[{"data":1,"prerenderedAt":72},["ShallowReactive",2],{"q-fire-114-1-fire-science-003":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-114-1-火災學概要-003","fire-114-1-fire-science-003",114,1,3,"下列有關儲槽火災之敘述何者錯誤？",{"A":16,"B":17,"C":18,"D":19},"儲槽內液體燃料之溫度以液面為最高","泡沫為最常用之滅火系統","儲槽內熱量傳遞之主要方式為熱傳導","燃料液面上儲槽牆面的高度會影響儲槽火災燃燒速率","C",null,[],false,"本題考點：儲槽火災的燃燒與熱傳特性，重點在槽內液體的熱量以何種方式傳遞為主。\n【正解理由】儲槽內的液體受上方火焰加熱後，表層溫度升高、密度改變，液體因浮力形成自然對流循環，熱量主要靠流體的整體位移在槽內傳遞。液體的熱傳導係數低，單靠傳導無法解釋槽內的溫度分布與高溫層向下推進的速度。因此儲槽內熱量傳遞之主要方式為對流，本選項寫成熱傳導與此不符，故選 C。\n【逐項排除】\n(A) 火焰位於液面上方，熱量自液面向下傳遞，故液體溫度以液面處為最高，敘述正確。\n(B) 儲槽火災屬油類火災，泡沫覆蓋液面可阻絕可燃蒸氣與空氣接觸並兼具冷卻作用，是此類場所最常用的滅火系統，敘述正確。\n(C) 槽內液體以自然對流為主要熱傳方式，並非熱傳導，敘述錯誤。\n(D) 液面至槽壁頂端的高度會改變空氣進入火焰的路徑，以及火焰對液面的熱回饋，實驗上燃燒速率隨之改變，敘述正確。\n【記憶點】油槽火災三句話：液面最熱、槽內靠對流、滅火靠泡沫。","儲槽火災是液池火災的放大版，理解它要先分清三種熱傳在其中各自的角色。火焰對液面的加熱以輻射為主，液面吸熱後蒸發出可燃蒸氣供應燃燒；槽內液體的熱量分布由自然對流主導，受熱的表層與較冷的下層之間因密度差而形成循環；熱傳導只在槽壁、槽底等固體邊界與液體之間扮演次要角色。液體的熱傳導係數本來就低，若假設槽內靠傳導傳熱，熱量根本來不及往下推進。\n重質油品的儲槽還會形成熱波。油品是多種沸點成分的混合物，燃燒時輕質成分優先蒸發，殘留的高沸點成分溫度升高、密度增加而向下沉降，在液面下方形成一層溫度遠高於水沸點的高溫帶並持續下移。當熱波抵達槽底的水墊層，水瞬間汽化膨脹，把上方仍在燃燒的高溫油品推出槽外，即為沸溢；若水源是油品中的乳化水或落到高溫油面的射水，規模較小、發生較早，則稱為濺溢。這也是油槽火災不以水柱直接射入液面作為滅火手段的原因。\n滅火方式的分類依據可以回到《滅火器認可基準》壹、二、（一）之用語定義：B 類火災又稱油類火災，指石油類、有機溶劑、油漆類、油脂類等可燃性液體及可燃性固體引起之火災。油類火災的滅火主軸是窒息，泡沫在液面形成連續泡沫層，阻斷可燃蒸氣的供應並兼具冷卻，因此固定式泡沫滅火設備是儲槽場所的主力；同基準壹、二、（二）4 並定所充填之機械泡沫滅火藥劑量在二十公升以上者為大型滅火器。\n延伸考點：液面與槽壁頂端之間的高度會影響空氣捲入與火焰對液面的熱回饋，因此同一座槽在滿液位與低液位時的燃燒速率並不相同；液池直徑也會影響熱回饋的主導機制，小直徑液池以槽壁傳導為主，直徑增大後改由火焰輻射主導。這一組對照常與本題的熱傳方式合併命題。",true,[28,32,36,39,43,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-114-1-fire-science-002","建築物火災成長過程中有關衰退期的敘述何者錯誤？",2,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-114-1-fire-science-004","下列有關隧道火災之敘述何者錯誤？",4,{"webId":37,"stem":38,"number":12,"year":11,"session":12},"fire-114-1-fire-science-001","火場中輻射為熱傳遞主要的方式之一，輻射熱之性質及其計算的方式下列何者錯誤？",{"webId":40,"stem":41,"number":42,"year":11,"session":12},"fire-114-1-fire-science-005","火災煙毒氣體之危害主要是下列何種氣體？",5,{"webId":44,"stem":45,"number":46,"year":47,"session":12},"fire-113-1-fire-science-040","有關複燃之敘述，下列何者錯誤？",40,113,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-114-1-fire-science-006","依據我國公共危險物品之分類，下列有關可燃液體與易燃液體之敘述，何者正確？",6,[53,56,60,64,68],{"webId":54,"year":47,"stem":55,"number":13},"fire-113-1-fire-science-003","當起火區域產生閃燃時，人在其中是無法存活的，對於閃燃現象之敘述，下列何者錯誤？",{"webId":57,"year":58,"stem":59,"number":13},"fire-112-1-fire-science-003",112,"下列何者非為火災之特性？",{"webId":61,"year":62,"stem":63,"number":13},"fire-111-1-fire-science-003",111,"實效濕度低於多少時，日本即發布火災警報？",{"webId":65,"year":66,"stem":67,"number":13},"fire-110-1-fire-science-003",110,"依據建築物火災的特性，當進入「穩態燃燒」階段時，釋熱率（Q）與時間（t）的關係為何？",{"webId":69,"year":70,"stem":71,"number":13},"fire-109-1-fire-science-003",109,"依用戶用電設備設置規則及建築技術規則，下列避雷設置敘述何者錯誤？",1785129965932]