Numerical simulations on airflow to the double-skin façade cavity by an adjacent room fire

The architectural feature of double-skin façades has been proposed in green or sustainable buildings. However, there are potential fire risks and so the design was normally not accepted by the authorities having jurisdictions. The scenario of trapping heat and smoke in the façade cavity is identified as hazardous and should be better understood. Hot smoke flowing out of openings driven by an adjacent room fire to the double-skin façade cavity was simulated using computational fluid dynamics (CFD). A five-level building model was taken as an example. A fire occurred in a room at the third level under two different heat release rates of 1 MW and 5 MW, and cavity depths of 0.5 m, 1 m and 2 m were considered. Based on the simulation results, three stages of flame spreading from the room fire to the adjacent façade cavity were proposed in fire hazard assessment for this architectural feature. Results suggested that wider cavity depths would be more dangerous, having a greater chance to break the adjacent upper interior glass panes. Smoke or even flames can then spread to the upper levels. Copyright © 2010 by ASME.