Wind effects on performance of static smoke exhaust systems: Horizontal ceiling vents

For static smoke exhaust systems, such as horizontal ceiling vents, buoyancy of the smoke layer is the driving force for smoke removal. However, wind effect should also be considered, as the smoke layer interface height can be raised up or pulled down, depending on the conditions. Key equations on calculating the smoke exhaust rates and the required vent area will be reviewed first in this paper. Modifications of those equations with wind effects are discussed. An atrium is taken as an example to study the wind effects under two scenarios: a fire at the atrium floor to give an axisymmetric plume and a fire at a shop adjacent to the atrium to give a balcony spill plume.