Honeycomb Paper Pallets: Load Rating, ISPM 15 and the Moisture Question

A paper honeycomb pallet avoids the wood packaging rules that apply to solid wood, because it is not wood; it still has to carry the load, survive the rack and stay dry. Compare it on dynamic load at the humidity of the route, on rack load rather than static load, and on the handling equipment it will meet. A pallet rated for a dry warehouse can fail in a humid container, and the failure is usually at the deck edge or at the stringer joint rather than in the middle of the deck.

Scenario

An exporter replaces wood pallets with honeycomb paper pallets to avoid fumigation delays and to present a recyclable pack. The sample pallet carries the stated load in the supplier's test. The first container arrives with two pallets collapsed at the corner and one deck delaminated. The supplier tests another pallet and reports the same rating. The exporter has a valid test and a failed shipment, and the forwarder points out that the pallets were stored on a wet dock for two days before loading.

Pain Point

The rating describes an idealised load. A pallet in service sees a dynamic load during handling, a rack load that concentrates force on the stringers, and a forklift impact at the entry. Paper honeycomb carries compression along the cell axis, so the deck is strong when the load is distributed and weak when a point load sits between the stringers. Moisture changes all of it: the fiber softens, the adhesive in the deck laminate weakens, and a pallet that was rated for a dry store loses a large share of its capacity on a wet dock. The failure at the corner is a handling impact, the delamination is adhesive failure from water, and neither appears in a static test on a new pallet in a dry room.

Solution

Specify the pallet as a handling system.

The load case: static load, dynamic load, rack load and the number of pallets in a stack, each stated separately. Ask for a rating for each, because a supplier quoting one number is quoting the easiest one.

The moisture condition: the rating at the humidity of the route, plus a coating or a wrap if the pallet will be exposed. A pallet stored on a wet dock is exposed, and the specification should say so.

The handling: forklift entry height, the position of the stringers relative to the forks, and a corner protector if the pallet will be handled roughly.

The testing: a rack test with the rated load held for the storage duration, and a drop or impact test at the corner.

Result

An exporter that rebuilt the specification found three separate causes. The pallets had been stored on a wet dock, the corner had been struck by a forklift during loading, and the rack load in the destination warehouse was higher than the tested figure because the pallets were double stacked. With a shrink wrap on the pallet stack, corner protectors, a rack rating that matched the warehouse and a handling instruction on the shipping document, the failures stopped. The pallet did not change; the load case did.

ISPM 15 and What It Does Not Cover

ISPM 15 applies to solid wood packaging, including wood pallets, crates and dunnage, and it requires heat treatment or fumigation with a mark. A paper honeycomb pallet is a processed paper product and is outside that scope, which is one reason exporters consider it. The exemption is not a blanket freedom: the destination country may still have requirements for the pallet's strength, for its phytosanitary condition if it is contaminated with soil, and for the way it is declared at customs. Confirm with the importer and, if the pallet uses any solid wood component such as a block or a stringer, treat that component as wood and mark it. A mixed pallet is the case that most often causes a delay, because the paper part is exempt and the wood part is not. For the fuller picture, see how honeycomb paper handles gsm selection.

Rack Load Versus Static Load

A static load test puts weight on a pallet supported across its whole underside. A rack test supports the pallet only at two edges, so the deck and the stringers carry a bending moment. Paper honeycomb is much better in compression than in bending, so a pallet that looks strong in a static test can sag visibly on a rack, and a sagging deck can drop the load or jam the rack. Ask for a rack load rating specifically, with the support span, and compare it with the rack in the destination warehouse. If the warehouse uses a narrower span than the test, the effective rating is lower and should be recalculated rather than assumed.

Moisture, Coating and the Return Journey

A paper pallet in a humid container takes up water through the deck edges and the exposed cell ends. A coating on the faces slows the uptake; sealing the edges slows it more, because the open cells are the fastest path. For a route with a wet dock or a long sea voyage, wrap the pallet stack and add a desiccant, and treat the wrap as part of the pack rather than as an optional extra. If the pallet is intended for a return journey, inspect it at the destination, because a paper pallet that has been wet and re-dried has lost capacity and should not carry the same rating on the way back.

Handling and the Forklift

Most pallet failures in service begin with a fork. A fork that enters at an angle, or that hits the stringer instead of the entry, splits the deck and starts a delamination. Specify the entry height and mark it on the pallet, train the loading crew, and use corner protectors when the pallet is moved with a pallet truck that has no side support. The cost of a protector is small and the cost of a collapsed pallet in a container is a claim, a repack and a delay. If the customer's warehouse uses a specific truck type, test with that truck rather than with the one at the supplier's plant.

Writing the Purchase Order

State the static, dynamic and rack ratings with the humidity condition, the handling entry height, the coating or wrap requirement, the corner protection and the pallet marking. Add a first-article test report with the conditioning details, and a retained sample. Then add a clause requiring notification of any change in paper grade, adhesive or deck construction, because those changes move the rating without changing the drawing. A pallet is a structural product, and the specification should read like one.

Bottom Line

A paper pallet avoids the wood rules and inherits the paper rules: it must be rated for the real load case, tested at the route humidity, protected at the corner and stored dry. Ask for separate static, dynamic and rack ratings, confirm the ISPM 15 position for any wood component, and treat the wrap as part of the pack., see our note on Honeycomb Paper Pallet Static Load Derating.