Brittany, I would want some additional context on this. What kind of a space is it? Is it integral to the project building, or separated in some way? What credits are you grappling with relative to this determination?
For example, if the issue is a difficult in providing daylighting per IEQc8.1 due to hurricane codes, then I bet you could provide a narrative to get around that. If the issue is more about ventilation and occupant comfort, then it seems like a storm shelter would definitely want to provide a high level of IEQ and should be considered regularly occupied.