(1) In single grade rooms, the maximum class size shall be:

(a) no more than 20 students in kindergarten and grades 1 and 2;

(b) no more than 28 students in grades 3 and 4;

(c) no more than 30 students in grades 5 through 8.

(2) In multigrade classrooms, the maximum class size shall be:

(a) no more than 20 students in grades K, 1, 2, and 3;

(b) no more than 24 students in grades 4, 5, and 6;

(c) no more than 26 students in grades 7 and 8.

(3) Multigrade classrooms that cross grade level boundaries (e.g., 3-4, 6-7) shall use the maximum of the lower grade.

(4) In one-teacher schools, the maximum class size shall be 18 students.

(5) Instructional aides are mandatory when class size or teacher load exceed the standards. An instructional aide shall be assigned a minimum of 1 1/2 hours per day, per student overload up to six hours.

(6) An overload of five students per classroom is considered excessive.