[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-109-1-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-109-1-火災學概要-007","fire-109-1-fire-science-007",109,1,7,"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：",{"A":16,"B":17,"C":18,"D":19},"窒息","冷卻","抑制連鎖反應","阻止擴展","B",null,[],false,"本題考點：滅焰器(flame arrester)阻火的作用機制,對應四大滅火原理中的冷卻(淬熄)。\n【正解理由】滅焰器由多層金屬網或密集的細窄流道構成,孔隙尺寸小於該可燃氣體的淬熄距離。火焰欲通過時,燃燒反應區的熱量被大面積金屬迅速傳導帶走,反應區溫度降到無法維持鏈鎖傳播的程度,火焰便在通過前熄滅,可燃氣體仍可通行而火焰不得穿越。其本質是吸熱降溫,屬冷卻作用,故選 B。\n【逐項排除】\n(A) 窒息是降低氧濃度或隔絕空氣供應;滅焰器的孔隙讓氣體照常通過,並未改變混合氣的氧含量,不屬窒息。\n(B) 金屬網把火焰的熱大量吸走,使反應區溫度低於維持燃燒所需,正是冷卻(淬熄)原理,為應選項。\n(C) 抑制連鎖反應是靠鹵素或乾粉的負觸媒捕捉 H·、OH· 自由基,屬化學滅火;滅焰器不含任何化學藥劑,純為物理熱傳。\n(D) 阻止火焰擴展是加裝滅焰器要達成的結果,不是滅火原理本身;四大原理為冷卻、窒息、除去可燃物與抑制連鎖反應,並無「阻止擴展」一項。\n【記憶點】滅焰器＝金屬網把火焰的熱吸走,冷到燒不下去,靠冷卻不是靠隔絕。","滅焰器的理論基礎是淬熄距離。可燃性混合氣的火焰在狹窄通道中傳播時,反應區產生的熱有一部分被管壁帶走;當通道尺寸小到某個臨界值,散熱速率超過產熱速率,火焰便無法維持而熄滅,這個臨界尺寸即淬熄距離。淬熄距離與最小點火能量正相關:氫氣、乙炔的淬熄距離極小(約 0.6 mm 以下),故其滅焰器孔隙必須做得比甲烷、丙烷用的更細密。\n常見構造分為金屬網式、皺摺板(波紋帶)式與砂礫、多孔陶瓷填充式,共同點都是以極大的比表面積換取高熱傳導速率。應用場所包括石化廠區進出車輛的排氣管、儲槽的通氣口與呼吸閥、可燃氣體管線、油氣回收系統與火炬設備。裝在排氣管的用意很直接:引擎排氣可能挾帶火星或高溫碳粒,一旦廠區空氣中已有可燃性蒸氣,火星逸出即可能點燃並回火,滅焰器把火焰擋在管內,是典型的預防性防爆措施。\n易混淆概念對照:滅焰器阻擋的是爆燃(deflagration)等次音速火焰;若管線內已發展成爆轟(detonation)等超音速壓力波,一般型式擋不住,需用耐爆轟型。與滅焰器常被並列的還有阻火閥、防火阻絕器與礦工安全燈——戴維燈正是最早利用金屬網淬熄原理的裝置,原理與本題完全相同。要特別分清楚的是,滅焰器阻擋的是火焰在管線或容器口的傳播,防火門、防火閘門阻擋的則是建築空間之間的延燒,兩者的尺度與手段完全不同。\n四大滅火原理的代表配對也是高頻考點:冷卻對應水與滅焰器的熱傳導、窒息對應二氧化碳與惰性氣體、除去可燃物對應關閉燃料閥與防火間隔、抑制連鎖反應對應海龍、鹵化烴與乾粉。判別題只要問「機制」而非「效果」,就要回到這四格作答。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-109-1-fire-science-006","某次閃電的過程中，雲的底部和地面之間，電壓高達 1 千萬伏特，並在約 0.02 秒內輸送 20 庫倫的電量至地面。下列與閃電有關的敘述何者正確？",6,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-109-1-fire-science-008","1 度電為 1,000 瓦．小時（1 kWh），試問 1 度電約等同多少千卡（kcal）？",8,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-109-1-fire-science-005","下列有關二氧化碳（CO2）滅火劑之敘述，何者錯誤？",5,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-109-1-fire-science-010","有水之場所的插頭應加裝何種裝置以防止感電發生？",10,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-109-1-fire-science-004","某一火災成長至 2,000 kW 所需時間為 400 秒，請問該火災屬何種成長性火災？[Q：釋熱率（MW）； 1\u002F2 t：經過時間（sec）；k：火災成長常數（sec\u002FMW ）]",4,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-109-1-fire-science-011","某一線徑 2.0 m\u002Fm 之電線 1 km 長之電阻值為 5.657 Ω，熱阻抗為 378。若周遭溫度為 20℃，當此 10 cm 長之電線通過 10 安培時，其芯線溫度（℃）約為多少？",11,[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-108-1-fire-science-007",108,"下列有關蒸氣爆炸的敘述何者錯誤？",{"webId":66,"year":67,"stem":68,"number":13},"fire-107-1-fire-science-007",107,"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？",{"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？",1785123162700]