Fitting Database Excel _hot_ — Ashrae Duct

Ensure your sheet calculates velocity pressure based on standard air (

If you are currently building a custom design sheet, let me know:

The Excel file is organized into multiple sheets, generally including:

For example, fitting represents a S upply, R ectangular, Type 3 (Elbow), design number 5 . Each unique fitting code maps to an empirical formula or data table used to compute the dynamic loss coefficient ( Dynamic Loss vs. Friction Loss ashrae duct fitting database excel

: Manually or via exported reports, input these pressure loss values into an External Static Pressure (ESP) Calculation Sheet Sum Total ESP

Many users want to take the vetted loss coefficients from the DFDB and use them directly within their Excel models. The full DFDB includes features to bridge this gap:

The database contains loss coefficients ($C$-values) for hundreds of specific fittings—from round elbows to rectangular transitions, fire dampers, and junctions. The core formula it relies on is: Ensure your sheet calculates velocity pressure based on

You can create custom calculators tailored to your specific project needs.

Professional practice in the HVAC industry spans both I‑P and SI unit systems. The ASHRAE DFDB supports both, and your Excel tool should as well. Build your spreadsheets to accept inputs in either system, perform conversions internally, and display results in the user’s preferred units. This flexibility is essential for international projects and collaboration across borders.

Disclaimer: Ensure you are using the most current version of the ASHRAE Handbook-Fundamentals to maintain compliance with the latest loss coefficient data. The full DFDB includes features to bridge this

=IF(Velocity_FPM * Hydraulic_Diameter_Ft / Kinematic_Viscosity < 4000, Use_Transition_Coeff, Turbulent_Coeff)

ASHRAE has a clear AI policy prohibiting the entry of content from any ASHRAE publication or related IP into any AI tool without express written permission. While this does not preclude using ASHRAE data in your own spreadsheets for internal design work, it does mean you should not upload the data to generative AI services or use it to create derivative works that would be distributed without authorization.

Instantly see how changing a duct dimension or fitting type impacts the total external static pressure (ESP) of the fan.

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When building your own Excel-based calculator, these standard ASHRAE-aligned formulas are used: How To Calculate Duct Size: A Comprehensive Guide from h2x 3 Feb 2026 —