Describes tests conducted in an experimental fire tower simulating a typical multi-storey, open floor plan building to investigate various parameters affecting critical air velocities needed to prevent smoke backflow. The parameters investigated were fire temperature, venting of the fire floor with exterior wall vents and an exhaust fan, angle of stair door opening, number of open stair doors and method of air injection for stair pressurisation.

KEYWORDS: Testing, air flow, speed, smoke, smoke ventilation, pressurisation, pressurised stairs, Canada