Section 27-360. Travel distance

(a) General requirement. The maximum travel
  distance from the most remote point in any room or space to  the  center
  of  a  door opening directly on an open exterior space, a vertical exit,
  an interior stair, an exit passageway or to a horizontal exit shall  not
  be greater than the limit specified in table 6-1 for the occupancy group
  classification of the room or space.
    (b)  Travel distance within dwelling units. In buildings classified in
  occupancy groups J-1 and J-2,  the  maximum  travel  distance  from  the
  centerline  of  a  door  from  any habitable room within a dwelling unit
  either to the centerline of a door opening  on  a  corridor  or  to  the
  center  of  a  door  opening  on an exit shall not be greater than forty
  feet, except that for buildings classified in  occupancy  group  J-2  of
  construction  class  I-A,  the  distance may be increased to fifty feet.
  Such travel distances shall be included in the maximum  travel  distance
  established in subdivision (a) of this section.
    (c) Measurement. Travel distance shall be measured along a natural and
  unobstructed  path of travel. Where the path of travel is over an access
  stair, it shall be measured along an inclined straight line through  the
  center of the outer edge of each tread.