What is Firestopping?

Firestopping is the containment of fire or smoke through rated assemblies by the application of tested fire rated assemblies. There are four primary types of openings or joints associated with fire and smoke resistive rated assemblies, to which tested firestopping systems may be applied to prevent the spread of fire, smoke or gases:

Joints - Joints between fire-rated construction    components (e.g. wall to wall, wall to floor, wall to    ceiling).
Floor Perimeters - Slab edge / exterior wall cavity
Penetrations - Openings containing mechanical,    electrical, structural, security, communication,
   piping or wiring .
Electrical Outlet Box Protection - Fire-Rated Putty    Pads applied to electrical boxes where required by    code.
Electrical boxes whose combined openings exceed    100 square inches in 100 sqaure feet of wall.
Electrical boxes on opposites sides of a wall    separated by a horizontal distance of less than 24    inches within the same stud cavity.