Commons B-01

, also named Commons Blue, is a generic United Nations Space Command term for one of the commons modules on the port side of an Orbital Magnetic Accelerator Cannon Platform. It consists of a standard-sized rectangular room, with "islands" regularly spaced to the edges of the room. Security B-01 overlooks Commons B-01.

Cairo Station Commons Blue
Cairo Station Commons Blue was the United Nations Space Command portside commons of Cairo Station closer to the bridge.. During the First Battle of Earth, Covenant boarders invaded Commons Blue, pushing back Marines to the far side of the room and pinning them down by overlapping fields of fire from Plasma Cannons on the "islands", along with Grunts and Elites. However, they were repulsed by SPARTAN-117.