The present work has employed the Fire Dynamics Simulator "FDS – PyroSim program" to analyze the
computational design, the spread of fire and distribution of particles. The FDS is used in modeling the present
standard hanger building, through studying the effectiveness of using different ratios of Nitrogen gas flow rate
injection compared with water mist flow rate amount at various water mist particles size and different fire source
positions such as center and corner on fire extinguishing time, that shows a pronounced optimum ratio results of 1:1.
The results showed that time of fire suppression is decreasing with decreasing the droplet size and increasing the
water mist flow rate. The best mixing ratio of Nitrogen gas with water mist is found to be 1.1 for minimum
suppression time 175 second .and the total optimum Nitrogen flow rate is 60 l/min and the diameter of the water
droplet is 50 μm; and of total flow rate 60 l/min. The FDS is also used for the smoke flow modeling in different
ventilation conditions, tunnel fires and multi-floors buildings.