When fire escapes are to be attached to buildings within a city, they shall be constructed under the supervision of and subject to the approval of the commissioner or superintendent of public buildings within such city, and if there be no such office within such city, they shall be subject to the approval of the chief of the fire department of such city. Whenever a fire escape attached to any building located within a city shall, upon inspection by the commissioner or superintendent of public buildings, or chief of the fire department of such city, be found in an unsafe and dangerous condition, the owner, lessee, proprietor or keeper of said building shall forthwith rebuild or repair same or replace same in safe condition, upon written notice of such commissioner or superintendent. When fire escapes are to be attached to buildings not within the limits of any city, they shall be subject to the approval of the sheriff of the county in which such building is located. And should such fire escape, through age or otherwise, be or become unsafe or dangerous, the same shall be repaired and placed in safe condition, upon written notice by said sheriff to the person in charge of such building. All stair fire escapes shall have proper and safe balconies for each story thereof, surrounded on the sides with wire bank and pipe rail not less than three feet in height, with openings from the building to said balconies. Whenever a stair fire escape is to be constructed, the stairway shall, where practicable, be of an angle of not more than fifty-five degrees and constructed so as to be placed on a blank wall. The stair fire escape shall be provided with one or more landings in each story, and enclosed on the sides with wire bank and pipe rail not less than three feet in height and running on the same angle as the stairs.