Why are penetrations and sleeves required in fire-rated assemblies?

• A. To improve air exchange around openings
• B. To preserve fire resistance around openings by sealing and detailing penetrations
• C. To reduce construction time
• D. To simplify painting around openings

Answer: (B)

Penetrations disrupt the fire-rated barrier, creating paths for flames, heat, and smoke. To keep the rated performance, penetrations are sealed and detailed with sleeves so the fire-resistance continuity is restored around the opening. The sleeve defines the space and provides a proper substrate for firestop materials, which expand or set during a fire to close gaps and insulate against heat transfer. This preserves the wall or floor assembly's rated fire resistance by preventing rapid flame spread and heat transfer through the opening. The goal isn’t improving air exchange, reducing construction time, or simplifying painting; those are not about maintaining fire performance.