Our morning custodians in academic buildings unlock all classroom and exterior doors in the morning between 5 am - 6 am.  These doors remain unlocked throughout the day until Campus Security locks them between 9 pm - 11 pm. Our buildings are active between 7 am - 6pm, but outside of those hours the buildings are open and accessible to everyone with minimal to no staff  and our buildings currently do not have security cameras monitoring activity.  Does anyone have procedures or policies for who locks/unlocks door, which doors are left unlocked through a day, and the duration those doors are left locked/unlocked?  Thanks!