[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-108-1-fire-science-030":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-030","fire-108-1-fire-science-030",108,1,30,"下列何種措施，可以防止由大樓窗口噴出的火焰向上層延燒？",{"A":16,"B":17,"C":18,"D":19},"加大窗戶面積以提升對流","降低窗戶高度，增加寬度，修改窗戶為橫型窗戶","採用定溫型火警探測器","增加上下層窗戶間的側壁高度","D",null,[],false,"本題考點：窗口噴出火焰造成上下層延燒的機制，以及以側壁（腰壁）高度阻絕的原理。\n【正解理由】室內火災進入通風控制階段後，未燃的高溫可燃氣體會自窗口噴出，在外牆面獲得空氣續燒形成噴出火焰，藉輻射與直接接觸引燃上層開口。上下層窗戶之間的外牆（側壁、腰壁）愈高，火焰上竄至上層開口的行程愈長，沿途捲入空氣冷卻，火焰溫度與輻射熱明顯衰減，上層玻璃破裂並引燃的機會隨之降低，故選 D。\n【逐項排除】\n(A) 加大窗戶面積會提高開口因子與進氣量，室內熱釋放率與噴出火流規模同步增加，反而加速向上層延燒。\n(B) 改為低矮寬扁的橫型窗時，噴出火焰兩側不易捲入空氣，會緊貼外牆向上竄升，比縱長型窗口更容易延燒到上層。\n(C) 定溫式探測器的功能是感知溫度並發出警報，屬偵知與通報手段，對已噴出窗外的火焰沒有阻絕作用。\n(D) 增加上下層窗戶間的側壁高度，可拉長火焰行程並阻隔輻射熱，是抑制上下層延燒的有效構造對策，為正解。\n【記憶點】要擋上層延燒靠「腰壁夠高」，把噴出火焰與上層開口的距離拉開。","窗口噴出火焰是通風控制燃燒的必然結果：當室內火災進入最盛期，開口供氣量不足以支持全部可燃氣體在室內燃燒，未燃的高溫裂解氣體被推出窗外，在外牆面獲得空氣後續燒，形成沿外牆上竄的噴出火流。其規模與開口因子 A√H（A 為開口面積、H 為開口高度）密切相關：開口愈大、進氣愈多，室內熱釋放率與噴出火焰長度都隨之增加，這也是 (A) 錯誤的理論依據。\n橫井（Yokoi）的經典研究指出窗形的關鍵影響：縱長型（高而窄）窗口噴出的火焰，兩側捲入空氣充分，火流軸線會離開牆面向外偏，對上層的直接加熱較輕；橫長型（寬而矮）窗口噴出的火焰不易捲入空氣，會緊貼外牆爬升，對上層窗口的輻射與接觸加熱最嚴重。把窗戶改成橫型不但無助於防止延燒，反而是最不利的形式。\n阻絕上下層延燒的構造對策，依原理可分三類：一是加大上下窗之間的側壁（腰壁）高度，把火焰與上層開口的距離拉開，一般以 90 公分以上為常見基準；二是設置水平突出的雨庇、陽台或遮煙板，把貼壁火流推離牆面；三是開口部與外牆採用具防火時效的構材與防火窗，並避免可燃外裝與可燃保溫材。\n延伸考點：上層延燒的路徑不只窗口噴出火焰，還包括外牆帷幕與樓板間隙的層間塞不良、可燃外裝材的表面延燒，以及管道間、電梯道的煙囪效應；而閃燃後由燃料控制轉為通風控制、開口因子與燃燒速度的關係，也常與本題型合併命題。\n數量上也有可記的規律：噴出火焰的高度隨開口因子增大而增加，且水平突出物與垂直腰壁具有替代性——設置一定深度的雨庇可等效減少所需的腰壁高度，因為兩者都在做同一件事：延長火焰到達上層開口的路徑並遮斷輻射熱。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-108-1-fire-science-029","煙霧的流動為由高壓處往低壓處流，因此加壓造成壓力差可以有效控制煙霧流動。若於一安全梯間流入體積流率為 Q(m3\u002Fs)的空氣，形成 P 的壓力差，現欲將壓力差提高到 2P，則流入的空氣體積流率應為多少？",29,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-108-1-fire-science-031","假設建築物外部風速為 V 時，其迎風面的風壓為 P，當風速提高為 2V 時，建築物所受風壓變為：",31,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-108-1-fire-science-028","火場中煙霧的成分複雜且多具毒性，火災時若吸入下列何種氣體，會妨礙細胞中氧化酵素之活性，造成細胞呼吸停止？",28,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-108-1-fire-science-032","下列有關防止靜電災害的方法中，何者錯誤？",32,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-108-1-fire-science-027","有關粉塵的最小發火能量，下列敘述何者正確？",27,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-108-1-fire-science-033","電氣火災中，下列何者為積污導電現象？",33,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-111-1-fire-science-030",111,"下列對高樓逃生通道設計原則的描述，何者錯誤？",{"webId":58,"year":59,"stem":60,"number":13},"fire-110-1-fire-science-030",110,"某建築物火場產生大量煙霧，正向煙囪效應在中性帶以上 10 公尺處的壓力差為 12 Pa，若建築物內、外的溫度差不變，請問中性帶以上 20 公尺處的壓力差為何？",{"webId":62,"year":63,"stem":64,"number":13},"fire-109-1-fire-science-030",109,"海龍替代滅火藥劑中，下列何者在大氣之滯留時間最久？",{"webId":66,"year":67,"stem":68,"number":13},"fire-107-1-fire-science-030",107,"固體燃料火焰延燒最快的方式為下列何者？",{"webId":70,"year":71,"stem":72,"number":13},"fire-106-1-fire-science-030",106,"依照 McCaffrey 火羽流理論，下列何者正確？",1785123163336]