FIBC Bulk Bag Safety: What Is SWL?

what is SWL

Workplace injuries are not to be taken lightly. According to the U.S. Bureau of Labor Statistics, in 2017, the United States saw over 2.8 million nonfatal workplace injuries and illnesses, 136,510 of those cases involving employees who were struck by objects or equipment while on the job. Additionally, in 2017, the United States saw 5,147 workplace fatalities, 695 of those caused by contact with objects or equipment.

Fortunately, in industries that use flexible intermediate bulk containers (FIBCs), more commonly known as bulk bags, safety standards help reduce the occurrence of workplace injuries and fatalities that result from bag failure. Every FIBC comes with a numerical rating for its safe working load and safety factor, and these numbers help employers determine how to use their bags safely.

Below, we’ll explain what safe working load and safety factor are and discuss why safe working load, in particular, is so important in the workplace.

What the Terms “Safe Working Load” and “Safety Factor” Mean

So what is safe working load, and how is it different from a bag’s safety factor?

The safe working load (SWL) of a bulk bag is the bag’s maximum safe carrying capacity. The SWL is expressed in pounds. That number of pounds is the most the bag can safely carry. Because the security of thousands of pounds suspended in the air is paramount, every component of the bags, from stitching to the choice of material to the size of the loops, is chosen to support the bulk bags’ SWL.

The safety factor (SF) of a bag is a ratio, typically 5:1 or 6:1. An SF of 5:1 indicates a single-use bag, and an SF of 6:1 indicates a multiple-use bag, or sometimes a HAZMAT bag. A single-use bag is just that — a bag designed for one use — whereas a multiple-use bag can handle repeated loads, though you should always inspect your bag carefully between loads to make sure it has not sustained too much wear and tear.

How Is Safety Factor Determined?

To determine the safety and usability of a bag, manufacturers use what is known as the peak load test.

During the peak load test, a bag with an SF of 5:1 should be able to hold up under five times the SWL after being used through 30 cycles — or the cyclic test — of twice the SWL. If the bag fails under these conditions, it is not suitable for industrial or commercial use. For example, if the SWL of a bag were 1000 pounds, the bag would pass testing if it could withstand up to 5000 pounds of pressure after undergoing the cyclic test at 2000 pounds of pressure 30 times.

A bag with an SF of 6:1, on the other hand, should be able to hold up under pressures of six times the SWL after being used through 70 cycles of three times the SWL. Because this test is more rigorous, if the bag does not break before completing the test, it can be classified as a multiple-use bag. In this case, if the SWL of the bag were 1000 pounds, the bag would pass the 6:1 testing if it could withstand up to 6000 pounds of pressure after undergoing the cyclic test at 3000 pounds of pressure 70 times.

What Standards Establish Proper Safe Working Load and Safety Factor?

The European Flexible Intermediate Bulk Container Association (EFIBCA) established SF standards for FIBCs in the 1980s to help provide for safety in the workplace. More recently, the International Organization for Standardization’s ISO 21898:2004 cemented the criteria above to ensure quality, reliable bags and protect worker safety.

Importance of SWL

the importance of SWL

SWL is an essential part of providing a hazard-free workplace. SWL gives workers confidence that the bags they raise into the air will not come crashing down on top of them.

It is vital that companies not exceed the SWL of their bags during use. FIBCs are incredibly heavy when fully loaded, and they are often suspended precariously in the air over both employees and workplace equipment. So any malfunction could have catastrophic consequences for whoever is underneath. A bag carrying 4,000 pounds when it is rated for only 2,200 is likely to break during operation. Forcing a bag to carry more weight than its SWL allows for can lead to serious workplace injuries or fatalities.

Fortunately, many companies that use FIBCs have scales available to use to ensure that no bag exceeds the maximum weight that its SWL allows. For example, most pallet wrappers have scales built in for convenient weighing of bulk bags.

SWL and the Role It Plays in the Bulk Bag Industry

SWL plays an essential role in allowing users to calculate the loads their bags can safely lift. Forcing a bag to carry more weight than its SWL allows for can lead to serious workplace injuries or fatalities. Knowing the SWL of your bags enables you to calculate, using your products’ bulk density, how much product you can safely fill the bags with.

The following is an example of how to calculate the SWL of bulk bags.

You probably know there are 27 cubic feet in a yard. If you also know that wheat flour has a density of about 42 pounds per square foot, then you can multiply 27 by 42 to get 1,134, the total number of pounds that a cubic yard of wheat flour weighs. So you could safely put a cubic yard of wheat flour into a bag with an SWL of 2,200 since 2,200 is more than 1,134.

But if you had two cubic yards of wheat flour, together they would weigh 2,268 pounds. Even though 2,268 is only slightly larger than 2,200, you still should not put both cubic yards of flour into a single bag with an SWL of only 2,200. To keep your workers safe, you would need to separate the products or use a higher-rated bag.

Contact Bulk Bag Reclamation for All Your Bulk Bag Needs

When you need a safe, sturdy FIBC, Bulk Bag Reclamation should be your first stop. We refurbish bulk bags that have been used only once, make sure they are safe and ready for further use and sell them on to extend their lifespans.

contact bulk bag reclamation

When you work with us, you’ll get quality bags that work for your budget. You’ll also get the satisfaction of knowing you’re helping the environment by investing in recycled, eco-friendly bags. Our baffle bulk bagsduffle top bulk bagsspout top bulk bags and open top bulk bags give you options while always providing you with clean, chemical-free bags that have only previously held products meant for humans or animals to consume.

We have bags for use in a variety of different applications, including bags rated B through D for controlling static electricity, and we are happy to talk with you about the SWL of our FIBCs. Contact us today to learn more or request a quote online.