What devices are used to control the flow of smoke and fire in ducts?

The correct choice highlights the use of smoke and fire dampers as essential devices in managing the flow of smoke and fire in ducts. Smoke and fire dampers are specifically designed to prevent the spread of smoke and flames in the event of a fire. They are installed within ductwork and automatically close to block airflow when temperatures rise, thereby controlling smoke movement and protecting other parts of the building from potential fire hazards.

These dampers serve a critical role in system design by enhancing safety and ensuring compliance with fire codes and regulations. They are a key component of fire protection systems, helping to compartmentalize a building and provide occupants more time to evacuate safely during a fire emergency. This capability to react to dangerous conditions sets them apart from other devices that might be found in mechanical systems.

While fire suppression systems focus on extinguishing flames, air filters are designed mainly for removing particulates from air, and heat exchangers facilitate heat transfer between fluids without mixing them. None of these options directly control the movement of smoke and fire in ductwork the way smoke and fire dampers do.