The ISPM 15 mark, informally called the wheat stamp because of its logo, proves that a wooden pallet or crate has been treated under the international wood packaging standard. It has four parts: the IPPC symbol, a two-letter country code, a number that identifies the producer or treatment provider, and a code for the treatment applied, such as HT for heat treatment.
The four elements
A valid mark combines these components in a defined layout:
| Element | What it shows | Example |
|---|---|---|
| IPPC symbol | The stylized ear-of-wheat logo of the International Plant Protection Convention | Left side of the mark |
| Country code | ISO 3166-1 alpha-2 code of the country that authorized the producer | DE, TR, PL, US |
| Producer or provider number | A unique number assigned by the national plant protection organization (NPPO) to the company that treated or marked the wood | 12345 |
| Treatment code | The treatment the wood received | HT, MB, DH or SF |
A typical mark reads as a symbol followed by something like XX-000 HT, where XX is the country code, 000 is the producer number and HT the treatment. The elements are separated by hyphens or arranged in lines. Some countries add a regional code between the country and producer numbers; German marks, for example, include a federal-state code, as in DE-BY-12345 HT. Those details follow each NPPO's own scheme, and the mark's meaning does not change.
The four treatment codes
- HT (heat treatment): the wood core reached at least 56 °C for at least 30 minutes. This is by far the most common code. See heat treatment.
- MB (methyl bromide): fumigated with methyl bromide, a treatment that is declining for environmental reasons; see methyl bromide.
- DH (dielectric heating): microwave or radiofrequency heating to 60 °C for one minute; see dielectric heating.
- SF (sulfuryl fluoride): fumigated with sulfuryl fluoride; see sulfuryl fluoride.
"KD" (kiln dried) is not a treatment code under ISPM 15. Kiln drying alone does not qualify unless the kiln schedule and monitoring also meet the heat-treatment requirement; the difference is explained in kiln-dried vs heat-treated wood.
Where and how the mark must be applied
ISPM 15 specifies how the mark appears on the packaging:
- Placement: on at least two opposite sides of the article, in a visible location, so that inspectors can see it without unstacking the load. For a pallet, this usually means a stamp on the end of a block or on a stringer on two sides.
- Legibility and permanence: the mark must be legible, permanent and not transferable. Methods include stamping, branding, stenciling and burning.
- Color: the use of red or orange is discouraged, because those colors are used for dangerous-goods labels.
- No hand drawing: marks must not be hand drawn.
- Size and clarity: the symbol and codes must be large enough to read, with the elements clearly separated from other markings.
Additional information such as a batch number, kiln number or company logo can sit next to the mark, and some NPPOs require such traceability data. It must not be confused with the mark itself. Check the rules of the authorizing country. The wider management process is described in ISPM 15 certification and ISPM 15 documentation.
Reading a mark: a checklist
- Is the symbol correct? It should be the official IPPC wheat symbol, not an imitation.
- Is the country code real? It should be a valid ISO code for the country of the producer, not necessarily the country where the pallet is used.
- Is there a producer number? A mark without a number cannot be traced.
- Is the treatment code one of HT, MB, DH or SF?
- Is the mark present on two sides? One mark on one side only is a common fault.
- Is it legible? Faint, smeared or painted-over marks may be rejected.
You can check the producer number only with the NPPO or an official register of the issuing country; the mark alone does not prove that treatment really took place, which is why audits and records matter.
Repaired, reused and mixed pallets
A pallet that is repaired or remanufactured may need its mark checked or replaced. Components added to a treated pallet must themselves be treated and marked, and a repairer needs authorization before applying a mark. Old marks that remain on a pallet with untreated replacement boards can mislead inspectors. The rules are covered in reused and repaired wood packaging.
Common reasons marks fail inspection
- Hand-drawn or unofficial symbols.
- Unreadable or partially removed marks.
- Marks that cover only one side.
- Marks on pallets made partly of untreated wood.
- Invalid producer numbers or treatment codes.
Importing countries can reject, treat or re-export consignments in such cases; see ISPM 15 non-compliance. The general framework is in ISPM 15 explained.
Frequently asked questions
What does HT mean on a pallet?
HT stands for heat treatment. It shows that the wood was heated to a core temperature of at least 56 °C for at least 30 minutes, as required by ISPM 15.
Why is the mark called the wheat stamp?
The IPPC symbol resembles an ear of wheat, so shippers and customs officers often use "wheat stamp" for the whole mark.
Can a pallet be stamped with a different country code than where it is used?
Yes. The country code shows where the producer is authorized, not where the pallet will travel. A pallet made in Poland can be used anywhere the mark is accepted.
Is a printed or hand-drawn stamp acceptable?
The mark must be permanent and legible, but it must not be hand drawn. Official methods include stamping, branding, stenciling and burning.
Sources
- ISPM 15 (2018 edition, Korean translation) — International Plant Protection Convention
- ISPM 15: Regulation of wood packaging material in international trade (French edition) — DRAAF Bourgogne-Franche-Comté / IPPC
- ISPM 15 — Wikipedia
- Ahşap Ambalaj Malzemelerinin Isıl İşleme Tabi Tutulması ve İşaretlenmesine Dair Yönetmelik (guidance) — Ministry of Agriculture and Forestry, Türkiye