In the three-sided approach to wind and exposure for vertical ventilation, which factors are considered?

• A. Wind direction, backdraft risk, exposure to adjacent structures
• B. Roof pitch, gas presence, crew location
• C. Interior temperature, smoke color, time of day
• D. Ladder length, anchor points, tool selection

Answer: (A)

In the three-sided approach to wind and exposure for vertical ventilation, the impact of wind and the safety of surrounding areas are evaluated in three ways: wind direction, backdraft risk, and exposure to adjacent structures. Wind direction tells you which way the exhaust plume will move and how heat, smoke, and flames will travel, so you place and size the vent to steer those products upward and away from occupants while minimizing pushing fire toward exposures. Backdraft risk is about the potential for a sudden, dangerous ignition when air is introduced into a fuel-rich, oxygen-poor environment; if backdraft is likely, you use controlled, staged openings instead of a single large vent to avoid a violent event. Exposure considerations focus on nearby buildings or hazards; you choose vent locations and exhaust paths that prevent smoke, heat, or embers from extending the fire to exposures or causing harm to neighboring structures. The other factors listed don’t directly address how wind, backdraft potential, and nearby exposures interact during vertical ventilation.