This spreadsheet can be used to calculate wall effect adjustment factors (WAFs) for rectangular ducts or stacks in accordance with Conditional Test Method (CTM-041) - Determination of Volumetric Gas Flow in Rectangular Ducts or Stacks Tacking into Account Velocity Decay near the Stack or Duct Walls. Return to Rectangular Duct Wall Effects for more information.

• Rectangular Duct WAF Calculation Spreadsheet Instructions (PDF)(2 pp, 85 K)