Where should ducts be led to minimize fire hazard?

• A. Into the building’s central utility shaft
• B. Into a crawl space
• C. Exterior of the building
• D. Into the attic

Answer: (C)

When thinking about fire safety, vents and ducts should be kept out of interior concealed spaces so they don’t become channels for flames, heat, or smoke. Routing ducts to the exterior prevents the ductwork from acting like a tunnel that carries fire between rooms and floors. If ducts run into an attic, crawl space, or a central vertical shaft, a fire can rapidly travel through that hidden path, spreading heat and smoke with little resistance. Releasing or drawing air directly to the outside reduces the interior fire’s access to oxygen through ducts and limits the spread of smoke into occupied areas. In short, venting to the exterior helps contain the fire and keeps the inside safer while limiting how quickly it can move through the building.