Investigation of quasi-noncombustible plywood made from trees grown in Hokkaido [Japan]
2007
Kawarasaki, M.(Hokkaido. Forest Products Research Inst., Asahikawa (Japan)) | Hiradate, R. | Yoshida, S. | Takizawa, K. | Okano, A.
Manufacture of quasi-noncombustible plywood made from trees (Cryptomeria japonica, Larix leptolepis, Abies sachalinensis, and Tilia japonica) grown in Hokkaido was investigated. Veneers of those species wood were impregnated with boron-type fire retardant solution in hot bath treatment. In 30% fire retardant solution, the chemical contents in veneer after treatment were 237kg/cubic m for C. japonica (sapwood) and 217kg/cubic m for C. japonica (heartwood). The chemical content in veneer after treatment was influenced by the species. In comparison with C. japonica (sapwodd), the chemical contents of L. leptolepis, A. sachalinensis and T. japonica were lower being 41%, 75% and 70% respectively, in 30% fire retardant solution treatment. The chemical content impregnated in L. leptolepis was extremely low, showing that more investigation about treatment conditions was needed for L. leptolepis. Therefore, the fire performance of plywood made of treated veneer, except for L. leptolepis, was evaluated by cone calorimeter. For C. japonica, the 15-mm-thick plywood consisted of sapwood veneers and heartwood veneers treated with a chemical content of 208kg/cubic m satisfied the standard for quasi-noncombustible materials in the cone calorimeter. For A. sachalinensis and T. japonica, the total heat release of the plywood made of treated veneer tended to be high in comparison with C. japonica. The increase of total heat release of those species may be attributed to the behavior of the exposed area and the difference of the mass loss rate during heating.
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