[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-107-1-fire-science-031":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-031","fire-107-1-fire-science-031",107,1,31,"下列何者並非造成電氣火災的原因？",{"A":16,"B":17,"C":18,"D":19},"短路","斷路","積污導電","半斷線","B",null,[],false,"本題考點：電氣火災的成因分類,重點在辨識哪一種電氣異常會產生足以起火的熱能。\n【正解理由】電氣火災的能量來源,是電流通過異常電阻或異常路徑時產生的焦耳熱與電弧熱,常見型態包括短路、過負載、接觸不良、半斷線、積污導電與漏電。斷路指電路被切斷、電流歸零,既然沒有電流通過就不會有焦耳熱,反而是保護裝置動作後的安全狀態,自然不會是起火原因,故選 B。\n【逐項排除】\n(A) 是原因:短路瞬間電流極大,接點產生高溫電弧與熔珠飛濺,足以引燃被覆與周圍可燃物。\n(B) 非原因:電流中斷即無發熱源,理由如上;考生常與「斷線」「半斷線」字面混淆而誤選。\n(C) 是原因:插頭與插座間長期附著灰塵並吸收濕氣,兩極間產生微小放電使塑膠表面逐步碳化,形成導電路徑後持續電弧而起火。\n(D) 是原因:導線素線部分斷裂後,剩餘導體截面積變小、電阻上升,同樣電流下發熱量倍增,並在反覆彎折處產生間歇電弧。\n【記憶點】會起火的是「電流走不順」,不是「電流走不通」——斷路無電流即無熱。","電氣火災的起火機制可依發熱型態整理成兩大類:一是焦耳熱型,包含過負載、接觸不良與半斷線,共同特徵是電阻異常增大,發熱量正比於電流平方乘電阻,溫度長時間累積後引燃被覆或周圍可燃物;二是電弧型,包含短路、積污導電與部分漏電,特徵是局部瞬間出現數千度高溫,直接點燃絕緣材料並產生熔痕。\n積污導電是本題最值得展開的機制:插座與插頭之間的縫隙長期附著灰塵,吸收空氣中濕氣後在兩極間形成微弱導電通路,反覆微放電使塑膠表面碳化,碳化痕逐漸連成低電阻路徑,最終演變成持續電弧而起火。它的可怕之處在於設備即使未使用、只要插著就可能發生,常見於床頭、電視櫃、神明桌等長期不拔插頭且積塵之處。半斷線則常見於延長線、吹風機與充電線的彎折處,外觀完好而內部素線已斷數股,通電時發熱與間歇電弧同時出現。\n概念對照:短路是相間或相與地之間的低阻抗直接接通,電流暴增;過負載是電流未超過保護裝置動作值卻長期偏高,導線持續升溫;漏電是電流經由非預期路徑流向大地,接地不良時可在接點產生電弧;斷路則是電路開放、電流為零,屬於保護結果而非災因。\n把保護裝置放進來看更清楚:無熔絲開關與保險絲的作用,正是在過負載或短路時主動製造「斷路」,以中斷電流阻止繼續發熱,因此斷路在電氣安全體系裡是結果與對策,不是原因。反過來說,延長線串接、單一插座並用多具高功率電器,使電流長期逼近容許值卻不足以讓保護裝置跳脫,才是過負載型電氣火災最典型的成因。\n延伸考點:火災調查上會以短路痕辨別起火先後——起火前造成的一次痕與受火害後形成的二次痕,金相組織與熔痕形狀不同,是判定電氣是否為起火原因的重要證據;另外電氣火災長年高居建築物火災起火原因前列,也是統計題常出現的素材。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-107-1-fire-science-030","固體燃料火焰延燒最快的方式為下列何者？",30,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-107-1-fire-science-032","下列何者並非防火區劃構件構造之性質？",32,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-107-1-fire-science-029","下列何者並非學校實驗室火災之特性？",29,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-107-1-fire-science-033","燃燒時若生成的熱與散失的熱保持平衡，燃燒溫度保持均勻之燃燒為下列何者？",33,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-107-1-fire-science-028","下列何者並非古蹟火災防護之特性？",28,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-107-1-fire-science-034","建築物火災發生後，若火勢由局部火災擴散至全面火災之短時間現象稱為？",34,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-111-1-fire-science-031",111,"常見消防機關宣導，使用延長線勿將其綑綁，以免引發火災，究其原因為何？",{"webId":58,"year":59,"stem":60,"number":13},"fire-110-1-fire-science-031",110,"有關影響粉塵爆炸的因素，下列何者錯誤？",{"webId":62,"year":63,"stem":64,"number":13},"fire-109-1-fire-science-031",109,"建築物火災在閃燃發生後之全盛期火災的特性，不包括下列何者？",{"webId":66,"year":67,"stem":68,"number":13},"fire-108-1-fire-science-031",108,"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：",{"webId":70,"year":71,"stem":72,"number":13},"fire-106-1-fire-science-031",106,"建築物火災時要防止火勢由外牆的窗戶向上延燒，下列改善措施何者錯誤？",1785123163792]