Minimum Order Quantity (MOQ): 1 pallet (typically 125–250+ bulk bags)
To specify uncoated fabric on an FIBC purchase order, do not simply write “uncoated bulk bag.” State that the FIBC requires uncoated woven polypropylene fabric and reference the approved fabric specification and drawing. Then define the rest of the packaging system: product, particle characteristics, bulk density, target payload, Safe Working Load (SWL), safety factor, body construction, top, bottom, seams, liner requirements, lift loops, dimensions, tolerances, filling method, air-displacement requirements, discharge method, pallet requirements, printing, packing, and specification revision. “Uncoated” tells the supplier one thing about the fabric. It does not define the complete FIBC.
Here is the kind of purchase order description that causes trouble:
“Heavy-duty uncoated FIBC. White. Standard loops.”
That sounds specific.
It isn’t.
What product?
What particle size?
What bulk density?
What payload?
What SWL?
What safety factor?
Why uncoated?
How breathable does the packaging system need to be?
What body construction?
What top?
What bottom?
What seams?
Is there a liner?
How is the FIBC filled?
How does displaced air escape?
How is it discharged?
What does “standard loop” mean?
Which drawing revision?
A repeatable FIBC needs a repeatable specification.
Uncoated fabric generally means the woven polypropylene fabric does not have the additional polypropylene coating used to close more of the natural openings between the woven tapes.
That typically means greater fabric breathability compared with comparable coated fabric.
It can also mean less resistance to:
Fine-particle migration through the weave.
Moisture movement through the fabric.
That tradeoff is why the fabric should be selected intentionally.
A useful starting point is:
Fabric: Uncoated Woven Polypropylene Per Approved FIBC Specification and Drawing
If your company controls specifications by revision, include the appropriate reference.
For example:
Fabric Construction: Uncoated Woven Polypropylene Per Approved FIBC Specification, Drawing and Current Revision
That is much better than:
Uncoated bag.
You could have two completely different FIBCs that both use uncoated fabric.
One could be:
Circular construction.
Open top.
Flat bottom.
No liner.
Another could be:
Four-panel construction.
Filling spout.
Discharge spout.
Internal liner.
Both are uncoated.
They are not the same FIBC.
Ask this before issuing the purchase order:
Why are we specifying uncoated fabric?
Possible reasons include:
Greater fabric breathability.
Improved natural air displacement.
Product particles are sufficiently coarse.
Fine-particle migration is not a concern.
Moisture resistance through the outer fabric is unnecessary.
A separate liner provides the required barrier.
Coating provides no measurable operational value.
If nobody knows why the fabric is uncoated, you have a specification habit—not necessarily a specification requirement.
Maybe it costs less.
Maybe it doesn’t once the entire system is considered.
If uncoated fabric creates:
Product loss.
Dust.
Cleanup.
Moisture damage.
Rejected product.
Customer complaints.
Then the lower purchase price does not matter much.
Uncoated woven fabric generally provides greater natural airflow.
But the complete FIBC may include:
A liner.
Closures.
Special seam construction.
Filling equipment interfaces.
Other components.
Those can change overall airflow behavior.
Specify the actual process requirements.
| Specification | What to Define |
|---|---|
| 📦 Product | Actual material being packaged |
| 🔬 Particle characteristics | Size, shape, fines, dust behavior |
| ⚗️ Bulk density | Actual value or approved range |
| ⚖️ Target payload | Intended product weight |
| ⚖️ SWL | Required Safe Working Load |
| 🛡️ Safety factor | Required intended-use classification |
| 🧶 Body | Circular, U-panel, four-panel, baffle, etc. |
| 💨 Fabric | Uncoated woven polypropylene |
| 🪡 Seams | Structural and containment requirements |
| 🛍️ Liner | Type/configuration if required |
| 🔝 Top | Open, duffle, filling spout, etc. |
| ⬇️ Bottom | Flat, discharge spout, duffle, etc. |
| 🌬️ Air | Air-displacement requirements |
| 🌫️ Dust | Acceptable containment performance |
| 💧 Moisture | Required protection |
| ⚡ Static | Electrostatic requirements if applicable |
| 🪢 Loops | Style and dimensions |
| 📐 Dimensions | Required empty dimensions |
| 📏 Filled geometry | Critical loaded dimensions |
| 🪵 Pallet | Required compatibility |
| ⚙️ Filling | Actual filling process |
| 🔻 Discharge | Actual unloading process |
| 🏷️ Printing | Approved artwork and markings |
| 📦 Packing | Empty-FIBC packing requirement |
| 📄 Revision | Current approved specification |
Do not write:
Granular material.
Or:
Powder.
Or:
Dry product.
Identify the actual product whenever practical.
The product determines whether uncoated fabric makes sense.
Particle size is especially important with uncoated woven fabric.
The natural openings in the weave may allow sufficiently fine material to migrate.
If your product is coarse, that may not matter.
If it is extremely fine, it may matter a lot.
Do not stop at average particle size.
A mostly coarse product can contain enough fines to create:
Dust.
Sifting.
Product loss.
Housekeeping problems.
Communicate the actual material behavior.
Particle shape can influence:
Flowability.
Abrasion.
Fabric wear.
Liner wear.
Discharge.
Sharp or angular material deserves particular attention.
Does the product create dust during:
Filling?
Handling?
Transportation?
Discharge?
Does dust appear on the outside of existing FIBCs?
Document it.
Bulk density affects:
Required volume.
Target payload.
Filled geometry.
SWL selection.
Pallet fit.
Warehouse cube.
Transportation.
Use real data when possible.
State how much product the FIBC is intended to carry.
Do not write:
Fill completely.
Define the target weight.
Do not substitute vague descriptions such as:
Heavy duty.
Extra strong.
Industrial strength.
Specify the required SWL.
The safety factor should match the intended use of the approved FIBC design.
Do not treat safety factor as extra carrying capacity above the rated SWL.
Call or Text us at 832.400.1394
Uncoated tells you about fabric treatment.
It does not define body architecture.
Specify:
Circular.
U-panel.
Four-panel.
Baffle.
Another approved construction.
A purchase specification might state:
Body Construction: Circular / Tubular Woven FIBC Body Per Approved Drawing
Fabric: Uncoated Woven Polypropylene Per Approved Specification
Now both body construction and fabric treatment are controlled.
State:
Body Construction: U-Panel FIBC Per Approved Drawing
Fabric: Uncoated Woven Polypropylene Per Approved Specification
State:
Body Construction: Four-Panel FIBC Per Approved Drawing
Fabric: Uncoated Woven Polypropylene Per Approved Specification
If shape control is required:
Body Construction: Approved Baffle / Form-Stable FIBC Construction Per Drawing
Fabric: Uncoated Woven Polypropylene Per Approved Specification
Do not assume every uncoated woven polypropylene fabric is interchangeable.
The approved fabric still needs to support:
Payload.
Handling.
Abrasion.
Containment.
Filling.
Discharge.
Overall FIBC performance.
If the approved design controls fabric weight, GSM, denier, or related fabric characteristics, reference those requirements in the technical specification.
Do not reduce the entire fabric specification to:
Uncoated.
Seams remain critical.
They affect:
Structural performance.
Containment.
Shape.
Top construction.
Bottom construction.
An uncoated body does not make seam requirements disappear.
An application may use uncoated fabric and still require additional containment at seam areas.
If sifting matters, define the performance requirement.
For coarse materials, this may be irrelevant.
For finer products, needle penetrations can become potential migration paths.
Evaluate the actual material.
This is a major point.
Uncoated does not mean unlined.
An uncoated woven outer FIBC can use an internal liner.
Possible reasons include:
Fine-particle containment.
Moisture protection.
Product-contact protection.
Contamination control.
Chemical compatibility.
Other barrier requirements.
Know what the liner is supposed to accomplish.
Do not write only:
With liner.
Specify the approved liner configuration.
For example:
Liner: Loose-Insertion Liner Per Approved Specification
Or:
Liner: Form-Fit Liner Per Approved Specification
If product compatibility or barrier performance depends on liner material, control it.
If thickness is part of the approved design, include it in the controlled specification.
Make sure the liner works with the filling process.
Make sure it also works with discharge.
If liner attachment or positioning is important, control it.
Loose liners can:
Shift.
Wrinkle.
Fold.
Move.
Interfere with filling.
Interfere with discharge.
This is critical.
You may choose uncoated fabric specifically because you want better air movement.
Then add a liner that severely restricts air movement.
Now the complete package behaves differently.
Evaluate the whole system.
Possible options include:
Open top.
Duffle top.
Filling spout.
Other approved configurations.
Choose around the actual filling process.
A purchase order might state:
Top Construction: Full Open Top Per Approved Drawing
State:
Top Construction: Duffle Top With Approved Closure Per Drawing
State:
Top Construction: Filling Spout Per Approved Drawing
Then control critical dimensions and interface requirements.
Tell the supplier how the FIBC is actually filled.
For example:
Gravity chute.
Filling head.
Conveyor.
Pneumatic system.
Manual loading.
Other process equipment.
This becomes especially important when uncoated fabric is being selected for breathability.
If filling speed matters, communicate it.
Ask:
How much air enters with the product?
How much air is displaced?
Where should that air go?
Does the process rely partly on airflow through the fabric?
If yes, document that requirement.
If the complete FIBC requires a specific venting arrangement, define it in the approved specification.
Do not assume uncoated fabric automatically solves every air-management problem.
If excessive inflation creates problems, evaluate it during testing.
Greater fabric breathability can be useful.
But you still need acceptable product containment.
That balance should be tested with the actual product.
Choose based on the real discharge process.
Possible configurations include:
Flat bottom.
Discharge spout.
Duffle bottom.
Other approved constructions.
State:
Bottom Construction: Flat Bottom / No Discharge Spout Per Approved Drawing
State:
Bottom Construction: Discharge Spout With Approved Closure Per Drawing
Then define:
Outlet dimensions.
Closure.
Receiving-equipment interface.
Other critical requirements.
State:
Bottom Construction: Duffle Bottom / Wide-Opening Discharge Per Approved Drawing
Then verify that downstream equipment can handle the product flow.
Does the material:
Flow freely?
Bridge?
Cake?
Clump?
Compact?
Interlock?
The discharge design needs to match actual behavior.
Where does the material go?
Hopper?
Mixer?
Conveyor?
Bin?
Process vessel?
Other container?
Design around the real destination.
Determine whether you need:
Controlled discharge.
Rapid discharge.
Partial discharge.
Metered flow.
Do not leave this to assumption.
Uncoated woven polypropylene provides less fabric barrier to moisture than comparable coated fabric.
If moisture matters, define:
Exposure.
Duration.
Humidity.
Storage.
Transportation.
Liner requirements.
Top closure.
Bottom closure.
If FIBCs will be stored outdoors, communicate:
Duration.
Rain exposure.
Humidity.
UV exposure.
Temperature.
Covering method.
Do not assume uncoated woven polypropylene alone provides sufficient environmental protection.
If the FIBCs will experience meaningful outdoor exposure, document the expected conditions and approved requirements.
Uncoated does not define electrostatic classification.
If the application requires a particular FIBC type for static control, specify it separately.
Uncoated does not mean food grade.
Document applicable food-contact requirements independently.
Uncoated does not mean UN certified.
If regulated dangerous goods are involved, specify the complete approved UN packaging requirement.
Abrasive product can wear:
Fabric.
Seams.
Bottom areas.
Discharge components.
Communicate the actual product.
Sharp material can create:
Puncture risk.
Localized fabric wear.
Liner damage.
Do not hide this information behind a generic product description.
Communicate unusual operating temperatures.
Define:
Loop style.
Loop location.
Loop dimensions.
Equipment compatibility.
Loop length affects:
Forklift access.
Filling equipment.
Discharge equipment.
Hanging height.
Operator efficiency.
Consider:
Body.
Loops.
Top.
Bottom.
Then verify equipment clearance.
Define required dimensions and appropriate tolerances.
Loaded dimensions may matter more than empty dimensions.
Control critical:
Width.
Length.
Height.
Footprint.
When required by the operation.
Do not write:
Standard pallet.
Identify the actual pallet requirement.
If overhang matters, define acceptable performance.
Then test the loaded FIBC.
Consider:
Loaded footprint.
Loaded height.
Handling clearance.
Humidity.
Storage duration.
Product protection.
Consider:
Vibration.
Settling.
Humidity.
Temperature changes.
Handling.
Transit duration.
Pallet movement.
The FIBC must perform through the entire logistics chain.
Call or Text us at 832.400.1394
Define required:
Product identification.
Company information.
Warnings.
Handling instructions.
Lot information.
Traceability.
Other markings.
Use controlled artwork where appropriate.
If placement matters, define:
Printed sides.
Orientation.
Location.
Approved artwork.
How should the FIBCs arrive?
Folded?
Palletized?
Baled?
Liners installed?
Specific orientation?
Packing can affect production efficiency.
Once the FIBC has been approved, give it a controlled identity.
For example:
FIBC Item UNC-310 — Rev. C
Now purchasing can reorder a specific packaging system rather than a description assembled from memory.
If the design changes, update the controlled revision.
Possible changes include:
Fabric.
Body construction.
Seams.
Top.
Bottom.
Liner.
Loops.
Dimensions.
SWL.
Printing.
Packing.
Which previous order?
Which revision?
Which liner?
Which fabric?
Which top?
Which bottom?
Reference the controlled item and revision.
Operations says:
“The bag needs to vent faster.”
Quality says:
“We are seeing too much dust.”
Warehouse says:
“The bag is overhanging the pallet.”
Production says:
“The liner keeps moving.”
Those approved changes need to reach the controlled specification.
A practical description might read:
FIBC — [Approved Body Construction] / Uncoated Woven Polypropylene Fabric / [Approved Top] / [Approved Bottom] / [Required SWL] / [Required Safety Factor] / [Liner Requirement] / [Lift Loop Configuration] / Per Approved Specification and Drawing [Revision]
That gives purchasing a controlled reference.
A controlled specification might include:
Product: Approved dry bulk material
Particle Characteristics: Per approved product data
Bulk Density: Approved value or range
Target Payload: Approved fill weight
Body Construction: Approved circular, U-panel, four-panel, baffle, or other construction
Fabric: Uncoated woven polypropylene per approved specification
Top Construction: Approved configuration
Bottom Construction: Approved configuration
SWL: Required Safe Working Load
Safety Factor: Required intended-use classification
Seams: Structural and containment requirements per approved specification
Liner: Approved configuration if required
Air Management: Per approved filling-process requirement
Lift Loops: Approved style and dimensions
Empty Dimensions: Per approved drawing
Critical Filled Dimensions: Per approved specification
Tolerances: Per approved drawing
Pallet: Approved configuration
Filling Method: Approved process
Discharge Method: Approved process
Dust Requirements: As applicable
Moisture Requirements: As applicable
Static Requirements: As applicable
Printing: Per controlled artwork
Packing: Per approved requirement
Revision: Current approved revision
Before releasing the purchase order, confirm:
Common mistakes include:
Writing only “uncoated bag.”
Specifying uncoated only because it may cost less.
Assuming uncoated means weak.
Assuming uncoated means low quality.
Assuming uncoated means highly breathable regardless of liner.
Ignoring particle size.
Ignoring the fine fraction.
Ignoring dust.
Ignoring product migration through the weave.
Ignoring moisture sensitivity.
Ignoring bulk density.
Ignoring target payload.
Ignoring SWL.
Ignoring safety factor.
Ignoring body construction.
Ignoring seams.
Ignoring needle penetrations.
Ignoring top construction.
Ignoring bottom construction.
Ignoring filling equipment.
Ignoring filling rate.
Ignoring air displacement.
Ignoring liner effects on airflow.
Writing only “with liner.”
Ignoring liner movement.
Ignoring discharge.
Ignoring product flowability.
Ignoring abrasion.
Ignoring sharp material.
Ignoring product temperature.
Assuming uncoated means food grade.
Assuming uncoated means UN certified.
Ignoring static requirements.
Ignoring lift loops.
Ignoring hanging height.
Ignoring filled geometry.
Ignoring pallet fit.
Ignoring settling.
Ignoring warehouse conditions.
Ignoring outdoor exposure.
Ignoring nationwide transportation.
Ordering from a photograph.
Writing “same as last time.”
Failing to control revisions.
Make sure every supplier is quoting the same:
Product application.
Particle characteristics.
Bulk density.
Target payload.
SWL.
Safety factor.
Body construction.
Fabric requirement.
Top.
Bottom.
Seams.
Liner.
Loops.
Dimensions.
Tolerances.
Filling requirements.
Air-management requirements.
Discharge requirements.
Printing.
Packing.
Revision.
Otherwise you are not comparing the same FIBC.
Use the actual product whenever practical.
Use the intended payload.
Use the actual filling equipment.
Run at the intended production rate.
Measure:
Filling cycle time.
Air displacement.
Bag inflation.
Product backup.
Dust.
Product migration.
Operator intervention.
Inspect:
Fabric.
Seams.
Top.
Bottom.
Liner if applicable.
Then palletize it.
Use the actual pallet.
Measure:
Width.
Length.
Height.
Overhang.
Allow representative settling.
Measure again.
If the product is sensitive to moisture, evaluate realistic:
Humidity.
Temperature.
Storage duration.
Indoor or outdoor exposure.
Handling.
Do not approve the package based only on what it looks like immediately after filling.
Evaluate:
Vibration.
Settling.
Humidity changes.
Temperature changes.
Handling.
Pallet movement.
Product containment.
Use the intended receiving equipment.
Measure:
Discharge time.
Flow.
Bridging.
Surging.
Dust.
Spillage.
Liner behavior.
Residual product.
Operator intervention.
After successful testing, lock down:
Internal item number.
Approved drawing.
Uncoated fabric requirement.
Body construction.
Top.
Bottom.
Seams.
Liner.
Loops.
Dimensions.
Tolerances.
SWL.
Safety factor.
Printing.
Packing.
Revision.
Then purchase against that controlled standard.
Start with the application.
Identify:
Product.
Particle size.
Fine-particle content.
Particle shape.
Bulk density.
Flowability.
Dust behavior.
Moisture sensitivity.
Abrasion.
Sharpness.
Temperature.
Static considerations when applicable.
Target payload.
Then ask:
Why are we using uncoated fabric?
If the answer is:
Greater breathability.
Better natural air displacement.
The product does not sift significantly.
Fabric moisture resistance is unnecessary.
A liner handles the barrier requirement.
Coating provides no measurable value.
Good.
Now you have a reason.
Next define:
SWL.
Safety factor.
Body construction.
Top.
Bottom.
Seams.
Liner.
Loops.
Dimensions.
Tolerances.
Pallet.
Filling.
Air displacement.
Discharge.
Printing.
Packing.
Revision.
Then specify:
Fabric: Uncoated Woven Polypropylene Per Approved FIBC Specification and Drawing.
Now test it.
Fill it with the actual product.
Use the intended payload.
Use the real filling equipment.
Run at production speed.
Watch:
Air displacement.
Bag inflation.
Product backup.
Dust.
Fine-particle migration.
Liner behavior.
Measure filling cycle time.
Put the loaded FIBC on the actual pallet.
Measure:
Width.
Length.
Height.
Overhang.
Allow representative settling.
Measure again.
Store it under representative conditions.
Move it through representative nationwide transportation conditions.
Discharge it through the actual receiving equipment.
Measure:
Discharge time.
Flow.
Bridging.
Surging.
Dust.
Spillage.
Residual product.
Liner interference.
Operator intervention.
Then calculate total economics.
FIBC cost.
Filling labor.
Cycle time.
Product loss.
Cleanup.
Pallet utilization.
Warehouse cube.
Transportation utilization.
Discharge labor.
Damage.
Downtime.
Annual volume.
If the uncoated fabric provides the required strength and containment while delivering the breathability your process needs, approve it.
Lock the specification.
Assign the revision.
And reorder against the controlled design.
Because “uncoated” should define a deliberate fabric requirement—not become shorthand for a generic bulk bag.
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