Stack Gas Velocity Calculator

Keeping Exhaust Velocity in a Safe, Effective Range

Stack exit velocity affects both plume dispersion and pressure loss — too slow and flue gas can wash back down around the stack, too fast and pressure loss and noise both increase unnecessarily.

The Formula

Stack Gas Velocity = Volumetric Flow / Stack Cross-Sectional Area

Worked Example

A stack passing 3 m3/s through a 0.3 m2 cross-section:

Velocity = 3 / 0.3 = 10 m/s

How to Use This Calculator

Enter the Volumetric Flow through the stack.
Enter the Stack Cross-Sectional Area.
Select Calculate to get stack gas velocity.

Related Calculations

Need the flow rate this is based on? See the Flue Gas Flow Calculator, or check the density affecting this flow in the Flue Gas Density Calculator.