435.8.7 Floor Separation
Group R-3.1 occupancies with non-ambulatory clients housed above the first floor shall be provided with a non-fire resistance constructed floor separation at stairs which will prevent smoke migration between floors. Such floor separation shall have equivalent construction of 0.5 inch (12.7 mm) gypsum wallboard on one side of wall framing.
Doors within such floor separations shall be tight fitting solid wood at least 13/8 inches (35 mm) in thickness. Door glazing shall not exceed 1296 square inches (32 918 mm2) with no dimension greater than 54 inches (1372 mm). Such doors shall be positive latching, smoke gasketed and shall be automatic-closing by smoke detection.