Risk Potemtial Analysis and Assessment for Local Area Toxic Substances Disasters

[[abstract]]環保署為管理毒化物災賣預防與應變工作，讓救災支援體系及民間機構深入瞭解本身潛在危險狀況，故擬發展地區毒災害潛勢，以分析與評估災害可能發生位置與風險，以事前洞悉掌握有助於以降低危害影響。本計畫即針對毒災害潛勢分析，於九十六年十二月十三日提出期末報告，完成下列工作項目： 完成台南縣地區背景資料蒐集，規劃建置相關資料表格與圖資，如災因分析、近年災害事故案例列表、分析災害特性以設定地區災害境況模擬…等。評估PHAST與ALOHA擴散模式適用性，由於ALOHA軟體符合地區潛勢應以保守為宜之要點，且在價格上、內件資料庫數量及操作上，皆能符合本計畫需求，故本計畫以ALOHA軟體為潛勢分析之模擬程式。改良以往毒性化學物質災害潛勢分析方法，過去研究僅考慮毒化物災害洩漏型態，本計畫再增加火災與爆炸災害類型，以完整呈現毒性化學物質災害潛勢風險。並綜合分析考慮洩漏、火災與爆炸三種型態，與考慮三者中最大者互相比較，前者較能顯現風險之差異。風險定義取「危害半徑平方×人口密度×頻率」比選擇「危害半徑×頻率」更能彰顯社區危害的潛勢風險值加乘權重後顯示科學園區之風險降低，但傳統工場風險未改變。故建議災害潛勢模擬評估1.潛勢風險值取「火災+爆炸+洩漏」2.風險定義=危害半徑平方×人口密度×頻率3.加成權重分析由台南縣五百多家場廠中完成篩選分析，挑選出１1０家毒化物運作廠，且與未篩選前結果做比較，可知依據本計劃篩選流程得出之篩選場家具有代表性，且能大幅減少潛勢圖之繪製時間。應用潛勢風險分析結果，將高風險區之避難場所篩除，製作台南縣地區避難場所點位圖，決策單位可依據此圖，進行減災整備預防措施。[[abstract]]EPA is in-charge of the prevention and response of toxic chemical disasters. In order to better understand the potential risk, it is required to develop methodologies for analyzing the risk potential to evaluate the possible location and risk associated with the use of toxic chemicals. The results can be used to minimize the possible consequence for toxic incidents. This project focuses on the development of methodologies for analyzing the risk potentials of toxic chemicals. In this project, the following work items have been carried out and completed: Complete the collection of background information for Tainan County and summarize in graph and table. The results will be used in risk potential analysis. Evaluate the suitability for PHAST and ALOHA dispersion models. The ALOHA dispersion model is conservative in results, free to use, ease to operate, and is thus choose as the dispersion model to be used in this project. Improve the methodologies for risk potential analysis. The existing method considers only the effects of toxic release. The effects of fire and explosion are added. It is found that adding the three effects are better in showing the risk potential than choosing the largest effects. The risk is better defined as: “square of hazardous radius × population density × incident frequency” in showing the risk potential than defined as “hazardous radius × incident frequency” Risk value after weighting of facility response capability showed that Science Park has a lower risk but the risk in traditional operating facilities remains the same. Thus, the final conclusions for defining the risk is: 1. Summing the risk from release, fire and explosion, 2. define risk value as “square of hazardous radius × population density × incident frequency”, 3. Weighting of facility response capability should be used. Propose a selection criterion for choosing 110 operating facilities from a total of 500+ facilities. The resulting risk potential map is compared with the raw potential map and showed small discrepancy. The selection criterion will largely reduce the time required for preparing the risk potential map. The results of risk potential is used to prepare a map for evacuation refugee. The map can be used in planning evacuation in case of a major disaster occurred.[[note]]96A19