Effects Of Ascending Fire Fighters On Stair Evacuation In A Multi-story Building

In recent years,building fire safety accidents have been common.Ensuring the safety of people in a fire is a meaningful research topic.In high-rise evacuation,factors such as the staircase structure of the high rise building,the evacuation behavior of people,and the evacuation guidance conditions will all affect the evacuation process and the safety of people's lives.No matter at home or abroad,research on personnel evacuation needs to be further expanded in depth and breadth.Although recently there are many studies about pedestrian evacuation in the staircase,most of them only focus on the unidirectional movement either along the descending or ascending direction,ignoring the bidirectional movement condition.The quantitative characteristics of such movement are rarely known and less paid attention.To investigate such movement pattern quantitatively,we conducted a controlled experiment in a multi-story building within the same stairwell was considered for bi-directional flow.The fire-fighters were getting into the building and the occupants were leaving the building.The effects of conditions have been analyzed both quantitatively and qualitatively.According to the results of this study,the speed of the population with counterflow was 0.5-0.6m/s and the speeds were 0.7 to 0.81m/s without counter-flow.This experiment showed the wing without firefighter counter-flow had a higher speed than the wing with counter-flow.Results of this study also demonstrate that the higher an occupant entered the stairwell the effects of counterflow become more significant Throughout the evacuation process the wing with counter-flow maintained high dense conditions.The speed decreased more sharply with the increase of density when there was counterflow,further indicating the negative impact of counterflow on pedestrian movement.Behavioral patterns such as holding objects,twisting,socializing,non-adaptive behaviors,and interaction with the fire-fighters were determined to have a significant influence on the occupant's performance.It is also seen from the experiment above 50%of the population was holding something in their hands.Due to this the average speed of male was 0.77m/s and that for female were 0.71m/s with counterflow.This shows that male speed always faster than female and difference is greater when there is counterflow.The research results can provide corresponding suggestions for future fire-fighting work and pedestrian evacuation.