Before you quote
ISPM 15 · HT| Part 1 | IPPC symbol, the mark of the convention |
|---|---|
| Part 2 | Country code, two letters |
| Part 3 | Producer or facility number |
| Part 4 | Treatment code |
| Beside it | Quality mark of the accredited agency |
| Where | A minimum of two opposite sides |
The stamp, part by part
The stamp is a small rectangle, usually branded or stencilled on the lumber. At the left is the IPPC symbol, a stylised wheat ear that shows the mark belongs to the International Plant Protection Convention. Its presence means the wood is claiming to meet ISPM 15.
Next to it is the country code, two letters, the ISO code of the country where the producer is located. For lumber treated in the United States that is US. Then the producer number, the unique identifier of the facility or company assigned by the agency that supervises it. Last is the treatment code.
A fifth mark sits beside the stamp: the quality mark of the agency. APHIS says heat-treated packaging in the US program must carry the ISPM 15 official mark together with the quality mark of an ALSC accredited agency.
| Part | What it tells you | Example form |
|---|---|---|
| IPPC symbol | Wood claims ISPM 15 treatment | Wheat-ear mark |
| Country code | Country of the producer | US |
| Producer number | Which facility treated or marked it | Agency-issued digits |
| Treatment code | Which method was used | HT |
| Agency mark | Who supervises the producer | Quality mark beside the stamp |
Reading the treatment code
NELMA lists four approved treatments. HT is heat. MB is methyl bromide, a fumigant. SF is sulphuryl fluoride, added in 2018. DH is dielectric heating. On crates and skids made in the United States for export, HT is the one you will see most.
The code is the part buyers misread. Letters that look similar are not treatment codes. If you see KD on a board, it likely means kiln-dried, which is a different thing. Kiln drying alone is not the ISPM 15 treatment unless the run meets the HT schedule and the lumber is marked HT.
Where the stamp should be and how many
NELMA says finished pallets, skids, crates and boxes are stamped with the facility's IPPC stamp on a minimum of two opposite sides. Two opposite sides means that whichever end an inspector walks up to, a mark is visible. On a crate, that is usually the two end walls or the two ends of the skid.
The mark should be on solid lumber, not on a panel. Plywood and other processed panels are exempt, so a stamp on one carries no weight and can raise a question. Look for it on the skid runner, a cleat or the lid frame.
Checks to make before you accept a crate
Treat the stamp as a document that is attached to the wood. Look at it in good light. Check that every part is present and legible, that the treatment code is one of the four, and that the mark is on the lumber of the skid and frame. If you are receiving a crate from another supplier, ask who the producer is and which agency supervises them.
Check also for repairs. A crate that has had boards replaced should show a stamp on each replacement. NELMA says a remanufacturer must re-stamp each component with its own agency-issued HT stamp, so a patched crate with one old mark is suspect.
If you receive a crate and doubt a mark, photograph it close up with a coin or rule beside it, note the producer number, and send the picture to your supplier. Photographs settle disputes about readability, while memory does not.
- IPPC symbol present and not smeared
- Two-letter country code readable
- Producer number complete
- Treatment code one of HT, MB, SF or DH
- Quality mark of the agency beside the stamp
- Stamps on at least two opposite sides, on solid lumber
What a stamp does not tell you
A stamp says the wood was treated. It does not say whether your destination requires the treatment, how strong the lumber is, or whether the crate is built correctly for your load. It also does not say the crate will clear customs on other grounds, such as the contents.
For the destination rule, ask APHIS and the plant-protection authority of the receiving country. For the crate itself, send us the inside dimensions, gross weight and destination and we write the spec.
Why the stamp matters to your shipment
Inspectors at ports of entry look for marks first and ask questions second. A clean, complete stamp lets the officer wave a crate through; a faint one starts a conversation that can end in a hold, a treatment order at your cost or a refusal to unload. The stamp is the cheapest piece of paperwork on the crate, and it rides on the wood itself.
It also protects the shipper's name. Because the producer number ties back to a facility and an agency, an incorrect mark traces to the source. Responsible crate builders therefore guard their branding tools and log which lumber goes where.
Common faults seen on stamps
Faults come in a handful of forms. Ink stamps wash off in rain. Branded marks scorched too lightly vanish under sanding or paint. Stamps get cut through when a board is trimmed to length. And boards from two different producers get mixed in one crate, so a viewer sees two producer numbers and wonders why.
Another fault is the lookalike mark. Some pallets carry a brand logo, a load rating or a manufacturer's code that resembles a stamp but has no wheat ear and no country code. If the wheat ear is missing, it is not an ISPM 15 stamp.
Questions to put to a supplier
Ask which agency supervises the lumber yard. Ask for the producer number of the mill or treatment plant. Ask whether the boards are marked before or after cutting, and whether replacements will be re-marked. A supplier who answers these in a few lines is organised; a supplier who hesitates is a risk to your shipment.
Ask us the same questions. We answer them in the quote.
Questions buyers ask
What does the HT in a stamp mean?
HT is the code for heat treatment. It is one of four approved ISPM 15 treatment codes, alongside MB, SF and DH.
What is the mark next to the stamp?
It is the quality mark of the accredited agency that supervises the producer. APHIS says heat-treated packaging carries the ISPM 15 mark together with that agency mark.
Can a stamp be on plywood?
Plywood is exempt, so a stamp there proves nothing. Look for the mark on the solid lumber of the skid, runners and cleats.
Is KD the same as HT?
No. KD usually means kiln-dried. Kiln drying alone is not the ISPM 15 treatment unless the run meets the HT schedule and is marked.