How do I select the right damper actuator torque?

Damper actuator torque selection begins with calculating the required torque in N·m, which is a function of damper face area (m²) multiplied by the total pressure drop across the damper (Pa) and a torque coefficient (typically 0.005–0.01 for opposed-blade dampers). Per ASHRAE Handbook HVAC Systems and Equipment, you must also account for blade type (parallel vs. opposed), seal friction, and safety factors of 1.2–1.5. For rectangular dampers over 1 m², Belimo's selection software recommends minimum 10 N·m actuators, while Honeywell MS系列 actuators are commonly sized using 6 N·m per square meter as a conservative rule of thumb. Always verify the actuator's rated torque at the maximum differential pressure the damper will see during close-off conditions.