Vacations shall be taken at a time mutually agreed upon between the department head and the employee. Department heads shall take their vacations at a time mutually agreed upon between themselves and the mayor. The minimum vacation allowance to be taken by an employee shall be one hour even increments or one duty shift for fire department employees. (Ord. 3278 § 1, 1978; Ord. 3152 § 1, 1977; 1957 code § 1.26.010(i).)