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Damper Actuator Torque Calculator
Estimate rectangular damper torque from width, height, and an explicit torque loading per unit area.
Quick start
Enter rectangular damper width and height in inches or millimetres. Review the torque loading against the actual damper data, then select Calculate. The default loading is a conditional teaching example.
Inputs
Result
Enable JavaScript to calculate.
Method & assumptions
Area(ft²) = width(in) × height(in) / 144
Torque(lbf·in) = Area(ft²) × torque loading
Torque(N·m) = Torque(lbf·in) × 0.112984829
Width and height define rectangular face area. Torque loading must represent the actual blade design, seals, pressure / velocity conditions, and linkage. Siemens Table 1 gives an interim very-low-leakage estimate of 7 lbf·in/ft² at approach velocities of 1200 fpm or less. Its very-low-leakage category is less than 5 CFM/ft² at 1 inH₂O static pressure drop. This is a conditional example, not a universal torque requirement or leakage certification.
Reference: Siemens · Damper Actuators Selection and Sizing, Table 1 · Methods, conversion conventions, and source notes
Worked example
24 × 24 inches (609.6 × 609.6 mm) gives 4 ft². At the example 7 lbf·in/ft², estimated torque is 28 lbf·in = 3.1636 N·m.
Frequently asked questions
Why is a torque loading needed?
Equal-area dampers can require different torque because of blade construction, seals, operating conditions, and mechanical arrangement. A width/height-only answer would hide this assumption.
Recommended parts
Product recommendations have not been added. Calculated values are not product endorsements.
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