Improved reliability analysis and assessment method of occupant evacuation and its application in building fires

Occupant evacuation is a critical issue in emergency events especially in fire accidents. The safety level of occupant evacuation is assessed using the method of reliability analysis and assessment in this study, which has been increasingly employed to describe parameters uncertainty and reliability probability. First, the concept of reliability probability index is proposed and defined as AEST divided by RSET, which can be adopted to develop the quantitative relationship between the reliability probability index and the reliability probability. Second, the correlation analysis between reliability probability and influencing factors is conducted through a case study. Third, the safety design zone and the dangerous design zone are further divided to provide guidance for engineering designers. Lastly, the sensitivity analysis is conducted to analyze the global sensitivity of the uncertainty parameters of occupant evacuation. The results show that the sensitivity of pre-movement time is the highest among the parameters, reaching 0.419, suggesting that it takes on a critical significance in the calculation of evacuation model, and the method proposed in this study can be well adopted to assess the reliability of occupant evacuation in building fires.