- by Elay Plastic
- 02 August 2026
FIBC Inner Liners and Coated Fabric: How to Choose
A buyer-focused comparison of coated fabric, polyethylene liners and combined constructions for containment and product protection.
Containment needs begin with the product
Fine powders, moisture-sensitive materials and products requiring a cleaner contact surface may need more containment than uncoated woven fabric provides. The correct solution can be coated fabric, a separate polyethylene liner, or a combination of both.
These options solve different problems. A coating modifies the woven fabric surface; a liner creates an additional inner package. Neither should be selected solely from a generic product category.
What coated fabric can do
A polymer coating can reduce the passage of fine particles through the weave and can improve resistance to moisture transfer compared with uncoated fabric. It may also affect air permeability, which matters during high-speed filling.
Seams, needle holes, closures and inlet or outlet construction remain potential paths for dust or moisture. For demanding applications, coating must be considered together with seam design and filling conditions.
What an inner liner can do
A liner can provide an additional barrier between the product and the outer FIBC. Liners may be loose inserted, attached, shaped or form-fitted, depending on the bag geometry, filling process and discharge method.
Liner material, thickness, dimensions, openings and attachment method should match the product and equipment. Excess liner material can fold or obstruct discharge, while an unsuitable attachment can allow movement during filling.
Air evacuation and filling speed
Powders can carry significant air into a bag. Reducing fabric permeability with coating or a liner can slow air escape, increase filling time or create pressure in the package. The supplier therefore needs the filling rate, product aeration behaviour and any dust-control or vacuum requirements.
Vent designs or specialized liner constructions may be considered, but they must preserve the required level of containment.
Electrostatic and food-contact considerations
A liner can change the electrostatic behaviour of an FIBC system. In hazardous explosive atmospheres, the bag, liner, labels and document pockets must be evaluated as a complete system under the applicable electrostatic specification.
For food or pharmaceutical uses, request the required declarations, traceability and production controls for the specific materials and manufacturing site. ‘Food grade’ should never be assumed from appearance alone.
A useful quotation checklist
State particle size, moisture sensitivity, required barrier, filling temperature, filling rate, dust expectations, discharge method, food-contact status and electrostatic environment. Samples or trial fills may be appropriate where performance is difficult to predict.
The agreed quotation should identify the coating and/or liner construction explicitly, including liner type and attachment—not simply state ‘lined bag’.
Relevant standards and guidance
- IEC 61340-4-4:2018 — electrostatic classification of FIBCs and liners
- ISO 21898:2024 — FIBCs for non-dangerous goods
Important: Final suitability depends on the packed product, process, handling environment and approved technical specification. Consult the responsible safety or dangerous-goods specialist where applicable.