Solid materials used to prevent or limit the vertical and horizontal spread of fire and the products of combustion in hollow walls or floors, above false ceilings, in penetrations for plumbing or electrical installations, in penetrations of a fire-rated assembly, or in cocklofts and crawl spaces?

• A. Fire Door
• B. Fire Stop
• C. Fire Wall
• D. Cast-in-place Concrete

Answer: (B)

Fire stopping is the use of solid materials to seal openings in hollow walls and floors and in penetrations for plumbing or electrical installations, as well as in false ceilings, fire-rated assemblies, cocklofts, and crawl spaces. The purpose is to prevent or slow the vertical and horizontal spread of fire, smoke, and hot products of combustion through concealed spaces, helping maintain the integrity of fire-rated assemblies. Materials used include cementitious mortars, mineral wool, intumescent wraps, and sealants that expand or harden when exposed to heat. This differs from a fire door, which is a protective barrier that must be operated to stop fire spread; a fire wall, which is a full-height barrier separating buildings or sections; and cast-in-place concrete, which is a structural element with inherent fire resistance but not specifically a fire-stop product for penetrations.