(A)   The provisions of this Fire Prevention Code shall be supplemental to the Indiana Fire Code, Indiana Building Code, Indiana Mechanical Code, and Indiana Fuel Gas Code as adopted by the State Fire Prevention and Building Safety Commission.
   (B)   The provisions of this chapter shall apply to maintenance of fire prevention and life safety features as herein described. The provisions of this chapter shall apply to existing conditions as well as to the conditions arising after the adoption thereof.
   (C)   Buildings, systems, uses, processes, and equipment legally in existence on the effective date of this chapter shall be permitted to continue so long as they are maintained in a condition that is equivalent to the quality and fire-resistive characteristics that existed when the building was constructed, altered, added to, or repaired.