Exit doors to cells, day rooms, and other rooms where inmates are confined, up to a capacity of 48 inmates, shall have a minimum clear width of 28 inches. The minimum width of all other exit doors shall be calculated at 0.2 inches of clear width for each inmate utilizing the door for exit access, but in no case shall such width be less than 36 inches. Stairs shall provide 0.3 inches of width for each inmate utilizing stairs for exit access, but in no case shall such width be less than 44 inches. (Exception: Facilities in operation or initiated prior to March 31, 1991, may utilize exit doors having a minimum clear width of 28 inches.)