such rules and regulations as, in its opinion, may be necessary for the particular locality under its jurisdiction; provided, such rules and regulations do not conflict with the laws of the commonwealth or the provisions of the code. Said code may provide for the demolition, removal, repair or cleaning by local boards of health and, in the cities of Boston, Worcester and Cambridge, by the commissioner of housing inspection, of any structure which so fails to comply with the standards of fitness for human habitation or other regulations in said code, as to endanger or materially impair the health or well-being of the public. Said code or a supplement thereto shall designate those conditions which, when found to exist upon inspection of residential premises, shall be deemed to endanger or materially impair the health or safety of persons occupying the premises. This designation shall not be construed as prohibiting an inspector or other authorized person from certifying that any other violation or combination or series of violations of said code or other applicable laws, ordinances, by-laws, rules or regulations may endanger or materially impair the health or safety of said persons when such certification is otherwise appropriate.