細水霧系統應用於一般電器設備火災之滅火效能評估

The Extinguishment Performance of Water Mist System in General Electrical Equipment Fires

李易修(Yi-Xiu Li)

指導教授 ： 何三平

長榮大學/健康科學學院/職業安全與衛生研究所/碩士(2009年)

https://doi.org/10.6833/CJCU.2009.00016

摘要

本研究分為固定式細水霧與移動式細水霧二大部分進行實驗評估，探究各項變化下之滅火效能。利用固定式細水霧系統，進行不同遮蔽情形下之滅火實驗，當火源受尺寸為60公分 × 45公分 × 15.5公分之變電箱，且變電箱下緣與火源容器底部距離為43公分之遮蔽時，細水霧噴灑至油盤受變電箱遮蔽部份時，其細水霧明顯受到阻礙而向外擴散，而未遭受遮蔽之部分，尚能有效透過火源之吸引空氣之效應(entrain air)，將細水霧拖曳(drag)至遭受遮蔽部份下之火源(firebase)，進而將火源撲滅。但當其噴頭架設高度達6公尺時，其滅火效能將顯著下降。
當火源受尺寸為40公分 × 18.5公分之鐵板遮蔽，且鐵板與火源容器底部之間距為43公分之情形下，噴頭架設高度3公尺與4公尺時，其油盤受鐵板遮蔽率達50％以上，即大大降低吸引(entrain)細水霧進入火源之效，導致無法完成滅火。當噴頭架設高度變化至6公尺時，因噴頭與油盤之間距加大後，促使利用噴頭放射之末端較低動量之細水霧，提升藉由吸引(entrain) 細水霧進入火源內之機制，故於油盤受鐵板之遮蔽率為64％時尚能達成滅火。
當火源受尺寸為40公分 × 18.5公分之鐵板遮蔽，且鐵板與火源容器底部之間距為101公分之情形下，噴頭架設高度於3與4公尺時，因遮蔽物高度較高，細水霧受此遮蔽物阻礙而向外噴散，其油盤受鐵板遮蔽率超過50％時，將無法順利滅火。將噴頭高度升高至6公尺後，其滅火效能卻有下降之情況產生，油盤受鐵板遮蔽率超過25％時，將無法順利滅火
移動式細水霧系統應用於尺寸為60公分 × 45公分 × 15.5公分之變電箱時，於低操作壓力之系統下，雖因具有較大出水量，以致擁有較佳之滅火效能，但於火勢尚未撲滅之前就已發生漏電之情事；而改變為高操作壓力之系統時，因霧化效果佳，故無論滅火距離遠近皆於5分鐘內不會發生漏電之情事，但於距離60公分以內或3公尺以後之情況下均致使滅火效能之降低。

關鍵字

細水霧滅火設備 ； 漏電

並列摘要

The fixed water mist system and the mobile water mist system are more popular systems for fire suppression in industry. The larger shelter area with a 60cm*45cm*15.5cm switch box above a 30cm diameter pool fire with 43cm height caused higher challenge for fire suppression, but the fires were all suppressed in every tests with different nozzle discharge pressures and distances from 3 meter to 6 meter height.
The fire was not extinguished with over 50% panel block when a 40cm*18.5cm panel was located 43cm above the fire base and the nozzle was set at 3m or 4m height. The fire was suppressed with over 64% panel block when the nozzle was located at 6m height because lower momentum water mist was entrained into the fire base along with the air entrainment. The similar scenario took place again when the panel was located 101cm above the fire base and the nozzle was set at 3m or 4m height, but the fire only could be suppressed when the nozzle was at 6m height and the fire was blocked less than 25% of the panel above the fire. The water mist was entrained away from the fire base because of the higher panel location with 101cm height.
The lower discharge pressure and higher flow rate system could suppress the fire early but cause circuit short before fire suppression. The smaller droplet water mist system had great fire suppression effect and did not cause circuit short during five minutes fire test.

並列關鍵字

the water mist system ； circuit short

參考文獻

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【12】 HONG-ZENG YOU ,“Investigation of Spray Patterns of Selected Sprinklers with the FMRC Drop Size Measuring. ”