Almost every pallet or crate that leaves the European Union carries a small burned-in stamp: a stylised ear of wheat, a country code, a number and one or two letters. That is the ISPM 15 mark. Plant health inspectors around the world treat it as the difference between a shipment that clears and one that is held at the border, treated at your expense, re-exported or destroyed. It is worth understanding exactly what it certifies — and, just as importantly, when you do not need it at all.
What the standard is for
ISPM 15 is an international phytosanitary standard published under the International Plant Protection Convention. It exists for one reason: raw wood carries pests. Bark beetles, wood-boring larvae and nematodes travel comfortably inside untreated boards, and packaging timber has historically been one of the most effective ways of moving forest pests between continents. The standard therefore requires that solid wood packaging used in international trade is debarked, treated in a way that kills those organisms, and marked so that any inspector can confirm at a glance that it was done.
It applies to pallets, crates, boxes, cases, dunnage, cable drums and spools — in short, to the wood that carries your goods rather than the goods themselves.
How to read the mark
A compliant mark always carries four elements:
- the IPPC symbol — the stylised ear of wheat;
- the two-letter ISO country code (LT for Lithuania);
- the unique code of the producer or treatment provider, issued by that country's plant protection authority;
- the treatment code.
The treatment codes are HT for heat treatment, DH for dielectric heating, MB for methyl bromide and SF for sulphuryl fluoride. In practice, packaging produced in Europe is almost always marked HT. Methyl bromide is an ozone-depleting substance that has been withdrawn from use in the European Union, so if it appears on packaging you are offered, ask where that packaging came from.
The mark has to be legible, permanent and applied to at least two opposite sides of the unit. It must not be hand-drawn, and it must not be red or orange — those colours are reserved for hazard marking. A stamp that has been altered, over-stamped or applied with a marker pen is grounds for rejection on its own.
What heat treatment actually involves
Heat treatment is not simply "putting the wood in a warm room". The standard sets a specific schedule: the wood must reach a minimum core temperature of 56 °C and hold it for at least 30 continuous minutes, measured through the entire profile of the timber rather than at the surface. Dielectric heating is an alternative schedule — 60 °C for one continuous minute throughout the profile. Debarking is required in addition to the treatment; small residual pieces of bark are tolerated only if they are less than 3 cm wide, or, if wider, smaller than 50 cm² in area.
One distinction causes regular confusion: heat treatment is not the same thing as kiln drying, even though both often happen in the same chamber. Kiln drying is about reducing moisture content so that the wood is dimensionally stable and less prone to mould. Heat treatment is a defined time-and-temperature schedule aimed at killing pests. A supplier can do both, and we do, but one does not automatically imply the other — so if the moisture content of your packaging matters to you, specify it separately.
When you actually need it — and when you do not
Within the EU single market, you generally do not. Wood packaging moving between member states is in free circulation and does not require ISPM 15 treatment or marking. Plenty of buyers pay for treated packaging on purely internal shipments because they assume it is compulsory; it usually is not.
There is one exception worth remembering inside the EU: Portugal, and certain designated areas of Spain, maintain requirements connected with the pine wood nematode. If you ship there, check the current rules rather than assuming free circulation.
Outside the EU, assume you need it. The standard has been adopted by the large majority of trading nations, and the practical consequences of arriving without a valid mark fall on the consignee, not on the packaging supplier.
The plywood trap
Plywood, OSB, particle board and veneer are exempt from ISPM 15. Manufacturing them with glue, heat and pressure already renders them free of pests, so no treatment or mark is needed.
The catch is in one word. The exemption applies to packaging made wholly of processed wood. A plywood case mounted on a solid-timber skid base, or one with solid-wood cleats and corner battens, is not exempt — those solid components fall squarely under the standard and need to be treated and marked. This catches exporters out regularly, because the case looks like a plywood box and is described as one. If your packaging mixes plywood panels with sawn timber, treat it as in scope.
Reuse, repair and remanufacture
The standard is unusually helpful here, and the detail matters if you run a returnable packaging system:
- Reuse. A unit that was treated and marked, and has not been repaired or altered since, needs no re-treatment and no new mark for the rest of its service life. A crate can travel for years on its original stamp.
- Repair. If up to roughly a third of the components are replaced, the replacements must themselves be treated wood or exempt processed wood, and each added treated component is marked individually.
- Remanufacture. If more than roughly a third is replaced, the unit counts as new: the old marks must be permanently obliterated, and the unit re-treated and re-marked from scratch.
"ISPM 15 certified" is not a real category
You will see suppliers advertise packaging as "ISPM 15 certified". There is no such certificate. The standard does not create a certification scheme for crates; what it creates is a register of treatment providers authorised by their national plant protection organisation, each with a code that appears inside the mark. In Lithuania that authority is the State Plant Service.
So if a supplier offers you a certificate, what you actually want is their registration number, confirmation of the treatment code applied, and assurance that the mark is applied to the correct number of faces. That is what an inspector will look at.
What to ask before you order
- Which countries is this packaging going to, and does that route require the mark at all?
- Is the treatment HT, and under whose registration number is it applied?
- Is the mark on at least two opposite sides of each unit?
- For plywood cases: are there any solid-wood components, and are they marked?
- If moisture content matters for your product, has it been specified separately from the treatment?
We heat-treat and mark under our own registration number in Judrėnai, so packaging leaves our yard ready for export paperwork. If you are unsure whether your route needs treated packaging at all, ask us before you pay for it — on some lanes the honest answer is that you do not.
