Since 11/22/2021, access to the ZHB has been in accordance with 3G rules. Furthermore, masks are mandatory in the entire building. From 11/29/2021, the following applies additionally:
Only masks without an exhalation valve of the FFP2, FFP3, N95, KN95, P2, DS2 or KF94 standards are permitted as suitable mouth-nose cover.
The use of surgical masks is therefore no longer permitted.