Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

• the most efficient way to navigate the Engineering ToolBox!

# Air Ducts - Friction Loss Diagram

Friction loss (head loss) in standard air ducts:

The diagram is based on standard air 0.075 lb/ft3 in clean round galvanized metal ducts.

• 1 inch water = 248.8 N/m2 (Pa)= 0.0361 lb/in2 (psi) = 25.4 kg/m2 = 0.0739 in mercury
• 1 ft3/min (cfm) = 1.7 m3/h = 0.47 l/s
• 1 ft/min = 5.08x10-3 m/s
• 1 inch = 25.4 mm = 2.54 cm = 0.0254 m = 0.08333 ft

### Example - Friction Loss in Air Duct

Friction loss in a 60 inches duct with air flow 100,000 cfm can be estimated to approximately 0.4 inches water per 100 feet duct as shown in the diagram above. Air velocity can be estimated to approximately 5000 feet per minute.

## Related Topics

### • Ventilation

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 - SI units.

### Air Ducts - Friction Loss Diagram

A major friction loss diagram for air ducts - Imperial units ranging 10 - 100 000 cfm.

### Darcy-Weisbach Equation - Major Pressure and Head Loss due to Friction

The Darcy-Weisbach equation can be used to calculate the major pressure and head loss due to friction in ducts, pipes or tubes.

### Energy Equation - Pressure Loss vs. Head Loss

Calculate pressure loss - or head loss - in ducts, pipes or tubes.

## Search Engineering ToolBox

• the most efficient way to navigate the Engineering ToolBox!

## SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!