The database retains its .DFD file format, but Version 6.00.05 introduces a plugin pathway for Revit and AutoCAD MEP via a COM interface. This allows dynamic lookup of C-values directly from a 3D model—a major time-saver for large projects.
: The ASHRAE Duct Fitting Database is frequently integrated into HVAC design software like Autodesk Revit to automate pressure loss calculations across entire duct systems. Duct Fitting Database - ASHRAE
The database assumes clean, straight, fully developed flow at the inlet. Add 10–20% margin for field-installed ductwork with burrs, misalignments, or protruding gaskets.
: The Version 6 interface allows for real-time updates—meaning calculations refresh instantly as you adjust input fields. Access and Availability ASHRAE Duct Fitting Database v6.00.05 is available as a single-user cloud-based subscription For professionals on the move, ASHRAE also offers the DFDB Lite app Apple App Store ashrae duct fitting database version. 6.00.05
For mechanical engineers and HVAC designers, precision in calculating pressure loss is the difference between a high-performing system and an inefficient, noisy one. The ASHRAE Duct Fitting Database (DFDB) has long been the gold standard for this task. The Version 6.00.05
for choosing a more efficient fitting. This helps justify "better" (and often more expensive) fittings to clients by showing a clear payback period. Automatic Material Transition Alerts:
Enter the upstream volumetric airflow rate. The database retains its
For the selected fitting, input the required dimensions, flow rate, and other relevant variables. The interface displays the fitting’s schematic drawing alongside the input fields, so you can verify that the correct geometry is being used.
Suppose a site measurement shows total static pressure 0.6 in. w.g. above design value. Using the database, you can systematically check each fitting's design C vs. as-built conditions. A common discovery: short-radius elbows installed instead of long-radius, raising C from 0.15 to 0.45.
: Design configurations can be saved into project files for easy transfer or future reference. Access and Availability Duct Fitting Database - ASHRAE The database assumes
Users input the physical dimensions of the fitting alongside the volume flow rate. The engine instantly calculates: and Velocity Pressure ( Pvcap P sub v ) Loss Coefficient ( Cocap C sub o ) Total Pressure Drop ( ΔPcap delta cap P ) across the fitting Why Version 6.00.05 Matters for Modern HVAC Design Overcoming the Flaws of "Rule of Thumb" Sizing
Historically, some designers relied on static friction charts or arbitrary "rules of thumb" (such as assuming a flat 0.1 inches of water column loss per 100 feet for the entire run, including fittings). This practice leads to two critical errors:
Designers use this database to determine , which is essential for selecting the correct fan or Air Handling Unit (AHU).