Key takeaways
- A 5:1 FIBC is built for one fill; a 6:1 is built to be refilled. A single-trip bag should not be refilled.
- Cleaned bags look identical; the printed spec panel is the main difference, and panels fade, tear and get cut off.
- Before buying used bags, ask about history, cleaning, inspection and the stated safety factor.
- Polypropylene loses strength under UV without visibly changing, so storage history matters as much as fill history.
There is one question to ask before buying any used bulk bag, and it is not about price, cleaning process or safe working load. It is: what was the original safety factor?
ReGaylord Boxes focuses on gaylord boxes. This article is general product knowledge for buyers who also handle bulk bags, and it does not describe a service we provide.
What the ratio means
The ratio is the relationship between the load a bag was tested to and its stated safe working load. A 5:1 bag was tested to five times its rated load; a 6:1 to six times.
That difference is not a margin bolted on for comfort. It reflects different construction and different design assumptions about repeated stress cycles.
| Attribute | 5:1 | 6:1 |
|---|---|---|
| Design intent | Single trip | Multi-trip |
| Typical construction | Built for one fill and discharge | Built for repeated loading |
| Suitable for refilling? | No | Yes, if its history and condition are known |
| Key check | Treat as single use | Confirm ratio, history and inspection |
Why this gets blurred
Because a used 5:1 bag looks essentially identical to a used 6:1 once it has been cleaned. The printed spec panel is the difference, and spec panels fade, tear and get cut off.
A seller with a bag of unknown ratio has two honest options: describe it as unknown, which few people want, or not offer it at all. The temptation is to let the buyer assume. That is how the used bulk bag market acquired a mixed reputation, and why asking matters.
What to ask for
- Known history. Unknown previous contents is a reason to pass.
- Cleaning appropriate to the previous product, followed by full drying. A damp bag in storage can become a mould problem.
- Inspection of loops, seams, fabric, spout condition and any prior patching, with the date.
- Evidence of how the bag was assessed, if the seller claims it has been tested.
- The ratio, in writing, for every bag.
Bags that fail any check should not be refilled. There is no lower grade of FIBC that is safe to fill.
UV degradation, the invisible one
Polypropylene loses tensile strength under ultraviolet light. A bag that spent a summer stored outdoors can have lost a substantial share of its fabric strength while looking entirely normal, with no fading and no brittleness to the touch.
That is why outdoor storage history matters as much as fill history, and why bags whose storage cannot be established are best avoided.
Bag or box?
Bags win on empty storage footprint, shipping weight and discharge control for flowing product. Boxes win on stacking without a frame, on protecting fragile product, and on cost per trip for dense material.
Many operations run both, and the split is usually rational: bags outbound, boxes for internal movement and storage.
Questions