[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-110-1-fire-science-033":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-033","fire-110-1-fire-science-033",110,1,33,"當一小爆炸發生時，其壓力波將全廠之粉塵揚起，再被隨後而至之燃燒引爆所引起之全廠性爆炸，此現象為何？",{"A":16,"B":17,"C":18,"D":19},"閃燃","複燃","塵爆","二次塵爆","D",null,[],false,"本題考點：二次塵爆的定義，以及與閃燃、複燃、一般塵爆的區辨。\n【正解理由】題幹描述的流程有先後兩段：先發生一次規模較小的爆炸，其壓力波把沉積於地面、樑架、管線與設備上的粉塵吹揚成濃度更高的粉塵雲，隨後而至的火焰再將這片粉塵雲引燃，造成範圍遍及全廠、威力遠大於第一次的爆炸。這種由前一次爆炸誘發、以揚塵為橋梁的接續性爆炸，學理上稱為二次塵爆，故選 D。\n【逐項排除】\n(A) 閃燃指室內火災中受熱面輻射使區劃內可燃物幾乎同時起火，火災由成長期瞬間轉入最盛期的現象，主角是可燃氣體與輻射熱，與揚塵無關。\n(B) 複燃指通風受限空間內火勢因缺氧而衰退、卻積蓄大量未燃氣體，開門或破窗使新鮮空氣突然進入時瞬間劇烈燃燒，關鍵是補進空氣而非揚起粉塵。\n(C) 塵爆為粉塵爆炸的通稱，泛指懸浮粉塵雲被引燃的爆炸，並未包含題幹強調的「由前一次爆炸的壓力波揚塵再引爆」這層先後關係。\n(D) 正確，完全對應題幹的兩階段接續機制，也是粉塵災害整廠連鎖擴大的主因。\n【記憶點】先小爆、再揚塵、後大爆，三步驟連起來就是二次塵爆。","二次塵爆的物理圖像可拆成三個時間尺度。一次爆炸多發生在設備內部(粉碎機、乾燥機、集塵機或輸送管),持續僅數十毫秒；其壓力波以音速在廠房內傳播，速度遠快於火焰，因此壓力波先一步掃過廠區，把積在水平面上的粉塵揚成濃度落在爆炸範圍內的粉塵雲；數十至數百毫秒之後，火焰才抵達這片新形成的粉塵雲並將其引燃。由於此時的燃燒發生在開闊廠房而非小容器內，參與反應的粉塵量可達第一次的數十倍，災情因而遠大於起始爆炸。\n關鍵的量化概念是堆積粉塵厚度：僅約一公釐厚的粉塵層被揚起後，即足以在數公尺高的空間內達到每立方公尺數十公克以上的爆炸下限濃度，這說明為何看似清潔的廠房仍可能發生大規模二次爆炸。學理上討論的抑制手段都圍繞著切斷這條鏈：降低堆積量、以隔離閥或旋轉閥阻斷設備之間的火焰與壓力波傳播、於設備設置洩爆口把壓力導向安全方向，以及在管線上採用抑爆裝置於毫秒內噴入抑制劑。\n另一個放大因素是結構：一次爆炸往往同時破壞設備外殼與隔間，使原本侷限於機具內部的燃燒與整座廠房連通，粉塵雲得以擴散到更大的體積再被引燃。統計上，粉塵爆炸事故的重大傷亡多發生在二次爆炸階段，而非規模有限的起始爆炸。\n名詞對照可一併整理：閃燃是區劃火災由成長期轉最盛期的臨界現象，判準常以上層煙氣溫度約 500 至 600℃、地板輻射熱通量約 20 kW\u002Fm² 為指標；複燃是缺氧環境突然補進空氣後的爆燃；滾燃則是天花板下未燃氣體先行竄燒。三者同屬區劃火災現象，與粉塵爆炸分屬不同章節，卻常在同一題的選項裡互相干擾，判別關鍵在於題幹講的是輻射熱、補進空氣，還是揚起粉塵。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-110-1-fire-science-032","有關爆炸性物質之特性，下列何者正確？",32,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-110-1-fire-science-034","液體變化為氣體之物理現象中，若變化速度至為急速時，因能量在極短的時間內大量放出，即形成爆炸現象，此現象之名稱為何？",34,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-110-1-fire-science-031","有關影響粉塵爆炸的因素，下列何者錯誤？",31,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-110-1-fire-science-035","面對廚房油鍋起火燃燒，下列何項應對動作的風險最大？",35,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-110-1-fire-science-030","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？",30,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-110-1-fire-science-036","為防止靜電發生放電時引火造成火災，請問下列有關靜電災害之防止對策何者錯誤？",36,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-113-1-fire-science-033",113,"對於金屬鈉的敘述，下列何者錯誤？",{"webId":58,"year":59,"stem":60,"number":13},"fire-112-1-fire-science-033",112,"當防火門兩側的壓力差加倍時，其透過門縫所流出的氣體體積流率有何變化？",{"webId":62,"year":63,"stem":64,"number":13},"fire-111-1-fire-science-033",111,"執行危害性化學品災害搶救指導原則（HAZMAT），下列有關區域管制（Zoning）敘述何者錯誤？",{"webId":66,"year":67,"stem":68,"number":13},"fire-109-1-fire-science-033",109,"乙醇之燃燒化學反應式為下列何者？ 9 3",{"webId":70,"year":71,"stem":72,"number":13},"fire-108-1-fire-science-033",108,"電氣火災中，下列何者為積污導電現象？",1785129967138]