Induced-pressure measurements were made in the tower of an eleven-story office building usiInduced-pressure measurements were made in the tower of an eleven-story office building using a fan. The fan was used to depressurize the entire tower as well as a single floor. Sulphur hexafluoride (SF6) tracer gas was used totrace air movements from floor to floor during single-floor depressurization. Average flow coefficients for the tower and for the single floor were estimated from single point measurements. The effect of opening and closing office doors also was determined.