Which of the following is a characteristic of dynamic fire dampers?

Dynamic fire dampers are specifically engineered to close in response to smoke or heat, effectively sealing off airflow in the event of a fire. This characteristic is critical for controlling smoke spread and enhancing fire safety within HVAC systems. When the temperature rises to a predetermined level, the damper reacts by shutting, thereby preventing the further movement of smoke and potentially harmful gases through the ductwork. This capability to close against airflow distinguishes dynamic fire dampers from other types, ensuring that they actively respond to fire conditions rather than remain passively closed or only serving to regulate ventilation.

While it is true that some of the other choices may apply to different types of dampers, they do not reflect the operational functions and design of dynamic fire dampers. Understanding this characteristic is vital for HVAC professionals tasked with ensuring safety and compliance in building systems.