Section 257. Illumination

1. In every factory proper lighting shall be
  provided during working hours for:
    a. All places where persons work or pass, or may have to work or  pass
  in emergencies;
    b. All elevator cars and entrances;
    c. All halls and stairs leading to workrooms;
    d. All moving parts of machinery not required to be guarded by section
  two  hundred and the rules of the board, and which are dangerous because
  of their location.
    2. In every factory workroom the lighting shall be such  as  will  not
  cause strain on the vision or glare in the eyes of workers.
    3.  In  the public hallway upon each floor of every factory building a
  proper light shall be kept burning near the stairs during  each  working
  day  from  the  opening  of  the building until its closing, except when
  natural light  suffices.  Such  lights  shall  be  arranged  to  operate
  reliably  when  through  accident  or  other  cause  other lights of the
  building are extinguished.