Damage shows up, and the first call is usually to the box supplier. That call changes the price of every case you ship for the next year. It may not touch the thing that actually broke the goods.
Most damage is not spread evenly across a year's shipments. It is made at a handful of fixed places: one bay in the warehouse, one forklift move, one stacking habit, one stretch of the journey. Find those places and the cheapest fixes are usually paint, a schedule and a conversation. Buy a stronger box first and you pay for every unit shipped in order to fix something that happened in three afternoons.
This article is about the order of work: how to find where damage is made, which free levers exist, and how to test the packaging cheaply when you genuinely suspect it.
Start with a damage bill that names places, not products
A glass packaging company in Pathum Thani recorded four damage events in 2024. The research that followed put the year on one page.
| What happened | Pallets | Value (baht) | Share |
|---|---|---|---|
| Loads toppling in the warehouse | 34 | 98,281.60 | 52% |
| Damaged packaging | 21 | 58,701.00 | 31% |
| Packaging soiled by bird droppings | 18 | 17,480.00 | 9% |
| Pallets wet through | 6 | 13,982.00 | 7% |
| Total | 79 | 188,444.60 |
Read that list as a buyer of packaging. Only one line of the four, the 31%, is even arguably about how strong the packaging is. A load falling over, bird droppings and water are the building, the roof and where things were put down. A thicker board answers none of them.
Now read it as a buyer of time. The 34 toppled pallets did not happen across the year. They happened in three months: 11 pallets and 30,371 baht in June, 10 pallets and 23,554 baht in August, 13 pallets and 44,356.60 baht in September. The other nine months were zero. A damage rate expressed as a percentage of annual shipments would have shown a small, steady, unremarkable number, and would have hidden the entire problem.
The causes, once somebody asked why, were mundane. Loads were being placed too far back in the bay, where they struck a steel beam. Loads were being placed on a section of floor that had settled. The lighting was inspected once a month.
The measures were repainted placement lines so that nothing is set down against a beam or on the sloping section, a lighting inspection every 15 days instead of monthly, and a briefing so the forklift crews worked the same way. January to September 2025 recorded zero baht on that line.
One site, one product, nine months of follow-up. Do not take the zero as a promise. Take the shape of it: the largest number on the page was removed with paint and a calendar entry.
Four things break goods, and a stronger box answers one of them well
The list of recognised transport packaging tests tells you what the industry believes damages a load. A test house will run compression, stacking, drop, incline impact, vibration at a fixed frequency and random vibration. Underneath those six tests sit four mechanisms.
- Static load. Weight from above, in the warehouse and in the vehicle, for hours or months. This is what compression and stacking tests measure, and it is the one a stronger board genuinely answers.
- Impact. Handling. A forklift tine, a tailgate, a pallet set down hard, a load struck by another load. Drop and incline impact tests cover it. Stronger board helps some, but it is a race you lose, because the energy in a drop rises with the height and the cheap fix is to stop the drop.
- Vibration. The road, for hours. It rarely breaks a box. It chafes, loosens and fatigues, and it finds the goods that were free to move. Board grade barely touches it.
- Instability. The load falls over. No test on the list measures it, because it is not a property of the box at all. It is a property of how the load was built and where it was put down.
Put your own damage record into those four terms before you buy anything. Crushed bottom cases are static load. A split corner or a burst seam is impact. Contents rubbed, worn or rattled loose is vibration. A whole load on its side is instability, and in the Pathum Thani case that was 52% of the money.
You are probably throwing away strength you already paid for
The single largest free gain in most operations is on the pallet, and it is called overhang: cases hanging over the edge of the deck.
Virginia Tech's Center for Packaging and Unit Load Design measured this properly for the Fibre Box Association. The second phase ran 900 box compression tests across 15 box designs and three board grades, with overhang between 0.25 and 3.25 inches, roughly 6 to 83 mm, on the width, on the length, or on two sides at once. Combined with a first phase of more than 1,600 boxes, the finding was that overhang costs between nothing and 40% of a box's measured compression strength. The Fibre Box Handbook's own working estimate is a loss of 20% to 40%.
Two results from that work decide the argument for a buyer.
First, the board grade makes no difference to the share you lose. In the combined model, neither the edge crush value of the board nor the height of the box had any significant effect on the percentage of strength lost to overhang. A stronger box overhanging by the same amount keeps the same fraction of its strength.
Work that through. Moving from a 32 ECT board to a 44 ECT board buys 37.5% more edge crush strength in the board, on every case, forever. Whatever box compression strength that converts into, an overhang costing 30% takes 30% of it, because the share lost does not move with the grade. Squaring the load up to the deck returns that 30% at no cost at all, and only then can you tell whether the upgrade was needed.
Second, where the overhang sits matters as much as how much of it there is. After the two overhang measurements themselves, the strongest term in the model was whether the overhang sat on one side of the box or on two adjacent sides. That is the corner. A box carries most of its vertical load in its four corners, and a corner hanging over the edge of the pallet carries nothing.
The check costs ten minutes. Take a straight edge to the pallet edge on a built load in the outbound bay. Anything past it is overhang, and overhang is almost always a stacking pattern or a carton size problem rather than a pallet problem. How a pallet size decides the pattern, and how the loaded pallet has to be measured rather than the empty one, is in how pallet size decides how many fit on a truck.
The bottom box holds the stack, and the stack gets taller when you are busy
In block stacking, pallets sit directly on each other with no racking. It is the cheapest storage there is, and the height is limited by two things: whether the lower loads can carry the weight, and whether the stack stays upright. Those are connected. Once the bottom loads start to crush, the stack leans, and a leaning stack is the toppling line in the table above.
Pallet posts or collars solve it. They also cost money, and they take time to fit and to remove on every pallet, every time.
The free version is a rule and a place to write it. Set a maximum stack height for each product, put it on the location rather than in somebody's memory, and make exceeding it a decision a named person takes. Without that, the stack height is set by how full the warehouse is, which means it rises in exactly the weeks when nobody has time to watch it.
Two things make a stack worse than its height suggests, and both are free to check:
- A floor that has settled. A stack on a slope is not vertical. Its weight moves onto one edge of the bottom pallet, which is the edge with the least support.
- Loads that are not square. An overhanging or leaning load transfers the stack above it into the wrong part of the box below.
Count the touches
Every handling is another chance to drop something. The unit load exists for this reason: choosing the right one cuts the number of times goods are moved, lets standard equipment do the moving, shortens loading and unloading, and protects the product, all at once.
So count. For your top ten products, how many times is the load built, broken down and rebuilt between the moment it is made and the moment the customer signs? Each break-and-rebuild is a full set of handlings that a different unit load, a different order quantity or a different pick face might remove entirely.
This is also where the responsibility question sits. Whoever physically stacks and unstacks the goods holds the risk of what stacking does to them, which is why the split has to be written down site by site rather than assumed: loading and unloading, whose job is it.
A second Thai case, where nothing that worked was packaging
A warehouse serving the gasoline automotive parts trade ran the same exercise on its outbound side. Pareto analysis of 18 problem trips split the transport problems three ways: late delivery 13 trips or 72%, quantity not matching the system 3 trips or 17%, and goods stacked on top of one another 2 trips or 11%.
The estimated damage cost was 57,810 baht a month from transport, 693,720 baht a year, and a further 67,950 baht a month, 815,400 a year, from the goods position and quality check.
The measures were a truck schedule and a standard check point in the process. Afterwards, transport problems fell from 69% to 34%, the position and barcode check from 63% to zero, the estimated transport damage cost from 693,720 to 355,320 baht a year, the quality check line from 815,400 to zero, and customer complaints by more than 75%.
Read the list of measures again. A schedule and a check point. No packaging change appears anywhere in it, and one of the three transport problems was literally that goods had been stacked on top of each other.
When you do suspect the packaging, test it instead of buying it
Sometimes the box really is the problem. The mistake then is to upgrade on a hunch, because the upgrade is permanent and the hunch is free.
The Thai Packaging Centre, part of the Thailand Institute of Scientific and Technological Research, publishes a price list for exactly this. From the list dated November 2019, per sample and before VAT:
| Test | Method | Baht |
|---|---|---|
| Compression strength | ASTM D642 | 1,000 |
| Stacking | ISO 2234, ISTA | 1,000 |
| Drop, visual inspection, under 40 kg | ASTM D5276, ISO 2248, TAPPI T802 | 1,000 |
| Drop, visual inspection, over 40 kg | as above | 1,400 |
| Vibration at a fixed frequency, under 60 kg | ASTM D999, ISO 2247 | 1,200 |
| Incline impact | ISO 2244, TAPPI T801, ASTM D880 | 1,000 |
| Pallet compression | JIS Z 0602 | 1,000 |
Random vibration, which is the one that resembles a real road, is charged by time at 2,800 baht an hour. The list itself says the fees may change without notice, so confirm the current rate before budgeting. What does not change is the order of magnitude: the three tests that answer "is my box the problem" cost roughly what a few hundred upgraded cases cost, and they answer it before you commit to the upgraded cases.
One detail on that list matters more than the prices. Paper is tested in a conditioned atmosphere, because the same board tested in different air gives different results. ISO and ASTM set the standard condition at 23 °C and 50% relative humidity. Thailand's TIS standard condition, and the condition the Thai Packaging Centre runs these tests at, is 27 °C and 65% relative humidity, which the list notes is also what tropical countries may use.
So if your box strength figure came from an international specification, it was measured in drier air than a Thai warehouse in the rainy season. That is not an argument for buying a stronger box. It is an argument for knowing which number you are holding, and for testing at the condition your goods actually live in, before concluding that the specification was met or missed.
What to do this week
- Rewrite last year's damage record with a place and a cause on every line, not a product code. If the line reads "60 cases of product X", it is not yet usable. If it reads "loads struck the beam in bay 4", you can act on it.
- Sort by value and look at the top line only. The Pathum Thani case found 52% of the money in one cause. Work out how much of yours sits in one.
- Check the month pattern. Damage that appears in three months of twelve has a cause tied to something that changes, such as a season, a shift, a stand-in operator or the warehouse filling up. An annual average hides it.
- Take a straight edge to five built pallets in the outbound bay. Measure the overhang on each side. Anything more than a few millimetres is a measurable share of the box strength you are already paying for.
- Write a maximum stack height on the location, per product, and name who may change it.
- Walk the route the goods take and count the handlings. Then ask which of them a different unit load would remove.
- Only then, if the evidence still points at the box, send one sample for a compression, stacking and drop test and let the result decide, rather than a quote.
If the goods do arrive damaged and the question becomes who carries it, that is a separate problem with its own answers in Thai law: who pays when goods arrive damaged.
The one sentence to remember
A stronger box is a price rise on every unit you will ever ship, bought to fix a problem that usually lives in three specific places, and you can find those three places for the cost of a straight edge, a tin of paint and one honest look at last year's damage record.