World's Largest Round Vault Door

[VaultDoors]

The South Vault (1935) lies beneath the oldest section of the building and is built of a better grade concrete with 3 foot thick walls. Its entrance is of the cylinder type, and when closed, it forms a vacuum inside. The vault plus its housing weigh 80 tons and is in the form of a suspended chamber encircled by a narrow walkway. Prisms allow security personnel to look beneath and around it.[/INDENT]

Is the 'South Vault' in the Philly Fed similar to the cylinder doors at the NY Fed and PA Treasury?