A firestop is a fire protection system made of various components used to seal openings and joints in fire-resistance rated wall and/or floor assemblies. Firestops are designed to restore the fire-resistance ratings of wall and/or floor assemblies by impeding the spread of fire by filling the openings with fire-resistant materials. Unprotected openings in fire separations cancel out the fire-resistance ratings of the fire separations, allowing the spread of fire, usually past the limits of the fire safety plan of a building. They are also used to separate the intersection of concealed spaces such as between wall, floor, and stair cavities.
Firestops do not achieve the fire resistance rating without following all manufacturer's guidelines. For example, a firestopping sealant may require a mineral wool backer and a steel pipe surround.
Firebreak materials are not suitable for use in firestops and will state this on the product.