Sec. 13. "School employee" means a full-time certificated person in the employment of the school employer. A school employee is considered full time even though the employee does not work during school vacation periods and accordingly works less than a full year. The term does not include:
(1) supervisors;
(2) confidential employees;
(3) employees performing security work;
(4) noncertificated employees; and
(5) adjunct teachers who hold permits issued under IC 20-28-5-27.