We started photographing every container against its manufacture plate in late 2020, for a boring reason: customers kept asking whether the tote in the quote was the tote on the truck, and a photograph settles that argument in one second. It was never intended as research. But by the end of 2022 we had 4,062 usable intake photographs, each tied to a grading decision made by one of three people, and it occurred to Marisol that we were sitting on the closest thing this trade has to a dataset.
So we spent three wet weeks in January re-examining them. What follows is not a peer-reviewed study — it is one yard's observations, from one region, on containers that arrived here for a reason. But it changed how we inspect, and it is more evidence than most people in this business have ever put in one place.
Finding one: failure starts at the nodes, not the spans
A composite IBC cage is a lattice of welded tube. Intuitively, you would expect the long unsupported spans to be where a frame gives up — that is where a beam bends. In practice, 71% of the cages we downgraded for structural reasons had their first visible defect at a welded intersection, and in 84% of those cases the defect was at one of the four corner columns rather than on a face.
The mechanism is not mysterious once you see it. Welding leaves a heat-affected zone where the galvanising has burned off and the grain structure has changed. Water sits in that joint. Chloride — road salt in winter, brine residue in a municipal fleet, sea air on a container that came in through a port — finds it. Corrosion begins in exactly the spot that carries the stacking load.
Finding two: surface rust tells you almost nothing
This one genuinely surprised us. We scored every photograph for visible surface oxidation on the tube faces — the orange bloom that makes a container look neglected — and compared it against the eventual structural decision. The correlation was weak enough to be useless.
| Visible surface rust | Containers | Failed structurally | Rate |
|---|---|---|---|
| None | 1,184 | 39 | 3.3% |
| Light | 1,761 | 84 | 4.8% |
| Moderate | 842 | 51 | 6.1% |
| Heavy | 275 | 24 | 8.7% |
A heavily oxidised cage is not quite three times as likely to fail as a clean one — but the base rate is so low that nine out of ten ugly cages are structurally fine. If you are buying on photographs, ugly is a very poor proxy for unsound, and any seller pricing on appearance alone is pricing on the wrong variable. That works in a careful buyer's favour.
Finding three: forklift damage has an address
Of 613 containers with base damage, 447 had it on the same rail — the one that faces a driver approaching from the long side with the forks slightly low. Not randomly distributed at all. Once you know to look there first, base inspection takes fifteen seconds instead of a minute.
It also gave us something useful to tell customers who generate empties. If your containers consistently come back with damage on one rail, it is not bad luck, it is an approach angle and a fork height, and it is fixable with twenty minutes of conversation on your own dock. Several of our regular sellers have improved their grade mix — and therefore what we pay them — by exactly that much effort.
Finding four: the pallet base predicts the era
Wood-based composite IBCs essentially disappeared from our intake between 2021 and 2022. In the 2020 photographs they were 6% of arrivals; by late 2022 they were under 1%. Steel and composite bases dominate, and plastic bases have grown steadily with food and wash-down customers.
- Steel base: most repairable, most common in reconditioned fleets, fails by rust-through at the fork pockets.
- Composite base: good balance, fails by deck cracking and delamination at the corners.
- Plastic base: lightest and most hygienic, cannot be repaired, fails by cracking at the fork pockets.
- Wood base: rots in wet service, and we replace it as a matter of course rather than sell it on.
What we would tell another yard
Photograph everything, even if you think you are only doing it for customer service. The photographs cost nothing to take and they turn into evidence. Ours told us we had been spending inspection time on the wrong things — grading cosmetics carefully and structure quickly, when the money and the liability are both in the structure.
We had been grading with our eyes and pricing with our gut. The photographs let us grade with our hands and price with a number.— Renée Haddad, intake and grading
The second thing we would say is that the base rates are lower than the trade's folklore suggests. A used composite IBC is a much more durable object than its reputation, and most of what makes people nervous about buying one is dirt rather than damage. That is good news for anyone trying to keep containers out of the ground.