What is the function of fire stopping in wall and floor assemblies?

• A. To prevent flame and smoke from traveling through concealed spaces
• B. To improve acoustic isolation
• C. To reduce electrical hazards
• D. To increase heat conduction

Answer: (A)

Preventing the spread of flame and smoke through concealed spaces is the function of fire stopping. In walls and floors, there are cavities and gaps around structural members and around penetrations for pipes, cables, and ducts. If these gaps are left open, fire and hot gases can travel quickly between rooms and climb between floors, bypassing the fire-rated portions of the assembly. Fire stopping fills and seals these gaps with materials that are rated to resist fire for a set period, helping to maintain the assembly’s fire resistance, slow the spread of fire, and limit smoke movement. This provides time for occupants to escape and for responders to act. While fire stopping can have secondary benefits, its primary purpose is to preserve compartmental integrity, not to improve acoustics, reduce electrical hazards, or increase heat conduction.