Electromagnetic shield-type doorway for buildings and electromagnetic

Abstract

An electromagnetic shield-type doorway for a building is provided with two doors having a curved passageway between them. By lengthening the passageway to such an extent that the two doors cannot be opened simultaneously, electric waves can be blocked at either of the doors. The electromagnetic shielding effect can be enhanced by installing a revolving door in the passageway and attaching electrically conductive brushes to at least the lower edge and one side edge of the revolving door to fill the gaps at these edges. In a system for electromagnetically shielding a building, a doorway passageway of the building is partitioned by three or more doorways each having an electromagnetic shielding function. When persons leaving and exiting a building simultaneously approach entrance and exit doors at the ends of the doorway passageway so that these doors open at the same time, the central doorway remains closed to maintain the integrity of the electromagnetic shield. If a large number persons are entering and exiting, the doors are opened and closed in an interlocked manner so that one of the three doorways will always be closed, thereby maintaining the integrity of the shield in reliable fashion without hampering entry and exit.