A door system suitable for installation in data centers to limit airflow to and from aisles between rows of equipment cabinets has a door assembly with a door panel and a plurality of vertically spaced hinge assemblies having powerful permanent magnets manually movable between connected and disconnected positions, enabling the door assembly to be aligned and positioned on the side wall panel of an equipment cabinet and then removably mounted in place by engagement of the magnets. Each magnet can be mounted in a rotatable threaded magnet carriers received in a threaded recesses in the hinge assembly and rotation of the magnet carrier is operable to move the magnet into the connected and disconnected positions. The hinge assemblies also include registration tabs that engage slots in the cabinet for proper alignment and orientation of the door system.