For quick field calculations, ASHRAE offers a free "Lite" version available on the Apple App Store . It includes a subset of common fittings for on-the-go use.
Searching for a ".rar" version of this database often leads to unofficial file-sharing sites. Be aware of the following: Duct Fitting Database - ASHRAE Download ASHRAE Duct Fitting Database rar
A more comprehensive mobile version covers all 240+ fittings listed in the ASHRAE Handbook of Fundamentals and allows for project saving and report emailing. For quick field calculations, ASHRAE offers a free
