Firestop

A firestop is a fire protection system made of various components used to seal openings and joints in fire-resistance rated wall or floor assemblies. For penetrating cables, these can also be called as Multi Cable Transits (MCTs). Firestops are designed to restore the continuous fire-resistance of wall or floor assemblies, impeding the spread of fire by filling the openings in them with fire-resistant materials.

A firestop is a fire protection system made of various components used to seal openings and joints in fire-resistance rated wall or floor assemblies. Firestops are designed to restore the fire-resistance of wall or floor assemblies, 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.

There are a number of openings with which firestoppage is concerned.

Fire test of mortar based firestop

Mechanical pipe with metallic piping through-penetrations in a 2-hour concrete floor slab

Inadequate attempt at firestop using rockwool alone

Typical construction drawing of a firestop

Firestop mortar seal of an electrical cable tray

Firestop components include intumescents, cementitious mortars, silicone, firestop pillows, mineral fibers, and rubber compounds.

...
Wikipedia