Numerical Studies on Effects of Cavity Width on Smoke Spread in Double-skin Facade

Abstract

Double-skin façade is more and more popular in modern buildings in recently years due to it can provide the building with improved thermal and sound insulation compared with a traditional glazed facade. But fire safety is a problem, the inner glass wall broken during a fire would lead to the smoke and flame spread to the adjacent levels, this might be dangerous for the occupants in those areas. Many such projects failed to comply with the fire safety codes at present. Engineering approach similar to performance-based fire codes practicing in some countries was applied to demonstrate the design is safe. Fire hazard assessment should be supported by the further investigations on the smoke and fire spread in DSF. Cavity depth effects, one of the key factors which can influence the smoke flow in DSF would be studied by numerical method in this paper. By examining the results for cavity depth of 0.5, 1.0 and 1.5 m, it is found that a wider cavity might give better fire safety under the scenarios studied. The outer glass panel would be broken rapidly for the cavity of 0.5m deep. a Cavity depth of 1.0 m might be the most risky design comparing with the other two cavity depths studied, the inner glass panel might be broken before the outer panel, this might lead to the fire spread to the adjacent upper levels, high strength glasses should be used or other protection measures should be taken for the DSF design under this condition. Further studied should be required for an in-depth understanding the smoke and fire spread in DSF in the further.