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Bambang Subyakto Toshimitsu Hata Isamu Ide Shuichi Kawai 《Journal of Wood Science》2001,47(3):199-207
Creep under fire of laminated veneer lumber (LVL) joined with metal connectors was studied. The fire-resistant performance of LVL butt joints connected with metal plates protected with graphite phenolic sphere (GPS) sheeting was discussed. The GPS sheeting was overlaid on the joint in different sizes and locations. The joint was exposed to a burner with a top flame temperature of 800°C and loaded with a load of 200 N to test for creep under fire. The results showed that the fire-resistant performance of the joint was markedly improved by the sheeting. The size and location of the GPS sheet significantly affected the time to rupture of the specimen, which was six times longer than that without GPS. Temperature measurements at the joint showed that the GPS sheeting distributed the heat along the surface and delayed failure. Thermographic images and analyses clarified the improvement in fire-resistant properties due to GPS. 相似文献
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Subyakto Toshimitsu?Hata Isamu?Ide Takeshi?Yamane Shuichi?KawaiEmail author 《Journal of Wood Science》2004,50(2):157-161
Laminated veneer lumber joints made with metal plate connectors were protected with wood carbon phenolic spheres (CPS) sheeting and tested for creep under fire. The effects of the carbonizing temperature of charcoal, used as raw material for the CPS sheets, the thickness, and the location of the sheet on the joint regarding the fire-resistance performance of the joint were studied. The time to rupture of the joints covered with CPS sheets made from charcoal carbonized at 800°C (CPS800) was slightly prolonged compared with that of uncovered joints. On the other hand, the time to rupture of CPS sheets made from charcoal carbonized at 1600°C (CPS1600) was markedly extended. The changes in the charcoal properties due to increasing the carbonizing temperature might be the main reason the CPS1600 sheets had higher fire-resistance performance. The thickness and location of CPS1600 sheets have significant effects on the fire resistance of the joint. A highly fire-resistant laminated veneer lumber joint was obtained using a CPS1600 sheet. The CPS1600 sheet with a thickness of 3mm covering three sides of the joint prolonged the time to rupture 16-fold compared with that of unprotected joints.Part of this paper was presented at the 4th International Wood Science Symposium, Serpong, Indonesia, September 2002 相似文献
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Subyakto Bambang Subiyanto Toshimitsu Hata Shuichi Kawai 《Journal of Wood Science》2003,49(3):241-247
Some tropical fast-growing woods were converted to edge-jointed lumber, and their fire-retardant properties due to chemical
coating were evaluated using cone calorimetry and a standard fire test. The woods used were Indonesian and Malaysian albizia
and gmelina plantation trees, with Japanese hinoki as a reference. The lumber was coated with 100 g/m2 of trimethylol melamine phosphoric acid in a 25% aqueous solution. The treated and untreated lumber was tested in a laboratory-scale
exposure furnace in accordance with JIS A 1304 and the cone calorimeter test with heat flux of 40 kW/m2 following the ISO 5660. Results showed that fire endurance of all lumber was enhanced by the treatment. The fire-retardant
properties were improved with increasing surface density. Though a similar trend was seen, the fire-retardant properties of
the lumber revealed by the cone calorimeter test were inferior to those seen with standard fire test. Addition of thermocouples
to the cone calorimeter allowed us to obtain information on the critical temperature (260°C) and charring temperature (300°C)
of the lumber.
Received: January 23, 2002 / Accepted: July 15, 2002
Acknowledgment The authors thank Dr. Shigehisa Ishihara, Professor Emeritus of the Wood Research Institute, Kyoto University for his suggestions
about this experiment. 相似文献
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Subyakto Toshimitsu Hata Shuichi Kawai Yuji Imamura Isamu Ide 《Journal of Wood Science》2000,46(1):16-21
Anisotropic thermal properties of molded carbon phenolic spheres (CPS), a mixture of sugi wood charcoal powders and phenol formaldehyde resin molded with a hot press, were investigated. The effects of the carbonizing temperature, particle size of chars, and density of the CPS on thermal properties were discussed. The molded CPS specimens were measured for their thermal properties using the laser flash method in both horizontal and vertical directions. The configuration of the CPS was observed by scanning electron microscopy. Anisotropy of the thermal properties (thermal diffusivity and thermal conductivity) between horizontal and vertical directions of the molded CPS was much higher than that of the uncarbonized molded phenolic spheres. Therefore, converting wood into molded CPS is an effective way to enhance the thermal-anisotropy properties. More marked effects of the carbonizing temperature, particle size, and density were observed in the horizontal direction than in the vertical direction. Anisotropy in thermal properties of the molded CPS may be considered an advantage for developing a new fire-retardant material for wood composites.An outline of this study was presented at the 47th and 48th annual meetings of the Japan Wood Research Society, Kochi and Shizuoka, 1997 and 1998. 相似文献
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Wen-Yu Su Subyakto Toshimitsu Hata Koei Nishimiya Yuji Imamura Shigehisa Ishihara 《Journal of Wood Science》1998,44(2):131-136
A practical approach to enhancing the fire retardancy of wood-based materials by adding fire-retardant chemicals to the glue was developed. Plywoods were manufactured using urea melamine formaldehyde resin mixed with ammonium pentaborate or dihydrogen phosphate. Treated plywoods had better incombustibility than untreated ones. X-ray photoelectron spectroscopy (XPS) analysis clearly demonstrated the distribution of boron and phosphorus, which had migrated from the glue to the wood, contributing to better fire retardant properties. The cross-sectional micrographs from scanning electron microscopy showed that untreated specimens exhibited a foamy structure near the interface in the glue layer and the deformed structure of wood cells. The cell structure and cell wall thickness retained intact in the specimens treated with urea melamine formaldehyde resin mixed with ammonium pentaborate or dihydrogen phosphate. When observing the effect of the thickness of overlay veneers on incombustibility, a shorter glowing time was obtained from the specimens with a thicker surface layer when the fire retardant chemical was added at 2%, but the differences were smaller at the higher chemical retention of 4%. A similar tendency was observed for the char length.Part of this paper was presented at the International Tropical Wood Conference in Kuala Lumpur, Malaysia, June 1997 相似文献
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