VIDEPAK FIBC Bags: A Practical Guide to duffle top, filling top, conical fill spout, full open top and discharge spout Designs
Bulk packaging is easy to underestimate. From a distance, a flexible intermediate bulk container may look like a large woven bag with four lifting loops. In real production, however, every opening has a job, every seam carries a force, and every choice affects what happens before filling, during lifting, in transport, and at final emptying. That is why VIDEPAK approaches FIBC Bags as complete material-handling systems rather than simply large sacks. The body holds the product, the loops connect the load to handling equipment, the filling top controls how material enters, and the discharge spout determines how material leaves. VIDEPAK’s public product range includes open, duffel and filling-spout top options, several bottom configurations, U-panel, circular, four-panel and baffle constructions, plus different lifting arrangements.
The most important purchasing question is therefore not, “Which bulk bag looks strongest?” A more useful question is, “Which combination works with our product and our process?” Free-flowing pellets and dusty flour behave differently. Fine mineral powder and coarse aggregate behave differently. A plant filling through a fixed chute has different needs from a plant loading with a conveyor or loader bucket. The right duffle top, filling top, conical fill spout, full open top or discharge spout is selected by understanding these differences first. Industry guidance likewise treats filling and discharging options as process-dependent choices, while ISO 21898:2024 covers material, construction, design, type-test and marking requirements for FIBCs intended for non-dangerous solid materials.
VIDEPAK PRODUCT LOGIC: Good FIBC Bags should not force a production line to work around the package. The package should work with the production line. Wide access when wide access is needed. Controlled filling when dust matters. Fast discharge when speed matters. Metered discharge when control matters.
Understanding VIDEPAK FIBC Bags as a Complete System
Start With the Product, Not With the Bag Drawing
Before selecting a duffle top, filling top, conical fill spout, full open top or discharge spout, the product itself should be defined. What is its bulk density? Is it a fine powder, a grain, a pellet, a flake or an irregular solid? Does it flow freely, or does it tend to bridge and hold together? Is dust control important? Is the product sensitive to moisture? Does the production environment require electrostatic risk control? These questions decide more than the nominal dimensions of FIBC Bags; they decide how the complete container should interact with equipment and operators.
VIDEPAK publishes an engineering reference window of roughly 500–2,000 kg Safe Working Load across its FIBC project ranges and approximately 160–240 g/m² fabric weight in published working ranges. These values are useful starting points, not universal specifications. Actual fabric weight, dimensions, seams, loops, coating, liner, inlet and outlet must be selected around the required load, product density, bag geometry and validated performance. In other words: larger is not automatically safer, heavier is not automatically better, and one standard specification cannot serve every product.
The values and options above reflect VIDEPAK’s published FIBC engineering information and should be used as specification starting points rather than fixed values for every application. ISO 21898:2024 treats an FIBC as a complete design that must meet applicable construction, type-testing and marking requirements.
The Top and Bottom Must Work Together
A common sourcing mistake is to select a top and a bottom independently. Yet filling and emptying are two ends of the same process. A controlled filling top may be ideal for a dusty material, but the same process may lose that advantage if the bag is opened through an uncontrolled bottom. Likewise, a large full open top may make filling extremely simple, while a properly selected discharge spout can still provide controlled emptying later. Good FIBC Bags balance access with containment, speed with control, and simple operation with product protection.
KEY BUYER POINT: Do not specify a duffle top, filling top, conical fill spout, full open top or discharge spout because it is familiar. Specify it because it solves a clearly defined filling, containment or discharge problem.
duffle top and full open top: Maximum Access With Different Closure Logic
What Is a duffle top?
A duffle top uses a large tubular woven skirt around the upper opening of the bag. The opening follows much of the bag’s upper dimensions, so operators gain broad access while filling. After the required quantity has entered the bag, the skirt can be gathered and secured. FIBC industry terminology also calls this structure a duffel or skirt top, and VIDEPAK describes the same basic design as offering nearly open-top access during filling while still providing a practical closure afterward.
This simple combination explains why a duffle top is so useful. Open wide. Fill easily. Close afterward. It sits between two different ideas: the complete simplicity of a full open top and the more restricted, equipment-focused entry of a filling top. The duffle top therefore works especially well when the product comes from above through a broad chute, conveyor or gravity-fed system and the buyer wants a closure after filling but does not need a narrow machine connection. VIDEPAK identifies grains, feed, granules and similar materials as common application areas for this arrangement.
Wide Filling Access
The duffle top keeps the upper opening broad, making it easier to accept products that do not need a small fixed inlet.
Closure After Filling
Unlike a basic full open top, the duffle top provides an extended skirt that can be gathered and secured.
Flexible Loading
A duffle top is attractive when broad loading flexibility matters more than a tight connection between the bag and filling machine.
What Is a full open top?
A full open top is the most direct top arrangement in this guide: the upper face of the bag remains open rather than being restricted by a central spout. In standard industry terminology this is generally called an open top, and FIBC industry guidance recognizes open top as one of the common filling configurations. VIDEPAK positions open-top designs for maximum access, while its duffle top adds the skirt needed for a more practical post-fill closure.
The strength of a full open top is obvious: almost the entire bag mouth can receive material. Large particles, irregular products and coarse bulk materials do not have to pass through the narrower neck of a filling top. Loading equipment also has more positional tolerance. The trade-off is equally clear. More open area means less inherent containment around the filling point. When dust, hygiene, moisture protection or a controlled machine connection becomes a priority, a filling top may provide a better interface.
That contrast is important. The full open top says “maximize access.” The filling top says “control the entry path.” The duffle top stands between them and says “keep broad access, then close the bag.” None is automatically better. Each answers a different operating question.
QUICK CHOICE: Choose a full open top when unrestricted access is the first priority. Move to a duffle top when you still need broad access but want a practical closing skirt. Move toward a filling top when the filling chute and the bag should work as a more controlled interface.
filling top and conical fill spout: Controlled Entry for Modern Filling Lines
Understanding the filling top
In this guide, filling top refers to the FIBC top interface built around a central fill spout, commonly called a fill spout, inlet spout, top spout or spout top in industry terminology. FIBCA defines a fill spout as the inlet used for filling an FIBC and notes that it is designed to fit the customer’s filling chute. VIDEPAK likewise describes a cylindrical filling tube sewn into the upper panel and designed around the customer’s filling equipment.
This equipment match is the real advantage of a filling top. Instead of allowing material to fall through the entire bag opening, the filling line directs the product through a defined inlet. The connection can help limit unnecessary open exposure around the product stream, improve housekeeping and create a repeatable position between the filling head and the bag. For powders, pellets, food ingredients, cement-related materials and many industrial products, VIDEPAK presents spout-top filling as the more controlled alternative to broad open filling.
Diameter matters. Length matters. Chute geometry matters. So does the way the filling top is secured before and after use. This is why VIDEPAK does not treat the filling top as a decorative accessory. A poorly matched inlet can make operators fight the package every cycle; a correctly matched filling top can make the bag and filling machine behave like parts of one system.
When a Standard filling top Makes Sense
For many free-flowing powders and granules, a cylindrical filling top gives a practical balance of filling speed and containment. It can be matched to the plant chute, filled through a smaller defined opening and then closed using the designed tie or closure arrangement. Compared with a full open top, this arrangement gives up some access in exchange for greater control. Compared with a duffle top, it is less flexible for broad loading but better suited to repeatable machine filling. VIDEPAK’s published selection rule summarizes the distinction clearly: maximum access favors open top, broad access with tie closure favors duffel, and controlled machine filling favors a spout top.
Why Consider a conical fill spout?
A conical fill spout, corresponding to VIDEPAK’s conical spout-top concept, changes the upper geometry from a simple flat top around a cylindrical inlet toward a funnel-like form. The cone helps guide incoming material toward the main bag body. VIDEPAK notes that this design can support smoother filling when product flow, filling-head arrangement or useful upper volume makes a conventional flat spout top less suitable, and that cone geometry, inlet diameter and inlet length can be engineered around the filling equipment.
The difference between an ordinary filling top and a conical fill spout is therefore not simply visual. It is geometric. A standard filling top creates a defined tube into the bag. A conical fill spout also shapes the transition from the filling point toward the main body. Where filling geometry is difficult, where material must spread efficiently, or where the top profile needs to work more closely with the filling head, the conical fill spout gives designers another tool.
ENGINEERING RULE: A conical fill spout should not be selected because “conical sounds more advanced.” It should be selected when the filling geometry benefits from the funnel-like transition. The simpler filling top remains an efficient choice whenever a cylindrical inlet already matches the product and filling equipment.
Containment Is a System, Not One Piece of Fabric
A filling top can reduce open exposure during filling, but buyers should not assume that a tied spout automatically creates a hermetic or moisture-proof package. VIDEPAK specifically notes that an added flap over a filling spout does not by itself make the bag moisture-proof or hermetic; coating, liner construction and closure design must also be specified when higher barrier performance is required. Form-fit liners can also be designed around fill and outlet spout dimensions to support filling and discharge performance.
This is a useful principle for every FIBC Bags project: never ask one component to perform the work of the entire package. The filling top controls entry. The liner can improve internal containment or barrier performance. The woven body carries mechanical load. The seams connect the structure. The loops manage lifting. The discharge spout controls exit. Performance comes from the combination.
discharge spout: Turning Storage Into Controlled Product Flow
Why the discharge spout Matters
The bottom of FIBC Bags is often discussed after the top, yet it can be just as important to daily operations. FIBCA defines a discharge spout, also called a bottom spout, as an outlet used to empty an FIBC. VIDEPAK’s standard concept places a cylindrical outlet in the center of the base, secured while the bag is stored or transported and opened over receiving equipment when discharge begins.
The central benefit of a discharge spout is control. Cutting a closed base can produce a rapid, difficult-to-stop release. A designed discharge spout, by contrast, gives the product a defined flow path toward a hopper, process vessel or receiving station. For powders, grains, pellets and granules, VIDEPAK positions this bottom style as one of the most versatile choices because it combines direction, practical flow control and easier connection to industrial discharge systems.
Diameter and Length Should Follow the Product
VIDEPAK’s published guidance gives approximately 14 inches in outlet diameter and around 18 inches in length as a commonly used starting format for a discharge spout, while also stressing that broader custom dimensions are available. These dimensions should not be copied blindly. Particle size, bulk density, cohesion, expected discharge rate and the receiving-equipment opening all affect the correct outlet geometry. A smaller discharge spout may help control flow but can slow coarse material. A larger discharge spout can accelerate emptying but may reduce metering control.
This creates a useful contrast: the biggest opening is not always the best opening. Fast is useful, until fast becomes uncontrolled. Small is useful, until small causes bridging. Good FIBC Bags are built around the required flow, not around the largest available outlet.
For Free-Flowing Products
A correctly sized discharge spout can create a clean, directed stream into a receiving hopper.
For Coarse Material
The discharge spout must be large enough to avoid unnecessary restriction; very difficult material may justify a wider full-opening bottom instead.
For Controlled Feeding
Outlet geometry should be matched to the downstream process rather than specified from bag capacity alone.
Pairing the discharge spout With the Right Top
A discharge spout can be combined with any suitable top configuration because filling and emptying solve different process problems. A full open top plus discharge spout gives broad, forgiving loading and controlled unloading. A duffle top plus discharge spout keeps broad filling access, adds a post-fill closure and still provides directed emptying. A filling top plus discharge spout creates controlled interfaces at both ends and is well suited to processes where the bag connects to equipment during filling and again during discharge.
A conical fill spout can also be combined with a discharge spout when upper filling geometry needs special attention but the receiving operation still requires a conventional controlled bottom outlet. The design lesson is simple: top and bottom are partners, not twins. They do not need the same geometry; they need compatible jobs.
Comparing duffle top, filling top, conical fill spout, full open top and discharge spout
The comparison follows common FIBC terminology together with VIDEPAK’s published top- and bottom-selection guidance: open tops maximize access; duffel tops add a broad closing skirt; fill-spout tops are designed around filling equipment; conical spout tops change the entry geometry; and bottom spouts provide a defined outlet for emptying.
Typical Combinations for Real Applications
For coarse construction material loaded from above, full open top FIBC Bags may keep the filling operation simple. Where the same broad access is needed but customers also want a practical upper closure, the duffle top becomes the stronger candidate. For grains or feed, a duffle top paired with a discharge spout can combine flexible loading with controlled unloading. For fine powders filled through fixed equipment, a filling top with a discharge spout can create a defined material route at both ends. VIDEPAK’s guidance similarly emphasizes that the final combination should follow the product, filling system and receiving process rather than a universal “best” configuration.
A Practical Selection Flow for VIDEPAK FIBC Bags
A good specification starts with the material and moves outward. VIDEPAK’s published engineering sequence begins with material properties and flow, considers the electrostatic environment, selects the top and bottom interfaces, then confirms construction, liner, lifting system, Safe Working Load, dimensions, testing and handling requirements. This system-based approach is consistent with ISO 21898:2024, which addresses FIBC materials, construction, design, type testing, marking, selection and safe use for its stated scope.
Bulk density • particle size • flow • dust • moisture sensitivity • handling environment
↓
Broad access → full open top | Broad access + closure → duffle top | Fixed chute → filling top
↓
If a funnel-like upper transition adds real process value, evaluate a conical fill spout
↓
Controlled product stream → specify a correctly sized discharge spout
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Body construction • coating • liner • loops • dimensions • SWL • electrostatic class • testing
Do Not Ignore Electrostatic Conditions
Top and bottom geometry is only part of safe FIBC selection. Moving powders can create electrostatic charge, so applications involving combustible dust, gas or vapor require the correct electrostatic FIBC design and operating method. IEC 61340-4-4:2018 covers electrostatic classification, test methods, design and performance requirements, labeling and safe-use considerations for FIBCs within its defined hazardous-atmosphere scope. VIDEPAK’s portfolio includes Type A, B, C and D options, but the appropriate type must be selected from the actual material and surrounding environment rather than from the top style alone.
A filling top does not make an FIBC electrostatically safe. A discharge spout does not make an FIBC electrostatically safe. A liner does not automatically change an unsuitable FIBC into a suitable one. The safety class, liner, grounding requirements where applicable, product and environment must be assessed together. IEC 61340-4-4:2018 specifically includes classification and testing requirements for both FIBCs and inner liners used in the covered applications.
SAFETY FIRST: Never choose FIBC Bags only by capacity or opening style when combustible powders or explosive atmospheres may be present. The complete electrostatic risk and applicable requirements must be evaluated before the final bag specification is approved.
Why Specify VIDEPAK FIBC Bags Around the Customer’s Process?
Customization Has Value Only When Every Choice Has a Reason
VIDEPAK’s public FIBC portfolio supports multiple top options, bottom options, body constructions and lifting systems rather than one fixed bag format. That flexibility matters because an agricultural customer, a mineral processor and a chemical operation may all buy FIBC Bags, yet their equipment interfaces can be completely different. One may require a full open top. Another may prefer a duffle top. A third may need a machine-matched filling top and a controlled discharge spout. A specialized filling system may justify a conical fill spout.
That is also why VIDEPAK’s engineering guidance treats dimensions as adjustable rather than universal. Published reference ranges cover different Safe Working Loads, fabric weights, construction styles, top designs and bottom designs, with the final values driven by product density, equipment, filled geometry, handling and validated design. The purpose of customization is not to create more options for a catalog. It is to remove mismatches between packaging and production.
THE VIDEPAK APPROACH
Fill with purpose. Lift with confidence. Transport with control. Empty with predictability. A well-designed full open top is valuable because it gives access. A well-designed duffle top is valuable because it combines access and closure. A well-designed filling top is valuable because it connects the package to the filling process. A well-designed conical fill spout is valuable because its geometry solves a specific entry problem. A well-designed discharge spout is valuable because it turns stored material into controlled flow.
From a Bag Specification to a Bulk-Handling Solution
The strongest buying process therefore begins before dimensions are finalized. VIDEPAK first needs to understand what will be packed, how much will be packed, how the product flows, how the bag will be filled, how it will be lifted, how it will travel, and how the receiving plant expects it to empty. Only then should the exact duffle top, filling top, conical fill spout, full open top and discharge spout configuration be locked into the specification.
For simple loading, simplicity can win. Choose a full open top when maximum access is the real need. Choose a duffle top when broad access must be followed by a practical closure. Choose a filling top when the bag needs to work closely with a fixed filling chute. Evaluate a conical fill spout when the upper transition geometry can improve the process. Choose and size the discharge spout according to the material and receiving equipment, not merely according to bag capacity. VIDEPAK’s published guidance follows this same process-first principle.
Strong fabric matters. Reliable seams matter. Lifting loops matter. But the best FIBC Bags do more than carry weight: they connect one industrial step to the next. Material enters through the right opening, remains contained through handling, and leaves through the right outlet. Wide when wide is useful. Controlled when control is essential. Simple where simple is enough. Engineered where engineering adds value.
That is the purpose behind VIDEPAK FIBC Bags: not one bag for every customer, but the right combination of duffle top, filling top, conical fill spout, full open top, discharge spout, body construction, liner and lifting system for the process that actually happens on the factory floor. One container. Two interfaces. Many possible configurations. One goal: make bulk handling safer, cleaner, simpler and more predictable.