A lot of time is spent at National Bulk Bag answering questions from buyers. We get a ton of questions ranging anywhere from FIBC construction to specific questions about the many different applications of bulk bags. However, the specific question of “what are breathable bulk bags?” is of particular interest because it has many facets. It’s not as simple to say, “this bag is breathable and this one is not”. There are lots of things to consider that we will examine in this post.

Woven Polypropylene and What it Means for Breathable FIBCs

FIBCs or flexible intermediate bulk containers are created by weaving strands of polypropylene together to form a sturdy mesh while maintaining the flexibility that give bulk bags their name, strength and usefulness. To learn more about this, check out this blog we wrote a while back explaining in greater detail just what woven polypropylene is.

Because of this weave, by default, bulk bags are not water or air tight. This means that the bags breathe naturally to a certain extent. How much they breath depends on a variety of factors that involve the construction of an individual bag. 

Coated vs Uncoated FIBCs

Coated bulk bags are FIBCs with a laminate coating applied in the factory. Before the bag is sewn together, an additional polypropylene film is added to the bag’s fabric sealing the smaller gaps in the weaves. For more information about coated vs uncoated bags, check out this blog detailing the differences, uses, and applications.

The reason the coated vs uncoated discussion is relevant to breathable bulk bags is that the coating when applied actually finds its way into the small gaps in the weaves, creating greater cohesion between them. Coating doesn’t make the bag 100% air and water tight, however it does make them significantly less breathable. If you’re looking for a more breathable bag, avoid bags with coating. 

Vented Bags

If you need that next level of breathability, look no further than vented bulk bags. Vented bags have strips that run vertically along each side. These strips have small strands of polypropylene that are not woven, allowing much more air to pass between the fabric. These are by far the most breathable FIBCs manufactured and should be the preferred option if you can find a vented bag that meets your specs for your application.

Applications

There really isn’t any single application that stands out as perfect for bags that are more breathable, however, we tend to see a lot of use in the produce industry where moisture can cause the product to mold. Any application where moisture can be a detriment, breathable bags are a great solution as the increased airflow will prevent the retention of moisture that causes mold.