Duct Sizing Calculator (Equal Friction Method)
Calculate duct sizing using the equal friction method. Designed for HVAC engineers and professionals.
Full original guide (expanded)
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)
\[','\]
','
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.
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)
\[','\]
','
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.
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)
\[','\]
','
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.