What is the correct role of dampers in air-side economizer systems?

• A. They adjust only the position of dampers.
• B. They help in selecting and sizing dampers based on characteristics and pressure drop.
• C. They provide filtration for outdoor air.
• D. They determine the color of dampers.

Answer: (B)

Dampers in an air-side economizer are chosen and sized based on how much outdoor air they can pass and the pressure drop they create, so the system can achieve the desired outdoor-air fraction without wasting energy. The damper’s characteristics—such as leakage, blade and frame design, and the resulting pressure loss at the required airflow—directly affect both ventilation and fan energy. If the damper is too restrictive, the fan must work harder, increasing energy use; if it’s too open or undersized, you may not deliver enough outdoor air or you may fail to meet economizer control needs. Proper selection and sizing ensure the economizer can modulate accurately across operating conditions, balancing IAQ and energy savings. Dampers don’t provide filtration and aren’t about color and positioning alone—their physical and performance characteristics determine the system’s ventilation control and efficiency.