Section 15-112. Working hours

a. The commissioner shall divide the deputy
  chiefs,  battalion  chiefs,   captains,   lieutenants,   engineers   and
  firefighters,  marine  engineers  and  pilots in boats of the department
  into platoons, and such divisions  shall  be  fully  completed  and  the
  provisions  hereof  fully  effectuated.  None  of  such platoons, or any
  member thereof, shall be assigned to more than one tour of duty  in  any
  twenty-four  consecutive  hours.  The  commissioner  shall install a two
  platoon system.
    The two platoon system shall consist of not more  than  two  tours  of
  duty  of  not more than nine hours each, to be followed by a rest period
  of at least forty-eight hours for all members. After  such  rest  period
  there  shall be not more than two tours of duty of not more than fifteen
  hours to be followed by a rest  period  for  all  members  of  at  least
  seventy-two hours which shall continue in such sequence so that not more
  than  six  nine-hour  tours  of  duty and six fifteen-hour tours of duty
  shall be worked in any twenty-five consecutive calendar days, except, in
  the event of conflagrations, riots or other similar emergencies  or  for
  the  necessary  time consumed in changing tours of duty, in which events
  such platoons or members thereof shall be continued  on  duty  for  such
  hours as may be necessary.
    This  section shall in no manner affect any provision of law providing
  for furlough or leave of absence of such members of the department.
    b. The mayor and all other officials charged with such duty are hereby
  authorized, empowered and directed to carry out the provisions  of  this
  section  and  to  provide  any and all necessary funds to effectuate the
  purposes thereof.
    c. Notwithstanding the provisions of any other section of this  title,
  the  provisions  of  this  section,  as  amended,  in  relation  to  the
  establishment and continuance of the platoon system  and  the  tours  of
  duty   and   the  hours  thereof  shall  not  be  repealed,  superseded,
  supplemented or amended by local law, and the same may only be repealed,
  superseded, supplemented or amended as prescribed in section  eleven  of
  article  nine of the constitution and upon the affirmative action of the
  qualified voters of the city of New York on a referendum submitted at  a
  general election.