A minimum of one Floor Warden per floor shall be designated to perform the duties required by this section. Additional Floor Wardens shall be required if the occupant load of a floor exceeds 500 people. The Floor Warden shall obtain and maintain a valid Floor Warden Certificate, approved by the Fire Department, and shall present their certificate for inspection upon request by Fire Department personnel. Alternate Floor Wardens shall also obtain a certificate as Floor Warden and be designated for each floor, and be prepared to assume the Floor Warden duties when necessary. In a residential building, the Floor Warden shall be a resident on that floor or an employee of that building owner or manager. In a non-residential building, the Floor Wardens shall be employees on that floor. The Floor Wardens shall receive training at least once each year in order to maintain a valid certificate. Exemptions to this regulation may be granted only upon a written request approved by the Fire Code Official. The building owner shall be responsible for payment of the annual fee associated with the issuance of the required number of Floor Warden Certificates by the Fire Department.