1. No person shall smoke in a factory. A notice of such prohibition stating the penalty for violation thereof shall be kept posted in every entrance hall, elevator, stairhall and room of a factory in English, and in such other languages as the fire commissioner of the city of New York in such city and elsewhere the commissioner shall direct.2. The board in its rules may permit smoking in protected portions of a factory, or in such classes of occupancies where in its opinion the safety of the employees will not be endangered thereby. The fire commissioner of the city of New York in such city and elsewhere the commissioner may issue such permits in accordance with rules adopted by the board.3. The fire commissioner of the city of New York in such city and elsewhere the commissioner shall enforce this section.