Normal Lighting (all lighting is available).Life safety depends upon occupants being able to evacuate interior spaces in three lighting levels: To supplement the UL performance standards, ASTM or ISO standards are often used. In North America, UL924 is the standard for exit signs and other (above the door) emergency lighting, and UL1994 is the standard for (floor level) luminous exit path markings. All emergency lighting - non-electrical (photoluminescent, radioluminescent) & electrical (LED, fluorescent, incandescent, electroluminescent) - is tested and listed to the same performance standards.