R302.12 & R302.12.1

Section R302.12 is titled 'Draftstopping' and covers the requirements for sectioning off areas of a concealed floor-ceiling assembly with an open design. The purpose of this section is to slow the spread of fire, heat, and smoke through a floor/ceiling assembly, which allows additional time for occupants to escape and emergency responders time to perform extinguishing and rescue operations, before failure of the floor. The materials allowed for draftstopping are covered in section R302.12.1 which is titled 'Materials'.

The model shows an open-web truss joist floor-ceiling assembly being constructed. Half inch gypsum board is being installed parallel to the floor joist, approximately splitting the area in half, and creating less than 1000 sq. ft. areas.