To use the database effectively:
The ASHRAE Duct Fitting Database (2016) is available for purchase through the ASHRAE Bookstore as a downloadable package, including: ashrae duct fitting database 2016
: Features a streamlined database with fully available input and output calculations that update in real-time as users modify parameters. To use the database effectively: The ASHRAE Duct
Here's a useful feature that can be built on top of this database: ashrae duct fitting database 2016