Understanding Duct Sizing
Proper duct sizing is crucial for efficient HVAC system operation.
- Air Flow Rate Volume of air moved through the duct per minute (CFM).
- Air Velocity Speed of air movement, affects noise and pressure loss.
- Duct Type Round or rectangular shapes have different flow characteristics.
- Friction Loss Pressure drop due to air resistance in the duct.
Design Considerations
Velocity Limits
Main ducts: 700-900 FPM, Branch ducts: 500-700 FPM
Noise Control
Higher velocities increase noise levels.
Space Constraints
Consider available space for duct installation.
System Balance
Proper sizing ensures even air distribution.
Installation Tips
- Sealing Properly seal all joints to prevent air leakage.
- Support Install hangers at recommended intervals.
- Insulation Insulate ducts in unconditioned spaces.
- Access Provide access panels for maintenance.