The inspection of elevators in existing buildings and the enforcement of the Building Code for elevators shall be in compliance with the regulations adopted by the Board. The building department may also provide for such inspection by an approved agency or through agreement with other local certified elevator inspectors. An approved agency includes any individual, partnership or corporation who has met the certification requirements established by the Board. The Board shall establish such qualifications and procedures as it deems necessary to certify an approved agency. Such qualifications and procedures shall be based upon nationally accepted standards.