[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-107-1-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-107-1-火災學概要-038","fire-107-1-fire-science-038",107,1,38,"以下那一現象為燃燒完全度高之火災特徵？",{"A":16,"B":17,"C":18,"D":19},"放熱多","煙量大","一氧化碳產生量大","火焰顏色偏黃色","A",null,[],false,"本題考點：燃燒完全度高低所對應的產物與熱量差異，屬燃燒化學的基本判讀。\n【正解理由】依燃燒化學計量關係，碳氫化合物在氧氣供應充足時完全氧化為二氧化碳與水蒸氣，燃料所含化學能可全數轉為熱能釋出，單位質量燃料的放熱量趨近其理論燃燒熱；反之氧氣不足時只氧化到一氧化碳並析出游離碳粒，一部分化學能被鎖在未完全氧化的產物裡放不出來。因此燃燒完全度愈高，最直接的外顯特徵就是放熱多、火場溫度高、輻射熱強，故選 A。\n【逐項排除】\n(A) 正確。完全氧化使燃燒熱幾乎全數釋放，同樣質量的燃料放出的熱最多，這正是完全燃燒的定義性表徵。\n(B) 錯誤。煙的主體是未燃碳粒與凝結性熱裂解產物，燃燒愈完全碳粒生成愈少、煙量反而愈小；濃煙滾滾是通風不足、燒不完全的指標。\n(C) 錯誤。一氧化碳是碳氧化不完全的中間產物，其產率隨氧氣不足而急遽升高，與完全燃燒的特徵正好相反。\n(D) 錯誤。火焰偏黃橙是焰中碳粒受熱到白熾而發光，屬擴散燃燒、燃燒不完全的現象；完全燃燒的預混火焰偏藍且幾乎不冒煙。\n【記憶點】完全燃燒＝高溫、少煙、藍焰、二氧化碳；不完全燃燒＝濃煙、一氧化碳、黃焰。","燃燒完全度要放在「燃料控制」與「通風控制」的架構下理解。室內火災初期開口進氣充足，屬燃料控制燃燒，可燃物汽化多少就燒多少，燃燒效率高；火勢成長到進氣量不敷所需後轉為通風控制，當量比大於一，燃料過剩而氧氣不足，燃燒效率下降，未燒盡的碳粒與可燃氣體隨熱煙流帶出室外，於是濃煙與一氧化碳同步暴增。\n量化依據是熱釋放率式 Q＝χ×ṁ×ΔHc，其中 ṁ 為燃料質量燃燒速率（kg\u002Fs）、ΔHc 為單位質量燃燒熱（kJ\u002Fkg）、χ 為燃燒效率。完全燃燒時 χ 接近 1，通風不良時 χ 明顯下滑，同一批燃料因此放出較少的熱、留下較多未燃產物。這條式子正是「放熱多代表燒得完全」的推導來源，也是熱釋放率計算題的共同基礎。\n產物面的對照要成組記憶：碳完全氧化得二氧化碳，不完全氧化得一氧化碳；氫則得水蒸氣。一氧化碳與血紅素的親和力遠高於氧，是火場致死的首要因素，而它大量生成這件事本身就宣告了燃燒不完全。焰色是另一組線索：本生燈進氣口全開時空氣預混充分，焰色偏藍且無煙；關小進氣口改為擴散燃燒後，碳粒在焰中白熾發光而呈黃橙色並冒黑煙，這個實驗現象可直接套用到火場判讀。\n延伸考點：通風控制階段累積的未燃可燃氣體，一旦因開門或破窗突然補入空氣而急速燃燒，即為回燃；閃燃則是室內火災由成長期躍升至最盛期的臨界現象，兩者都建立在「氧氣供應改變燃燒完全度」這個主軸上。命題常以放熱量、煙量、一氧化碳濃度、焰色四個指標交叉出題，判準始終只有一個——問的是燒得完全，還是燒不完全。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"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":33,"stem":34,"number":35,"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":37,"stem":38,"number":39,"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":41,"stem":42,"number":43,"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,{"webId":45,"stem":46,"number":47,"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":49,"stem":50,"number":12,"year":51,"session":12},"fire-108-1-fire-science-001","假設火場中只含一種燃料且均勻分布，起火後火勢循 t2 成長理論持續成長，且火災成長常數呈定值。已知起火後第 1 分鐘燒耗燃料 1 公斤，則再經 2 分鐘後，從起火開始起算總共燒耗若干公斤之燃料？",108,[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":71,"stem":72,"number":13},"fire-109-1-fire-science-038",109,"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？",1785129967924]