[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-107-1-fire-science-035":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-107-1-火災學概要-035","fire-107-1-fire-science-035",107,1,35,"描述火勢大小之物理量為下列何者？",{"A":16,"B":17,"C":18,"D":19},"溫度","熱通量","熱釋放率","熱焓","C",null,[],false,"本題考點：以哪一個物理量描述「火勢大小」最恰當,核心是熱釋放率的定義與單位。\n【正解理由】火勢大小指的是火在單位時間內釋放能量的能力,對應的物理量是熱釋放率,定義為可燃物的質量損失速率乘以有效燃燒熱,單位為千瓦或百萬瓦,數值直接反映火源規模;它同時是火災成長曲線、煙層下降時間與排煙量推算的輸入值,國際上公認為描述火災規模最重要的單一參數,故選 C。\n【逐項排除】\n(A) 錯誤:溫度是狀態量,只描述某一點的冷熱程度,小火源在密閉小空間也可能量到高溫,無法代表火源規模。\n(B) 錯誤:熱通量是單位時間通過單位面積的熱量,單位為每平方公尺千瓦,描述某個受熱面承受的加熱強度,屬局部承受量而非火源總輸出。\n(C) 正確:以單位時間釋放的總熱能表示火源規模,理由如上。\n(D) 錯誤:熱焓是熱力學狀態函數,表示系統所含的能量,本身沒有時間維度,無法表達火勢強弱的變化速率。\n【記憶點】看火多大就看熱釋放率——單位是千瓦,帶「每秒」才叫火勢。","熱釋放率的基本式為質量損失速率乘以有效燃燒熱再乘燃燒效率,亦即單位時間燒掉多少燃料、每公斤燃料放出多少熱。實驗室量測則多採耗氧量熱法,其原理是大多數有機可燃物每消耗一公斤氧氣約放出十三點一百萬焦耳的熱,誤差在百分之五左右,因此只要量測排氣中氧濃度的下降量,即可回推熱釋放率,錐形量熱儀與家具量熱儀都建立在這個原理上。\n火災成長常以平方時間火災模式描述:熱釋放率與時間平方成正比,依成長係數分為慢速、中速、快速與超快速四級,對應達到約一千零五十五千瓦所需時間分別約為六百秒、三百秒、一百五十秒與七十五秒,這組數字是煙控與避難時間計算的常用假設。常見火源規模也值得記:紙類垃圾桶約數百千瓦,沙發或床墊可達二至三百萬瓦,小客車則約四至五百萬瓦。\n易混淆對照:熱釋放率是火源的輸出功率,熱通量是受熱面接收的強度,兩者單位差一個面積。熱通量的門檻值同樣常考——約每平方公尺二點五千瓦時人體皮膚感到疼痛,約二十千瓦則是判定閃燃的地板輻射熱通量。溫度雖然直觀,但同一熱釋放率在不同空間體積與通風條件下溫度差異極大,因此不適合當規模指標。\n熱釋放率之所以被稱為火災的單一最重要參數,是因為它幾乎是所有後續推算的起點:煙的生成量與煙層下降速度、火羽流捲吸的空氣量、上層氣體溫度、構件受熱程度乃至可用避難時間,全都以熱釋放率為輸入;火災模擬中所謂「設計火源」,講的也就是設定一條熱釋放率對時間的曲線。\n延伸考點:熱釋放率與煙層生成速率、排煙風量、可用避難時間之關係,以及火載量(單位樓地板面積的可燃物熱值總量)與熱釋放率的差別——前者是能量總量,後者是能量輸出速率,兩者不可混用。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-107-1-fire-science-034","建築物火災發生後，若火勢由局部火災擴散至全面火災之短時間現象稱為？",34,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-107-1-fire-science-036","下列何項不是閃燃發生之條件？",36,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-107-1-fire-science-033","燃燒時若生成的熱與散失的熱保持平衡，燃燒溫度保持均勻之燃燒為下列何者？",33,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-107-1-fire-science-037","針對連鎖反應之滅火機制為何？",37,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-107-1-fire-science-032","下列何者並非防火區劃構件構造之性質？",32,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-107-1-fire-science-038","以下那一現象為燃燒完全度高之火災特徵？",38,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-111-1-fire-science-035",111,"下列何者為乾粉最主要滅火原理？",{"webId":58,"year":59,"stem":60,"number":13},"fire-110-1-fire-science-035",110,"面對廚房油鍋起火燃燒，下列何項應對動作的風險最大？",{"webId":62,"year":63,"stem":64,"number":13},"fire-109-1-fire-science-035",109,"有關引火性液體的敘述，下列何者正確？",{"webId":66,"year":67,"stem":68,"number":13},"fire-108-1-fire-science-035",108,"為避免液化石油氣儲槽因外圍起火燃燒，一時無法撲滅而發生 BLEVE 現象，可採取之防救策略下列何者正確？",{"webId":70,"year":71,"stem":72,"number":13},"fire-106-1-fire-science-035",106,"五層樓的建築物，每層設有特別安全梯，樓梯採正壓且加壓壓力為 35 Pa，每層特別安全梯之前室採正壓且加壓壓力為 25 Pa，居室則未設煙控設計，居室避難到特別安全梯，需經過設有煙控之前室，且空間均為密閉構造，唯一開口為安全門，流動面積為 0.01 m2，試問每一排煙室設加壓煙控時，應送的風量為多少？",1785123163829]