Any person who is a graduate of an accredited four-year college or university and who has at least five years of progressively responsible experience in development and administration of a public or private personnel program, including responsibility for development and administration of company or agency policies, supervision of staff or programs, negotiations of personnel matters with other agencies or organizations and a demonstrated knowledge of public personnel administration, testing, classification, wage and salary administration, recruiting, certification, and modern office procedures may be appointed as Director of Personnel; Provided, that not more than two years’ experience as a full-time paid faculty member with primary responsibilities for teaching in public or business administration, industrial engineering, sociology or psychology may be substituted for two of the five years’ experience required; and provided further, that not more than one year of graduate training in one of the foregoing fields may be substituted for one year of experience.