65 ILCS 5/10-3-6
In all cities and villages which have adopted "An Act to regulate the hours of labor of employees in the fire department in cities and villages," approved June 26, 1913, as therein provided for, or which adopt this section as provided for in Section 10-3-7, no employee of the fire department shall be compelled to be on duty more than 10 consecutive hours during the period between sunrise and sunset, nor more than 14 consecutive hours during the period between sunset and sunrise.
The head or chief officer of the department shall so arrange the working hours of the employees of the department that each employee shall work, as near as may be, an equal number of hours per month. However, the head or chief officer of the department, his aids or assistants, in their discretion, in cases of great emergency or necessity, may require the employees to continue at their work or duties until, in the judgment of the head or chief of the department, his aids or assistants, the work or services of the employees is no longer required.
65 ILCS 5/10-3-6