Fire Stop Systems Brochure SA727 - USG Corporation

While electrical, plumbing and mechanical systems are a necessity in
building construction, it is often necessary to pass these systems through
hourly fire-resistive floor or wall assemblies. Typically, openings are
cut or drilled through the floor or wall, and then the penetrating items
are installed.
However, this leaves an opening, or annular space, through which
fire can spread. Firestop materials are installed within the openings and
around the penetrants to prevent the passage of flames and hot gases
through an otherwise fire-resistive assembly.
Fire Spread Prevention