The administrative officials in charge of the Fire Department of the City of Portsmouth, Ohio, be, and they are hereby authorized and directed to divide the uniform forces into not less than three (3) platoons. Each platoon shall be on duty for twenty-four (24) consecutive hours, except in case of extraordinary emergencies. The Chief of the Fire Department, with the approval of the City Manager shall arrange the work schedules so that each member of the platoons will work an average of fifty-six (56) hours per week, excluding vacations and other time off as granted by law.