Abstract: Using FDS，the paper studies the single-side open, indoor fire with the phenomenon of “fire point offset”, changing the number and location of air outlet parameters in simulation. It analyzed the differences of fire spread development, temperature distribution, flame and smoke distribution and HRR under different ventilation conditions. Based on the fire traces in the investigation, the paper discussed the relationship of air vents of number and location with fire spread development and burning patterns, and discussed the causes of "fire point offset" phenomenon. The results provides references as eliminating interference traces and accurately determining the fire location (point) for fire investigation in similar places.

Key words: ventilation condition, single-side open, indoor fire, ignition point, numerical simulation