FIBC types are the four static safety grades of bulk bag, and choosing the wrong one can turn a routine shipment into a fire risk. Fortunately, choosing the right one is simpler than it looks, once you understand what separates them.

There are four FIBC bags: Type A, B, C and D. Although they look almost identical, the difference between them is invisible. In the wrong situation, however, it is the difference between a safe delivery and an explosion.

An FIBC, also called a bulk bag or jumbo bag, carries up to two tonnes of dry material. From the outside, one woven bag looks much like another. Yet they are not the same, because the four FIBC types exist for one serious reason: static electricity. For the full technical detail, the flexible intermediate bulk container standards go deeper still.

This guide explains the four FIBC types in plain language. In other words, what each one does, where it is safe, where it is dangerous, and how to pick the right one. It also sits within the wider world of bulk packaging, where a small detail decides whether a shipment arrives safely.

Why FIBC types exist: it all comes down to static

When dry powder or granules pour into a bag, the movement creates static electricity. As a result, the bag and its contents build up an electrical charge, much like rubbing a balloon on your hair.

Usually that charge is harmless. However, if the material is flammable, or if you fill the bag near flammable dust, gas or solvent vapour, a single spark can ignite it. In short, the four FIBC types are four different ways of handling that charge, from doing nothing about it to removing it completely.

The four FIBC types, explained

Here is what each one does, in order of how much static protection it offers.

Type A: the standard bag with no static protection

A Type A bag is plain woven polypropylene with no special static control. Naturally, it is also the simplest and cheapest option. Use it only for products that are not flammable, and never near flammable dust, gas or vapour. For dry sand, many minerals and many food ingredients in a safe environment, for example, Type A works perfectly well.

Type B: built to stop dangerous sparks

A Type B bag uses a fabric that prevents the most dangerous kind of static discharge, the propagating brush discharge. It does not remove the charge, though, so it is not antistatic. Even so, it stops the worst spark from forming. As a result, Type B suits dry flammable powders, provided there are no flammable gases or solvents in the surrounding air.

Type C: grounded and fully conductive

A Type C bag, also called a conductive bag, contains conductive threads running through the fabric. Crucially, you must connect it to a proper earth ground while filling and emptying. Ground it correctly, and it carries the charge away safely for flammable powders and flammable atmospheres. The catch, however, is human: if someone forgets the ground connection, the bag becomes dangerous.

Type D: antistatic without any grounding

A Type D bag uses special antistatic fabric that dissipates static safely on its own, and needs no ground connection. This removes the biggest weakness of Type C, the forgotten ground. Because of that, Type D is ideal for flammable powders and flammable atmospheres. Keep it clean, though, since grease or the wrong coating can reduce how well it works.

In short: Type A gives no static protection, while Type B stops dangerous sparks. Type C stays safe only when grounded, whereas Type D is safe on its own, with no grounding needed.

How to choose between the FIBC types

You do not choose a type by price. Instead, you choose it by what you are filling and where. In practice, two questions decide almost everything.

First, is your product flammable or combustible as a dust or powder? Second, will you fill or empty the bag near flammable gases, vapours or solvents? Together, your answers point straight to a type. A safe product in safe surroundings allows Type A, while a flammable powder in clean air allows Type B. Flammable atmospheres, by contrast, need Type C or Type D, and Type D removes the risk of a missed ground connection.

Safety note: When flammable gases or solvents are present, only Type C (properly grounded) or Type D bags are safe. Type A and Type B, by contrast, are not.

Why getting FIBC types wrong is so expensive

Choosing the wrong type is not a small mistake. At best, a buyer overpays for protection they do not need. At worst, the wrong bag ignites a dust cloud and causes a fire or an explosion, with real danger to people.

Moreover, there is a quieter cost. A supplier who ships the wrong type, or who cannot explain which type a customer needs, signals that they do not fully understand the product. In this industry, that kind of doubt is exactly what pushes a buyer elsewhere. Ultimately, knowing your FIBC types is part of being a supplier worth trusting.

Frequently asked questions

What are the four FIBC types?

The four FIBC types are A, B, C and D. Essentially, they differ only in how they handle static electricity. Type A offers no static protection, whereas Type B prevents dangerous sparks. Type C is conductive and needs grounding, while Type D is antistatic and works safely without it.

What is the difference between Type C and Type D?

Both stay safe around flammable atmospheres, but in different ways. Type C, for instance, must connect to an earth ground every time you fill or empty it. Type D, on the other hand, dissipates static on its own, which removes the risk of a forgotten or faulty ground.

Which FIBC type do I need for flammable powders?

If the powder is flammable but the air around it stays clean, Type B is usually enough. However, if flammable gases, vapours or solvents may be present, you need Type C with proper grounding, or Type D. When in doubt, describe both the product and the environment to your supplier, and let them confirm.

Are FIBC types the same as bag sizes?

No. The type describes static safety, not dimensions. In fact, a bag of any size or capacity can be a Type A, B, C or D. Size, capacity, loops and liners, meanwhile, are separate choices you make alongside the type.

The bigger picture

The four types look identical on a pallet, yet each one suits a very different job. Match the type to your material and your environment, and a bulk bag becomes one of the safest ways to move product on earth. Get it wrong, though, and the same bag turns into a hazard.

Not sure which type you need? Tell us what you are shipping and where, and our team will point you to the right one. Meanwhile, explore our FIBC range or talk to our team.

Written by UWON Packaging, an FIBC and bulk bag manufacturer and exporter that helps buyers choose the right bag, not just any bag. About UWON · Our FIBC range · Talk to our team