[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-112-1-fire-science-029":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-112-1-火災學概要-029","fire-112-1-fire-science-029",112,1,29,"有關重油油槽發生火災時可能產生的大規模沸溢（boilover）現象，下列敘述何者錯誤？",{"A":16,"B":17,"C":18,"D":19},"槽底水層因受熱升溫產生過熱氣化是關鍵機制","向下沈降的高溫熱波是導致沸溢的重要熱源","肇因於油層中的乳化水受熱沸騰","在火災過程中可能重複發生","C",null,[],false,"本題考點：重油等寬沸程油品之油槽火災沸溢（boilover）現象的成立機制，題目問錯誤敘述。\n【正解理由】依沸溢的成立要件，油品須為寬沸程而能在燃燒表面下形成向下傳遞的熱波，槽底須存在水層（水墊層），且油品黏度足以在水汽化時把上方油品拋出。熱波下沈接觸槽底水層後使水過熱汽化，水變成蒸氣時體積膨脹可達約一千七百倍，瞬間把上層高溫油品向槽外大量噴溢。沸溢的水源是槽底的水層，而非油層中的乳化水，故選 C。\n【逐項排除】\n(A) 槽底水層受熱波加熱而過熱汽化，正是沸溢的關鍵機制，敘述正確。\n(B) 向下沈降的高溫熱波是把熱量帶到槽底水層的重要熱源，敘述正確。\n(C) 把肇因說成油層中乳化水受熱沸騰並不正確，那描述的是含水油品受熱起泡、緩慢溢流的情形，與大規模沸溢的機制不同，為本題應選項。\n(D) 槽底水層未被一次耗盡、熱波持續下沈時，沸溢在同一場火災中可能重複發生，敘述正確。\n【記憶點】沸溢＝寬沸程油品＋熱波下沈＋槽底水層汽化，水在槽底而不在油裡。","油槽火災的溢流現象有三個常一起考的名詞，機制與規模都不同。沸溢（boilover）發生於原油、重油等寬沸程油品，燃燒表面輕質成分先蒸發，殘留的重質成分溫度可達數百度並向下沈降形成熱波，熱波抵達槽底水層時使水急速汽化，蒸氣挾帶大量高溫油品由槽口噴出，火勢瞬間放大且可噴及數倍槽徑的距離。濺溢（slopover）是滅火時射入的水滴落到高溫油面，表層局部汽化把少量油品濺出，規模小且屬表面現象。泡溢（frothover）則是含水油品在加熱或注入高溫油品時起泡外溢，甚至不一定伴隨燃燒。\n沸溢的三要件可以整理成好記的口訣：一要寬沸程油品（單一成分的純物質不易形成熱波），二要槽底有水（雨水、蒸氣冷凝水或注水滅火殘留水），三要油品黏度夠高、能被蒸氣托起。熱波下沈速度與燃燒表面退縮速度不同，兩者的差值決定沸溢發生的時間，因此可用槽內油層厚度除以熱波下沈速度粗估發生時刻，這也是油槽火災搶救時序判斷的理論基礎。\n水汽化體積膨脹是本題的核心數值：常壓下一體積的水汽化為蒸氣約膨脹一千七百倍，這個數字同時也是水系滅火藥劑窒息效果的來源，兩處考點可以互相印證。另須注意熱波現象只出現在多成分寬沸程油品，汽油、輕油等窄沸程油品因表層溫度接近沸點且不會累積高溫重質層，一般不產生典型沸溢。\n三者的規模差異也常入題：沸溢是全槽性的大規模噴溢，可能重複發生；濺溢與泡溢屬局部、小規模溢流，通常不重複且不伴隨劇烈火勢放大。判斷題只要抓住「水在哪裡」就能分辨——水在槽底是沸溢，水在油面是濺溢，水混在油裡是泡溢。本考點常延伸考油槽火災的燃燒速率、輻射熱危害距離，以及泡沫滅火藥劑在油槽表面的鋪展與封閉。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-112-1-fire-science-028","下列那一種前期現象比較可能因後續的消防滅火或救援作為而引發複燃？",28,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-112-1-fire-science-030","滅火藥劑的供給率關乎火災初期的滅火成敗、滅火時間與藥劑使用量，下列敘述何者錯誤？",30,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-112-1-fire-science-027","下列何種措施於室內發生火災時有助於防止或延緩閃燃的發生？",27,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-112-1-fire-science-031","在長寬高為10×10×4 公尺的密閉空間中以高壓式二氧化碳作為滅火防護設備。若欲將空間中的氧氣濃度降至 15%以下以達到鈍化效果，至少應加入多少立方公尺的二氧化碳？",31,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-112-1-fire-science-026","下列何種靜電災害預防措施旨在防止靜電蓄積，而與其他旨在減少靜電產生的措施有所不同？",26,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-112-1-fire-science-032","將大塊的木頭切碎為小片的木屑時，下列敘述何者錯誤？",32,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-113-1-fire-science-029",113,"火場中的單位長度光學密度為 1 m-1 時，此火場中的發光物體之能見度約為多少公尺？",{"webId":58,"year":59,"stem":60,"number":13},"fire-111-1-fire-science-029",111,"建築物內部裝潢材料對閃燃時間（F.O.T.）的影響，下列敘述何者錯誤？",{"webId":62,"year":63,"stem":64,"number":13},"fire-110-1-fire-science-029",110,"工廠使用之乙炔（C2H2），為防止爆炸引起火災，常利用裝有某化學物質與多孔性物質充填物之鋼瓶加壓保存，請問該化學物質為何？",{"webId":66,"year":67,"stem":68,"number":13},"fire-109-1-fire-science-029",109,"有關防火塗料敘述，下列何者錯誤？",{"webId":70,"year":71,"stem":72,"number":13},"fire-108-1-fire-science-029",108,"煙霧的流動為由高壓處往低壓處流，因此加壓造成壓力差可以有效控制煙霧流動。若於一安全梯間流入體積流率為 Q(m3\u002Fs)的空氣，形成 P 的壓力差，現欲將壓力差提高到 2P，則流入的空氣體積流率應為多少？",1785129966583]