It shall be the duty of the Fire Department to inspect or cause to be inspected, as often as may be necessary, all buildings, particularly all mercantile buildings, manufacturing plants, warehouses, garages, hotels, boarding houses, rooming houses, theaters, auditoriums and all places of public assemblage, for the purpose of discovering the violation of any fire preventive law or any fire hazard and ascertaining and causing to be corrected any conditions liable to cause fires and to see that all places of public assemblage, hotels and rooming houses have sufficient and unobstructed facilities for escape therefrom in case of fire.