FIBC & Bulk Bag Technical Glossary
“The vocabulary, defined plainly.”
Executive Summary
Bulk packaging involves technical terminology and shorthand. Ambiguity between buyers and manufacturers leads to specification errors. This glossary sets out the authoritative definitions Coastal FIBC works to across construction, safety, fabric, lifting, and trade.
Construction and Anatomy
• FIBC — Flexible Intermediate Bulk Container. The standardized technical designation for jumbo bags, bulk bags, or big bags.
• Baffle — Internal fabric panels with perforations sewn into each corner to restrain side walls and maintain a cubic footprint.
• Four Panel — An FIBC constructed with four separate vertical side panels stitched together along four corner seams.
• Circular / Tubular — Fabric woven on circular looms into a seamless tubular cylinder, eliminating vertical side seams.
• U-Panel — Construction where one continuous fabric sheet forms the bottom and two opposite sides in a cradle, closed by two end panels.
• Duffle Top / Skirt — An extended fabric skirt sewn to the bag rim that folds over and secures with a drawstring cord.
Load, Safety & Testing
• SWL (Safe Working Load) — The maximum certified payload weight the bag is engineered to lift and transport under normal conditions (kg).
• Safety Factor (SF) — The ratio of ultimate breaking strength to SWL (e.g., 5:1 for 5,000 kg test load on a 1,000 kg SWL bag).
• Cyclic Test — An automated rig test that repeatedly applies cyclic tensile stress to simulate the dynamics of transport before a final break pull.
• Bulk Density — Mass per unit volume (kg/m³). The crucial metric required to translate cargo weight into exact internal bag cubic meters.
Fabric & Material Engineering
• PP (Polypropylene) — The 100% virgin polymer resin extruded into high-tensile tape yarns and woven into bulk packaging fabric.
• GSM — Grams per square metre. Fabric mass measurement directly governing tensile burst resistance and tear strength.
• Coated Fabric — Polypropylene fabric with an extruded micron-thin polyethylene lamination that seals weave interstices against moisture and powder sift.
• UV Stabilisation — Polymer compounding with hindered amine light stabilisers (HALS) to resist molecular breakdown from solar radiation.
• Sift-Proofing — Polypropylene cord or felt inserted into sewn seams to seal needle perforations against sub-micron powder leakage.
Lifting, Filling & Discharge Configurations
• Cross-Corner Loops — Webbing loops attached across the corners so they remain erect and open for swift single-operator forklift engagement.
• Stevedore Straps — Connecting slings that bundle multiple loops to enable heavy crane loading onto marine bulk freighters.
• Filling Spout — A cylindrical fabric inlet designed to clamp over pneumatic loading chokes for dust-tight filling.
• Iris Closure — A drawstring safety throttle mechanism that operates like a camera iris, allowing operators to modulate or arrest discharge.
• Full Open Bottom — A release base that unlatches the complete bottom perimeter, permitting instantaneous drop of cohesive bridging loads.
International Trade & Quality Standards
• ISO 21898 — The international standard governing non-dangerous goods FIBC design, test procedures, and markings.
• IEC 61340-4-4 — The global standard establishing electrostatic classification (Types A, B, C, D) for bulk containers.
• Incoterms — International rules (FOB, CIF, CFR, DDP) determining legal handoff points, freight costs, and maritime insurance.
• Batch QC File — In-house quality verification records (rig test, GSM, tensile, UV) linked to specific production lot numbers.
Coastal FIBC Technical Engineering Desk · Rajkot, India
Have specific material or electrostatic calculations? Send your inquiry to our engineering team.