[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-110-1-fire-science-013":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-110-1-火災學概要-013","fire-110-1-fire-science-013",110,1,13,"有一開口面積為 10.0 m2，開口高度為 1.44 m 之居室，當其發生火災而形成通風控制燃燒時，根據 P. H. Thomas 之研究結果，則燃燒速度為多少 kg\u002Fmin？",{"A":16,"B":17,"C":18,"D":19},"R=25.0 ~ 27.3","R=39.6 ~ 43.2","R=66.0 ~ 72.0","R=79.2 ~ 86.4","C",null,[],false,"本題考點：P. H. Thomas 通風控制燃燒速度經驗式與通風因子 A√H。\n【正解理由】通風控制時，燃燒速度受限於開口供氣量，Thomas 由實驗歸納出 R = (5.5 ~ 6.0)·A·√H，R 單位 kg\u002Fmin、A 為開口面積 m²、H 為開口高度 m。代入 A = 10.0 m²、H = 1.44 m 得 66.0 至 72.0 kg\u002Fmin，故選 C。\n【逐項排除】\n(A) 25.0 ~ 27.3 kg\u002Fmin 對應係數 2.1 ~ 2.3，遠低於本式。\n(B) 39.6 ~ 43.2 kg\u002Fmin 對應係數 3.3 ~ 3.6，等於誤取六成。\n(C) 66.0 ~ 72.0 kg\u002Fmin 恰為 5.5 至 6.0 乘上通風因子 12.0 m^2.5，正確。\n(D) 79.2 ~ 86.4 kg\u002Fmin 對應係數 6.6 ~ 7.2，取值偏高。\n【演算步驟】\n公式：R = (5.5 ~ 6.0) × A × √H\n√H = √1.44 m = 1.2 m^0.5\nA√H = 10.0 m² × 1.2 m^0.5 = 12.0 m^2.5\n下限：R = 5.5 × 12.0 = 66.0 kg\u002Fmin\n上限：R = 6.0 × 12.0 = 72.0 kg\u002Fmin\n結果：R = 66.0 ~ 72.0 kg\u002Fmin\n【記憶點】先算 A√H，再乘 5.5 至 6.0。","Thomas 這條式子並非憑空而來，可由質量守恆推導。室內火災進入通風控制後，冷空氣自開口下半部流入、熱煙自上半部流出，中性帶高度與內外密度差決定流速；把柏努利式沿開口高度積分並取典型火場溫度，可得空氣流入質量流率約 ṁ_air ≈ 0.5·A√H（kg\u002Fs），換算為每分鐘即 30·A√H（kg\u002Fmin）。木材類可燃物完全燃燒的理論空氣量約 5.3 至 5.5 kg 空氣\u002Fkg 燃料，以流入空氣量除以此值，即得 R ≈ 5.5 至 6.0 A√H（kg\u002Fmin），係數的區間正反映燃料種類與燃燒效率的差異。\n式中的 A√H 稱為通風因子，單位為 m^2.5，是室內火災學最核心的參數。它同時決定三件事：通風控制下的燃燒速度、閃燃所需熱釋放率中的空氣加熱項，以及火災持續時間。火載量 W（kg）除以燃燒速度 R 即得約略延燒時間 t = W\u002FR，這是本式最常見的延伸考法。\n單位換算與代入的陷阱有三個。其一，H 指開口本身的高度，不是天花板高度或樓層高度；其二，開口若有數個，A√H 須逐一計算後相加，不可先加面積再開方；其三，本式的 R 單位是 kg\u002Fmin，若題目要求 kg\u002Fs 須再除以 60。\n燃料控制與通風控制的分界也是必考對照：火災初期室內空氣充足，燃燒速度由燃料表面積與熱裂解速率決定，稱燃料控制；當開口供氣不足以支應燃料所能釋放的可燃氣體時，即轉為通風控制，此時擴大開口會使燃燒速度上升、火勢更猛，而縮小開口則使未燃氣體累積，形成回燃的前提。理解這層因果，才不會把「開窗排煙」與「開窗助燃」的考點答反。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-110-1-fire-science-012","根據 NFPA265 對閃燃現象（flashover）之定義，下列敘述何者錯誤？",12,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-110-1-fire-science-014","自然發火性物質中的原棉，主要是因為下列何種熱之蓄積而發火？",14,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-110-1-fire-science-011","輻射熱是造成木造建築物延燒原因之一，下列何者正確？",11,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-110-1-fire-science-015","下列有關液化天然氣（LNG）與液化石油氣（LPG）之比較，何者正確？",15,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-110-1-fire-science-010","甲基乙基酮過氧化物（MEKPO）常用於聚合物的生產，加熱至 100 ℃時會發生爆炸，此化合物屬於那一類公共危險物品？",10,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-110-1-fire-science-016","市面上販售的 ABC 乾粉滅火器內充填的乾粉滅火藥劑主要成分為：",16,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-111-1-fire-science-013",111,"高層建築物火災特性下列何者錯誤？",{"webId":58,"year":59,"stem":60,"number":13},"fire-109-1-fire-science-013",109,"下列的滅火設備，何者屬於窒息法滅火原理？",{"webId":62,"year":63,"stem":64,"number":13},"fire-108-1-fire-science-013",108,"比較室內火災閃燃（Flashover）與複燃（Backdraft），下列敘述何者正確？",{"webId":66,"year":67,"stem":68,"number":13},"fire-107-1-fire-science-013",107,"假設大氣中氧氣容積為 21%，現在一密閉空間（體積為 V）內，有三分之一體積（V\u002F3）為惰性氣體時（壓力仍為一大氣壓），該空間內氧氣濃度為多少%？",{"webId":70,"year":71,"stem":72,"number":13},"fire-106-1-fire-science-013",106,"氣體本身受到壓縮，增高溫度時，亦可發火，此稱為：",1785123162354]