The ISPM 15 plywood exemption

What the exemption says

ISPM 15 targets raw wood that can harbour live insects. NELMA states that plywood, particleboard, OSB, flakeboard and veneer are exempt from the standard. These panel products are built by cutting wood into thin layers, strands or chips and bonding them under heat and pressure, which leaves nothing for a pest to live in.

The exemption matters a great deal for crate design. A crate whose walls and lid are plywood has far less solid lumber than a slatted or solid-lumber crate, and so less that has to be treated and stamped.

It is a short rule with a long tail of misunderstandings, which is why this page exists.

Shippers gain from the line: fewer treated boards mean a lighter, cleaner, quicker-to-build crate.

What the exemption does not cover

The exemption covers the panel. It does not cover the lumber that holds the panel in place. In a cleated plywood crate, the cleats around each panel are lumber. The skid under the crate is lumber. The runners, the corner posts and the lid frame are lumber. All of these are wood packaging material and fall under the standard when the destination applies it.

A typical mistake is to buy a plywood box and assume it needs no treatment. A plywood-skinned crate may still ship with an untreated softwood skid, and that skid is what a port inspector will find.

Another is a plywood-only pallet or base. A base made wholly from exempt panels is not common in heavy crating, because it lacks the strength of lumber runners.

What it means for each crate type

A cleated plywood crate has a plywood skin and a lumber skeleton, so it carries the stamp on the skeleton. A sheathed crate has the same structure but a heavier frame, with more lumber to mark. A slatted crate has almost no panel, so the exemption does little for it. A solid-lumber crate has none.

The practical effect is that sheathing changes how much of the crate is lumber, not whether the lumber rule applies. If your goal is the lightest compliant crate for an air lane, cleated plywood is usually the shortest route. See the cleated plywood page for how it is built.

Blocking and bracing inside the crate

The wood inside a crate counts too. Blocking and bracing cut from lumber and bolted to the base are wood packaging material, so they fall under the same rule as the skid. Blocking cut from plywood or OSB is exempt.

Where a rule applies to a whole crate, we choose blocking from stamped lumber or from panels so nothing unmarked rides inside. Mark the packing list accordingly if your forwarder asks what wood is in the shipment.

One more trap is glued laminated or engineered timber. A beam built up from laminations is not a thin sheet product, and a wooden spacer block cut from a large timber is still lumber. When a member is neither plainly panel nor plainly sawn board, ask the program rather than assume, and we flag such members on the spec.

Confirm with the destination, then tell us

We do not list which countries require ISPM 15. Ask APHIS and the plant-protection authority of the destination country whether the standard applies to your cargo, and whether they accept the exemption as written. Rules change, and some import programs ask for more documents than the stamp.

Send us the answer with the quote request. We write the crate spec to match, and record which members are exempt panel and which are marked lumber so the next order is built the same way.

A worked example: a 60 x 40 x 48 in machine

Take a press brake controller cabinet measuring 60 x 40 x 48 in, bound for a foreign plant. A cleated plywood crate suits it: half-inch panels fixed to pine cleats, a two-runner skid, and an inner frame that clamps the cabinet's lower flange. Count the pieces and the split becomes obvious.

The wall and lid panels are exempt. Everything else is lumber: the skid members, the cleats, the corner posts, and the braces that keep the cabinet from rocking. When we quote, we list those lumber pieces separately so your broker can see exactly which items carry a mark and which do not.

That list also helps a forwarder who is asked by a carrier, a terminal or a customs officer what the crate is made of. The answer is two sentences instead of a phone call.

Common questions from inspectors and forwarders

Inspectors tend to ask three things. Is the wood processed or solid? Where is the stamp? Does anything unmarked sit inside? A crate that answers all three at a glance rarely gets delayed. We lay out the stamp so it faces the end of the skid and the lid frame where an inspector would look first.

Forwarders ask a different thing: can the crate be broken down and returned flat? Plywood panels unscrewed from cleats can be stacked, while lumber frames may be re-used or scrapped. Knockdown crates handle that case, and the same exemption logic applies to them.