[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-107-1-fire-science-007":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-007","fire-107-1-fire-science-007",107,1,7,"可燃物於無明火等火源之條件下，在大氣中僅因受熱而開始自行燃燒所需之最低溫度稱為下列何者？",{"A":16,"B":17,"C":18,"D":19},"自燃溫度","閃火點","沸點","閃燃點","A",null,[],false,"本題考點：燃燒學中各種特徵溫度的定義辨識，特別是「無外部火源、僅因受熱而自行燃燒」對應的名詞。\n【正解理由】依燃燒學之定義，自燃溫度（發火溫度、autoignition temperature）指可燃物在大氣中不需明火、電弧等外部引火源，僅因受熱使氧化反應自行加速而開始燃燒所需之最低溫度。題幹敘述的「無明火等火源」「僅因受熱而開始自行燃燒」「最低溫度」三個要件完全對應此定義，故選 A。\n【逐項排除】\n(A) 自燃溫度正是不需外部火源、僅靠受熱即自行起火的最低溫度，與題幹三項要件相符，敘述正確。\n(B) 閃火點是液面上蒸氣濃度達到燃燒下限、遇外部火源可閃出火焰的最低液溫，其成立前提正是「有火源」，與題幹「無明火」的條件相反。\n(C) 沸點是液體飽和蒸氣壓等於外界壓力而沸騰的溫度，屬相變化的物理量，與是否燃燒無關。\n(D) 閃燃點一詞在中文語境中指室內火災的閃燃現象，屬全室性火災行為的轉變階段，並非描述單一可燃物的起火溫度。\n【記憶點】不用點火、光靠加熱就燒起來的最低溫度，就是自燃溫度。","把燃燒學的幾個特徵溫度排成一條數線，是這一族群考題最有效的準備方式。由低到高依序是：閃火點（見火閃燃、移開火源即熄）、著火點或稱燃點（見火燃燒且移開火源後仍能持續燃燒，通常較閃火點高數度至十數度）、自燃溫度（完全不需外部火源，僅受熱即起火，量級常在數百度）。以汽油為例，閃火點約在攝氏零下 40 度以下，自燃溫度卻約在攝氏 280 度上下，兩者差距極大；柴油的閃火點約 60 度以上，自燃溫度反而約 220 度，比汽油低。這個「閃火點高者自燃溫度未必高」的反直覺現象，正是命題者最愛設計的陷阱。\n自燃的物理機制是熱平衡的失衡：可燃物內部的氧化放熱速率若持續大於向環境散熱的速率，溫度就會自我加速上升直至起火，這即是熱著火理論的核心。也因為機制取決於熱的產生與散失，自燃溫度並非物質的絕對常數，而會隨容器形狀、堆積體積、氧濃度、壓力與量測方法而變動——堆積體積越大，散熱面積相對越小，越容易自燃，這解釋了為何大量堆放的油布、稻草、廢紙或煤堆會發生自然發火，而少量同樣材料卻不會。\n易混淆概念對照：自然發火（自然發熱起火）強調的是常溫下由微生物作用、氧化、聚合、吸附或分解產生的自發蓄熱過程，是「怎麼熱起來」的問題；自燃溫度則是「熱到幾度會燒」的門檻值，兩者相輔但不同義。此外，自燃溫度與最小引火能量也不同，後者衡量的是引燃可燃混合氣所需的最小電火花能量。\n相關考點連結：本觀念常與燃燒界限（爆炸上下限）、閃火點分級（NFPA 與我國第四類公共危險物品）、以及自然發火性物質之儲存管制合併命題。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-107-1-fire-science-006","危害物質災害現場搶救標準作業程序（H.A.Z.M.A.T.）之說明，下列何者為正確？",6,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-107-1-fire-science-008","描述熱傳遞（heat transfer）之物理量為下列何者？",8,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-107-1-fire-science-005","根據美國防火協會危險物品表示規定，將危險類別記載於菱形方塊上，其中黃色表示何種危害？",5,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-107-1-fire-science-009","要做好火災預防工作，從理論觀點上，可由火災預防之「3E 政策」著手，下列敘述何者不屬於「3E 政策」項目？",9,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-107-1-fire-science-004","下列那一個可燃性氣體產生火災爆炸之風險最低？",4,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-107-1-fire-science-010","下列有關二氧化碳滅火劑之敘述，何者錯誤？",10,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-111-1-fire-science-007",111,"油類火災為何種火災？",{"webId":58,"year":59,"stem":60,"number":13},"fire-110-1-fire-science-007",110,"己烷在閃火點時的飽和蒸氣壓為 9.12 mmHg，根據 Burgess-Wheeler 定理其燃燒熱約為多少 kcal\u002Fmole？",{"webId":62,"year":63,"stem":64,"number":13},"fire-109-1-fire-science-007",109,"進入石化工廠，車輛會被要求在排氣管加裝滅焰器（flame arrester）以避免火災爆炸之發生，加裝該措施防制火災爆炸之原理為：",{"webId":66,"year":67,"stem":68,"number":13},"fire-108-1-fire-science-007",108,"下列有關蒸氣爆炸的敘述何者錯誤？",{"webId":70,"year":71,"stem":72,"number":13},"fire-106-1-fire-science-007",106,"請指出下列何種氣體的比重小於 1？",1785123163530]