FIBC Frequently Asked Questions

An FIBC (Flexible Intermediate Bulk Container) commonly referred to as a “Bulk Bag”, “Big Bag” or “Tote” is an intermediate bulk container, having a body made of a flexible woven material (typically polypropylene), which

• Is handled mechanically by forklift trucks, cranes or hoists when filled.
• Is designed to be lifted from the top by means of integral, permanently attached devices (lift loops, stevedores or sleeves).
• Is intended for shipment of solid materials (including, but not limited to, materials in powder, flake, or granular form).
• Does not require further packaging

The dimensions, handling, filling, discharging and barrier features of an FIBC can be customized based on the needs of the customer. FIBCs typically hold anywhere from 1000 – 4000 lbs (500 – 2000 kg) of product.

Want to know more about the history of FIBCs?  Click here for a summary in the Resource Center.

FIBC’s are commonly used for dry flowable products such as, but not limited to grains, seeds, salts, powdered coatings, sands, clays, cement, ferroalloys, and resins.  They are frequently used in the food, pharmaceutical, agricultural and chemical industries.

When FIBCs are utilized for non-standard items, it is crucial that the design is robust enough to ensure the performance of the FIBC is not negatively affected by these materials. Extensive consultation with the manufacturer or distributor is necessary to select a suitable design. If there are concerns that a non-standard item may impact the FIBC’s performance, additional testing must be conducted. Testing for materials or debris that exhibit relatively consistent properties can be effectively evaluated. However, testing for mixed construction debris poses challenges as each load can vary significantly. The type and arrangement of debris can lead to considerable variations in test results. Thus, extensive testing of representative materials in potential configurations must be conducted to determine if industry standards and performance levels are met.

In addition to conducting comprehensive custom testing to assess suitability, education plays a vital role when handling materials such as mixed construction debris that could potentially impact the FIBC’s performance. Materials must be loaded in a tested configuration where the performance is known. Furthermore, individuals handling filled FIBCs must receive training on safe handling methods, as outlined in the FIBCA Safe Handling Guidelines posters, documents, and videos.

Ultimately, it is crucial to ensure that an FIBC is only shipped, stored, and handled if it meets industry standards, is used according to the manufacturer’s recommendations and industry safe handling guidelines, and if the contents do not adversely affect its performance.

Additional details will be required for the filling and discharging environment, but here are a few product details that are needed to help ensure you get a FIBC that will meet the basic requirements of your product.

• Product bulk density (lbs. per cubic foot or kg per cubic meter)
• Safe working load (SWL) / Net fill weight needed per FIBC
• Is the product a hazardous material / dangerous good
• Does the FIBC need to meet food safety requirements
• Does the FIBC need to meet pharmaceutical industry requirements
• Product mesh size
• Moisture percentage
• Special barrier needs (i.e. hydroscopic?)
• Product characteristics (free flowing, bridging, static build up)
• Filling temperature

FIBCA developed a FIBC Design Guide to help potential Bulk Bag (FIBC) users identify the answers to critical questions when determining what FIBC best fits their particular application. The guide is intended to assist those users/buyers when sourcing a bulk bag and for those who have never spec’d out their package, but now must.  Click here to get a copy of the FIBC Design Guide.

• U-Panel: A bag that has one panel forming two opposite sides and the bottom, creating a “U” panel shape.
• Circular: Also called a tubular bag, is made from fabric woven on a circular loom, which is then cut to the proper length for a specified bag height; thereby, eliminating the vertical seams on each of the bag’s sides.
• Four Panel: Four separate pieces of fabric are sewn together to create the body of the bag.
• Baffle: Pieces of fabric or other material sewn across each corner of a tubular or four – panel bag to improve a bag’s squareness, appearance, improve the stability of the load and to more efficiently utilize storage or shipping space.

FIBC’s are commonly mechanically handled by one of the following means:

• Lift Loops: Loops are located at the corners of the FIBC.  The loops are either sewn onto the body of the FIBC or they are sewn into the side seams.  The size of the loop opening, the length of the ends and strength of the webbing can be customized depending on the handling needs and safe working load.
• Stevedore Straps: A belt or rope connecting either two adjacent lift loops, or all four loops, used for single point lifting.
• Single Point Lift:  Created by extending the lift loop material or body fabric so it can be gathered at one point above the bag.
• Sleeve Lift:  The tubular sleeves running along two opposite edges of the FIBC

Yes, FIBC’s can be used with or without liners depending on the needs of the product and the distribution environment.  Should a liner be needed, there are two basic styles of liners:

• Form Fit: Designed to take the exact shape of the FIBC.  Form-Fit Liners will allow improved filling and complete discharging of product. Unlike a basic “tube liner”, Form-Fit Liners offer a flat top and bottom and incorporate a spout diameter and length to best compliment the FIBC’S fill and discharge spouts.
• Tubular: A liner with no spouts or contours, it is a straight cylinder, which may or may not have one end heat-sealed.

Both of these liners can be loosely inserted or secured with ties, tabs or glue.  Liners can also provide antistatic or barrier properties such as oxygen, moisture or UV.

Common filling options include an open top, duffle top, conical top or a spout top.  Discharging/bottom options include a duffle bottom, conical bottom or a flat bottom.  The filling and discharging options selected are going to be dictated by a number of factors including:

• Filling Method (i.e conveyer, gravity, bulk bag filler)
• Where FIBC will be Filled (clearance, electro static concerns, flammable products, etc.)
• The FIBC Filling Equipment Desired or Currently Used
• Desired Fill or Packaging Rate
• Sizing Restrictions / Constraints
• Fill Spout Dimensions Required
• Controlled Discharge Desired
• Discharge Method (i.e. gravity, screw, conveyor, bottom cut, full dump)
• Where FIBC will be Discharged (clearance, manual, electro static concerns, flammable products, etc.)
• Desired Discharge Rate
• Discharge Spout Dimensions Required
• Handling Preference: Existing Hoist and Fork Loaded Trolly Frame

SWL or Safe Working Load is the amount of load, (in pounds or kilograms), which a bag is designed to carry. The design of the FIBC and the sewing method used, combine with the strength of the fabric, determines the Safe Working Load.  This SWL is printed on the manufacturing label.

A coated bag incorporates an interior or exterior layer of polypropylene (PP) to reduce moisture intrusion or sifting of the contents.  Also called Non-breathable or laminated fabric/bags.  The uncoated FIBC has no PP coating.

A type of an FIBC construction that provides resistance from product sifting when the bag is filled with very fine materials.  This typically utilizes coated fabric and filler cord in the sew lines.  Commonly used in combination with a coating or an interior liner.

A feature of an FIBC fabric that provides protection from prolonged exposure to the sun’s degrading UV rays.  An additive is blended with the resin prior to extrusion of the yarns to provide this protection.  UV protection performance should be evaluated per the procedures set forth in the ISO 21898 standard.

Portions of a FIBC are 100% recyclable and facilities specializing in recycled plastic may or may not require these items/parts to be separated.  The Flexible Intermediate Bulk Container Association has compiled a list of FIBC Recycling Resources which is available to view and download using the link provided.

FIBCs should only be reused within a ‘Closed Loop’ system. In a Closed Loop system the FIBC is cleaned, reconditioned and qualified for reuse to handle the same product in the same application for which the FIBC was originally designed. A Closed Loop system usually involves the cooperation of the manufacturer of the FIBC, the customer purchasing the FIBC and the end user of the FIBC.

To safely reuse FIBCs these guidelines should be followed:

Cleaning

1. Remove all foreign matter from the FIBC’s interior.
2. Ensure statically held dust is less than 4 ounces total.
3. Replace liner if applicable.

Reconditioning

1. Replace web ties.
2. Replace labels and tickets critical to safe FIBC use.
3. Replace cordlocks if necessary.

Reasons for Rejecting a FIBC

1. Lift strap damage
2. Contamination
3. Damp, wet, mold
4. Wood splinters
5. Printing is smeared, faded or otherwise unreadable

Tracking

1. The manufacturer should maintain a record of origin, product used in the FIBC and the quantity of uses or turns.

Testing

1. FIBCs should be randomly selected for top lift testing. The frequency and quantity shall be determined by the manufacturer and/or user based on their specific situation.
2. The top lift testing will be conducted per the latest version of the ISO 21898 standard.
3. Test results should be maintained by the manufacturer for a minimum of three years.
   

Only stack FIBCs if they are designed to be stacked, you are sure of their stability and they are stacked using a “Pyramid” or “Supported” stacking method:

• Pyramid Stacking: Each bag above the first layer must sit on at least four lower bags. Each layer is subsequently tiered inwards forming a pyramid structure.
• Supported Stacking: Formed against two retaining walls of sufficient strength.

Never approach or repair a damaged bag without first removing all bags stacked on top.

As of this present date, the FIBCA is not aware of, nor has it ever been presented with any data, test reports, or studies determining the shelf life of an FIBC. Any recommendations in regards to the shelf life of an FIBC, are solely the responsibility of each company making such declarations.  The Flexible Intermediate Bulk Container Association does not endorse any typical shelf life for a FIBC / Bulk Bag. Variables such as UV inhibitor used, construction (fabric weight, thread, webbing, etc.), exposure to environmental hazards (UV, temperature and humidity), storage methods, handling methods and the contents of the FIBC can dramatically impact the shelf life of a FIBC.  The best method for determining if a FIBC remains suitable for use is to conduct periodic performance testing (top lift, UV, etc.) on samples and compare the results to the results from the newly manufactured samples from same lot. Samples should continue to meet industry standards such as those set forth in ISO 21898.

Always protect your FIBCs from the harmful effects of UV rays (sunlight) and inclement weather (rain, snow, etc.).  Over time, exposure to UV rays and inclement weather will weaken the strength of a FIBC.  Always try to store your empty FIBC’s inside a covered facility or warehouse that is free from any water or moisture contamination that could come into contact with your FIBCs and damage them.  Storing empty or filled FIBC’s outside is not recommended, but if you do, you should always cover them with some type of material that will prevent their exposure to UV rays and inclement weather. There is no guarantee that FIBCs stored outside & unprotected from the UV rays & inclement weather will be safe to handle.