Performance-based　design　used　to　be　applied　to　fire　safety　provisions　in　many　green　building　projects　that　have　difficulties　in　complying　with　prescriptive　fire　codes　in　the　Far　East.　Thermal　fire　models　are　widely　used　for　fire　hazard　assessment.　In　this　paper,　the　thermal　environment　in　a　stage　fire　within　an　underground　auditorium　will　be　studied.　Consequences　of　different　scenarios　were　simulated　by　a　thermal　fire　zone　model.　Objective　of　the　study　is　to　evaluate　whether　requiring　a　shutter　of　4-hour　fire　resistance　period　is　really　necessary.　Variations　of　the　smoke　layer　temperature　and　smoke　layer　interface　height　with　time　would　be　predicted.　Numerical　results　indicated　that　all　the　stage　was　full　of　smoke　after　5　min.　The　upper　layer　temperature　was　higher　than　400°C　even　for　a　6　MW　fire.　Therefore,　it　would　not　be　dangerous　for　the　occupants　staying　at　the　auditorium　for　2　hours.　High　air　temperature　would　be　reached　and　kept　for　a　period　but　shorter　than　2　hours.　Therefore,　a　fire　shutter　of　2-hour　fire　resistance　rating　is　sufficient.　Copyright　©　2009　by　ASME.