[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-111-1-fire-science-017":3},{"subject":4,"subjectSlug":5,"subjectKicker":6,"subjectShort":7,"question":8,"related":27,"sameNumber":52,"hasEssay":26},"火災學概要","fire-science","火災學 · Fire Science","火災學",{"id":9,"webId":10,"year":11,"session":12,"subject":4,"number":13,"stem":14,"options":15,"answer":20,"answerNote":21,"images":22,"imagesPending":23,"lawTimestamp":11,"explanation":24,"explanationDeep":25,"freq":12,"indexable":26},"fire-111-1-火災學概要-017","fire-111-1-fire-science-017",111,1,17,"有關閃燃（Flashover）與複燃（Backdraft）的敘述，何者錯誤？",{"A":16,"B":17,"C":18,"D":19},"閃燃是一種爆炸現象，釋放的能量常造成門窗破壞；複燃是火勢快速發展的現象","依火災發展時期，閃燃常發生在成長期；複燃常發生在成長期或衰退期","閃燃發生的原因為「熱能」；複燃發生的原因為「助燃物」","火場中，閃燃有可能比複燃早發生","A",null,[],false,"本題考點：閃燃與複燃兩種室內火災急遽變化現象在成因、發生時期與外顯特徵上的比較。\n【正解理由】閃燃是室內熱煙層蓄熱達到門檻後，地面可燃物幾乎同時起火、火勢在極短時間內遍及全室的急速成長現象，驅動因素是「熱」；複燃則是通風受限、火勢因缺氧而趨於停滯後，門窗突然開啟使空氣灌入，室內堆積的未燃可燃氣體瞬間著火膨脹，具爆炸性且常將門窗震破，驅動因素是「助燃物」。選項將兩者特徵對調，把爆炸與門窗破壞歸給閃燃、把火勢快速發展歸給複燃，敘述錯誤，故選 A。\n【逐項排除】\n(A) 具爆炸性、常造成門窗破壞者為複燃，閃燃才是火勢快速發展至全面燃燒的現象，兩者敘述顛倒，為本題應選者。\n(B) 閃燃發生於成長期末段，複燃須先經缺氧悶燒累積可燃氣體，故常見於成長期後段或衰退期，敘述正確。\n(C) 閃燃的關鍵在蓄積的熱能，複燃的關鍵在突然補入的助燃物（空氣中的氧），敘述正確。\n(D) 兩者並無固定先後順序，火場中閃燃可能先於複燃發生，敘述正確。\n【記憶點】閃燃缺「熱」不成、複燃缺「氧」不成；會把門窗炸開的是複燃。","閃燃與複燃是室內火災兩個最經典的急遽變化現象，考試幾乎年年出現，關鍵在於分開記憶四個面向：成因、時期、前兆、外顯。\n閃燃的成因是蓄熱。火災成長期中熱煙層逐漸增厚增溫，向地面放射的輻射熱通量累積到約每平方公尺二十千瓦、熱煙層溫度達攝氏五百至六百度時，地面可燃物幾乎同時被引燃，室內由局部燃燒轉為全面燃燒。它的前兆包括熱煙層明顯下降、室內溫度急遽上升，以及天花板下方未燃氣體被引燃而出現舌狀火焰快速掠過的滾燃現象。閃燃之後即進入最盛期，室內溫度可達攝氏八百度以上，此時火勢由通風條件支配。\n複燃的成因是缺氧。當開口極少時，燃燒消耗氧氣而無足夠補充，火焰縮小甚至熄滅轉為悶燒，但高溫仍持續使可燃物熱分解，室內因而充滿一氧化碳等未燃可燃氣體，濃度落在爆炸範圍之上（過濃）。此時只要門窗被開啟或玻璃破裂，空氣灌入將混合氣稀釋回爆炸範圍內，遇高溫餘燼即瞬間著火，燃燒波與膨脹的高溫氣體向開口衝出，形成火球並震破門窗。其前兆包括門縫出現吸吐脈動的煙流、濃厚油狀黑煙、玻璃被燻黑並附著油污、以及室內無明顯火焰卻異常高熱。\n易混淆之處在於「爆炸性」的歸屬：閃燃是燃燒面積的急速擴大，過程中壓力上升有限；複燃則是預混氣體的爆燃，具明確的壓力波，這是選項 A 顛倒之處。另需注意滾燃屬於閃燃的前兆而非獨立階段。延伸考點包括通風控制型與燃料控制型火災的分界、一氧化碳濃度與複燃危險的關係，以及排煙開口的開啟順序對兩種現象的影響。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-111-1-fire-science-016","比較積污導電與金原現象之差異，下列何者錯誤？",16,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-111-1-fire-science-018","下列何者非電線走火之原因？",18,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-111-1-fire-science-015","下列發火源在理化現象歸類上，何者與其他不同類別？",15,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-111-1-fire-science-019","有關火羽流及天花板噴射流的敘述，下列何者錯誤？",19,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-111-1-fire-science-014","普通木造建築物旁欲蓋 9 公尺高之建築物，其延燒係數為 3 級（係數為 0.15），其防火間隔應保持多少公尺？",14,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-111-1-fire-science-020","下列對於燃燒要素的敘述，何者錯誤？",20,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-113-1-fire-science-017",113,"建築火災中會被通風口的大小設計所影響，通風因子為下列何者？（A：通風口面積、W：通風口寬度、H：通風口高度）",{"webId":58,"year":59,"stem":60,"number":13},"fire-112-1-fire-science-017",112,"下列那一種爆炸屬於物理性爆炸？",{"webId":62,"year":63,"stem":64,"number":13},"fire-110-1-fire-science-017",110,"下列惰性氣體類海龍替代滅火藥劑中，何者的比重小於 1？",{"webId":66,"year":67,"stem":68,"number":13},"fire-109-1-fire-science-017",109,"T.N.T.炸藥化學名稱為三硝基甲苯（Trinitrotolene，C7H5N3O6），俗稱黃色炸藥，試問其氧平衡（Oxygen Balance, O.B.）為多少？",{"webId":70,"year":71,"stem":72,"number":13},"fire-108-1-fire-science-017",108,"危害物質可能因混合儲存或載運而衍生危險，則下列那兩類公共危險物品於混合載運時的危險性最低？",1785129966784]