本研究首先以「居室火災致命情境子模式」預測居室火災致命情境屆臨時間，且以「人員避難子模式」估算居室避難所需時間，再結合兩項時間之競合，建立「決定型居室火災人員避難成敗模式」。然後，輔以可靠度為基礎之設計及結構函數概念，建構「隨機型居室火災人員避難成敗模式」，並且界定模式中隨機型參數及其機率分配，運用蒙地卡羅模擬方法，產生參數之隨機亂數值，以估計居室內人員面臨一項或兩項致命情境（一氧化碳濃度達1400 ppm 或一氧化碳血紅蛋白濃度達30 %）導致避難失敗的機率值。模式建構完畢後，本文舉一酒吧場所為例，在容留人數為150 人及200 人等2 種情境下分別實施多次模擬，比較兩項致命情境之危害情形，提出研究結果與建議供消防實務界及後續研究者參考。

A sub-model of untenable situations in room fires was first developed to predict the onset time of untenable situations in this study. Then, a deterministic model of egress safety/failure in room fires was established by integrating the onset time of untenable situations with the required egress time obtained from the sub-model of occupant egress. Based on reliability-based design and structure function, the deterministic model of egress safety/failure in room fires was transformed into ＂the stochastic model of egress safety/failure in room fires＂. Moreover, stochastic parameters and probability distributions of the proposed model were assumed and random numbers of parameters were generated by the Monte Carlo simulation. The failure probabilities of occupant egress due to either one or both of the untenable conditions (when carbon monoxide concentration reaches 1400 ppm or carboxyhemoglobin concentration reaches 30 %) were obtained after simulations. After the model development, a pub is taken as an example to compare both dangerous threats by executing several simulations under 2 situations of 150 occupants and 200 occupants respectively. From the result comparison, some ideas for fire officers and future studies for fire researchers are recommended.