Double-skin　facade　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.　(C)　2012　The　Authors.　Published　by　Elsevier　Ltd.