HT vs KD vs MB: Pallet Treatment Stamps Explained

The short answer

HT (heat treatment) is the dominant UK ISPM15 treatment in 2026. MB (methyl bromide) was phased out in the EU and UK over a decade ago. KD (kiln-dried) is a drying process, not an ISPM15 treatment, and is only ISPM15-compliant if combined with the proper heat-treat cycle and certification. DB and DH are rare alternatives. For any UK exporter in 2026: you need HT.

HT: Heat Treatment (the UK standard)

HT stands for heat treatment under ISPM15. The timber is heated to a core temperature of 56°C for a continuous 30 minutes. This kills all stages of insect pests and fungal spores, making the pallet safe for international trade. HT is the dominant ISPM15 treatment in the UK, EU, and most developed markets. Accepted universally by every ISPM15-enforcing country. See our heat-treated ISPM15 pallets page for in-stock HT pallets, or the full ISPM15 guide for the standard in detail.

MB: Methyl Bromide Fumigation (phased out)

MB indicates pallets fumigated with methyl bromide gas in a sealed chamber for 24 hours. Historically this was the other approved ISPM15 treatment alongside HT. However, methyl bromide is an ozone-depleting substance and toxic to workers, so the UK, EU, and many other markets have prohibited it. In 2026, virtually no UK pallet supplier uses MB. Some destinations like Australia will still accept MB-stamped pallets, but HT is universally safer.

If you see an MB stamp on a UK-treated pallet in 2026, it is almost certainly old stock. HT is the modern default.

KD: Kiln-Dried (not a treatment)

KD means kiln-dried: timber moisture has been reduced in a kiln to a specified level (typically 18-19%). KD is a drying process, not a pest-control treatment. It does NOT automatically satisfy ISPM15. Some kiln-drying cycles reach the 56°C/30-minute ISPM15 threshold incidentally, but without the ISPM15-compliant audit trail (facility registration, process documentation, certified stamp), the pallet cannot be used for export.

KD-HT combined: some facilities run combined kiln-dry-plus-heat-treat cycles and stamp the pallet "KD HT" with full ISPM15 certification. That is valid for export. Look for the IPPC logo and treatment code, not just the KD mark.

DB: Debarked

DB indicates the timber has been debarked. ISPM15 requires that all wood used in the pallet has no remaining bark (bark is a pest vector). DB is often bundled with HT on the same stamp: HT means the pallet has been heat-treated AND debarked to current ISPM15 standard. DB alone is not an ISPM15 treatment.

DH: Dielectric Heating

DH is dielectric heating, a faster alternative to conventional heat treatment using microwave or radio-frequency energy to heat the timber. ISPM15-approved and increasingly used for speed, though less common in the UK than conventional HT chambers. DH-stamped pallets are fully valid for export wherever HT is accepted.

Quick comparison

• HT: ISPM15-approved. UK standard in 2026. Buy this.
• MB: ISPM15-approved historically. Phased out in UK/EU. Avoid.
• KD: Drying process, not ISPM15 by itself. Check if combined with HT and stamped.
• DB: Debarking, a requirement alongside HT, not a treatment alone.
• DH: ISPM15-approved. Valid for export. Less common in the UK.

Which stamp do you need?

For export to any ISPM15-enforcing country (US, Canada, Australia, China, UAE, etc.) in 2026: buy pallets stamped HT with the full ISPM15 markings (IPPC logo, country code, facility number, HT code). Our Widnes depot heat-treats in-house and can supply HT pallets same-day across Liverpool, Manchester, Warrington, Cheshire and Widnes. See pallets for export for the full compliance package.

For domestic UK and EU shipping: no ISPM15 stamp required. Buy the cheapest grade that fits the job (Grade A, B or C reconditioned is normally the sweet spot).