§ 19.05. This article not retroactive under certain conditions. Sections 19.01 and 19.03 of this article shall not be retroactive for any booth approved by the appropriate public authority or official prior to March third, nineteen hundred forty-one, provided such booth have or be so reconstructed of the same material as to have dimensions as specified in section 19.03 of this article; provided such booth conform to the specification of section 19.03 of this article as regards vent flue, box for storage of films, specifications for rewinding and repairing films and specifications for windows and doors, and provided such booth be of rigid fireproof material, and be insulated so as not to conduct electricity to any other part of the building and be so separated from any adjacent combustible material as not to communicate fire through intense heat in case of combustion within the booth.