The building we used when I was in the Marines had two back doors. One of them was at the end of a hallway that we used for storage, so the door was blocked. At some point an inspector noticed that it was blocked and said that fire safety regs prohibited blocking an exit.

The CO asked if we were required to have an exit there. When the answer was "No" he had the door welded shut. Now it's not a door, it's a wall. No problem.