[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-107-1-fire-science-037":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-037","fire-107-1-fire-science-037",107,1,37,"針對連鎖反應之滅火機制為何？",{"A":16,"B":17,"C":18,"D":19},"移除法","冷卻法","抑制法","窒息法","C",null,[],false,"本題考點：燃燒四面體與四種滅火法的對應關係，考的是連鎖反應該用哪一種機制打斷。\n【正解理由】燃燒的四要素為可燃物、助燃物、熱能與連鎖反應，四者各對應一種滅火法：移除可燃物為移除法、隔絕助燃物為窒息法、降低溫度為冷卻法，而針對連鎖反應者即為抑制法，又稱負觸媒法或化學抑制法。其原理是滅火藥劑受熱分解出的活性物種，在火焰區捕捉維持燃燒所需的氫自由基與氫氧自由基，使自由基鏈鎖反應無法延續，火焰因而熄滅，乾粉與海龍替代藥劑即屬此類，故選 C。\n【逐項排除】\n(A) 錯誤：移除法作用於可燃物，例如關閉燃氣供應閥、開闢防火間隔或搬離可燃物，與連鎖反應無關。\n(B) 錯誤：冷卻法作用於熱能，利用水的比熱與汽化潛熱把燃燒面溫度降到熱分解所需溫度以下。\n(C) 正確：抑制法直接作用於自由基連鎖反應，理由如上。\n(D) 錯誤：窒息法作用於助燃物，以二氧化碳、泡沫或防火毯降低氧濃度或隔絕空氣。\n【記憶點】四面體四招對號入座——可燃物用移除、氧用窒息、熱用冷卻、連鎖反應用抑制。","燃燒三要素加上連鎖反應構成燃燒四面體，是火災學最基本也最常考的架構。有焰燃燒必須靠自由基鏈鎖反應維持，其中最關鍵的分支反應是氫自由基與氧分子作用生成氫氧自由基與氧原子，一個自由基生成兩個，使反應呈幾何級數放大。化學抑制的作法就是投入能與自由基結合的物種，把鏈鎖反應的分支速率壓到低於終止速率，火焰即無法自持。\n藥劑對照可以這樣整理：海龍藥劑靠溴自由基捕捉效率極高，單位重量滅火效能是二氧化碳的數倍，但因臭氧層破壞潛值高，依蒙特婁議定書已管制生產，替代藥劑如七氟丙烷等潔淨藥劑則兼具化學抑制與吸熱作用；乾粉中的碳酸氫鈉、碳酸氫鉀受熱分解釋出鈉、鉀離子捕捉自由基，鉀鹽效率高於鈉鹽，而磷酸二氫銨系乾粉除抑制外，受熱後熔融被覆於固體表面阻絕空氣，因此可兼用於普通火災；二氧化碳與泡沫則主要靠稀釋氧濃度與隔絕空氣的窒息作用，水以冷卻為主。\n易混淆之處在於同一藥劑往往兼具多重機制，答題時要看題目問的是「主要」還是「兼具」:水是冷卻為主、蒸汽膨脹窒息為輔；泡沫是窒息為主、冷卻為輔；乾粉是抑制為主、窒息與被覆為輔。另需注意深層火災與可燃性金屬火災不適用一般抑制型藥劑，鈉鉀鎂等金屬火災須以專用乾粉或乾砂處理。\n從能量與物質的角度也能把四法分成兩類：移除法與窒息法斷絕物質供應，冷卻法把熱帶離系統，三者都改變要素的存量；抑制法則不減少燃料、氧氣或熱量，而是改變反應路徑，因此對有焰燃燒見效極快，往往數秒內即壓熄火焰，卻無法帶走蓄積的熱，餘燼仍具復燃風險，這正是化學抑制型藥劑常須搭配冷卻的原因。\n延伸考點：燃燒四面體與火災分類的對應、各滅火法的實例配對、以及「為何無焰的表面燃燒不易被化學抑制」,都是同一組題型的變化。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"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":33,"stem":34,"number":35,"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,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-107-1-fire-science-035","描述火勢大小之物理量為下列何者？",35,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-107-1-fire-science-039","因電器設備而發生之火災為何？",39,{"webId":45,"stem":46,"number":47,"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":49,"stem":50,"number":51,"year":11,"session":12},"fire-107-1-fire-science-040","下列何者並非長公路隧道火災之特性？",40,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-113-1-fire-science-037",113,"主成分為碳酸氫鉀的乾粉滅火藥劑不適用下列何種火災？",{"webId":58,"year":59,"stem":60,"number":13},"fire-112-1-fire-science-037",112,"升高環境溫度對於環氧乙烷的分解爆炸有何影響？",{"webId":62,"year":63,"stem":64,"number":13},"fire-111-1-fire-science-037",111,"存放乙醇倉庫發生火災，下列那一種泡沫滅火劑較適當？",{"webId":66,"year":67,"stem":68,"number":13},"fire-110-1-fire-science-037",110,"有關電氣火災防範對策中，電器設備之正確使用非常重要，在潮濕場所使用電器時，插頭應加裝何種裝置以防止感電發生？",{"webId":70,"year":71,"stem":72,"number":13},"fire-109-1-fire-science-037",109,"D 類火災可使用的滅火劑，何者適合？",1785129967915]