Learned something new today. I didn't realize that LH has a section called, "Lounge entry on arrival," and sure enough, long-haul LH Business gets access to LH Business Lounges on arrival, except at FRA (Welcome Lounge only). Also saw some other interesting access exceptions (CA F).

Antarius, it looks like you can access the LH Business Lounge at IAD organically. No need to waste a UC one-time pass or struggle with PP capacity limits!