Bulk bags are widely used across a number of industries to store or ship a wide range of products. To determine which bulk bag is ideal for your product and application, it is important to first evaluate the type of fabric you need.
Uncoated Fabric:
Bulk bags are commonly manufactured using either coated or uncoated woven polypropylene fabric. Uncoated woven polypropylene fabric is ideal for products requiring breathability as the fabric allows for air flow. A good rule of thumb for particle size is 120 microns or larger when using uncoated fabric. Here’s an example of some common products that are shipped or stored in bulk bags manufactured from uncoated fabric: grains, seeds, coffee beans, peanuts, almonds, pecans, gravel, rocks, minerals, debris, fly ash and fertilizer. If the particle size is smaller than 120 microns, it may be necessary to use a bag liner when using uncoated fabric.
Coated Fabric:
A 1 mil polypropylene coating can be added to one side of the fabric to reduce the breathability of the bulk bag, for moisture control and product contamination protection. Coated fabric is frequently used to hold products with small particle sizes. Here’s an example of products that are shipped or stored in bulk bags made from coated fabric: milled flour, milled corn, soy powders, powdered sugar, chemicals, cement, silica sand, soil, glass and steel. It is important to note that due to the construction of a bulk bag, a sift-proof design cannot be achieved unless an inner liner is used.
Double coated fabric is available as a special order. For assistance, you can speak directly to one of our expert customer service representatives.
Fabric Weight:
When choosing a bulk bag fabric, you want to maximize performance and minimize cost. One important specification to consider is the weight of the fabric. Fabric weights are directly related to the amount of product that the bulk bag will hold and are determined by the SWL or Safe Working Load. The higher the SWL, the heavier the fabric weight. At BAG Corp, 5 oz fabric is used for Super Sack® containers with a SWL of 2,200 lb, 6.5 oz fabric for 3,000 lb Super Sack® containers, and 8 oz fabric for 4,000 lb Super Sack® containers.
Fabrics and Static Electricity:
When bulk bags are filled or discharged, the movement of bulk powder substances can cause a buildup of static electricity. Preventing or removing an electrical charge is critical in an environment where flammable gases or combustible dust may be present. Here are the four types of bulk bag fabrics and their potential for use in and around combustible environments:
Type A FIBCs are made from plain woven polypropylene and other non-conductive fabrics. There is no static protection provided by Type A FIBCs, and therefore it is essential that they are not used to store or transport combustible materialsor used in flammable or combustible environments.
- Used to safely transport non-flammable products.
- No flammable solvents or gases should be present around the bag.
Type B FIBCs are made from plain woven polypropylene fabrics that have a low breakdown voltage to prevent the occurrence of highly energetic propagating brush discharges that can ignite a dust-air mixture. Type B FIBCs cannot be considered antistatic because they do not have any mechanism for dissipating static electricity.
- Used to safely transport dry, flammable powders.
- No flammable solvents or gases should be present around the bag.
Type C FIBCs are made from non-conductive polypropylene fabrics interwoven with conducting threads, normally sewn in a grid pattern, that connect the bag to ground via a grounding tab. The connection to ground or earth during filling and discharging is critical to the safe use of Type C FIBCs.
- Used to safely transport flammable powders.
- Used safely when flammable solvents or gases are present in the bag.
- DO NOT USE when ground connection is not present or has become damaged.
Type D FIBCs are made from antistatic and static dissipative fabrics designed to safely prevent the occurrence of incendiary sparks, brush discharges and propagating brush discharges without the need for a connection from the bulk bag to the ground. Type D FIBCs can be used to safely package combustible products and to handle products in combustible and flammable environments.
- Used to safely transport flammable powders.
- Used safely when flammable solvents or gases are present in the bag.
- DO NOT USE when the bag surface is contaminated or covered with conductive materials, such as water or grease.
Fabric Repair:
Super Sack® containers are flexible, yet able to withstand the weight of a metric ton or more. Because these bulk bags are made from woven polypropylene fabric, they are not indestructible. Bags are often punctured by a forklift driving a tine into the bulk bag or they get cut by a box cutter blade when the packaging is opened.
BAG Corp offers a unique product for these minor fabric repairs. Sack Patch Tape, with its unique adhesive formula and polypropylene fabric strength, can temporarily fix a cut bulk bag, allowing you to quickly get back to business.
To repair a bulk bag using Sack Patch Tape, take the following steps:
- First, cut a piece of Sack Patch Tape from the roll long enough to cover the hole on the bag. Make sure the area to be repaired is clean and dry before applying the tape.
- Once prepared, peel off the backing and apply the tape directly over the hole in the bag. In the situation where a filled bag was punctured and product escaped, apply the tape to the lower area of the puncture first. By patching the lower part of the hole first, the product will be contained as the tape is applied in an upward direction over the hole.
- Make sure the Sack Patch Tape is properly adhered to the bulk bag by firmly pressing the tape on the repaired area. It is important to note that Sack Patch Tape is intended for minor and temporary repairs.
- Once the repaired bag has been emptied, it should be disposed.
You can watch our step-by-step Sack Patch Tape how-to video here.
The Super Sack® container, Sack Patch Tape, and a diverse inventory of bulk bags are available through our online store for immediate shipment from our warehouse. If you need help establishing a bulk bag stocking strategy or require a custom bag solution, you can speak directly to one of our expert customer service representatives for assistance.
