A signal is received from an occupancy sensor each time a person passes through an access point corresponding to a building space, and is identified as indicating a person either entering or exiting the building space. An occupancy count is maintained for each of the building spaces by incrementing the occupancy count when the signal indicates a person entering and decrementing the occupancy count when the signal indicates a person exiting. A determination is made as to whether the occupancy count for any of the building spaces of the plurality of building spaces has reached a threshold for the corresponding building space. Action is taken in response to determining that the occupancy count for any of the building spaces of the plurality of building spaces has reached the threshold for that particular building space.