Section 3029. Hours of continuous duty for full time teachers

Except in a
  city having a population of one  million  or  more  persons  the  school
  authorities  of any school district employing two or more teachers shall
  fix the hours of duty for full time teachers so that no teacher shall be
  assigned continuous duty for a length of time in excess of  five  hours.
  When  the daily total hours of duty exceed five, duties must be assigned
  so as to provide a period of at least thirty  minutes  in  length  which
  shall  be  free from assigned duties and which shall be scheduled so far
  as practical during  the  hours  normally  allotted  for  pupils'  lunch
  periods.