N.Y. MRE Law § 56

§ 56. Exit and directional signs. Every means of egress shall be\nindicated by a sign reading "EXIT" in red letters at least eight inches\nhigh on a white background, or vice versa, illuminated at all times\nduring the day and night by a red light of at least twenty-five watts or\nequivalent illumination. Such light shall be maintained in a keyless\nsocket. On all stories where doors, openings or passageways giving\naccess to any means of egress are not visible from all portions of such\nstories, directional signs shall be maintained in conspicuous locations,\nindicating in red on a white background, or vice versa, the direction of\ntravel to the nearest means of egress. At least one sign shall be\nvisible from the doorway of each room or suite of rooms. Existing signs\nand illumination may be accepted if, in the opinion of the department,\nsuch existing signs and illumination serve the intent and purpose of\nthis section. Supplementary stairs, fire-stairs or fire-escapes which\ndo not lead to the entrance story or to a street or to a yard or court,\nleading to a street, shall be clearly marked "NOT AN EXIT" in black\nletters at least four inches high on a yellow background, and at the\ntermination of each such stair, fire-stair or fire-escape, there shall\nbe a directional sign indicating the nearest means of egress leading to\na street. All signs shall be constructed, located and illuminated in a\nmanner satisfactory to the department.\n