Heat treatment
Heat treatment (HT) is the ISPM 15 phytosanitary treatment in which wood packaging is heated until its core reaches at least 56 °C (133 °F) for 30 continuous minutes. Treated pallets carry an ISPM 15 mark with the code HT and can be used for international shipments.
Also called HT, ISPM 15 heat treatment
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How heat treatment works
Pallets or lumber go into a kiln or heat chamber until the core of the thickest piece holds 56 °C for 30 minutes. A certified facility, audited under a national program (in the US, the ALSC wood packaging program), then applies the ISPM 15 mark with the code HT.
ISPM 15 treatment codes
| Code | Treatment |
|---|---|
| HT | heat treatment, 56 °C core for 30 min |
| DH | dielectric heating, 60 °C for 1 min through the profile |
| MB | methyl bromide fumigation (being phased out) |
| SF | sulfuryl fluoride fumigation |
Rules that trip buyers up
- Wood must be debarked before treatment.
- Repaired, remanufactured and combo pallets must be re-treated and re-marked, with old marks removed.
- HT is not KD. Heat treatment targets pests, not moisture. Only KD-HT covers both.
- Exempt materials: plywood, OSB, presswood, plastic and metal need no treatment, but a pallet mixing plywood with solid wood still does.
When it is required
Most countries require ISPM 15 for wood packaging on imports. Between the US and Canada it is not required at the border; between the US and Mexico it is. See ISPM 15 and heat-treated pallet.
Questions
- What temperature is pallet heat treatment?
- The wood core must reach at least 56 °C (133 °F) and hold it for 30 continuous minutes.
- Do heat-treated pallets need re-treatment after repair?
- Yes. Under ISPM 15, repaired and remanufactured pallets must be re-treated and re-marked, with the old marks obliterated.
Related
- ISPM 15 markThe ISPM 15 mark is the stamp showing wood packaging was treated for export: the IPPC wheat symbol, country code, producer number and treatment code such as HT.
- Kiln-dried lumberKiln-dried (KD) lumber is dried in a heated kiln to a target moisture content such as 19%. KD is not the same as ISPM 15 heat treatment unless marked KD-HT.
- ISPM 15: heat treatment and marking for export palletsISPM 15 requires export wood pallets to be debarked and treated, usually heat treated to 56 °C core for 30 minutes, and stamped with the IPPC mark.
- Heat-treated pallet: ISPM 15 HT explainedA heat-treated pallet has had its wood core held at 56 °C for 30 minutes under ISPM 15 and carries the HT mark. What the stamp means, KD vs HT, who needs it.
- Pallets for export shippingExport pallets must meet ISPM 15: debarked wood, heat treated to 56 °C core for 30 minutes and marked. Sizes by destination, moisture and an RFQ checklist.
- Helical nailA helical nail has a spiral thread on its shank that turns as it is driven, resisting pull-out. It is the standard pallet nail for medium and dense hardwoods.
Sources
- ISPM 15 overview (Wikipedia)
- ISPM 15 stamp explained (Acadon)
- Uniform Standard for Wood Pallets (NWPCA, now Woodpack Global), 2012 edition
- Costco pallet policy