Examinations for candidates for special inspectors’ commissions shall be given at least once each year by the Commissioner of Administrative Services or by at least two examiners appointed by said commissioner. All examinations shall be in writing, shall be uniform for all candidates and shall be confined to questions formulated by the commissioner and designed to determine fitness and competency as a boiler inspector. The written examination may be supplemented by an oral examination or an interview by the commissioner or his designee which shall conform in general character with the written examination. Each candidate whether he passes the examination or not shall be notified by the board of his standing and grade as soon as possible after the examination has been completed. If an applicant for a special inspector’s commission fails to pass the examination, he may appeal to the commissioner or his designee for a hearing on his grade. The decision after such hearing shall be final, but an applicant who desires to improve his rating shall have the right to take another examination within ninety days. The record of an applicant’s examination, whether original or modified after appeal, shall be accessible to him and his employer.