University of Virginia Library

Sec. 494(28). Fire stops.

At each floor level in all buildings hereafter erected, all stud
walls, partitions, furring and spaces between joists where they
rest on division walls or partitions, shall be fire-stopped with incombustible
material in a manner to completely cut off communication
by fire through concealed spaces. Such fire-stopping shall
extend the full depth of the joists, and at least four (4) inches
above each floor level. Stair carriages shall be fire-stopped at
least once in the middle partition of each run.