[{"data":1,"prerenderedAt":72},["ShallowReactive",2],{"q-fire-108-1-fire-science-038":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-108-1-火災學概要-038","fire-108-1-fire-science-038",108,1,38,"可燃物不藉由火焰或電器火花引起燃燒，在大氣中僅因受熱而引發燃燒的最低溫度稱為：",{"A":16,"B":17,"C":18,"D":19},"發火點（ignition point）","閃火點（flash point）","燃燒點（burning point）","閃燃點（flashover point）","A",null,[],false,"本題考點：發火點、閃火點、燃燒點三個燃燒溫度參數的定義辨識，關鍵在「有無外部引火源」。\n【正解理由】題幹明確限定「不藉由火焰或電器火花」而「僅因受熱」即引發燃燒的最低溫度，亦即在無外部引火源的條件下，可燃物本身受熱到達某一溫度即自行起火，此參數的正式名稱為發火點(又稱著火點、自燃點)。閃火點與燃燒點的定義都以外部引火源接觸為前提，與題幹條件不符，故選 A。\n【逐項排除】\n(A) 發火點的定義正是在無外部火源下，僅因受熱即自行起火燃燒的最低溫度，與題幹敘述完全吻合，為本題應選者。\n(B) 閃火點是液體表面產生足量可燃蒸氣、遇外部引火源可閃出火焰的最低溫度，移開火源即熄滅，仍須靠外部點火。\n(C) 燃燒點是遇外部引火源點燃後、移開火源仍能持續燃燒的最低溫度，通常比閃火點高數度，同樣以外部點火為前提。\n(D) 閃燃並非物質的固有溫度參數，而是室內火災由成長期急遽轉入最盛期的瞬間現象，層次與前三者不同。\n【記憶點】要不要點火是分水嶺：自己燒起來的是發火點，得靠火才閃的是閃火點。","三個溫度參數的高低順序固定為：閃火點 \u003C 燃燒點 \u003C 發火點，理解其成因即不需死背。閃火點只要求液面上方蒸氣濃度達到爆炸下限，遇火源能瞬間閃燃；燃燒點則要求蒸氣的持續供應速率足以維持火焰，故溫度略高，一般高出閃火點約攝氏五至十度；發火點不倚賴外部火源，必須讓氧化反應自身的產熱速率超過散熱速率而失控，所需溫度自然最高。\n\n閃火點的測定方式會影響數值，是實務與考題的細節所在：閉杯法因蒸氣不易逸散，測得值較開杯法低，常見閉杯試驗器有標準閉杯與賓斯基馬丁閉杯，開杯法則以克利夫蘭開杯為代表。命題若未指明，通常以閉杯值為準。\n\n閃火點更是公共危險物品第四類分類的骨幹，可整理成數值梯：特殊易燃物、第一石油類(未達攝氏二十一度)、酒精類、第二石油類(二十一度以上未達七十度)、第三石油類(七十度以上未達二百度)、第四石油類(二百度以上)與動植物油類，管制數量隨類別遞增。\n\n發火點則須注意它不是恆定物性，會隨壓力、氧濃度、容器材質與形狀、有無觸媒而變動，文獻值僅供比較。常被引用的對照是汽油閃火點極低而發火點約攝氏二百五十度上下，柴油閃火點雖高出許多，發火點卻反而較汽油低，這種「閃火點高但發火點低」的反差是典型陷阱題。\n\n易混淆概念對照：自燃(發火點造成的起火)與自然發火不同，後者指堆積物因氧化、發酵、吸附等作用在常溫下蓄熱升溫而起火，如油布、稻草、煤堆；而閃燃(flashover)與閃火(flash)雖僅一字之差，一為室內火災階段現象，一為液體蒸氣的瞬間燃燒，務必分清。\n\n相關考點連結：同組概念常延伸至爆炸界限、蒸氣壓與蒸氣密度、以及第四類物質儲存場所的設置管制。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-108-1-fire-science-037","下列有關 GHS 制度之說明，何者錯誤？",37,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-108-1-fire-science-039","高壓氣體的爆炸界限，通常較常壓下為廣，爆炸上限也明顯提高，但下列何種氣體之爆炸範圍及爆炸上限在高壓下卻降低？",39,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-108-1-fire-science-036","下列何者不是 IG-541 氣體滅火藥劑的成分？",36,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-108-1-fire-science-040","建築物火災進入最盛期時，燃料數量龐大，但因對外開口相對較少的情況下，燃燒速度因開口通風量而受限，此現象稱為：",40,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-108-1-fire-science-035","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？",35,{"webId":49,"stem":50,"number":12,"year":51,"session":12},"fire-109-1-fire-science-001","已知辛烷的燃燒下限為 0.92（vol%），根據 Burgess-Wheeler 定理其燃燒熱約為多少？",109,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-113-1-fire-science-038",113,"惰性氣體滅火藥劑 IG541 的組成分不包括下列何者？",{"webId":58,"year":59,"stem":60,"number":13},"fire-112-1-fire-science-038",112,"當外部風的風向不變而風速加倍時，對處於煙囪效應下的大樓而言，下列敘述何者正確？",{"webId":62,"year":63,"stem":64,"number":13},"fire-111-1-fire-science-038",111,"在長 10 m、寬 8 m、高 3 m 的居室燃燒 1 kg 的乳膠枕頭，其 Dm=0.65 m2\u002Fg，估算此火場出口標示燈能見度？",{"webId":66,"year":67,"stem":68,"number":13},"fire-110-1-fire-science-038",110,"常見泡沫滅火藥劑含有界面活性劑成分，請問下列何者不是泡沫滅火藥劑滅火時界面活性劑的主要作用？",{"webId":70,"year":51,"stem":71,"number":13},"fire-109-1-fire-science-038","在橡膠中混入碳黑所製成的產品可防止人體帶靜電，其防止靜電發生的方法為？",1785129967664]