Safety factor 5:1 and 6:1: can a Big Bag be reused?

Reusing a Big Bag looks like an easy way to save money. But doing it with the wrong bag is one of the most common causes of lifting accidents. The short answer: only Big Bags designed for it, with a 6:1 safety factor, can be reused, and only under certain conditions.

What the safety factor is

Every Big Bag has a rated load, or SWL (Safe Working Load): the kilos it can carry safely. The safety factor says how many times that load it withstands in a break test. A 1,000 kg Big Bag with a 5:1 factor must hold at least 5,000 kg in testing; a 6:1 bag, at least 6,000 kg.

Why 5:1 is single-trip

The margin of a 5:1 bag is calculated for one cycle: filling, transport and discharge. During that cycle the fabric, loops and seams suffer stress, abrasion and sun exposure that are not always visible. Reusing it means working with a smaller margin than it was designed for, without knowing how much smaller.

When a 6:1 can be reused

• When the operation is a closed loop, for example between your plant and the same customer’s plant, and the Big Bag always returns to the same use.
• When it is inspected before each use: no cuts in the fabric, no frayed loops, no open seams and no residue from the previous product that could contaminate.
• When a record is kept of how many times it has been used.

Signs a Big Bag should no longer be used

• Loops with loose fibers, cuts or deformation.
• Open seams or broken threads.
• Fabric faded or brittle from the sun.
• Cuts, holes or areas worn by abrasion.

If your operation allows reuse, consider a 6:1 Big Bag from the start: it costs a little more, but pays for itself over its cycles of use. See more in our guide to thesafety factor.