assemblies; fire resistance performance of lightweight wood frame unrestrained floor assemblies; type X gypsum board ceiling finishes; full-scale load-bearing wood joist floor assemblies; effects of gypsum board screws spacing from board edges; parameters and results; exposed to heat in a propane-fired horizontal furnace; CAN/ULC-S101-M89 Standard; effect of number of sub-floor layers; effect of superimposed load magnitude