[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-111-1-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-111-1-火災學概要-031","fire-111-1-fire-science-031",111,1,31,"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？",{"A":16,"B":17,"C":18,"D":19},"易造成過負載","使溫度升高絕緣被覆熔解，造成電線短路","易累積灰塵、水分造成積污導電","電線間接觸不良，電流流通時產生局部過熱","B",null,[],false,"本題考點：電氣火災成因中「延長線盤捲綑綁」所對應的起火機制，屬散熱不良導致絕緣劣化的類型。\n【正解理由】延長線的導體本身具有電阻，通電時依焦耳定律持續產生熱量。線材成束綑綁或盤捲時，內圈導線被外圈包覆，熱量無法藉空氣對流散逸而不斷累積，線芯溫度上升；聚氯乙烯等絕緣被覆長時間受熱會軟化、熔解，兩條芯線的被覆一旦熔穿而相互接觸，即形成短路並產生電弧，點燃周圍可燃物。整段機制的關鍵順序是蓄熱、被覆熔解、再短路，故選 B。\n【逐項排除】\n(A) 過負載指使用端電流超過電線的安全容許電流，肇因是同時插接過多電器，與電線是否綑綁無關；綑綁本身並不會使負載電流增加。\n(B) 正確。綑綁使散熱受阻而蓄熱，被覆熔解後芯線相觸短路，正是宣導不得綑綁延長線的真正理由。\n(C) 積污導電發生在插頭刀刃或插座極間，因灰塵與水分附著使絕緣表面碳化形成導電路徑，位置在接點而非線身。\n(D) 接觸不良性局部過熱發生於端子、插接部鬆動或氧化處，屬接續品質問題，與線體盤捲蓄熱是不同機制。\n【記憶點】綑綁等於散熱不良，先熔被覆、後成短路。","電氣火災在火災學概要屬高頻考點，命題方式多為「給一個生活情境、問屬於哪一種起火機制」，因此把典型類型的發生部位與物理過程分開記憶最有效率。第一類短路，係兩極導體直接接觸使電阻趨近於零、瞬間電流極大並伴隨電弧，本題的綑綁延長線即是經由被覆熔解走到這一步。第二類過負載，是負載電流長期超過導線安全電流，全線發熱而非局部，肇因在用電行為而非配置方式。第三類積污導電，發生在插頭兩刀刃之間，灰塵與濕氣形成微小漏電流，反覆碳化後形成導電碳化路徑而終至短路，家具背後長期插著不拔的插頭最為典型。第四類接觸不良，發生在端子或接續點，因鬆動、氧化使接觸電阻變大而局部過熱。第五類半斷線，導線多股芯線部分斷裂，剩餘芯線通過相同電流使電流密度上升而發熱，常見於反覆彎折的電器出線口。\n就物理面而言，導線溫升取決於產熱與散熱的平衡：產熱正比於電流平方乘以電阻，散熱則靠表面對流與輻射。盤捲成束會同時造成兩個不利效果，一是有效散熱表面相對縮小，二是內圈被外圈保溫，等效散熱能力下降，於是同樣的電流可使線溫遠高於平舖時。聚氯乙烯被覆的長期容許溫度僅在攝氏六十至七十度的量級，超過後逐漸軟化、劣化，這也正是延長線標示額定電流時假設平舖使用的原因。\n易混淆對照可從火場鑑識痕跡切入：短路留下局部熔痕，過負載呈現全線被覆均勻劣化，積污導電在插頭極間留下碳化橋，接觸不良的熔損則集中於單一接點。相關考點還有電氣火災與帶電火災的滅火藥劑選擇，以及漏電斷路器與無熔絲開關各自防護的對象不同，前者防漏電、後者防過電流與短路，兩者不可互相取代。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-111-1-fire-science-030","下列對高樓逃生通道設計原則的描述，何者錯誤？",30,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-111-1-fire-science-032","下列何者非油槽火災發生沸溢或濺溢的主要因素？",32,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-111-1-fire-science-029","建築物內部裝潢材料對閃燃時間（F.O.T.）的影響，下列敘述何者錯誤？",29,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-111-1-fire-science-033","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？",33,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-111-1-fire-science-028","通風控制燃燒下，居室內有可燃物 1200 kg，該居室有一開口面積 6 m2，高度 2 m，則火災持續時間約幾分鐘？",28,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-111-1-fire-science-034","下列何者非細水霧滅火系統的特性？",34,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"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":58,"year":59,"stem":60,"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":62,"year":63,"stem":64,"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":66,"year":67,"stem":68,"number":13},"fire-107-1-fire-science-031",107,"下列何者並非造成電氣火災的原因？",{"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？",1785123162120]