The DFDB is a digital compilation of loss coefficient tables originally found in the ASHRAE Fundamentals Handbook. It allows engineers to quickly calculate pressure losses for various duct fittings (entries, exits, elbows, transitions, junctions) based on specific geometry and flow rates.
Version 6.00.05 represents a stable and advanced iteration of the database, often accessed via cloud-based annual subscriptions. This version introduced several refinements to improve accuracy and usability: ashrae duct fitting database version 60005 free