If you purchase the official ASHRAE DFDB Excel file, you typically get a structured workbook like this:
Streamline your workflow today by linking your project spreadsheets directly to the definitive standard in duct aerodynamics.
ASHRAE periodically refines its database based on new laboratory research. Ensure your Excel add-ins or underlying databases match the latest version of the fundamental handbook.
If you own the desktop version of the database, the backend often relies on a Microsoft Access ( .mdb or .accdb ) or SQL database. Locate the source database file on your local drive. In Excel, navigate to .
For cloud-based or modernized versions of the database, engineers leverage Excel’s Power Query or VBA MSXML2.ServerXMLHTTP requests to ping the database parameters. By inputting the Fitting ID (e.g., SD5-1 for a specific elbow) and the ratio of flow or area, Excel retrieves the precise Cocap C sub o value instantly. Step-by-Step Implementation Guide ashrae duct fitting database excel link
I can provide tailored formulas or a code snippet to match your layout.
Searching platforms like Eng-Tips HVAC Forum often yields user-created Excel tools that replicate specific sections of the DFDB, such as elbows, tees, or transitions. Building Your Own ASHRAE Duct Fitting Calculator in Excel
Create dedicated columns for the unique physical properties of each duct section: (e.g., AHU-1 Runout) Airflow Rate (CFM or L/s) Duct Shape & Dimensions (Diameter or Width x Height) ASHRAE Fitting Code (e.g., CR3-1 for a round elbow) Geometric Ratios (e.g., Step 2: Configure the Lookup and Calculation Engine
What (elbows, tees, transitions) do you use most often? If you purchase the official ASHRAE DFDB Excel
Use XLOOKUP or INDEX/MATCH formulas on your main calculation sheet to retrieve coefficients based on fitting codes and aspect ratios. 2. Utilizing Third-Party HVAC Design Software Add-ins
The ASHRAE Duct Fitting Database Excel file offers several benefits to users, including:
: For large projects, the database is often linked directly to design programs like Bentley OpenBuildings
ASHRAE coefficients are only valid within specific geometric and aerodynamic ranges (e.g., a Reynolds number greater than 10,000, or an aspect ratio between 0.25 and 4.0). Program your Excel sheet using or conditional formatting to flag a cell in red if a designer enters a duct size or airflow rate that exceeds the tested limits of that specific ASHRAE fitting. 3. Separate High-Velocity and Low-Velocity Systems If you own the desktop version of the
Contrary to some searches, the full DFDB is not a free, directly downloadable Excel file. Instead, access is obtained via purchase from ASHRAE’s official channels:
Some premium duct sizing add-ins (like ASHRAE’s own DFDB Toolkit for .NET) expose an ODBC interface.
Integrating the ASHRAE Duct Fitting Database with Microsoft Excel bridges the gap between official data and automated Engineering workflows. Understanding the ASHRAE Duct Fitting Database The ASHRAE DFDB is a compilation of loss coefficients ( Cocap C sub o