Air Duct Velocities
Air velocities in ducts and pipes should not exceed certain limits to avoid high pressure loss and unacceptable noise generation. The values below can be used as guidelines for some typical applications.
| Air Ducts | Air Velocity | |
|---|---|---|
| (m/s) | (ft/min) | |
| Combustion air duct | 12 - 20 | 2400 - 4000 |
| Air inlet to boiler room | 1 - 3 | 200 - 600 |
| Warm air for house heating | 0.8 - 1.0 | 150 - 200 |
| Vacuum cleaning pipe | 8 - 15 | 1500 - 3000 |
| Compressed air pipe | 20 - 30 | 4000 - 6000 |
| Ventilation ducts in hospitals | 5 - 8 | 1000 - 1500 |
| Ventilation ducts in office buildings | 7 - 11 | 1200 - 2000 |
Related Topics
• Ventilation Systems
Design of systems for ventilation and air handling - air change rates, ducts and pressure drops, charts and diagrams and more.
Related Documents
Air Ducts - Friction Loss Diagram
A major friction loss diagram for air ducts - Imperial units ranging 10 - 100 000 cfm.
Air Ducts - Friction Loss Diagram
A major friction loss diagram for air ducts - SI units.
Air Ducts - Major Friction Head Loss, Online Calculator
Head loss or major loss in air ducts - equations and online calculator for rectangular and circular ducts - Imperial and SI units.
Air Ducts - Minor Loss Coefficient Diagrams
Minor loss coefficient diagrams for air ductwork, bends, expansions, inlets and outlets - SI units.
Air Ducts - Sizing
Required duct area vs. air flow.
Air Ducts - Velocity Diagram
Air flow volume, duct size, velocity and dynamic pressure.
Duct Sizing - the Equal Friction Method
The equal friction method for sizing air ducts is easy and straightforward to use.
Duct Velocity
Calculate velocities in circular and rectangular ducts - imperial and SI-units - online calculator.
Ducts Sizing - the Velocity Reduction Method
The velocity reduction method can be used when sizing air ducts.
Rectangular Air Ducts - Velocity Diagram
Velocity diagram for rectangular air ducts - metric units.