A Dynamic Individual Risk Assessment Method Considering Synergistic Effect Of Fire,Toxicant Leakage&Explosion

In actual chemical industrial parks,once an accident occurs,it often involves fire,toxic substance leakage and explosion.The synergistic effect among these events may cause serious casualties.Individual risk is one of the key indicators to measure the accident consequence.Current research on individual risks mostly focuses on the spatial distribution of individual risk.However,accidents and the escape of people are dynamic processes,which require the evaluation of dynamic individual risk under multi-hazard accident synergistic effect.To address this,a dynamic individual risk assessment method considering multi-hazard spatialtemporal coupling accidents is proposed.Drawing from the human vulnerability model and the scenario that multiple fires occurred sequentially,a dynamic individual risk assessment method considering multi-hazard accident synergistic effect is proposed.First,the probit model is used to estimate the evolution sequence of multiple fires.Next,the Mudan model is used to calculate the dynamic heat radiation distribution.Then,the critical heat radiation dose thresholds of different casualty levels are acquired based on literature data and the human vulnerability model which is applied to evaluate the relationship between heat radiation and the casualty level.The critical casualty time is proposed to reflect the temporal and spatial variations of individual risks.The synergistic effect may decrease an individual’s ability to escape.particularly when considering the relationship between the degree of injury caused by toxic substances and explosions.As a result,a quantitative relationship has been established among an individual’s ability to escape,the dose of toxic substances,and the overpressure of an explosion.Then,based on human vulnerability model,a dynamic individual risk assessment method is established under the spatial-temporal coupling of fire,toxic substance leakage and explosion accidents.The proposed method could be used for the evaluation of several factors in the given accident scenario.These factors include:the variation of different individual casualty level zones over time,the critical casualty time of humans in different positions and at different casualty levels,the heat radiation dose and toxic substance dose accumulation in the process of escape,and the human casualty probability.The concept and calculation method of the critical safe escape distance are proposed.This method serves as a reference for determining the nearest distance individuals should be from the center of a fire source or toxicant leakage source.Furthermore,this method could be used for the analysis of dynamic individual risk as individuals escape along a specific route,making it a valuable tool for selecting the optimal escape route.