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FIBC Bulk Bag Frequently Asked Questions

What is an FIBC?

FIBC stands for Flexible Intermediate Bulk Container. They are more commonly known as Bulk Bags. The packages are classified as intermediate containers because of their size; typically having filled weights between about 500 and 4000 pounds. Bulk bags are not small enough to be moved easily by hand, however not large enough to be classified as a full bulk container, such as a truckload or railcar. FIBCs were originally developed in Europe in the 1970’s, but were widely adopted thereafter in the Americas and other developing industrial nations. Use of FIBCs today permeates nearly all industries, where dry bulk solids are handled including food, chemicals, and even pharmaceuticals.

What is a Bulk Bag Made From?

The most common material used in FIBC bag construction is 100% virgin polypropylene, petroleum based product which is a tough relatively inert thermoplastic.

What is woven polypropylene made from?

Woven polypropylene is made from extruded polypropylene resin, which is made from petroleum feedstock.

Are there other materials used in making a bulk bag?

Yes, many types of polyethylene bulk bag liners are used to line the interior of an FIBC. Other more exotic materials include polyamide (nylon), various metallic foils, carbon infused plastics, polyester, and more.

What sizes do bulk bags come in?

Bulk bags come in many different sizes and styles, and can be customized into almost any 3 dimensional size possible for your product. There are limits to the sizes, but a standard bulk bag base dimension is 35″ x 35”, while the height of a bulk bag can range up to 96” plus inches tall. Again, the size and dimensions of bulk bags are determined by safety, functionality, and usability by the customer.

What does SWL mean? 

SWL is an abbreviation for safe working load. A bulk bag’s safe working load is the amount of weight that the bag is rated and tested to hold safely.

What does 5:1 SF mean? 

A standard bulk bag is rated at a 5:1 Safety Factor Ratio as per ISO 21898 norms, which means that the bag is specified to hold 5 times the amount of the bags safe working load. A 5:1 Safety Ratio is for single use or single trip bags. Bags that are designed for multi-use or multi-trip bags are made with an increased SF ratio. The SF for a multi-trip bag is 6:1.

What is UV inhibitor? 

UVI stands for Ultraviolet Inhibitor, which is an additive that is added to the resin during the extrusion process. It assists in protecting the bulk bag from the harmful effects of UV rays, protecting it from degrading and becoming unstable and unsafe.

Can bulk bags be stored outaide? if so, How long?

Yes, however, bulk bags will degrade as a result of UV exposure. A standard bulk bag has a UV inhibitor added into the fabric at the manufacturing level. Manufacturers add enough UV inhibitor to resist UV rays for approximately 1600 hours. Although this is dependent upon where the actual bag is located and what type of weather conditions, sometimes extreme, can happen in this region. UV rays vary in strength and degree in different parts of the world.  Therefore, storing bulk bags outside is not recommended, but we do realize that it happens.

What types of FIBCS are available and what applications are FIBCS (Bulk Bags) typically used for? 

There are many common types of FIBCs available in the market place. The most commonly used bulk bags are constructed in the U Panel or Circular configuration and might incorporate a simple PE liner or no liner at all. Much of how bulk bags are referred to has to do with their construction, i.e., 4 Panel, U Panel, Circular, or their application, such as Type B, or Baffle Bags.

Below is a general list of commonly referred to terms used when describing an FIBC: 

  • By Shape or ConstructionCircular / Tubular
  • 4 Panel
  • U Panel
  • Baffle
  • By ApplicationFood Grade Bags
  • UN Bags
  • Multi-Trip Bags
  • Chemical Bags
  • Conductive or Static Dissipative Bags
  • Valve Bags or Liquid Bags
  • By Fabric Electrostatic ClassificationType A – No Electrostatic Protection
  • Type B – Surface Breakdown Voltage of <6kV
  • Type C – Electrically Conductive or Groundable
  • Type D – Static Dissipative

What is a U-Panel bag?

A U-Panel bag requires 2 seams along 2 opposite sides to create 2 panels and a “U” Panel shape. This style of bulk bag has become the industry standard in the United States.

What is a circular/tubular bag?

Circular bags are made from fabric that has been woven on a circular loom. The fabric is woven into a continuous tube of fabric and then cut to the correct size height. The tubular body design is ideal as a linerless option for fine materials. It is also an excellent alternative to the original four panel bag construction. Capacity is up to 4000 lbs.

What is a four panel bag?

A four panel bag is the original polypropylene design. This design requires seams along four separate pieces of fabric sewn to create a four panel bag. Capacity is up to 4400 lbs.

What is a baffle bag? What are baffles? 

Baffles are pieces of fabric that are sewn to the inside corners of a bag to maintain its cube shape after filling. The baffles have holes that allow the product to flow freely through them. The baffles also prevent the bag from bulging, which makes the bag stand up straight and in turn allows the bags to be more efficient in their use of space. Net and tie baffles are another type of baffle option, but not as common.

What is un certification?

UN Certification is a testing certification done by an independent testing facility that put the specified bulk bag through a set of rigorous test, i.e. drop test, topple test, and top lift test.

How long is a un certified  bulk bag certificate good for?

Usually 1 year from testing, but certain test houses will certify a bag for up to 3 years.

Do you stock un certified bulk bags?

Our UN certified bulk bag stock is stored primarily for a few of our customers. These bulk bags are tested by a certified third party testing facility. If the bag passes the test requirements, it is issued a specific UN Certification number, which is associated specifically to that bag. The UN number is specific to that particular bag being filled with a specific product, and tested for a specific packing group. The UN number has an expiration date, giving the bag a shelf life for usage.=

Can FIBC’s be used more than once?

FIBC’s can be used more than once if you have a bag with a 6:1 SF. Some users reuse a FIBC with a 5:1 SF but this is not recommended! If you reuse a FIBC with a 5:1 SF you have to take into consideration that the fabric might be worn down or the loops could be breaking down, etc. If you plan on using a bag more than once it is recommended that you custom order it with a 6:1 SF.

Can i reuse a bulk bag? 

Yes, bulk bags can be reused. This requires a multi-trip bulk bag, which is made with a 6:1 Safety Factor. This type of bag is designed to be used for a specific amount of uses. Some users reuse bulk bags with a 5:1 safety factor. In fact it is a common occurrence. We do not recommend this practice, as reusability must also take into consideration the reality that the bag may be worn, have a small hole in the fabric, the loops could be unstable, etc. Reuse of a 5:1 SF bulk bag, which covers the majority of bulk bags seen in the market, is NOT recommended. We recommend inspection in between uses and retiring a bag with any tears, rips, abrasions, etc. An additional bag tag is included for tracking usage if a bag is approved for further use after inspection. Global-Pak does not recommend using any bag more than 10 times.

Are bulk bags recyclable?

Yes, new bulk bags are made from 100% virgin polypropylene. See our FIBC recycling program page.

 How do you store FIBCS?

Empty FIBCs are usually stored on the pallets they arrive on and may be covered with a simple polypropylene or polyethylene cover and tied down with plastic banding, or they may be custom packed and sealed per the client’s specification. FIBC pallets can usually be stacked no more than two high on top of each other, but are best stored on space saving racking systems off of the ground. Steps should be taken to ensure they are kept dry and protected from other harsh elements, chemical environments, or other areas where they may be cut or damaged. When storing filled FIBCs, great care should be taken. This is also the case even if the filled FIBC will only be stored for a short period of time prior to transport or use of the contained materials. Dependent on bulk density of a product and other characteristics, some products may stack easily, even sometimes up to three high using the pyramid stacking technique. Other products having light bulk densities may not stack at all. The environments in which filled bulk bags are stored are heavily dependent upon the material inside the package, and also upon the style of package used. For example, if you are a starch producer and you are using a simple 4 panel bag design with coated fabrics and no liner, you will have to consider the possibilities of humidity transferring into your product before it reaches your end customer. If on the other hand, you are using a hermetically sealed vapor barrier liner, then your finished package is obviously less impacted by changes in humidity or even water droplets coming into contact with the bag. Please keep in mind that each FIBC feature has its pros and cons. A bag containing a liner that gets sealed off after filling may be water tight, but now may not lend itself well to stacking due to entrapped air that could rupture the liner if the full weight of one or two additional filled FIBCs were placed on top of it. Therefore, please consult with an expert if you have any questions about storage of your filled bulk bags.