Section R. 400.18615 - Exit signs and illuminationRule 615.
(1) Each exit shall be marked by means of an electrically lighted exit sign that has letters which are not less than 3 3/4 inches in height on a background of contrasting color and which have strokes that are not less than 3/4 of an inch in width and shall be installed so that the sign is legible from the direction of travel toward the sign. If doorways and signs are not readily discernible from a resident's room doorway, an adequate number of additional electrically lighted directional signs shall be provided and shall have an arrow pointing in the direction of the exits.(2) Adequate equipment shall be provided in all facilities for the lighting, at all times, of corridors, stairways, outside fire escapes, and egress passages.(3) In new construction, the lighting required by this rule shall be installed on separate circuits which are in nonflexible metallic conduit and which are fused ahead of the main entrance switch and cutout.(4) In new construction, other wiring shall not be in the same raceway or conduit that serves the exit lights and emergency lighting.Mich. Admin. Code R. 400.18615