Lighting is part of the environmental control system, which also includes sound control and heating, ventilation, and air conditioning (HVAC), within a building.
The prime purpose of a lighting system is to provide good visibility for the execution of the tasks to be performed within the building. With good visibility, occupants can execute their tasks comfortably, efficiently, and safely.
Lighting also is desirable for other purposes. For example, it can be used to develop color effects for pleasure or accident prevention.