Heat treatment is the most common method for making wood pallets compliant with ISPM-15 international phytosanitary standards. Here's exactly what happens inside our kilns — from loading to certification.
Step 1: Pallets are loaded into our industrial kiln, which holds up to 800 pallets per cycle. Loading is done carefully to ensure adequate air circulation between pallets — gaps are essential for uniform heat distribution.
Step 2: The kiln is sealed and heated. Our system uses a combination of forced hot air and steam to raise the temperature gradually. The target is 56°C (132.8°F) at the core of the thickest piece of wood — not just the surface.
Step 3: Temperature monitoring. Calibrated probes are inserted into the core of sample boards at multiple locations within the kiln. These probes feed data to our digital monitoring system in real-time, ensuring every pallet reaches the required temperature.
Step 4: Once all probes read 56°C, we hold that temperature for a minimum of 30 minutes. This is the ISPM-15 requirement — 56°C core temperature sustained for 30 continuous minutes. Our standard practice is 45 minutes for additional safety margin.
Step 5: After treatment, pallets cool naturally. They are then stamped with the IPPC mark, which includes our facility code, the treatment type (HT), and the country code (US). This stamp is applied to at least two opposite sides of each pallet.
Step 6: Documentation. We maintain detailed treatment logs including batch numbers, probe readings, timestamps, and operator certifications. These records are kept for a minimum of two years and are available for audit upon request.