Minimum Order Quantity (MOQ): 1 pallet (typically 125–250+ bulk bags)
To specify circular construction on an FIBC purchase order, do not simply write “circular bulk bag.” Clearly identify the body as a circular or tubular woven polypropylene construction, meaning the main body is woven as a continuous tube rather than assembled from separate sidewall panels joined by traditional vertical seams. Then define the product, bulk density, target payload, Safe Working Load (SWL), safety factor, top, bottom, fabric, coating, remaining seam requirements, liner, lift loops, dimensions, critical tolerances, filling method, discharge method, pallet requirements, printing, packing, and approved specification revision.
Here is the kind of purchase order that causes trouble:
“White circular FIBC. Heavy duty. Same as last order.”
Sounds specific.
It is not.
What product?
What bulk density?
What payload?
What SWL?
What safety factor?
What top?
What bottom?
Coated or uncoated?
Lined or unlined?
What loops?
What dimensions?
What bottom construction?
What filled footprint?
What revision?
And what exactly does the buyer mean by “circular”?
If those answers are not controlled somewhere, you do not have a repeatable FIBC specification.
You have a description.
Circular construction describes the primary body architecture of the FIBC.
The woven polypropylene body fabric is produced in a tubular form.
That tubular fabric creates the main sidewalls without requiring the traditional vertical panel-joining seams used to connect separate sidewall panels.
That is the construction you are identifying.
Circular does not necessarily mean the loaded FIBC is literally round.
It refers primarily to how the body fabric is woven and constructed.
A useful starting point is:
Body Construction: Circular / Tubular Woven FIBC Body Per Approved Drawing
For greater clarity:
Body Construction: Tubular Woven Polypropylene Main Body With No Traditional Vertical Side-Panel Joining Seams, Per Approved Drawing
Then reference the approved specification and revision.
Two circular FIBCs can be completely different.
One could be:
Open top.
Flat bottom.
Uncoated.
Unlined.
Another could be:
Filling spout top.
Discharge spout bottom.
Coated.
Lined.
Specially configured for fine powder.
Both can use circular body construction.
They are not the same bag.
This is a common terminology problem.
Circular refers to the tubular woven main body.
It does not guarantee a perfectly round filled package.
Depending on the complete design and product, the loaded FIBC may develop a generally square-ish footprint with rounded corners and outward sidewall expansion.
If filled geometry matters, specify and test it.
Avoid this unless you are describing something extremely specific and technically supported.
Circular construction reduces or eliminates traditional vertical side-panel joining seams in the main body.
Other seams remain.
These may include connections involving:
Bottom.
Top.
Lift loops.
Filling components.
Discharge components.
Other structural features.
A better description is:
Tubular Woven Main Body With No Traditional Vertical Side-Panel Joining Seams.
At minimum, control the important variables:
| Specification | What to Define |
|---|---|
| 📦 Product | Actual material being packaged |
| ⚗️ Bulk density | Actual value or approved range |
| ⚖️ Target payload | Intended product weight |
| 🔵 Body | Circular / tubular woven construction |
| 🔝 Top | Open, duffle, filling spout, etc. |
| ⬇️ Bottom | Flat, discharge spout, duffle, etc. |
| ⚖️ SWL | Required Safe Working Load |
| 🛡️ Safety factor | Required intended-use classification |
| 🧶 Fabric | Approved tubular woven polypropylene |
| 💧 Coating | Coated or uncoated |
| 🪡 Seams | Remaining structural/containment requirements |
| 🛍️ Liner | Type and configuration if required |
| 🪢 Lift loops | Style and dimensions |
| 📐 Dimensions | Required empty dimensions |
| 📏 Filled geometry | Critical loaded dimensions |
| 🎯 Tolerances | Critical dimensional tolerances |
| 🪵 Pallet | Required pallet compatibility |
| ⚙️ Filling | Actual filling method |
| 🔻 Discharge | Actual unloading method |
| 🌫️ Dust | Containment requirements |
| 💦 Moisture | Barrier requirements |
| ⚡ Static | Electrostatic requirements when applicable |
| 🏷️ Printing | Approved artwork and identification |
| 📦 Packing | Empty-bag packing requirements |
| 📄 Revision | Current approved specification |
Start with what goes inside.
Is it:
Powder?
Pellets?
Granules?
Plastic resin?
Mineral?
Agricultural material?
Food ingredient?
Chemical product?
Industrial raw material?
Something bulky or irregular?
The product should drive the FIBC specification.
Bulk density influences:
Required volume.
Payload.
Filled height.
Filled footprint.
SWL selection.
Warehouse cube.
Transportation.
Do not guess.
State how much product should be loaded into each FIBC.
Target payload should work with:
Bulk density.
Available volume.
SWL.
Safety factor.
Dimensions.
Handling.
Pallet.
Transportation.
Do not write:
Heavy duty.
Do not write:
Extra strong.
Specify the required SWL.
State the required safety factor or intended-use classification.
Do not use safety factor as permission to exceed the rated SWL.
The purchase order should state:
Body Construction: Circular / Tubular Woven
Then reference the approved drawing.
This makes the intended body architecture clear.
If the reduced vertical side-panel seam arrangement is specifically important, say so.
For example:
Main Body: Tubular Woven Polypropylene Construction Without Traditional Vertical Side-Panel Joining Seams
That communicates why circular construction is being requested.
U-panel construction generally uses:
One continuous main panel forming one sidewall, the bottom, and the opposite sidewall.
Two separate side panels complete the body.
Circular construction uses tubular woven fabric for the primary body.
Different construction.
Four-panel construction uses four separate side panels joined together vertically, with a separately attached bottom.
Circular construction uses tubular woven fabric for the main body.
Again:
Different construction.
Baffles are internal structures used to control outward sidewall expansion.
Circular describes the main body.
If shape control is required, specify baffles separately.
If the design requires internal baffles, state that explicitly.
Do not assume:
Circular = form stable.
It does not.
Define:
Width.
Length.
Height.
And any other critical empty dimensions.
Then define realistic tolerances.
Flexible woven polypropylene changes shape under load.
Product enters.
Sidewalls expand.
Corners round.
Material settles.
The footprint changes.
If loaded geometry matters, measure loaded geometry.
If the FIBC must work with:
Pallets.
Racking.
Filling equipment.
Discharge equipment.
Warehouse layouts.
Truck or container load plans.
Then identify the critical loaded dimensions.
If pallet fit matters, document the target footprint.
Then validate it with the actual product and payload.
Do not write:
Must fit pallet.
Define what acceptable fit actually means.
FIBCs are flexible packaging.
Not machined steel components.
Control tolerances that materially affect:
Equipment.
Pallet fit.
Filling.
Discharge.
Handling.
Storage.
Transportation.
Do not create unnecessary manufacturing complexity by tightening every dimension without a reason.
Call or Text us at 832.400.1394
Circular describes the body.
Not how the FIBC is filled.
The top must be specified separately.
A simple specification might state:
Body Construction: Circular / Tubular Woven
Top Construction: Full Open Top
Then reference the complete drawing.
State:
Body Construction: Circular / Tubular Woven
Top Construction: Duffle Top With Approved Closure
Then define critical dimensions and closure requirements.
State:
Body Construction: Circular / Tubular Woven
Top Construction: Filling Spout
Then specify:
Spout opening.
Spout length.
Closure.
Equipment interface.
Critical tolerances.
Tell the supplier how product actually enters the FIBC.
Examples include:
Gravity filling.
Conveyor.
Chute.
Filling head.
Manual loading.
Other process equipment.
The top should match the real operation.
If a filling spout connects to equipment, measure the equipment.
Do not guess the interface.
If throughput matters, communicate it.
A technically correct bag can still be operationally expensive if it slows production.
This can be particularly important with:
Fine powders.
Fast filling.
Coated fabric.
Liners.
Closed filling systems.
Product enters.
Air must leave.
The specification should support that process.
Circular construction can reduce traditional vertical body seam paths.
That does not solve every dust issue.
Consider:
Fabric.
Coating.
Remaining seams.
Liner.
Top closure.
Equipment interface.
Air displacement.
The body tells you nothing about how product exits.
The bottom must be specified separately.
State:
Body Construction: Circular / Tubular Woven
Bottom Construction: Flat Bottom / No Discharge Spout
Use this when controlled bottom discharge is unnecessary.
State:
Body Construction: Circular / Tubular Woven
Bottom Construction: Discharge Spout With Approved Closure
Then specify:
Outlet opening.
Outlet length.
Closure.
Receiving-equipment interface.
State:
Body Construction: Circular / Tubular Woven
Bottom Construction: Duffle Bottom / Wide-Opening Discharge With Approved Closure
Then verify that the receiving system can handle the resulting product flow.
Where does product go?
Into a:
Hopper?
Mixer?
Conveyor?
Bin?
Process vessel?
Other container?
The bottom should match the real receiving system.
Does the process need:
Controlled discharge?
Rapid full discharge?
Metered flow?
Partial discharge?
Define the requirement.
If operators need to stop and restart flow, communicate that before the bottom configuration is finalized.
Does the product:
Flow freely?
Bridge?
Cake?
Clump?
Compact?
Interlock?
This can determine whether the discharge system works.
Particle size may affect:
Containment.
Fabric.
Seams.
Dust.
Top opening.
Bottom opening.
Liner.
Flow.
Round pellets and irregular flakes do not necessarily behave the same.
Describe the actual material.
Abrasive material can wear:
Fabric.
Bottom areas.
Seams.
Discharge components.
That needs to be considered.
Sharp or angular material can create:
Puncture concerns.
Localized wear.
Stress.
Communicate it.
If the material is filled at unusual temperatures, document the actual operating condition.
Do not simply write:
Polypropylene.
Define the approved fabric construction through the controlled technical specification.
Fabric affects:
Strength.
Containment.
Abrasion resistance.
Handling.
Overall performance.
State it.
Coated fabric can help reduce fine-particle migration through the weave and improve resistance to moisture moving through the fabric.
Uncoated fabric generally provides more breathability.
Choose based on the application.
Circular construction reduces traditional vertical body panel seams.
It does not eliminate all seams.
Define any requirements for:
Bottom seams.
Top seams.
Spout seams.
Other component seams.
Structural performance.
Fine-particle containment.
If the product is fine enough to migrate through small openings, state the required containment performance.
Do not assume tubular construction alone solves sifting.
Liners may be needed for:
Moisture.
Fine particles.
Contamination control.
Product cleanliness.
Chemical compatibility.
Additional barrier performance.
Specify the requirement.
Do not write only:
With liner.
Specify:
Loose insertion.
Form fit.
Or another approved configuration.
If liner material or thickness affects the application, control it in the specification.
The liner must work with the selected filling method.
This becomes particularly important with filling spouts and closed filling systems.
If the FIBC discharges through the bottom, make sure the liner works with the discharge system.
Avoid vague terms like:
Waterproof.
Define the actual protection required.
Consider:
Fabric.
Coating.
Liner.
Seams.
Top closure.
Bottom closure.
Storage.
Nationwide transportation.
If dust or product loss matters, define the containment requirements.
Circular construction can help with one aspect of the body.
The complete FIBC determines the result.
For sensitive products, define:
Product-contact requirements.
Liner requirements.
Manufacturing conditions.
Closures.
Packing.
Handling.
Traceability when applicable.
Electrostatic requirements are separate from circular construction.
If the application requires a particular FIBC electrostatic classification, specify it independently.
Define:
Loop style.
Loop location.
Loop dimensions.
Equipment compatibility.
The FIBC has to be handled safely and efficiently.
Loop length can affect:
Forklift access.
Filling equipment.
Discharge equipment.
Operator handling.
Overall hanging height.
Control it when critical.
Calculate:
Body.
Loops.
Top.
Bottom.
Then compare the total suspended height with the actual equipment.
Call or Text us at 832.400.1394
If the circular FIBC will be palletized, define the actual pallet requirement.
Then evaluate:
Filled footprint.
Overhang.
Height.
Stability.
Handling.
Storage.
Transportation.
Ask:
Does the loaded FIBC fit the intended storage position?
Does bulging create interference?
Is clearance limited?
Does the bag waste warehouse cube?
Can forklifts handle it efficiently?
Use loaded dimensions.
Consider:
Payload.
Loaded dimensions.
Pallet configuration.
Settling.
Vibration.
Handling.
Truck or container loading.
Applicable weight constraints.
The FIBC needs to work through the complete logistics chain.
This can change the value of filled-shape control.
If shipments cube out, loaded footprint may have significant economic importance.
If shipments consistently reach applicable weight constraints first, geometry may have less transportation impact.
Understand the economics.
Define:
Company information.
Product identification.
Warnings.
Handling instructions.
Lot information.
Traceability.
Other required markings.
Use controlled artwork when appropriate.
If print placement matters, define:
Panel or body location.
Orientation.
Number of printed sides.
Artwork position.
Do not leave critical marking requirements open to interpretation.
Define how the empty FIBCs should arrive.
For example:
Folded.
Baled.
Palletized.
Liners installed.
Specific orientation.
Packing can affect plant efficiency.
Give the approved design a controlled identity.
For example:
FIBC Item CIR-210 — Rev. B
Now purchasing can order a specific FIBC instead of describing one from memory.
If something changes, update the revision.
That includes changes to:
Body.
Fabric.
Coating.
Seams.
Top.
Bottom.
Liner.
Loops.
Dimensions.
SWL.
Printing.
Other critical requirements.
Which last time?
Which PO?
Which drawing?
Which revision?
Which liner?
Which fabric?
Which bottom?
Reference the approved item.
Operations says:
“Make the loops longer.”
Quality says:
“Improve sift resistance.”
Engineering says:
“Change the filling spout.”
Production says:
“Add a liner.”
If those changes are approved, update the controlled specification.
Otherwise the next order can quietly revert to the old design.
A photograph may show:
General body appearance.
Top.
Loops.
Color.
Maybe the bottom.
It cannot reliably communicate:
Fabric specification.
SWL.
Safety factor.
Remaining seam construction.
Liner.
Critical dimensions.
Tolerances.
Use technical documentation.
A useful description might read:
FIBC — Circular / Tubular Woven Body Construction / [Approved Top] / [Approved Bottom] / [Required SWL] / [Required Safety Factor] / [Coated or Uncoated] / [Liner Requirement] / [Lift Loop Configuration] / Per Approved Specification [Revision]
Then reference the drawing.
A controlled specification might include:
Product: Approved dry bulk material
Bulk Density: Approved value or range
Target Payload: Approved fill weight
Body Construction: Circular / Tubular Woven
Body Description: Tubular woven polypropylene main body without traditional vertical side-panel joining seams
Top Construction: Approved configuration
Bottom Construction: Approved configuration
SWL: Required Safe Working Load
Safety Factor: Required intended-use classification
Fabric: Tubular woven polypropylene per approved specification
Coating: Coated or uncoated as required
Seams: Remaining structural and containment seams per approved construction
Liner: Approved configuration if required
Lift Loops: Approved style and dimensions
Empty Dimensions: Per drawing
Critical Filled Dimensions: Per 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
Now you have a controlled FIBC.
Body Construction: Circular / Tubular Woven
Top Construction: Full Open Top
Bottom Construction: Approved Bottom
All Remaining Construction: Per Approved Drawing and Revision
Body Construction: Circular / Tubular Woven
Top Construction: Duffle Top With Approved Closure
Bottom Construction: Approved Bottom
Then reference the complete specification.
Body Construction: Circular / Tubular Woven
Top Construction: Filling Spout With Approved Opening, Length, and Closure
Bottom Construction: Approved Bottom
Then define the actual filling-equipment interface.
Body Construction: Circular / Tubular Woven
Top Construction: Approved Top
Bottom Construction: Discharge Spout With Approved Opening, Length, and Closure
Then reference product-flow and receiving-equipment requirements.
Body Construction: Circular / Tubular Woven
Top Construction: Approved Top
Bottom Construction: Duffle Bottom / Wide-Opening Discharge With Approved Closure
Then verify actual discharge performance.
Before releasing the PO, confirm:
Common mistakes include:
Writing only “circular bag.”
Calling the entire FIBC seamless.
Assuming circular means round.
Assuming fewer vertical body seams automatically mean stronger.
Assuming circular construction eliminates all sifting.
Assuming circular means dustproof.
Assuming circular means waterproof.
Assuming circular means baffle.
Assuming the filled bag stays perfectly square.
Ignoring the actual product.
Ignoring bulk density.
Ignoring payload.
Ignoring SWL.
Ignoring safety factor.
Ignoring the bottom construction.
Ignoring remaining seam requirements.
Ignoring coating.
Ignoring liner requirements.
Ignoring filling equipment.
Ignoring discharge equipment.
Ignoring air displacement.
Ignoring dust.
Ignoring moisture.
Ignoring static requirements.
Ignoring loops.
Ignoring hanging height.
Ignoring filled dimensions.
Ignoring pallet overhang.
Ignoring warehouse requirements.
Ignoring nationwide transportation.
Ordering from a photograph.
Using “same as last time.”
Allowing changes to live only in email.
Failing to control revisions.
Ask:
How is the FIBC filled?
Does the current top work?
How long does filling take?
Does the liner move?
Does the product dust?
Does the loaded FIBC bulge?
Does it fit the pallet?
How is product discharged?
Does it bridge?
Does it surge?
How much remains after discharge?
Operators can reveal problems no purchase order can show by itself.
Ask:
Does the loaded FIBC fit the pallet?
How much overhang exists?
Does the load remain stable?
Are loops easy to access?
Does the loaded geometry waste storage space?
Does the FIBC interfere with adjacent loads?
Feed those answers back into the specification.
Ask:
What loaded dimensions matter?
How are the FIBCs transported?
Does the shipment cube out?
Does it weigh out?
Does bulging affect load planning?
Does settling change the package during nationwide transportation?
Packaging should fit the logistics system.
Ask:
Why is circular construction required?
What value do reduced vertical body seams create?
What fabric is required?
What remaining seam requirements apply?
What top is required?
What bottom is required?
Is a liner required?
What SWL is required?
What safety factor is required?
What dimensions are critical?
What tolerances actually matter?
Put those answers into controlled documentation.
An empty sample tells you surprisingly little.
Fill it.
Use the actual product.
Use the intended payload.
Use the real filling equipment.
Then evaluate:
Filling time.
Air displacement.
Dust.
Body behavior.
Remaining seams.
Liner behavior.
Loaded dimensions.
Pallet fit.
Overhang.
Loops.
Handling.
Settling.
Discharge.
Residual product.
That is the real test.
Run the FIBC through the complete process.
Fill it.
Measure it.
Handle it.
Palletize it.
Store it.
Move it.
Discharge it.
Then document the approved design.
Assign:
Internal item number.
Drawing.
Revision.
Approved sample when appropriate.
Now purchasing has a standard.
The PO does not necessarily need every manufacturing detail written directly on it.
But it should reference controlled documents that contain those details.
For example:
FIBC Item CIR-210, Rev. B — Circular / Tubular Woven Construction Per Approved Drawing and Specification
That can work when the referenced documents fully define the FIBC.
Standardization can improve:
Quote accuracy.
Supplier comparison.
Receiving inspection.
Quality consistency.
Inventory management.
Production efficiency.
Warehouse planning.
Repeat ordering.
Troubleshooting.
It also reduces one of the most expensive sentences in industrial packaging:
“These aren’t the same bags we got last time.”
Before comparing prices, make sure every quote is based on the same:
Product application.
Bulk density.
Target payload.
Circular body construction.
SWL.
Safety factor.
Top.
Bottom.
Fabric.
Coating.
Remaining seams.
Liner.
Loops.
Dimensions.
Tolerances.
Printing.
Packing.
Performance requirements.
Otherwise you are not comparing prices for the same FIBC.
Start with the product.
What is going inside?
What is the bulk density?
How does it flow?
What is the particle size?
Is it dusty?
Abrasive?
Sharp?
Moisture sensitive?
What is the target payload?
Then determine:
SWL.
Safety factor.
Now define the process.
How does product enter?
What filling equipment is used?
What top is required?
How quickly does product enter?
How does displaced air escape?
Then define discharge.
How does product leave?
What receiving equipment is used?
Do you need:
Controlled discharge?
Rapid discharge?
Partial discharge?
No conventional bottom outlet?
Now define the body:
Circular / Tubular Woven Construction.
Then specify:
Fabric.
Coating.
Remaining seam requirements.
Liner.
Loops.
Dimensions.
Critical tolerances.
Pallet.
Loaded footprint.
Printing.
Packing.
Revision.
Then test it.
Use the actual product.
Use the actual target payload.
Use the real filling equipment.
Time the fill.
Watch the air.
Check the dust.
Inspect the tubular body.
Inspect the bottom and other critical seams.
Check the liner.
Measure the loaded FIBC.
Put it on the actual pallet.
Check overhang.
Allow representative settling.
Measure again.
Have operators handle it.
Store it under representative conditions.
Move it through representative nationwide transportation conditions.
Then discharge it through the actual receiving system.
Measure:
Filling time.
Loaded dimensions.
Pallet fit.
Overhang.
Handling.
Discharge time.
Residual product.
Dust.
Spillage.
Operator intervention.
If it works, lock the specification.
Assign an item number.
Approve the drawing.
Control the revision.
Now purchasing can repeatedly buy the same packaging system without depending on photographs, assumptions, or somebody’s memory.
Because “circular” should clearly identify the tubular woven body construction—not leave the rest of the FIBC open to interpretation.
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