Minimum Order Quantity (MOQ): 1 pallet (typically 125–250+ bulk bags)
To specify a flat bottom on an FIBC purchase order, clearly state “Bottom Construction: Flat Bottom / No Discharge Spout” and then separately define the top style, body construction, Safe Working Load, safety factor, fabric, coating, liner, lift loops, dimensions, tolerances, product characteristics, filling method, unloading method, printing, and packing requirements so nobody has to guess what “flat bottom bulk bag” actually means.
Here is what you do not want on a purchase order:
“White flat bottom bulk bag.”
That leaves almost everything unanswered.
Flat bottom tells you one thing about one section of the FIBC.
It does not tell you how the bag is filled.
It does not tell you the body construction.
It does not tell you how much weight it is designed to carry.
It does not tell you whether there is a liner.
It does not tell you whether the fabric is coated.
It does not tell you what loops are required.
And most importantly, it does not tell anybody how the product will eventually come out.
A good purchase order removes assumptions.
Flat bottom means the lower portion of the FIBC is permanently closed rather than equipped with a conventional discharge spout.
The product enters through the top.
The bottom remains closed during filling, storage, handling, and transportation.
There is no standard bottom outlet that can be opened for controlled gravity discharge.
That distinction should be crystal clear on the purchase order.
A clear description is:
Bottom Construction: Flat Bottom / No Discharge Spout
That is better than simply writing:
Flat Bottom
Why add “No Discharge Spout”?
Because it removes ambiguity.
If purchasing, operations, engineering, quality, and the supplier all read the same line, they should all picture the same lower construction.
That is the goal.
Because the bottom is only one component.
Two flat bottom FIBCs can be completely different.
One might have an open top.
Another might have a filling spout.
One might be coated.
Another uncoated.
One might contain a liner.
Another might not.
One might be intended for lightweight recycling material.
Another might carry a dense industrial product.
Same bottom description.
Different bags.
At minimum, control these areas:
| Specification | What to Define |
|---|---|
| ⬇️ Bottom | Flat bottom / no discharge spout |
| 🔵 Top | Open, duffle, filling spout, etc. |
| 🏗️ Body | Circular, U-panel, four-panel, baffle, etc. |
| ⚖️ SWL | Required Safe Working Load |
| 🛡️ Safety factor | Required classification |
| 📦 Product | Material being packaged |
| ⚗️ Bulk density | Actual or approved range |
| 🧵 Fabric | Required FIBC fabric construction |
| 💧 Coating | Coated or uncoated |
| 🛍️ Liner | Type and configuration if required |
| 🪢 Lift loops | Style and critical dimensions |
| 📐 Dimensions | Required FIBC dimensions |
| 📏 Tolerances | Critical dimensional tolerances |
| ⚙️ Filling | How product enters the bag |
| 📤 Unloading | How product will be removed |
| 🏷️ Printing | Labels, warnings, identification |
| 📄 Revision | Current approved specification |
If the PO controls those items or references a controlled drawing that does, you are in much better shape.
Use direct language.
Do not make somebody infer what you mean.
A simple specification line is:
Bottom: Flat Bottom / No Discharge Spout
If the absence of an outlet is critical, spell it out.
This also helps prevent a supplier from quoting a similar configuration with a discharge spout simply because that is what they normally manufacture for the application.
Flat bottom says nothing about the top.
You still need to specify how the FIBC is filled.
Common options include:
Open Top / Flat Bottom
Duffle Top / Flat Bottom
Filling Spout Top / Flat Bottom
Those three bags share the same basic bottom style.
Their filling processes can be completely different.
Specify both ends.
For bulky or irregular products, open top plus flat bottom can provide maximum filling access with simple lower construction.
A PO description might include:
Top: Full Open Top
Bottom: Flat Bottom / No Discharge Spout
Then define the rest of the bag separately.
If broad filling access is needed but the upper portion should be closable afterward, specify:
Top: Duffle Top With Closure
Bottom: Flat Bottom / No Discharge Spout
Do not simply write “duffle flat bottom bag.”
Use controlled terminology.
If the FIBC connects to filling equipment but does not need controlled bottom discharge:
Top: Filling Spout Top With Closure
Bottom: Flat Bottom / No Discharge Spout
Then define the filling-spout dimensions and equipment interface separately.
Top and bottom perform different jobs.
Treat them that way.
Tell the supplier what is going inside.
Recycling material?
Scrap?
Debris?
Aggregate?
Powder?
Pellets?
Granules?
Mineral?
Agricultural material?
Industrial product?
Product characteristics affect almost every other part of the FIBC specification.
Do not hide the application.
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This matters especially with flat bottom construction.
Why was the discharge spout eliminated?
Maybe because the product is too bulky or irregular to flow through one.
If that is the reason, communicate it.
Product geometry affects filling, settling, fabric stress, and unloading.
Scrap and industrial materials can contain edges that challenge the fabric.
Aggregates and minerals can be abrasive.
If the material creates unusual wear or puncture concerns, that information belongs in the specification discussion.
“Flat bottom” does not tell the supplier any of this.
Bulk density connects weight to volume.
This is critical.
A dense material may reach the Safe Working Load before the FIBC appears physically full.
A lightweight product may fill the available volume while remaining below the SWL.
Provide realistic bulk-density information whenever possible.
How much product should go into each FIBC?
Do not leave that vague.
The target payload helps determine the appropriate FIBC size and Safe Working Load.
It also affects:
Filled geometry.
Handling.
Palletization.
Warehouse storage.
Transportation.
Discharge.
The bag should be designed around the actual load.
The purchase order or referenced specification should clearly state the required Safe Working Load.
Do not write:
“Heavy duty.”
“Strong bag.”
“Extra strong.”
Those are not engineering specifications.
Specify the actual requirement.
The required safety factor should also be documented where applicable.
And remember:
Safety factor is not extra payload capacity.
The stated SWL remains the working limit.
Do not increase fill weight because the safety factor sounds generous.
Flat bottom can be incorporated into different FIBC body styles.
Possible constructions include:
Circular.
U-panel.
Four-panel.
Baffle.
The body affects filled shape, handling, pallet utilization, and other performance characteristics.
Do not assume flat bottom defines the body.
If circular construction is required, state it.
For example:
Body Construction: Circular
Bottom Construction: Flat Bottom / No Discharge Spout
Simple.
No ambiguity.
Same principle.
Body Construction: U-Panel
Bottom Construction: Flat Bottom / No Discharge Spout
Do not rely on a photograph to communicate construction.
If four-panel construction is required:
Body Construction: Four-Panel
Then separately state:
Bottom Construction: Flat Bottom / No Discharge Spout
Again, body and bottom are separate specification fields.
If maintaining a more rectangular filled profile matters, baffle construction may be appropriate.
If required, specify:
Body Construction: Baffle FIBC
Bottom Construction: Flat Bottom / No Discharge Spout
Do not assume “square bag” means baffle construction.
Use the actual construction terminology.
Does the application require coated fabric?
Or uncoated?
Coated woven polypropylene may improve fine-particle containment and resistance to moisture moving through the woven fabric.
Uncoated fabric provides greater breathability.
Neither option is universally better.
Document the required construction.
This is a specification mistake.
A permanently closed bottom does not make the entire FIBC waterproof.
Moisture can potentially enter through:
Top closures.
Seams.
Fabric.
Other construction details.
If moisture protection matters, define the actual requirement.
Tell the supplier what the product needs.
Is the concern:
Humidity?
Rain exposure?
Moisture vapor?
Temporary outdoor exposure?
Long-term storage?
Those are different conditions.
The solution may involve coated fabric, a liner, storage practices, or other features.
If the product needs additional barrier protection, specify the liner.
Do not write only:
“With poly liner.”
That may still leave important details undefined.
Specify the appropriate liner style and performance requirements.
If liner geometry matters, define it.
Loose-insertion liners may be simple and economical.
Form-fit liners can provide more controlled positioning.
The correct option depends on the application.
Do not let the liner configuration change accidentally between orders.
This is especially important with flat bottom FIBCs.
You do not have a conventional bottom discharge spout.
So how is product being removed?
Does the liner remain inside?
Can it shift?
Can it collapse into the product?
Can material become trapped in folds?
Could it interfere with unloading equipment?
The liner needs to work with the discharge process.
How does product enter the FIBC?
Gravity chute?
Conveyor?
Filling head?
Manual loading?
Loader?
Other equipment?
The top construction needs to match the filling method.
Flat bottom does not answer that question.
This may be the most important flat-bottom-specific information on the entire specification.
How will the product come out?
If nobody can answer, stop.
Do not finalize the bag.
The entire reason to choose flat bottom is that a conventional discharge spout is unnecessary.
Prove that assumption before ordering thousands of bags.
This is backwards.
First determine whether controlled bottom discharge is unnecessary.
Then eliminate the discharge spout.
Then take the savings.
Do not begin with:
“Flat bottom is cheaper.”
And work backward.
Packaging cost is only one part of operating cost.
Will the entire FIBC be emptied at once?
Or does the process need part of the material now and the remainder later?
If partial discharge is common, flat bottom may be less convenient than a controlled discharge configuration.
Document the operational requirement before selecting the bottom.
Does the FIBC feed:
A hopper?
Mixer?
Conveyor?
Process vessel?
Other production equipment?
If that equipment expects a controlled bottom outlet, flat bottom may create a mismatch.
Do not design the FIBC separately from the machinery using it.
How quickly does the product need to be removed?
If unloading throughput matters, this can change the bottom decision.
A flat bottom might save money on packaging but increase cycle time.
Calculate both.
Is the product inexpensive debris?
Or a high-value ingredient?
That changes the economics.
If the unloading method loses a small percentage of product, calculate the annual cost.
Product loss can dwarf FIBC price differences.
Flat bottom eliminates a conventional bottom discharge opening during storage.
But dust can still become an issue during filling and unloading.
If the material is dusty, communicate the requirement.
Dust performance can depend on:
Top design.
Fabric.
Coating.
Liner.
Seams.
Filling process.
Unloading process.
Do not assume bottom style solves dust.
If product cleanliness matters, define it.
Potential contamination can involve:
FIBC manufacturing.
Fabric.
Liner.
Filling equipment.
Storage.
Transportation.
Unloading.
Flat bottom is only one part of the packaging system.
Certain products and environments require careful electrostatic consideration.
Flat bottom does not determine FIBC electrostatic classification.
If static control is relevant, document the actual application requirements separately.
Do not assume one feature tells you everything about the bag.
Now move upward.
How will the FIBC be lifted?
What equipment handles it?
What filling frame is used?
Possible loop configurations vary.
Specify the approved style.
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Loop length can affect:
Forklift handling.
Filling-frame fit.
Overall hanging height.
Discharge setup.
If the dimension interfaces with equipment, control it.
Do not rely on “standard loops.”
Define the required bag dimensions using a consistent convention.
Do not assume the supplier knows what dimensions you used on an old spreadsheet.
Also remember:
FIBCs are flexible.
Empty dimensions do not perfectly predict filled dimensions.
If filled geometry matters, test it.
Not every dimension needs an unnecessarily tight tolerance.
Identify the ones that matter operationally.
Overall bag height.
Footprint.
Loop length.
Filling-spout dimensions when applicable.
Other equipment interfaces.
Control what matters.
This is important for palletization and warehouse storage.
A flexible FIBC can bulge.
The filled footprint depends on:
Body construction.
Product characteristics.
Filling method.
Baffles when present.
Product settling.
Do not approve logistics based only on empty dimensions.
If the FIBC sits on a pallet, document relevant constraints.
Required pallet fit.
Overhang limitations.
Weight distribution.
Handling.
Warehouse storage.
Transportation.
A flat bottom bag can still be a terrible pallet load if the overall FIBC geometry is wrong.
Where will the filled bags go?
How long will they remain there?
How much space is available?
Does filled shape matter?
Are bags stored on pallets?
Are there moisture concerns?
Contamination concerns?
Outdoor exposure?
Warehouse requirements belong in packaging decisions.
The FIBC may move nationwide after filling.
Consider:
Forklift handling.
Loading.
Unloading.
Vibration.
Movement.
Palletization.
Environmental exposure.
The complete bag needs to remain suitable through the logistics cycle.
If outdoor storage is expected, state it.
Do not assume a closed bottom makes outdoor storage acceptable.
Consider:
UV exposure.
Rain.
Humidity.
Temperature.
Storage duration.
Surface conditions.
These factors can affect the packaging system.
Document required printing and labeling.
Product identification.
Handling instructions.
Warnings.
Traceability.
Company information.
Lot information.
Other required markings.
Use controlled artwork when appropriate.
How should the empty bags arrive?
Folded?
Baled?
Palletized?
Are liners already inserted?
How many bags are packed together?
These details can affect receiving, storage, and production efficiency.
If they matter, document them.
A repeat-order specification should have a controlled identity.
For example:
FIBC Item FB-204 — Rev. D
Now purchasing can reference an exact configuration.
That is much better than:
“Flat bottom super sack.”
Specifications change.
Maybe you change:
Top construction.
Body construction.
Liner.
Loop length.
Fabric.
Coating.
Printing.
Bag height.
Even the bottom itself.
Those changes should be documented under controlled revisions.
Otherwise old specifications eventually resurface.
This phrase causes unnecessary risk.
Which shipment?
Which revision?
Which supplier?
Were changes approved through email?
Did the previous order contain an exception?
Reference the approved item number and revision.
Operations asks for a change.
Supplier agrees.
New bags arrive.
Everybody likes them.
Nobody updates the controlled drawing.
Six months later purchasing reorders from the old document.
The old configuration returns.
Email communicates.
Specifications control.
Update the document.
A photograph can show:
General top style.
General bottom appearance.
General loop configuration.
Maybe printing.
It cannot reliably communicate:
SWL.
Safety factor.
Fabric requirements.
Liner performance.
Critical tolerances.
Detailed construction.
Use photographs as supporting references.
Not technical specifications.
A useful PO description could follow this structure:
FIBC — [Top Construction] / [Body Construction] / Flat Bottom, No Discharge Spout / [Required SWL] / [Required Safety Factor] / [Lift Loop Configuration] / [Coated or Uncoated] / [Liner Requirement] / Per Approved Specification [Revision]
Then the controlled drawing or specification contains the technical details.
That is concise enough for purchasing.
And detailed enough for control.
A controlled specification might contain:
Top: Approved open, duffle, filling spout, or other configuration
Body: Approved FIBC body construction
Bottom: Flat Bottom / No Discharge Spout
SWL: Per approved application requirement
Safety Factor: Per intended-use requirement
Product: Approved bulk material
Bulk Density: Approved value or range
Lift Loops: Approved configuration and critical dimensions
Fabric: Woven polypropylene per specification
Coating: Coated or uncoated as required
Liner: Approved configuration if required
Dimensions: Per approved drawing
Tolerances: Critical dimensions controlled
Printing: Per controlled artwork
Packing: Per approved logistics requirement
Unloading Method: Approved process
Revision: Current controlled revision
That structure tells the whole story.
For a simple collection-oriented application:
Top: Full Open Top
Bottom: Flat Bottom / No Discharge Spout
Then reference the complete FIBC specification.
Do not assume those two lines define the entire bag.
For broad filling access plus upper closure:
Top: Duffle Top With Closure
Bottom: Flat Bottom / No Discharge Spout
Then define body, SWL, safety factor, fabric, liner, loops, dimensions, and other requirements.
For controlled filling without controlled bottom discharge:
Top: Filling Spout Top With Closure
Bottom: Flat Bottom / No Discharge Spout
Then define the filling-spout dimensions and equipment interface.
This is a perfect example of why top and bottom need separate specification fields.
Before releasing the order, confirm:
If number fifteen is unknown, the bottom specification is not finished.
The most common mistakes are:
Writing only “flat bottom.”
Not explicitly stating “no discharge spout.”
Never documenting how the product will be unloaded.
Choosing flat bottom only because it costs less.
Ignoring downstream equipment.
Ignoring partial-discharge requirements.
Ignoring product flowability.
Ignoring bulk density.
Ignoring Safe Working Load.
Ignoring safety factor.
Ignoring body construction.
Ignoring liners.
Assuming coated means waterproof.
Ignoring lift loops.
Ignoring filled footprint.
Ignoring pallet fit.
Ordering from photographs.
Using outdated drawings.
And relying on “same as last time.”
All avoidable.
Ask:
How do we fill the FIBC?
How do we empty it?
Does anybody currently use the discharge spout?
Would eliminating it create a problem?
How long does unloading take?
Does product spill?
Does the liner cause problems?
Does the bag fit the equipment?
What feature of the current bag wastes the most time?
Do not guess.
Operations lives with the FIBC every day.
Ask which dimensions actually matter.
Bag footprint.
Overall height.
Loop geometry.
Top dimensions.
Equipment interfaces.
Filled shape.
Pallet fit.
Discharge process.
Control the dimensions that affect equipment and operations.
Do not tighten every tolerance unnecessarily.
Ask:
Does the filled bag fit the pallet?
Does it overhang?
Does it bulge?
Are the loops easy to access?
Does it fit the warehouse position?
Does the top remain properly secured?
Are there moisture problems?
Does the bag survive normal handling?
Warehouse feedback can reveal problems purchasing never sees.
An empty sample proves almost nothing about the discharge decision.
You need product inside it.
Fill the bag.
Reach the target payload.
Observe the filled shape.
Move it.
Palletize it.
Store it.
Then unload it using the actual process.
That final step is critical.
If unloading becomes a nightmare, you just discovered why the bottom specification matters.
Before approval, verify:
The top works with filling.
The body handles the product correctly.
The FIBC reaches the target payload without exceeding SWL.
The filled footprint works.
The loops work.
The liner works if present.
The bag can be moved efficiently.
The package works in storage.
The package works through nationwide transportation.
And most importantly:
The product can be unloaded safely and efficiently without a conventional discharge spout.
Then document the approved configuration.
Detailed enough that the supplier does not need to make important assumptions.
The purchase-order line can remain concise.
The referenced drawing or specification should contain the technical detail.
That gives purchasing a clean PO and operations a controlled product.
Once the correct configuration is established, standardization improves:
Quoting.
Supplier comparison.
Purchasing.
Receiving.
Quality control.
Inventory.
Operator training.
Troubleshooting.
Repeat orders.
Cost optimization.
You can compare equivalent bags instead of vaguely similar FIBCs.
Make sure every supplier is quoting the same thing.
Same top.
Same body.
Same flat bottom construction.
Same SWL.
Same safety factor.
Same fabric.
Same coating.
Same liner.
Same loops.
Same dimensions.
Same printing.
Same packing requirements.
Otherwise the lowest price may simply represent a different bag.
Start with the exact line:
Bottom Construction: Flat Bottom / No Discharge Spout
Then define the top.
Then the body.
Then the product.
Bulk density.
Target payload.
Safe Working Load.
Safety factor.
Fabric.
Coating.
Liner.
Lift loops.
Dimensions.
Critical tolerances.
Pallet requirements.
Warehouse requirements.
Nationwide transportation.
Printing.
Packing.
Revision.
And above all:
Define exactly how the product will be unloaded.
That is the entire reason the flat-bottom decision matters.
If the material is bulky scrap and a discharge spout would never work anyway, flat bottom may be obvious.
If the FIBC is a collection container and the outlet would never be touched, eliminating it may save money without changing the process.
But if a free-flowing product needs to feed a hopper and nobody considered discharge before buying the bag?
You have a problem.
The right purchase order does more than describe a piece of packaging.
It preserves the operational decisions that made that packaging work.
Specify the bottom.
Specify the process.
Control the revision.
Test the bag.
Then reorder the configuration that actually works.
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