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Standards

ISPM 15: heat treatment and marking for export pallets

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In short

ISPM 15 is the international phytosanitary standard for wood packaging. Solid-wood pallets crossing most borders must be debarked, treated (most often heat treatment, HT: 56 °C at the core for 30 minutes) and stamped with the IPPC mark showing the country code, producer number and treatment code.

On this page
  1. What ISPM 15 covers
  2. Approved treatments
  3. The ISPM 15 mark
  4. What is exempt
  5. Rules that catch people out
  6. How ISPM 15 shows up on a spec or drawing
  7. How to order an ISPM 15 pallet
  8. How palletdesign.ai uses it

What ISPM 15 covers

ISPM 15 is the International Standard for Phytosanitary Measures No. 15, issued under the International Plant Protection Convention (IPPC). It sets how solid-wood packaging, including pallets, crates and dunnage, must be treated and marked so it does not carry insects and disease between countries. It is the reason an export pallet is ordered differently from a domestic one.

Approved treatments

Code Treatment Requirement
HT Heat treatment Wood core held at 56 °C (133 °F) for 30 continuous minutes
DH Dielectric heating (microwave or radio frequency) 60 °C for 1 continuous minute throughout the profile
MB Methyl bromide fumigation Being phased out; some countries do not accept it
SF Sulfuryl fluoride fumigation Fumigant alternative to MB

Wood must also be debarked. Small bark remnants are tolerated: pieces under 3 cm wide of any length, or pieces over 3 cm wide with an area under 50 sq cm.

The ISPM 15 mark

The ISPM 15 mark is a bordered stamp that reads, left to right:

  1. the IPPC wheat symbol;
  2. the two-letter ISO country code (for example US);
  3. the producer or treatment-provider number assigned under the national plant protection program;
  4. the treatment code (HT, DH, MB or SF).

The mark must be legible and permanent and is often shown next to the certifying agency's logo. It goes on at least two opposite sides of the pallet. Some buyers ask for more: Costco wants both long sides, and Snap-on recommends all four.

In the US, heat-treatment marks are issued through the ALSC wood packaging material program, and there is a separate export fumigation program for MB.

What is exempt

  • Wood 6 mm thick or less.
  • Processed wood such as plywood, OSB and particleboard, which is why presswood pallets are exempt.
  • Non-wood pallets such as plastic, metal and corrugated.

A pallet that mixes processed panels with solid-wood parts still needs its solid wood treated.

Rules that catch people out

  • KD is not HT. A "KD" stamp describes moisture content, not phytosanitary treatment. "KD-HT" means both. See kiln-dried vs heat-treated.
  • Repairs reset compliance. Repaired, remanufactured and combo pallets must be re-treated and re-marked, with old marks obliterated. An intact compliant pallet can be reused without re-treatment.
  • North American borders differ. Costco's supplier policy notes that heat treatment is not required between Canada and the US, but is required between Mexico and the US.

How ISPM 15 shows up on a spec or drawing

A PDS-style spec sheet lists it under treatments, for example "ISPM-15 Compliance: Heat Treatment (HT)". An RFQ should state:

  • whether ISPM 15 is required and which method is acceptable;
  • where the marks go (2 or 4 sides);
  • whether a certificate or letter of compliance must ship with the order;
  • whether the lumber must also be kiln dried.

How to order an ISPM 15 pallet

  1. Tell the supplier the destination country and ship date. Some borders, such as Canada to the US, do not require treatment, but most export lanes do.
  2. Specify the treatment you accept. HT is the usual choice for new wood pallets; state whether MB is acceptable, since some countries reject it.
  3. Say where the marks go and how many sides.
  4. Ask for the certificate or letter of compliance you need for customs.
  5. If the pallet will be repaired or reused after return, plan for re-treatment and re-marking.
  6. If the load travels in a sealed container, consider kiln drying as well, since HT alone does not set a moisture level.

Solid wood vs processed wood

Material Needs ISPM 15 treatment?
Sawn lumber deckboards, stringers, solid-wood blocks Yes
Plywood or OSB deck panels No (processed wood)
Presswood (wood-composite) blocks No (processed wood)
Wood 6 mm thick or less No

A pallet with plywood decks on solid-wood stringers still needs the stringers treated and the pallet marked.

How palletdesign.ai uses it

When a request mentions export, overseas shipping or a destination such as Mexico or Europe, palletdesign.ai marks the design as heat treated. If a design is flagged for export and the lumber is not heat treated, the engine raises a blocking issue citing ISPM 15. The classification line then carries "HT (ISPM-15)", and the indicative cost estimate adds a default heat-treatment charge of $1.50 per pallet, an assumption rather than a quote. The heat-treated pallet page covers the pallet itself.

Questions

What temperature is required for ISPM 15 heat treatment?
The core of the wood must reach 56 °C (133 °F) and stay there for 30 continuous minutes. Dielectric heating instead requires 60 °C for 1 minute throughout the wood.
Do plastic or plywood pallets need an ISPM 15 stamp?
No. Plastic, metal and corrugated pallets are exempt, and so is processed wood such as plywood, OSB and presswood. Any solid-wood parts on the same pallet still need treatment.
Does a repaired pallet keep its ISPM 15 mark?
No. Repaired, remanufactured and combo pallets must be re-treated and re-marked, and the old marks obliterated.
Is kiln-dried lumber ISPM 15 compliant?
Not by itself. A KD stamp only shows moisture content. The wood also needs an approved treatment and the IPPC mark, often shown as KD-HT.

Sources