Calculate the pressure drop due to friction in a duct run based on duct diameter, airflow, duct length, and internal surface roughness.
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How this calculator works
Pressure drop is calculated using the Darcy-Weisbach equation. The friction factor (f) is derived from the Moody chart based on Reynolds number and relative roughness (ε/D). L is duct length, D is diameter, ρ is air density, and v is velocity.
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