The Occupational Safety and Health Administration (OSHA) is the Federal Agency responsible for workplace safety rules and guidelines. Most states also have a local OSHA department which imposes local rules and enforces them by levying fines and penalties against violators. State regulations, unless there is a compelling local reason, are based on the Federal requirements outlined primarily in 29CFR (Code of Federal Regulations) section 1910.
OSHA has Emergency lighting standards in place to ensure the safe evacuation of a facility if power to the normal lighting system is interrupted.
Signage Requirements
Every exit door must be marked by an illuminated sign bearing the word EXIT in letters not less than 6" tall (15.2cm). The light color must be distinctive and produced by a reliable source that will produce 5 foot candles on the surface of the sign. Section 1910.37(b)(6) of 29CFR allows the use of self illuminating or electroluminescent signs if the light level is .6 foot-lamberts.
Routes Clearly Marked
Exit routes must be clearly marked and illuminated so that an employee with normal vision can see along the route. If the exit door is not visible from any point along the route, directional signage must be provided and nothing may be in such a place as to obscure the straight line view of an exit sign.
Non-exit Doors Clearly Marked
If any door along the route leads to an area other than an exit, it must be clearly marked "Not an Exit" or with some language or sign designating its actual use (e.g., Electrical Room).