When bulk bags are filled and discharged, the flowing of the finely powdered substances can at times cause a buildup of static electricity. Properly mitigating the dangers associated with the buildup of static electricity can at times be the difference between life and death, especially when storing and transporting flammable and combustible materials.
There are four specific types of bags, each with unique features and safe uses. Lets examine each type of bag, define both safe and non-safe uses, as well as determine which types of bags help you mitigate the dangers of static electricity when storing and transporting flammable and combustible materials.
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Type A FIBC bulk bags
Type A bags are made of plain-woven polypropylene and other non-conductive fabrics. Static electricity is generated as products move over or rub against the inside surface of the bag when they are filled or discharged. Many organic materials as well as chemicals can form combustible clouds that can be ignited by electrostatic discharges from a type A bag.
It is important to remember that type A bags do NOT offer any static protection and they should NOT be used to store or transport flammable or combustible products. For safe and non-safe uses of type A bags, please see below:
Safe uses for Type A bags:
- To transport non-flammable products.
- No flammable solvents or gases present around the bag.
Do not use Type A bags for:
- Transporting flammable products.
- When flammable solvents or gases are present around the bag.
- Should not be used where a flammable atmosphere with a minimum ignition energy ≤1,000mJ is present.
Type B FIBC bulk bags
Type B bags are similar to type A bags in that they are made of plain-woven polypropylene fabrics or other non-conductive material. Also like type A bags, type B do not have any mechanism for dissipating static electricity.
An added benefit of type B bags is that they are made from materials that have a low breakdown voltage to prevent incidents where highly energetic, and dangerous propagating brush discharges (PBD) occur. Although type B bags can prevent PBD, they still are not considered anti-static because they do not have a mechanism to dissipate a static electricity charge. For an bag to be considered “anti-static”, bags must have a reliable mechanism for dissipating static electricity.
Aside from the risks of incendiary discharges, there are other consequences associated with not using an anti-static bag such as a type B bag:
- They can cause electrostatic shocks to operators (although not dangerous, these shocks are very annoying and can cause other accidents).
- Dust and other contaminants can become attracted to the surface of bag.
- Make it difficult to fully empty the bag. Product can become stuck to the side of the bags because of static electricity.
Safe use for type B bags:
- To transport dry, flammable powders.
- No flammable solvents or gases present around the bag.
- Intended to be used in environments with dust with ignition energies less than 3mJ.
Do not use type B bags:
- When flammable solvents or gases are present around the bag.
Type C FIBC bulk bags
Type C bags, also known as conductive or ground-able bags are made from non-conductive polypropylene fabrics interwoven with conducting threads traditionally sewn in a grid pattern. These conducting threads must be electrically interconnected as well as connected to a designated ground during filling and discharging.
As with any operation, ensuring that the type C bag is grounded properly is subject to human error. A proper connection to the designated ground during filling and discharging is imperative to the safe use of type C bags. For safe and non-safe uses of type C bags, please see below:
Safe use for type C bags:
- To transport flammable powders.
- When flammable vapors, gases, or combustible dusts are present.
Do not use type C bags:
- When ground connection is not present or has become damaged.
- Resistance from any location bag to designated grounding point.
Type D FIBC bulk bags
Type D bags are made from anti-static and static dissipative fabrics designed to safely protect against and prevent the occurrence of incendiary sparks, brush discharges, and propagating brush discharges without the need for a connection from the bag to a designated ground.
Type D bags such as Crohmiq™ bags are manufactured with fabric containing quasi-conductive yarns that safely dissipate static electricity into the atmosphere (as seen in the diagram to the left) via safe, low-energy corona discharge. These quasi-conductive yarns in bags such as Crohmiq™ bags do not need to be interconnected. The use of type D bags eliminates the possibility of human error associated with the manufacturing and use of ground-able type C bags.
Safe use for type D bags:
- To transport flammable powders
- When flammable vapors, gases or combustible dusts are present.
Do not use type D bags:
- When surface of bag is contaminated or coated with conductive material such as grease or flammable and or combustible materials.
What type of bag is right for my application?
As you can see, although type B bags have some anti-static properties, the only bags that are truly safe to use to store and transport flammable and combustible materials OR use when flammable vapors, gases or combustible dusts are present are type C & Dbags. Type C bags are safe to use in these scenarios when properly connected to a designated grounding point. Type D bags eliminate the possibility for human error associated with properly grounding the bag. Type D bags are manufactured with fabric that contains special yarns that dissipate static electricity.
For more information on types of bags, see our “Types of bags explained” page by clicking here. To speak with one of our experts to determine which type of bag is right for your application, click here to fill out our “Get Quote” contact form or call us at 1-888-237-4224.
Thanks for reading!
At National Bulk Bag, safety and reliability are our top priorities. No matter who you purchase your bulk bags from, it's extremely important to take great care when using them. Within this guide we explore comprehensive safety information, best practices, and key safety tips.
Our safety guide is split up into four sections for your convenience:
- Bulk bag safety: 5:1 SWL vs. 6:1 SWL
- Safely filling & discharging FIBCs
- Safely lifting FIBCs with cranes, hoists, & forklifts
- Safely storing empty and full FIBCs
Download our Official FIBC Bulk Bag Safety Guide by clicking the button below!
