Wednesday, May 23, 2007

閃燃 Flashover

香港荃灣德士古道品質工業大廈 5月21日晚發生3級火警,消防員入火場救火時,懷疑發生「閃燃」(Flashover),1名消防員(黃家熙)殉職,10人傷 (6名消防員 + 4名工人)。 黃家熙是最後一個撤離火場,亦是最接近火場的一位。

Since I wasn't sure what is 閃燃 (Flashover), so I did some research:

「閃燃」是火場上危險現象之一,通常在一個封閉火場發生,當物件起火時,被燃燒的有機物料,包括塑膠等,會因火勢而釋出易燃氣體,充斥整個火場。隨溫度不斷上升,當到達約攝氏500℃的自然燃燒界點時,所有物件和易燃氣體會在差不多同一時間燃燒,火勢更會隨熱氣體上升至天花,再向四方八面擴散,令現場瞬間變成一片火海。整個火場在不足一秒鐘內陷入火海,溫度升至近 800度,消防員雖有防火衣等裝備保護,但仍如「錫紙焗薯仔」般,身上的保護袍雖可免被火燒,但卻無法完全阻擋高熱,以致體內嚴重灼傷,高熱中暑(heat shock) 致死。

對於閃燃,資深消防隊目阿文坦言閃燃前出現的黑煙,並非那麼容易察看到,「火場內漆黑一片,要憑經驗去細心觀察」。阿文說,閃燃前黑煙會如漩渦般在天花板上捲起,黑煙一層一層於天花上積聚,由於閃燃會於指定溫度及空氣濃度內突然發生,故消防員有時要除去手套,以感受現場溫度作出評估。


This incident is like the movie Backdraft or other firemen movies. In movies, we always know that the main actor (fireman) will save everybody and survive. In real life, people are not that lucky. One fireman has died in this fire. It is always sad to hear this kind of news.

We are touched by firemen's selfless act. They have to put themselves in danger in order to save others. They are nameless heros. The really sad part is that they only receive public recognitions and fames after they die on duty...


Link:
八百度高溫閃燃 消防員殉職
閃燃 (Flashover) &複燃 (Backdraft)
Flashover

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