A person under sixteen years of age shall not be employed with or without compensation, except as provided in sections 92.2 and 92.3, before the hour of 7:00 a.m. or after 7:00 p.m., except during the period from June 1 through Labor Day when the hours may be extended to 9:00 p.m. If such person is employed for a period of five hours or more each day, an intermission of not less than thirty minutes shall be given. Such a person shall not be employed for more than eight hours in one day, exclusive of intermission, and shall not be employed for more than forty hours in one week. The hours of work of persons under sixteen years of age employed outside school hours shall not exceed four in one day or twenty-eight in one week while school is in session.