Studies were conducted on exterior wall venting in the context of the building pressurization approach to smoke control. It was shown that the venting rate depends on the amount of building pressurization, vent area and the leakage area of the floor enclosure. Tests on "two multi-story buildings indicated that a vent area equal to one percent of the total exterior wall area of the vented floor approximated the maximum venting rate. At this rate, the favorable pressure differences across the fire floor enclosure are at their highest values and are just a little less than one-half of the building pressurization with no venting. Tests also indicated that wind is unlikely to seriously affect the venting performance except for the case with the wall vents opened only on the windward wall.