木合板自燃現象之研究

The Study of Spontaneous Ignition of Plywood

在工廠裡，常使用木材作為建築材料，原因為修繕方便且易更換。但工程中仍免不了動火作業，在某工廠於修繕工程進行動火作業後數小時，發生火災，經判斷可能為木材之自燃現象，但是否有足夠熱能使其悶燒令人質疑，故本研究以此為研究方向。在文獻中提到，使用圓錐量熱儀可觀察木材燃燒之現象，其發現當輻射熱大於40 kW/m2以上時，木材會發生自燃。故本研究以常見之噴燈動火作業進行模擬實驗，並以常見的木合板作為實驗材料。經實驗結果發現，在圓錐量熱儀加熱使木合板發焰後，持續加熱一分鐘後移開，此時已無火焰，再以探照燈模擬太陽熱度照射4小時後，觀察發現木合板底部會有明顯碳化及火星之情形並有持續悶燒狀況，顯示木頭內部產生自燃現象，且有向外延燒之可能性，而使災情擴大。因此使用動火工具時需與木材建料保持一定距離，並使用防火毯等防護設備。 In factories, wood often been used as a constructed material, the reason for this is simplicity in repair and replacement. However, hot work during projects is inevitable. A fire occurred in a factory a few hours after they had performed hot work during a repair project. It was determined to be autoignition of the wood, but whether there was enough heat to cause smoldering was questionable, and is the main focus of this research. Literature states when using a cone calorimeter to observe the burning of wood, it was discovered that wood would autoignite when radiant heat exceeded 40 kW/m^2. This research used a conventional blowtorch to perform experiments while using plywood as the material. After the cone calorimeter allowed the plywood to bum, it was heated for another minute before being removed, at which there was no more smoke. After using a searchlight to simulate the sun shining for 4 hours, observations showed visible carbonization and sparks under the plywood, while also continuously smoldering. This shows autoignition within the wood, with the possibility to spread. Therefore, when using hot work equipment, it is recommended that a certain distance be kept from wood based materials as well as using fire blankets to protect these types of equipment.