The Fire Chief or officer of the Fire Department in charge at the scene of an emergency is authorized to place ropes, guards, barricades or other obstructions across any street, alley, place or private property in the vicinity of such operation so as to prevent accidents or interference with the lawful efforts of the Fire Department to manage and control the situation and to handle fire apparatus, and to prevent any and all persons from passing through any such barriers, and from entering into any space set apart or enclosed by means thereof, except persons having a pass as hereinafter specified.