Research On Technical Parameters Of The International Criteria For Heating Treatment Of Wood Packing Materials

ISPM 15 of the 《Criteria for Management of Wooden Packaging Material in International Trade》 specifies that "the wooden material be heated up to 56℃ and kept there for 30mins". Owing to the lack of detailed rules for implementation and regulations for operation in keeping in compliance with the criteria for heating treatment, enterprises find it hard to comply, thus often leading to failure to have the material thoroughly treated or completely cleared of hazard, which hinders normal trade.Based on the specific definition of the criterion for heating treatment "the wooden material be heated up to 56℃ and kept there for 30mins", and the principleof wood drying, the Kpeqe_TOB (Russian, 1980) theoretic formula could be used to calculate duration of heating to have the timber reach the specified internal temperature and to analyze relationship between or compare various environmental parameters that might affect effect of the heating treatment. With this calculated time duration as benchmark, tests are carried out in lab and kiln of heating timber samples in an environment varied in humidity for treating effect. Comparison of the time for the heated timber sample to reach the set temperature monitored with thermocouple or thermosensor is made with the benchmark.Results of the tests show that thickness of a timber is the major factor affecting duration of the heating treatment of wood packing material, and in an extremely significant relationship with the latter. Moisture content of the timber comes next. The initial temperatures of the timber and the medium do not have much influence. The results further indicate that in the technical index specified in the International Criteria for Heating Treatment of heating timber in a medium over 65℃ in temperature "up to 56℃ and then keeping it for 30 mins" is safe and effective. Nevertheless, the duration...