Mechanical • Hvac Microsoft Excel (.xlsx)

Duct Sizing (Velocity / Friction)

Round and rectangular duct sizing from flow and velocity or friction rate.

What this workbook is

A real, downloadable Microsoft Excel workbook — not a rendered demo. Every sheet is built around a single engineering method: inputs in one place, calculated results and a PASS / WARN / FAIL check sheet, with the method, sources and assumptions recorded next to the numbers. Open it in Excel, Sheets or LibreOffice, change the inputs, and the workbook recalculates.

  • Light cells are user-entered inputs on the Inputs sheet.
  • Dark cells are calculated automatically and are not editable.
  • The method and sources for every calculation are listed below and inside the workbook.

What you enter

  • Air flow
  • Velocity or friction rate
  • Duct aspect

What it calculates

  • Round diameter
  • Rectangular size
  • خ”P estimate

Method

Q = Aآ·V; خ”P = fآ·(L/D)آ·(Vآ²/2g); coefficients user-supplied

Sources

  • [1] ASHRAE Fundamentals duct design (method-level)

Inside the workbook

CoverTitle, scope and revision block
SummaryCore inputs and headline results
InputsYour project values (light cells)
CalculationsStep-by-step working sheet (dark cells)
OutputsReadback of results for reporting
ChecksPASS / WARN / FAIL against stated limits
ReferenceSources for each calculation
Notes & AssumptionsScope, exclusions and stated limits