Bulk Bags (FIBC)
Flexible Intermediate Bulk Containers for efficient storage and transport of dry goods. New and quality-graded used options with Type A through D static protection.
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What Are Bulk Bags?
Bulk bags -- formally known as FIBCs (Flexible Intermediate Bulk Containers) and commonly called super sacks, big bags, or tote bags -- are large industrial containers made from woven polypropylene fabric. They are engineered for the efficient storage, handling, and transportation of dry, flowable products in quantities ranging from 1,000 to 5,000+ pounds per bag.
Despite their enormous capacity, an empty FIBC weighs only 4.5 to 8 pounds, making them one of the most efficient packaging solutions by weight ratio in the industrial world. A single bulk bag can replace dozens of small bags, dramatically reducing labor costs, packaging waste, and handling time. They are stackable (up to 3-4 high depending on product density), forkable, and compatible with standard pallet infrastructure.
Bulk bags are manufactured in four types (A, B, C, D) based on their electrostatic protection properties, and are available with a wide variety of fill options, discharge configurations, coatings, liners, and closure mechanisms. Understanding these options is critical to selecting the right bag for your product and operating environment.
PackMesa supplies both new and quality-inspected used bulk bags from our Mesa, AZ facility. Used FIBCs can save your operation 40-80% compared to new bags while maintaining full structural integrity for non-food, non-hazmat applications.
Specifications
FIBC Types: A, B, C, and D
Bulk bags are classified into four types based on their electrostatic properties. Selecting the correct type is critical for safety, especially when handling flammable or combustible materials.
Made from plain woven polypropylene with no static protection features. These are the most common and economical bulk bags, suitable for transporting non-flammable products in environments where no flammable solvents or gases are present.
Suitable for: Sand, gravel, agricultural products, fertilizers, minerals
Not suitable for: Flammable powders, combustible dust, or environments with flammable gases
Constructed from plain polypropylene or polypropylene with a low breakdown voltage. Type B bags prevent propagating brush discharges and sparks on the surface of the bag, but they do not dissipate static charge. They offer a modest improvement in safety over Type A for certain applications.
Suitable for: Dry, flammable powders (with no flammable vapors present)
Not suitable for: Environments with flammable solvents, gases, or combustible dust
Manufactured with interwoven conductive threads (typically carbon or metal) in a grid pattern throughout the fabric. These threads must be interconnected and grounded during filling and discharging to safely dissipate static charges. Type C bags are effective for protecting against incendiary sparks, brush discharges, and propagating brush discharges.
Suitable for: Flammable powders, combustible dust, environments with flammable vapors (when properly grounded)
Not suitable for: Any situation where grounding cannot be guaranteed throughout the entire filling/discharge process
Made from specially engineered antistatic fabric that safely dissipates static electricity without requiring a grounding connection. The fabric contains quasi-conductive yarns or threads that provide a controlled, low-energy discharge. Type D bags offer the highest level of static protection for the widest range of applications.
Suitable for: Flammable powders, combustible dust, flammable vapor environments (no grounding required)
Not suitable for: When the surface of the bag is contaminated with conductive materials such as grease or water
Safety Factors: 5:1 vs. 6:1
The safety factor (SF) is the ratio of the bag's breaking strength to its Safe Working Load (SWL). It is the most important specification for safe FIBC use.
5:1 Safety Factor
The bag can hold 5 times its rated Safe Working Load (SWL) before failure. This is the standard for multi-trip bags that will be filled and emptied multiple times over their service life. A bag with a 2,000 lb SWL and 5:1 SF has been tested to hold 10,000 lbs before breaking.
Best for: Reusable / multi-trip applications
6:1 Safety Factor
The bag can hold 6 times its rated SWL before failure. This higher safety margin is required for single-trip applications, food-grade use, and UN-rated bags for hazardous materials. The increased factor accounts for the fact that the bag is not inspected between uses.
Best for: Single-trip, food-grade, hazmat, UN-rated
Fill and Discharge Options
The right fill and discharge configuration depends on your product, filling equipment, and unloading process.
Fill (Top) Options
Open Top
The entire top of the bag is open. Fastest filling method. Best for large-particle products loaded by conveyor, chute, or bucket. No restriction on fill speed.
Spout Top
A cylindrical fabric spout (typically 14" or 18" diameter) centered on the top panel. Provides a directed fill point, reduces dust and spillage. Required for automated filling lines. Can be tied closed after filling.
Duffel Top
A circular fabric flap that covers the entire top opening. After filling, the duffel is folded over and tied shut. Combines the fast fill of an open top with the closure security of a sealed bag. Popular for construction and agricultural products.
Closed Top
Fully sewn shut with no opening. The bag is filled from the bottom before the bottom spout is sealed. Used primarily for pre-filled bags or when the product is loaded through a side panel.
Discharge (Bottom) Options
Flat Bottom
Standard sewn-shut bottom panel. The bag must be cut open, inverted, or slit to discharge contents. Most economical option. Ideal when the bag will be used only once or when controlled discharge is not required.
Spout Bottom
A cylindrical fabric spout (typically 14" or 18" diameter) on the bottom panel, secured with a tie or drawstring. Allows controlled, gravity-fed discharge. Essential for hopper feeding, blending systems, and any process requiring metered flow.
Full Drop Bottom
The entire bottom panel opens to discharge the contents at once. Provides the fastest possible unloading. Used for rapid dumps into mixers, hoppers, or processing equipment.
Conical Bottom
The bottom of the bag is shaped into a cone (funnel). Promotes complete material discharge with minimal residue. Ideal for sticky, bridging, or cohesive products that resist flow.
Quality Grading System
Every used bulk bag we sell is cleaned, inspected, and assigned a quality grade so you know exactly what you are getting.
Brand new bags in original packaging. Full rated capacity with manufacturer certification. Required for food-grade, pharmaceutical, and single-trip UN applications.
Savings vs. New: 0%
Used once, thoroughly cleaned and inspected. All loops, seams, and fabric intact. No staining, holes, or UV degradation. Suitable for most non-food industrial applications.
Savings vs. New: 40-50%
Used 1-3 times with light cosmetic wear. May show minor discoloration or print residue. Structurally sound with all features intact. Ideal for general material handling and storage.
Savings vs. New: 55-65%
Multiple uses with visible wear. May have minor repairs, fading, or staining. All critical seams and loops intact. Best for non-critical storage, waste collection, or single-use applications.
Savings vs. New: 70-80%
Pricing Comparison
Used FIBCs offer dramatic savings over new bags. Actual pricing depends on type, size, features, and quantity.
| Bag Type | New Price | Used Price | Savings |
|---|---|---|---|
| Standard Type A (Spout/Spout) | $8 - $15 | $3 - $7 | 50-65% |
| Standard Type A (Open/Flat) | $6 - $12 | $2 - $5 | 55-70% |
| Coated / Moisture Barrier | $12 - $20 | $5 - $10 | 45-60% |
| Type C (Conductive) | $18 - $35 | $8 - $16 | 50-60% |
| Type D (Static Dissipative) | $22 - $40 | $10 - $20 | 50-55% |
| Food-Grade (6:1 SF) | $12 - $22 | N/A (new only) | -- |
| UN-Rated (Hazmat) | $20 - $40 | N/A (new only) | -- |
Prices are approximate per-bag in typical bulk quantities. Contact us for current quotes.
Testing Standards
Quality FIBCs are tested to rigorous international standards. Here are the key tests and certifications you should know.
ISO 21898
International standard for FIBC design, manufacturing, and testing. Covers safe working load, top lift, topple, righting, tear, drop, and stacking tests.
UN Certification
Required for transporting hazardous materials. UN-rated FIBCs must pass a battery of tests including drop, topple, righting, top lift, stacking, and tear propagation at specific performance levels.
Top Lift Test
The filled bag is lifted by its loops to verify they can support the rated load plus the required safety factor (5x or 6x SWL). Duration: 5 minutes minimum.
Drop Test
A filled bag is dropped from a specified height onto a hard surface. The bag must not rupture or spill its contents. Tests structural integrity under impact.
Topple Test
A filled bag is tilted on its base until it topples over. The bag must not rupture. Simulates accidental tipping during handling or storage.
Stacking Test
Loaded bags are stacked to a specified height for a specified duration. Tests the bag fabric and seams under sustained compressive load.
Common Applications
Industries Served
How to Choose the Right Bulk Bag
Selecting the right FIBC involves matching multiple specifications to your product, process, and safety requirements.
1. Identify Your Product
What is the product? Is it flammable or combustible? What is its bulk density? Is it free-flowing or cohesive? These answers determine bag type (A-D), size, and discharge configuration.
2. Determine the Required SWL
Calculate the weight of product that will fill the bag at your target volume. Add a margin. Then select a bag with a Safe Working Load that exceeds this weight. Do not guess -- overloading bags is dangerous.
3. Select the Safety Factor
Use 5:1 SF for multi-trip bags in non-food, non-hazmat applications. Use 6:1 SF for single-trip, food-grade, pharmaceutical, or UN-rated applications.
4. Choose Fill and Discharge Options
Match the top (fill) and bottom (discharge) configuration to your equipment. Automated filling lines typically require spout tops. Hopper feeding requires spout bottoms. High-volume operations benefit from open tops and full drop bottoms.
5. Consider Coatings and Liners
Moisture-sensitive products need coated bags or PE liners. Fine powders that sift through woven fabric need coated or lined bags. Food ingredients require food-grade liners. Hygroscopic products need sealed, coated bags.
6. New vs. Used
New bags are required for food-grade (direct contact), pharmaceutical, and UN-rated hazmat. Quality used bags are suitable for most industrial applications including construction, mining, agriculture, and general manufacturing.
Care and Maintenance Tips
Proper handling and storage extends bulk bag life and prevents safety incidents.
Inspect Before Every Reuse
Check all four lift loops for cuts, fraying, or elongation. Examine body panels and seams for holes, tears, or UV degradation (chalky white appearance). Verify that fill and discharge spouts are intact with functional closures.
Protect from UV Exposure
Polypropylene degrades under ultraviolet light. If bags must be stored outdoors, cover them or use UV-stabilized bags. Limit outdoor exposure to 6 months maximum, even for UV-treated bags.
Use Proper Lifting Equipment
Always use a forklift or crane with a spreader bar or lifting frame. Never lift a bulk bag by fewer loops than it was designed for. A 4-loop bag must be lifted by all 4 loops simultaneously.
Ground Type C Bags
If using Type C (conductive) bags, ensure the grounding connection is secure and verified before filling or discharging begins. A broken ground during operation negates all static protection.
Never Exceed the SWL
The Safe Working Load is the maximum weight the bag is designed to carry under normal conditions. Overloading stresses loops, seams, and fabric beyond their tested limits and creates a serious safety hazard.
Store Clean and Dry
After emptying, shake out residual product, fold the bag neatly, and store in a dry covered area. Contaminated or wet bags can develop mold, attract pests, and degrade faster.
Frequently Asked Questions
What is the difference between a 5:1 and 6:1 safety factor?
The safety factor (SF) indicates how many times the rated Safe Working Load (SWL) the bag can hold before failure. A 5:1 SF bag rated at 2,000 lbs has been tested to 10,000 lbs. A 6:1 SF bag rated at 2,000 lbs has been tested to 12,000 lbs. Use 5:1 SF bags for multi-trip applications where the bag is inspected between uses. Use 6:1 SF bags for single-trip, food-grade, and UN-rated hazmat applications.
Can I reuse bulk bags? How many times?
Yes, bulk bags designed with a 5:1 safety factor are intended for multi-trip use. With proper inspection between uses, a quality FIBC can typically be reused 3-5 times depending on the product being carried, handling conditions, and UV exposure. Always inspect loops, seams, and fabric for cuts, abrasion, UV degradation, and contamination before reuse. Never reuse a bag that has carried hazardous materials unless it has been properly decontaminated and recertified.
What is the difference between Type A, B, C, and D bags?
The types refer to electrostatic protection levels. Type A has no static protection and is for non-flammable products only. Type B prevents brush discharges but does not dissipate charge. Type C has conductive threads and must be grounded during use -- effective for flammable powders and vapors. Type D uses special antistatic fabric that dissipates charge without grounding. Choose based on the flammability of your product and the environment.
Do you offer food-grade bulk bags?
Yes. We stock food-grade FIBCs that comply with FDA 21 CFR and EU food contact regulations. These bags are manufactured in dedicated clean-room environments, use food-safe polypropylene fabric, and come with certificates of compliance. Food-grade bags are available in both new (required for direct food contact) and Grade A used (suitable for food products in separate inner packaging).
What size bulk bag do I need?
The most common FIBC sizes are 35x35x50 inches and 37x37x55 inches, which fit standard 48x40 pallets. For larger volumes, 41x41x60 or 45x45x65 bags are available. To determine the right size, consider: the volume and density of your product, the weight (must not exceed the bag SWL), the pallet size it needs to fit on, and any storage height restrictions. We can help you calculate the optimal bag dimensions for your specific product.
What is a coated vs. uncoated bulk bag?
An uncoated bag is made from standard woven polypropylene, which is breathable and allows some moisture and fine particles to pass through the weave. A coated bag has a layer of polyethylene (PE) laminated to the inside or outside of the fabric, creating a moisture barrier. Choose coated bags for moisture-sensitive products, fine powders that could sift through uncoated fabric, or outdoor storage. Uncoated bags are preferred when the product needs to breathe or when cost is the primary concern.
How should I store empty bulk bags?
Store empty bulk bags indoors or in a covered area, away from direct sunlight. UV radiation is the primary cause of polypropylene degradation and can significantly reduce bag strength over time. Keep bags in their original bales or on pallets, off the ground to prevent moisture absorption. Do not store near chemicals, solvents, or heat sources. With proper storage, new bags have a shelf life of 2-3 years. Used bags should be stored clean and dry.
What is the difference between cross-corner and side-seam loops?
Cross-corner loops are attached at the corners of the bag where the body panels meet, running diagonally across each corner. They provide a more square shape when lifted and are the most common design. Side-seam loops are attached along the seams of the bag body panels. They offer a more rectangular or cylindrical shape when filled. Cross-corner loops generally provide better weight distribution and are preferred for most applications.
Get a Bulk Bag Quote Today
Whether you need 50 bags or 5,000, PackMesa delivers competitive pricing on new and used FIBCs from our Mesa, AZ facility.
Tell us your product, desired SWL, fill/discharge preferences, and quantity. We respond to all quote requests within 24 hours.