Breathable Bulk Bags 101: Uses, Material & Ventilation

July 7, 2021 | General, Manufacturing

Flexible intermediate bulk containers have a range of applications and come in different types, supporting almost any industry. When you need to prevent moisture build-up in your goods, using breathable bulk bags allows air to circulate through the container to help keep your products dry and moisture-free.

With so many different elements to consider when choosing a breathable FIBC big bag, you can learn everything you need to know about ventilated and open-top bulk bags in this blog.

What are Breathable Bulk Bags?

Sometimes called ventilated FIBCs (Flexible Intermediate Bulk Containers), breathable bulk bags allow for air circulation through the bag lining and product. As bulk bag suppliers, Palmetto Industries has a range of FIBC construction types that promote airflow through the woven material, preventing moisture from building up inside the bag.

Most bulk bags allow for some degree of breathability, but some applications require an FIBC with less insulation used in the construction. A breathable bulk bag is lighter and comes in many different construction types that allow air to circulate easily through the lining without compromising the strength of your heavy-duty containers.

What are Breathable Bulk Bags Made Of?

Bulk bags are made from woven polypropylene strands for a sturdy mesh material. These material properties are common in UN approved bulk bags as it prevents dampness and mold from accumulating inside the container.

The virgin polypropylene material is a petroleum-based product that uses extruded resin from petroleum feedstock to make the woven material. Weaving together polypropylene strands is what makes most FIBCs highly breathable.

   So, Does Polypropylene Make Breathable Bulk Bags Waterproof?

Woven polypropylene is a versatile material that resists a variety of environmental factors and physical conditions. Unfortunately, the woven polypropylene isn’t waterproof or watertight by itself, although you can opt for a construction type that includes coating the material to include these properties.

Woven polypropylene fabric gives you:

• Lightweight and tear-resistant flexible intermediate bulk container material
• High-strength, flexible, and chemical resistant bulk bags
• Pest-resistant FIBC that is also moderately resistant to stretching and shrinking

Although most FIBCs are breathable to some extent, certain types of products require more breathability during storage or transport.

Applications for Breathable Bulk Bags

Wherever you need to prevent moisture build-up in a product during storage and transport, you’ll need a breathable bulk bag. By circulating the air through the container and product, you can prevent dampness building up and rotting or mildew from ruining your goods, improving the safety factor of your transport solution.

Some of the main breathable FIBC uses include:

• Agricultural goods and food products (breathable bags feature heavily when transporting large quantities of potatoes or other vegetables)
• Chemicals and any other goods where moisture can cause damage or a safety issue in the product
• Storing and transporting powders, grains, solids, or amorphous solids (although the construction of the bag may influence its breathability with finer products)

Factors that Impact FIBC Breathability

Moisture permeability in composite fabrics is based on the wet resistance of the materials. In FIBC bags, everything from the coated (or non-coated) woven material to the construction type of the strands will influence the bag’s breathability.

When goods need to stay dry during storage and transport, you can ask your bulk bag manufacturer to include an internal poly liner in the construction, which can prevent moisture build-up even when working with finer materials like sugar, flour, or salt.

   Coated vs. Uncoated Breathable Bulk Bags

Uncoated bags work well for larger goods like vegetables and firewood. The bag’s construction uses wider strands with gaps between pieces to allow for adequate airflow during storage and transport.

Once you start working with more refined grains, you’ll need to consider a coating or lining that prevents moisture from reaching the product. Liners and coatings are designed to keep moisture away from the product, but there may still be a buildup of dampness, which could require you to use a ventilated bulk storage bag with a spout or baffle.

   Vented Bulk Bags: Taking FIBCs a Step Further

Vented or ventilated bulk bags can take your FIBCs breathability to the next level. A vented bulk bag uses different construction types to improve circulation through woven materials. For example, you can opt for an open-top or bottom-vent or use vented strips built into the FIBCs sides.

A vented bag’s construction may include a duffel or flap to allow more air circulation when required. As these bags reduce moisture build-up even when the top and bottom are closed, vented FIBCs are the most popular when dealing with larger, non-flowable products but using internal poly liners in the construction can support finer materials.

Final Points on Breathable Bulk Bags

Breathable bulk bags have many uses and help protect goods from moisture build-up that can ruin a product. When choosing your type of ventilated bag, you need to consider the size of the goods, like fine or coarse materials, and make sure that you use the right style for your specific application.

If you need to add additional moisture protection to your bag, you’ll need to speak to a bulk bag supplier that’s an expert in the industry.

Some of the key takeaways regarding breathable bulk bags are:

• Come in many different construction types
• May include additional coated or non-coated materials depending on the application
• Popular when dealing with products that need protection against moisture and dampness
• Ideal for the produce industry where mildew and mold can ruin the product
• Breathable bags can use a poly liner to increase the wet resistance when you need to transport or store flowable products like grain, salt, or sugar