[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-107-1-fire-science-024":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-024","fire-107-1-fire-science-024",107,1,24,"容易著火之燃料具下列何種特性？",{"A":16,"B":17,"C":18,"D":19},"熱傳係數低","密度高","比熱高","接近黑體","A",null,[],false,"本題考點：材料著火難易的支配參數——熱慣性 kρc，其中熱傳導係數愈低者表面升溫愈快、愈易著火。\n【正解理由】固體受熱時能否達到著火溫度，取決於表面吸收的熱能有多少留在表層。著火時間與熱慣性 kρc（熱傳導係數×密度×比熱）成正比，kρc 愈小者表面溫度上升愈快、愈快到達著火點。熱傳導係數低代表熱不易往材料內部逸散，熱量集中在受熱表面，因此容易著火，故選 A。\n【逐項排除】\n(A) 熱傳係數低：熱難以導入內部，表面溫度快速累積至著火溫度，符合易著火的條件。\n(B) 密度高：單位體積可吸熱的質量大，熱慣性隨之提高，升溫慢而不易著火，方向相反。\n(C) 比熱高：使同一材料升高相同溫度所需的熱量增加，同樣拉高熱慣性，著火時間變長。\n(D) 接近黑體：黑體是輻射吸收與放射的理想化描述，吸收率高的同時放射率亦高，並非決定著火難易的支配參數，判斷仍應回到熱慣性。\n【記憶點】kρc 愈小愈易燒；發泡塑膠一點就著，金屬怎麼烤都不燃。","熱慣性 kρc 是固體引燃理論的核心參數。對厚材而言，受定值輻射熱通量 q″ 加熱時，著火時間 t_ig 正比於 kρc(T_ig−T∞)²\u002Fq″²，其中 T_ig 為著火溫度、T∞ 為初始溫度。這個式子同時說明三件事：熱慣性愈小著火愈快、著火溫度愈低著火愈快、外加熱通量加倍則著火時間縮為四分之一。\n把常見材料代進去就很直觀：聚氨酯發泡材與泡棉的 k、ρ 都極小，kρc 只有木材的數十分之一，受熱數秒即可起火，這正是沙發、床墊類製品火災成長極快的原因；木材居中；混凝土、磚石的 kρc 很大，同樣熱通量下表面升溫緩慢；金屬 k 極高，熱一到就被導走，表面根本升不到熱裂解溫度，加上本身不燃，故不會著火。\n厚材與薄材要分開看：薄材（如紙張、窗簾）厚度小到內部溫度可視為均勻，此時著火時間改與 ρcδ（δ 為厚度）成正比，與 k 無關，這是為什麼紙張比同材質的厚木板容易點燃。命題若給厚度資訊，往往就是要考這組區別。\n參數的物理意義各自分開記：k 決定熱往內部跑得多快，ρ 決定同體積要加熱多少質量，c 決定每公斤升高 1K 要多少熱量，三者相乘才是抗拒表面升溫的整體能力，因此密度高、比熱高都會使材料變得難以著火，方向與熱傳導係數低正好相反，這也是本題四個選項的設計邏輯。\n易混淆概念對照：著火溫度（材料本身性質）與熱慣性（升溫難易）是兩個不同維度，兩者都低才最危險；引燃與自燃也要分清，引燃需外部火源、自燃靠內部蓄熱到達自燃溫度。至於輻射吸收特性，表面顏色深、吸收率高確實會吸收較多輻射熱，但同一材料的放射率同步升高、散熱也快，因此在標準題型中仍以熱慣性作為判斷依據。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-107-1-fire-science-023","熱傳導之熱流動方向為何？",23,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-107-1-fire-science-025","下列何者並非複燃（backdraft）發生之原因？",25,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-107-1-fire-science-022","燃燒塔每分鐘需消耗 5.8 kg 之丁烷（C4H10），請估算在 NTP（25℃，1 大氣壓）之條件下，此燃燒塔每小時所需之燃燒理論空氣體積（LV）約為下列何者？",22,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-107-1-fire-science-026","在火勢擴大的過程中，下列那一現象並非成長期的常見特徵？",26,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-107-1-fire-science-021","油罐車在灌裝作業中，其累積電壓為 16 kV（其體積為 20 m3，電容為 1000 pF），試估算此作業所產生靜電能量為多少毫焦耳（mj）？",21,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-107-1-fire-science-027","下列何者並非高科技廠房火災之特性？",27,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-113-1-fire-science-024",113,"木材加熱到引火溫度時，可燃性氣體析出量迅速增加，木材的引火溫度約為多少℃？",{"webId":58,"year":59,"stem":60,"number":13},"fire-112-1-fire-science-024",112,"於空氣中加入氧氣會改變空氣組成，進而影響可燃性氣體的某些燃燒特性，下列何者所受的影響較為明顯？",{"webId":62,"year":63,"stem":64,"number":13},"fire-111-1-fire-science-024",111,"下列何者非影響建築物中煙霧流動與蔓延的主要因素？",{"webId":66,"year":67,"stem":68,"number":13},"fire-110-1-fire-science-024",110,"在充足的能量下，下列何種濃度（vol%）的氫氣（H2）為燃燒界限範圍內？",{"webId":70,"year":71,"stem":72,"number":13},"fire-109-1-fire-science-024",109,"在古蹟及歷史建築物火災風險評估指標中，有關防火因應措施安全評估項目中，不包括下列何項？",1785129967847]