Step by step
- Read the label. Find the sewn-in tag and confirm two things: the safety factor reads 6:1, and every field is still legible. If the rating says 5:1, or the print has worn to the point that you are guessing at the SWL, set the bag aside for recycling.
- Confirm what it carried last. Check the trip record or the pouch paperwork for the previous contents. The bag should return carrying the same product it left with. Unknown, mixed or hazardous residue ends its working life on the spot.
- Inspect every lifting loop. Run each loop through your hands from the body seam to the top. Look for cuts, fraying, abrasion marks from forks or hooks, and stitching that has started to pull. Compare loops against each other; one that looks stretched or thinner than its neighbors is a reject.
- Walk the seams. Follow the side, bottom and top seams around the body. Broken or skipped stitches, sifting stains along a seam line and gaps where product has worked through all mean the bag is done.
- Check the fabric for sun damage and wear. Rub the outer surface. Ultraviolet exposure softens the woven polypropylene and leaves a chalky powder on your fingers. A bag that has spent a long stretch outdoors should not be lifted again, however sound it looks. Also look for holes, tears and burn marks.
- Look over spouts and ties. Open and close the fill and discharge spouts. The spout fabric should be whole, and the tie cords or closures should still be attached and long enough to tie off. A missing or torn tie can't be swapped at the plant.
- Check the liner. If the bag uses a film liner, look for punctures, splits and residue. Make sure it sits correctly in the body and that any liner tabs are still in place. A damaged liner usually rules out the whole unit.
- Check the document pouch. The pouch should be intact and empty of the last trip's paperwork, so the next receiver gets only current papers. A torn pouch is minor on its own but tends to travel with handling damage elsewhere.
- Clean where the product calls for it. Shake out or blow out loose residue following the steps your bag maker's program sets out. After cleaning, look at the inside surfaces again; cleaning can reveal wear that dust was hiding.
- Record the result. Write down the bag's identifier, the date, who inspected it, the trip count and pass or fail with the reason. That log tells you when a batch is wearing out and keeps rejected bags from slipping back into service.
Who should follow these steps
These guidelines are for plants running 6:1 multi-trip bags in a closed loop, where the same product goes out and the same empties come back. They don't turn a single-trip bag into a reusable one, and they aren't a route for food or pharmaceutical lines, which take new bags.
The manufacturer handling guide we cite sets the baseline: inspect visually for damage before each use. Everything below is how that sentence looks on a busy dock, done one bag at a time with the empties laid out flat in good light.
Setting up the inspection bench
Checks go faster and catch more when the space is set up for them. Pick a clean, dry corner away from forklift traffic, with a table or a swept floor large enough to spread an empty bag out flat. Bright overhead lighting matters; frayed webbing and pinholes hide in shadow. Keep a hand lamp for looking inside the body and down the spouts.
Give rejects a home of their own, a marked cage or a taped-off pallet, so a failed bag can never be grabbed by mistake during a rush. Tag each one with the reason before it goes there. Passed bags get folded the way your filler crew prefers and stacked by product, ready for the next run.
Train two or three people rather than one, so the routine survives vacations and shift changes, and have them inspect the same sample bags together now and then. If they disagree about a bag, the stricter call wins.
Faults that fail a bag outright
Most inspection calls are easy. If any of the following turns up, the bag leaves service and goes to a recycler. Don't try to grade them as small or large.
- A 5:1 rating, or a tag too faded to read.
- Any cut, fray or pulled stitch on a lifting loop.
- Broken stitching or sifting along a seam.
- Chalky, soft or brittle fabric from sunlight.
- Holes, tears, scorch marks or chemical staining in the body.
- Missing ties or a damaged spout.
- A punctured or contaminated liner.
- Contents on the last trip that nobody can confirm.
Sunlight and storage between trips
Polypropylene and ultraviolet light don't mix well. The handling guide notes that UV exposure softens and powders the fabric surface, and that bags should not be lifted after prolonged sun exposure. A pallet of empties parked by the door all summer can fail even though nothing cut it.
Keep returned bales indoors or under cover, off the ground and away from sources of heat. Treat any bag whose history includes a spell outdoors as suspect, and if nobody can say how long it sat there, fail it.
Why the plant doesn't repair bags
The same guide is plain on this point: bags should not be repaired by the user. A rating describes the bag as it was built and tested. Restitching a loop, taping a hole or knotting on a new tie produces something no type test ever saw. You can't know its strength, so you can't put product in it and lift it over a person's head.
If a whole batch shows the same fault, that's a conversation for the bag maker. Their program may cover reconditioning; your plant floor shouldn't.
Repeated faults also point at causes you can fix. Loop abrasion on one side often traces back to a rough fork carriage. Torn bottoms can come from a pallet with a nail sticking up. Seam sifting near the spout may mean the discharge frame is pinching. Fix the equipment and the reject rate drops.
A simple trip log
Paper or spreadsheet, the log only needs a handful of columns. The point is that any bag in the loop can be traced back through every fill it has seen.
| Field | What it gives you |
|---|---|
| Bag identifier or lot | Ties each record to one bag, or to one production lot from the maker. |
| Trip count | Shows how hard a batch has worked. |
| Product carried | Proves the bag stayed on one material. |
| Inspection date and name | Shows who signed it off and when. |
| Pass or fail, with reason | Spots a fault that keeps recurring, such as loop abrasion from one forklift. |
Retiring the rejects
Failed bags still have value as material. Fold them, strap them into bales and keep them dry. When you have enough for a pickup, tell us the count and the dock ZIP and we'll book the empties on the same terms as an inbound load.
Questions
Can I reuse a 5:1 bag that passes all ten checks?
No. Passing a visual check doesn't change the rating. The maker recommends single-trip bags not be re-used, so a 5:1 bag goes to recycling.
How often should a multi-trip bag be inspected?
Before every fill. The guide's instruction is each use, not each month or each batch.
Is a small hole in the fabric acceptable if it's far from the loops?
No. A hole anywhere means the bag isn't the one that passed its tests, and you'd need a repair to close it, which the guide rules out.
Can we reuse bags across two different products if we clean them?
We'd advise against it. Keep each loop on one material so residue and wear stay predictable, and start a new product with new bags.
Who should do the inspecting, the shipper or the receiver?
Ideally both. The receiver flags obvious damage when emptying, and the shipper runs the full check before refilling. The record should show the shipper's sign-off, since that is the last look before product goes in.
Sources
- FIBC handling guidelines (manufacturer, 2023)
- ISO 21898:2024 summary
- Flexible intermediate bulk container (Wikipedia)
Standards named here (ISO 21898, IEC 61340-4-4, NFPA 77) are summarised, not quoted: read the standard and the bag maker's documents before you rely on a rating.