Load capacity for a honeycomb panel is not a single number and any supplier who gives you one without asking three questions is guessing. The three inputs are the span, how the load is distributed, and how long it will be there. Given those, capacity follows. Without them, a figure is meaningless.
Input one: span
The unsupported distance. Deflection rises very steeply with span – roughly with its cube – so halving the span makes an enormous difference and doubling it makes the panel useless. This is why the same panel is adequate on one pallet and hopeless on another.
Measure what is actually under the panel where it will be used. Pallet drawings lie; pallets with missing boards and worn decks are what the panel will sit on.
Input two: distribution
A hundred kilograms spread over the whole face is an easy problem. The same hundred on four small feet is a hard one – the panel has to resist local crushing as well as global bending, and those are governed by different properties.
So “two hundred kilos” is not an input. “Two hundred kilos on four feet of fifty millimetres, plus its own weight spread across the rest” is.
Input three: dwell, which everyone leaves out
Polypropylene creeps. Under sustained load it deforms slowly, and faster at higher temperature. A capacity figure measured over an hour is not a capacity figure for a month in a warm container.
If your panels sit loaded for long periods or travel hot, the working capacity is lower than the short-term figure, sometimes by a thickness step. State the dwell when you ask, and treat any answer that ignores it as a short-term number.
The honest caveat
Any capacity figure is an estimate made under stated conditions. We would rather give you a figure with its assumptions attached than a clean number that fails in month two. If you are sizing something where failure is expensive, ask for the assumptions and check them against your actual conditions.
The practical approach is to size conservatively and test: load a sample panel to your working load, leave it for a week in the conditions it will see, and measure. That is a better answer than any calculation, and it costs one panel.
Reading a data sheet
Compressive strength tells you about crushing through the thickness. It does not tell you about spanning. For a panel working in bending you want a flexural or deflection figure, at a stated span and load. We made this point in what to check before buying honeycomb panels, and it is the single most useful thing to know when comparing quotes.
What to do when the answer is marginal
Sometimes the calculation lands between two thicknesses, and the temptation is to take the thinner one because it is cheaper. In a marginal case, take the thicker one.
The cost difference is small compared with the cost of a failure, and a marginal calculation means the assumptions matter – the load is slightly different, the pallet has one more gap, the dwell is a week longer – and any of those pushes it over.
If the application is genuinely borderline, the better move is usually to change the application: add a support, spread the load, or shorten the dwell. All three are cheaper than uprating every panel.
What we can do
We supply PP honeycomb panels and will size one from your three inputs, with the assumptions stated. Send us span, load and dwell – and if you are unsure about any of them, send us the application and we will work through it with you.