某半導體公司極早期偵煙系統效能評估案例探討

Abstract

為減少半導體火災的損失，在廠房中裝設適當的消防安全設備是必要的，在無塵室廠房中受限於場所的特殊性，大多會以設置極早期偵煙系統VESDA(very early smoke detection apparatus)來達到安全防護之目的。本研究將探討廠內既有VESDA系統設置狀況，並透過無塵室內之煙霧模擬測試以了解現場氣流及煙霧流動路徑，廠區規劃變更時則對於VESDA系統在採樣管佈置、煙霧捕集效率等的影響，並藉由VESDA系統煙霧模擬測試來評估廠內現階段VESDA系統設置之有效性，及應用失效模式與效應分析(FMEA)手段來對於使用階段中的VESDA系統進行潛在性的風險評估，以找出可能造成系統重大影響之失效要因，並進行適當地處理。本研究發現無塵室現場氣流及回風條件、高架地板之蜂巢板佈置率、VESDA系統內的Laser chamber及抽氣風扇等設備原件，甚至是機台本身之發熱量及機台本體均會影響現場VESDA系統之捕集效率，在VESDA佈置及使用時均應特別注意。

In order to reduce the loss due to fire in the semiconductor fab, it is critical that an appropriate fire-fighting equipment has to be installed within the plants. Most of the clean rooms use very early smoke detection apparatus (VESDA) to achieve the safety protection objective as the space is very limited. This study investigated the installation status of the existing VESDA system within the plant to understand the air flow and smoke flow path via the simulation test of VESDA at the clean room. When the equipment deployment changes were made in the fab, the impact on the deployment of sampling pipeline and the smoke collection efficiency etc. was also investigated. Through the smoke simulation test of the VESDA, the effectiveness of the current VESDA system in the plant was examined. The failure mode and effect analysis (FMEA) was then used to assess the potential risk of the VESDA system in the operation stage to find out the causes of the major failure and adopt proper measure to tackle with the problems. As a result of this study, it was found that the air flow field and the return air flow conditions, the percentage of the honeycomb plate on the elevated floor, the laser chamber and the ventilation fans in the VESDA, even the heat generation and proper of the lab equipments would affect the collection efficiency of VESDA system in the fab, which all deserve attention in the deployment and use of the VESDA system.