Most countries have legal requirements that make it obligatory to provide an adequate means of escape in buildings where work is done and/or to which the public routinely has access. Emergency lighting is an essential part of an adequate means of escape. Emergency lighting can have three roles: escape, shutdown and continued operation. Escape lighting is lighting that is designed to ensure either the safe and rapid evacuation of a building or the ability to move to a place of refuge. To achieve this, escape lighting is designed to define the escape routes so that the occupants know which way to go and to illuminate the escape routes so that the occupants can move along them quickly and safely.