1008.1.11 Locking Certain Residential Sliding Doors
In dwelling units of Group R-2 buildings, exterior sliding doors which are one story or less above grade, or shared by two dwelling units, or are otherwise accessible from the outside, shall be equipped with locks. The mounting screws for the lock case shall be inaccessible from the outside. The lock bolt shall engage the strike in a manner that will prevent it from being disengaged by movement of the door.
Exception: Exterior sliding doors which are equipped with removable metal pins or charlie bars.