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# Air Ducts - Friction Loss Diagram

## A major friction loss diagram for air ducts - SI units.

Friction loss in standard air ducts:

• 1 m/s = 196.85 ft/min
• 1 m3/s = 3600 m3/h = 1000 dm3(liter)/s = 35.32 ft3/s = 2118.9 ft3/min = 13200 Imp.gal (UK)/min = 15852 gal (US)/min
• 1 mm H2O = 9.81 Pa = 9.807x10-6 N/mm2 = 0.0987 10-3 bar = 1 kp/m2 = 0.09678 10-3 atm = 1.422 10-3 psi (lbf/in2)

### Example - Air Duct and Friction Loss

As indicated in the diagram above, the friction loss in a 500 mm main duct with air flow 1 m3/s  - in a comfort system with air velocity limited to 5 m/s - can be estimated to 0.55 Pa/m (0.055 mm H2O/m).

## 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 Duct Velocities

Typical air duct velocities in applications like ventilation systems or compressed air systems.
• ### 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 - in imperial units ranging 10 000 - 400 000 cfm.
• ### 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 - Major Friction Loss vs. Temperature and Pressure

The influence of temperature and air pressure on major friction loss.
• ### Air Ducts - Minor Loss Coefficient Diagrams

Minor loss coefficient diagrams for air ductwork, bends, expansions, inlets and outletsĀ  - SI units.
• ### Air Ducts - Sizing

Required duct area vs. air flow.
• ### Circular Ducts - Dimensions

Standard size of circular ventilation air ducts.
• ### 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.
• ### Energy Equation - Pressure Loss vs. Head Loss

Calculate pressure loss - or head loss - in ducts, pipes or tubes.
• ### Equivalent Diameter - Rectangular vs. Circular HVAC Ducts

Rectangular equivalent diameter for air flows between 100 - 50000 cfm.
• ### Equivalent Length vs. Minor Pressure Head Loss in Pipe and Duct Components

Minor pressure and head loss in pipes vs. equivalent length in tubes and duct systems.
• ### Rectangular Air Ducts - Velocity Diagram

Velocity diagram for rectangular air ducts - metric units.

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## Citation

• The Engineering ToolBox (2008). Air Ducts - Friction Loss Diagram. [online] Available at: https://www.engineeringtoolbox.com/air-duct-friction-loss-diagram-d_328.html [Accessed Day Month Year].

Modify the access date according your visit.

7.8.15

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