The ASHRAE Duct Fitting Database (DFDB) Version 6.00.05 is a professional-grade software tool used by design engineers to calculate pressure loss for round, rectangular, and flat oval duct fittings. While the official full version is a paid subscription product, ASHRAE offers a free "Lite" mobile application for quick field calculations. Official Access & Versions
If you are an ASHRAE member, the price of the full database drops significantly. While a non-member might pay $600+, a member might pay $350. Join ASHRAE as an associate member (if you are early-career) for a reduced fee, then purchase the legacy download. They occasionally offer version 6.x as a legacy download for $99 during promotional periods. ashrae duct fitting database 6.00 05 free download
The file had also attracted attention from a new generation. An open-source group of graduate students had mirrored parts of the Archive online, arguing that practical engineering knowledge should be widely shared. That group’s mirror had been taken down once after a legal challenge from a supplier who argued that some scanned shop drawings were proprietary. The Archive—careful about provenance—had redacted those pages but kept the lessons: how proprietary details can stall broader safety improvements. The ASHRAE Duct Fitting Database (DFDB) Version 6