An eight-page building simulation paper. The design for the new Federal Building for San Francisco includes an office tower that is to be naturally ventilated. The EnergyPlus thermal simulation program was used to evaluate different ventilations strategies for space cooling and rationalize the design of the facade. The strategies include ventilation driven by different combination s of wind, internal stack and external stack. The simulation results indicate that wind-driven ventilation can maintain adequate comfort even during hot periods.