in the bag fabric or inner liner which might trap material and prevent complete emptying.

Baffle: Fabric or net sewn across the corners of a 4-loop FIBC to help retain the bag’s cuboid shape and prevent bulging, thereby maximising cubic storage capacity. In the case of perforated baffles, this design feature can also help to ensure that material flows smoothly into all corners of the bag.

Barrier liners: Inner liners for FIBCs, made from special multifilm or aluminium foil, designed to ensure total climatic protection against moisture vapour and oxygen while also preventing inward or outward odour transfer.

Big bag: see FIBC

Body fabric: The fabric (usually woven polypropylene) which forms the base and sides of an FIBC.

Breathable fabric: Fabric which is uncoated or non-laminated.

Builders bag: A basic low-cost FIBC used for transporting gravel, sand, construction waste and similar materials.

Bulk bag: see FIBC

Circular woven fabric: Fabric woven on a circular loom eliminating the need for vertical seams at the four sides of a 4-loop FIBC, thereby enhancing the bag’s overall strength.

Clean-room production: Rigorously controlled hygienic and aseptic conditions for manufacture of FIBCs destined for use in pharmaceutical and certain food applications.

Coated fabric: Fabric which is coated on one or both sides to improve impermeability and other physical properties. Although FIBCs made from coated fabric will be slightly more expensive, for certain applications they can be used without need for an inner liner.

Compression test: In the case of a standard-duty reusable FIBC (safety factor of 6:1), a compression test at four times the bag’s SWL is normally applied for 6 hours.

Denier: Weight of yarn in grams/9000m which defines the thickness of the yarn.

Document pouch: Pouch attached to the outside of an FIBC for holding shipping or identity documents.

Drop test: One of the tests required for UN-certified FIBCs. The bag, filled to maximum capacity, is dropped from a measured height (usually 80cm or 120cm, depending on the packaging group).

EFIBCA Standard: Established by members of the European Flexible Intermediate Bulk Container Association in 1985, this Standard formed the basis for many national and international FIBC codes of practice and statutory requirements which have subsequently come into force worldwide.

Electrostatic bags: FIBCs usually of Type C or Type D category designed to neutralise the danger of static electricity.

Fertiliser bags: FIBCs, usually of 2-loop or single point lift design and typically of 6-700kg SWL, widely used for transporting fertiliser materials.

FIBC: Flexible Intermediate Bulk Container: a bulk bag, usually made from woven polypropylene, designed to carry normally between 600kg and 2000kg of bulk material. It can safely carry up to 1000 times its own weight, top-lifted by means of one, two or four integral loops, or alternatively supported on a pallet and lifted from below. The largest size of filled FIBC can be handled by conventional forklift truck.

FIBCs-on-a-reel: A continuous spool of flat FIBCs for use with automatic filling rigs.

Fibrillated PP yarn: Light-weight and strong polypropylene yarn specially developed to provide reliable performance with sewing machines.

Flat fabric: Flat woven PP fabric used for the side panels of traditional 4-loop FIBCs.

Form-fit liners: Inner liners tailored to fit the contours of an FIBC. This means the liner is less likely to become creased during filling thereby causing material to become trapped and preventing complete discharge. Also the liner is less likely to be discharged along with the material. They are often glued into position as a further precaution against this happening.

Form-stable bags: FIBCs which are designed to retain their cuboid shape when filled, thereby ensuring better stacking stability and more efficient use of available storage volume.

Groundable: Groundable FIBCs (Type C) and inner liners are designed to be grounded/earthed to prevent potentially dangerous build-up of static electricity.

Heavy-duty reusable FIBCs: With an 8:1 safety factor, they can be used for multiple trips with a service life often calculated in years rather than number of trips. They are usually made from thermoplastic-coated material including PVC, EVA and chloroprene rubber. They are normally welded rather than stitched and are watertight. Unlike conventional woven-polypropylene FIBCs they are repairable. They can also be cleaned by washing. Although they cost 20-50 times more than conventional PP bags, they can prove to be more cost-effective for certain arduous applications including long-term closed-loop usage.

Jumbo bag: see FIBC

Label: All FIBCs must display a permanently attached outer label which provides proof of the bag’s safety. This is a legal requirement. Information provided on the label should include: safe working load; class of FIBC (e.g. ‘single trip’); standard to which the FIBC has been tested; number and date of the test certificate; name of the test house that issued the certificate; date of manufacture of the FIBC (month and year).

Lay flat width: Width of tubular fabric when laid flat – twice the width of one bag side. Orange Book: United Nations recommendations on the transport of dangerous goods, widely referred to as the Orange Book.

Pallet-less bags: FIBCs which incorporate reinforced sleeves or an integral pallet replacement system at their base, allowing them to be bottom-lifted by forklift truck as well as stacked in a stable and clean manner.

Q-bag: An FIBC with inner baffles which help to maintain its square shape when filled.

Safety factor: FIBCs have a safety factor of 5:1 for single-trip use, 6:1 for standard-duty limited reuse, and 8:1 for heavy-duty multi-trip use. This means, for example, that a single-trip FIBC with an SWL of 1000kg would need to show that it is capable of carrying 5000kg under test conditions. Although bags with an SWL of 4:1 or lower are known to be available, they would be illegal in most countries.

Single-trip FIBCs: With a 5:1 safety factor, they are to be used for one filling and one discharge only.

Stacking test: see compression test. Standard-duty reusable FIBCs: With a 6:1 safety factor, they are intended to be used for a limited number of fillings and discharges. They cannot be reused if damaged (they are not repairable). They must be reused for carrying the same type of contents as for the first filling.

Super sack: see FIBC SWL (Safe Working Load): The maximum certified filled load that an FIBC can carry in service.

Top lift test: In the case of a standard-duty reusable FIBC (safety factor of 6:1), a cyclic top lift test is recommended with 70 cycles at four times SWL, with a final top lift at six times SWL.

Type A bags: FIBCs which provide no electrostatic protection.

Type B bags: FIBCs made from materials that exhibit a low breakdown voltage of 4 kilovolts or less, sufficient to prevent the occurrence of dangerous propagating brush discharges. However, these bags cannot be classified as antistatic.

Type C bags: FIBCs normally made from non-conductive polypropylene interwoven with conducting yarns usually in a grid pattern. To fulfil their static-conductive function they need to be grounded/earthed.

Type D bags: These FIBCs are made from special static-dissipative fabric and there is no need for the bag to be grounded. In fact to do so would be dangerous.

Type D+ bags: FIBCs which combine the antistatic capabilities of Type D (static-dissipative) and Type C (static-conductive).

UN bag: UN-certified FIBC for international transport of dangerous goods – see also Orange Book. Tests to which such FIBCs are subjected include: cyclic top lift tests, stacking tests, drop tests, tear tests, topple tests and righting tests.

UN marking: All UN-certified FIBCs must display the UN Mark as defined in the Orange Book (qv).

UV degradation: Prolonged exposure to sunlight (ultra violet rays) can damage and reduce the strength of FIBC fabric and webbing. Various tests and treatments are available to protect against this problem.

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