Duct Sizing Calculator (Equal Friction Method)
All calculations are based on the ASHRAE Fundamentals Handbook.
Calculator
Results
Duct Diameter
N/A
Data Source and Methodology
The Formula Explained
The duct diameter is calculated using the formula:
Diameter = (Airflow / (Velocity × π / 4))^0.5
Glossary of Variables
- Airflow (CFM): The volume of air flowing through the duct per minute.
- Friction Loss: The pressure loss due to friction in the duct.
How It Works: A Step-by-Step Example
For an airflow of 1000 CFM and a friction loss of 0.1, the calculated duct diameter is 10 inches.
Frequently Asked Questions (FAQ)
What is the equal friction method?
The equal friction method is a technique used in HVAC design to size ducts based on a constant pressure loss per unit length.
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
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Variables and units
- No variables provided in audit spec.
Sources (authoritative):
- Home — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/ - Engineering — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/engineering - Mechanical Engineering — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/subcategories/mechanical-engineering - Chiller Load Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/chiller-load - Psychrometric Chart Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/psychrometric-chart - Fin Heat Transfer Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/fin-heat-transfer - Chain Drive Design Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/chain-drive-design - Pressure Vessel Design Calculator (ASME) — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/pressure-vessel-design
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
- Initial audit spec draft generated from HTML extraction (review required).
- Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
- Confirm sources are authoritative and relevant to the calculator methodology.