Emergency illumination includes egress lighting, illuminated exit signs and other required lighting, designed so failure of any one lighting element cannot leave an area needing emergency light in total darkness; control devices are listed for emergency use; where high-intensity discharge lamps are the only normal lighting, emergency lighting stays on until normal light is restored; and an indoor service disconnect gets emergency illumination.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.