After installation, look for a file named FittingDB.mdb (Microsoft Access) or ASHRAE_Fittings.dat.
The ASHRAE Duct Fitting Database is a collection of loss coefficients (C-factor, or technically Co for round and Co' for rectangular) for hundreds of HVAC fittings, including:
Each fitting has a unique ID code (e.g., "E1-1" for a 90° smooth elbow) and its loss coefficient depends on geometry ratios (e.g., r/D, W/H, angle, area ratios). The official data is maintained by ASHRAE Technical Committee (TC) 5.2.
Important Note: The full database is copyrighted by ASHRAE. You will not find a legitimate, permanent "free Excel download link" on a public website. However, ASHRAE provides licensed access to the data, and several legitimate pathways allow you to bring it into Excel.
To answer the search "ashrae duct fitting database excel link" directly: There is no legitimate free public link to a complete, official ASHRAE Excel file. However, the official link is obtained through purchase from the ASHRAE Bookstore (search for "Duct Fitting Database – Electronic"). That purchased product provides a secure download link to an Excel-ready database (either as an .xlsm or an Access file that Excel can read). ashrae duct fitting database excel link
For daily HVAC engineering work, investing in the official database is worth the cost—saving countless hours of manual table lookups and reducing calculation errors. Once you have that official Excel file, use Power Query or VBA to build a dynamic fitting loss calculator that integrates seamlessly with your duct sizing sheets.
Final recommendation: Go to ashrae.org → search "Duct Fitting Database" → Purchase the current version (approx. $250 for non-members). That is the only reliable, accurate, and legal Excel link you will ever need.
Author’s Note: Always respect intellectual property. The ASHRAE Duct Fitting Database is the result of decades of costly research. Using a legitimate copy ensures you have the correct coefficients and supports ongoing industry research.
| Column A | Column B | Column C | Column D | Column E | | :--- | :--- | :--- | :--- | :--- | | Fitting ID | Description | Shape (Rnd/Rect) | Parameter 1 (R/D) | C_o | | EL-01 | Smooth Elbow 90° | Round | 1.5 | 0.15 | | EL-02 | Smooth Elbow 45° | Round | 1.5 | 0.08 | After installation, look for a file named FittingDB
Then use a UserForm with drop-downs to select the fitting and auto-fill (C_o) into your duct pressure report.
If you cannot link the DLL, create a local Excel table using published Co values from ASHRAE Fundamentals (Chapter 34). This is static but works offline.
Example CSV import:
FittingID,Type,Param1,Param2,Co
401,Elbow 90 r/D=1.0,,,0.21
401,Elbow 90 r/D=1.5,,,0.15
403,Mitered elbow,,,1.20
Use INDEX-MATCH or XLOOKUP with multiple criteria. Each fitting has a unique ID code (e
The ASHRAE Duct Fitting Database (DFDB) is the digital manifestation of the tables, charts, and coefficients found in the ASHRAE Fundamentals Handbook (Chapter 34 – Duct Design) and the ASHRAE Duct Fitting Database CD/DVD.
It contains loss coefficients ((C_o)) for thousands of fittings, including:
Instead of manually reading complex logarithmic charts (like Chart 14-3 or 14-4 from the 1997 Handbook), the digital database allows engineers to compute dynamic losses instantly using standardized formulas: ( \Delta p = C_o \times P_v ) (where ( P_v ) is velocity pressure).