The impact of the number of open doorways on operational efficiency of system for exhausting smoke from structures during a fire

Purpose. When determining the flow rate of smoke exhaust system, only the air entrainment into the convection column of a fire seat is considered, accounting for the thermal properties of fire load. Such factors as smoke generation capacity of burning materials, the size and the number of smoke intake devices, the distance from a fire seat to a smoke intake device, the number of open doorways in a structure of a fire seat, etc., can influence smoke generation, spread, and removal processes. This study aims to verify the hypothesis about the impact of open doorways on heat and gas exchange in a structure with a fire seat and the operational efficiency of smoke exhaust ventilation system. Methods. The authors of the article have implemented an experimental and theoretical approach to assessing the impact of open doorways on heat and gas exchange in a structure with a fire seat and the operational efficiency of smoke exhaust ventilation system. Findings. The results of the numerical experiments obtained in the article confirm the hypothesis about the impact of open doorways on heat and gas exchange in the structure with a fire seat and the operational efficiency of smoke exhaust ventilation system. Research application field. The obtained results should be applied to correct the current methods of calculating smoke control parameters. Conclusions. With increasing the number of the open doorways, the smoke in the structure decreases. Smoke layer stratification occurs at a lower height in relation to the calculated value, which indicates insufficient efficiency of smoke control systems. To model the worst-case scenario of the exhaust smoke ventilation systems operation in structures, it is necessary to work out “real” scenarios for doorways state, taking into account their opening during evacuation of people and closing with appropriate devices.